Trying again: 150cc craigslist scooter

[fratermus]

I revived a little 50cc scoot (in sig) but am having title problems. So I'm using it as an around-the-farm beater and have been sniffing around for a cheap/non-running 150cc.

Picked up a TaoTao Evo (which appears to be the successor to the ATM-150) this morning. {Edited to add: I have all the paperwork on this one from the original/only owner. Title work should go well }

http://i722.photobucket.com/albums/ww222/fratermus/scooter/th_20160326_115804_zpszrttlu1a.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160326_115804_zpszrttlu1a.jpg.html)

Young man put 2400km on it before "it quit working". He dragged it home to the apartment complex where it sat until they started putting "we will tow this inoperable vehicle" stickers on it.

I have no idea what caused it to "quit working" but it will be fun to find out. Looking it over it's clear he slid it, breaking a mirror and skinning the plastics and pipe. The exhaust pipe mounting bolts are loose and at least one has fallen out. But it does not look abused which is a nice change from the little 50cc project.

Starting in on changing fluids, vacuum and fuel lines tonite. Will put the likely-dead battery on the charger. I have a plug, coil/wire, and CDI on the way courtesy of Amazon. I'll let you guys know how it goes. I learned a lot on the 50cc and hope to learn more on this one.

[BlackBike]

Is the evo already plated?

[fratermus]

Yes, plates were issued in June 2015. All the paperwork looks good/complete on this one.

[Weldangrind]

This story reminds me of when my Pastor skinned the plastics on the right side of his 50cc scooter, and it quit running. I pulled the rest of my hair out trying to determine what could have been damaged by a low-speed low-side crash. After much troubleshooting, it turned out to be that the valves required adjustment. For whatever reason, they picked that moment to present themselves as in need of service, which had nothing to do with laying the scooter down.

[lee47512]

If it is a 2012 or earlier could be the stator tao tao stators then were crud.

[humanbeing]

If it is a 2012 or earlier could be the stator tao tao stators then were crud.
DC-CDI is a quick fix for BAD "source coil"...

[fratermus]

It's a 2014.

Changed engine oil and tranny oil. Nothing scary in the oil screen.

Pulled the CVT cover and was delighted to see:

http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160329_001655_zpslzglnjn4.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160329_001655_zpslzglnjn4.jpg.html)

... an imploded drive belt. This could be Good News if that's why "it quit working".

I'd never seen one in person that had come apart; holy crap. Looked like a bomb went off in there. Luckily I already had a replacement Gates on order and it will be here in a couple days. The NGK plug and fuel/vacuum lines are in so I'll pull the plastics tomorrow and replace those. Will also set the valves tomorrow.

The battery was charged by this morning but appears to be very weak -- no surprise there. The signals / markers/ brakelights/horn work but no headlights. Dunno if they are burned from overvoltage or if a fuse/switch is dead. The weak battery will activate the starter but it doesn't have enough oomph to turn the motor. I can move the motor by hand so it's not seized.

THat's enough for tonight. Will pick it up tomorrow again.

CORRECTION - turns out the battery is not dead. The shredded belt shards in the front pully was preventing the engine from turning over very far. The scooter started but the exhaust manifold is clearly loose. I shut it off - both nuts are missing that should be holding the header onto the exhaust port. Doh!

[Weldangrind]

Wow, 2400km is not very much on that belt. At least it's nothing serious.


Sounds like this will be a runner in no time! :D

[culcune]

I remember reading the advrider.com thread about the father and son who crossed the country from San Francisco to New York; the father on a Skyteam CT70 replica (125cc) and the son on a $100 150cc scooter. According to the father, he wrote on the thread that all it needed was a battery. Hopefully that is one of the few things needed, as you already discovered it needed a new belt.

[fratermus]

Still looking good.

Set the valve clearance. Intake was tight, exhaust was very tight as I've come to expect. Put both to .1mm (approx .005").

Popped in the NGK; it was pre-gapped at .026 so I left it there. The old plug wasn't bad.


Here's the coffee filter I cleaned out the oilscreen over before. Two small bits in there:

http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160329_101853_zpsqhgqujth.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160329_101853_zpsqhgqujth.jpg.html)

The vacuum and fuel lines were of the expected quality and started to crack; they've since been replaced with silicone (heavy) and tygon respectively.

http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160329_171717_zpsh82vpesj.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160329_171717_zpsh82vpesj.jpg.html)

Part of the original vacuum line routing was poor and pulled on the (manifold?) between the topmounted air filter box and the carb until the rubber split:
http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160329_171742_zpstygcjzwp.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160329_171742_zpstygcjzwp.jpg.html)

Any ideas what that manifold thing is really called?

[tortoise]

Any ideas what that manifold thing is really called?
Airbox snorkel . . but the TaoTao Evo 150 port (http://beastparts.com/products/air-box) appears to be missing on many vendor images (https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1129&bih=562&q=Air+Filter+Intake+Tube+for+gy6+150cc+&oq=Air+Filter+Intake+Tube+for+gy6+150cc+&gs_l=img.12...1223.7676.0.9313.5.5.0.0.0.0.68.322. 5.5.0....0...1ac.1.64.img..0.0.0.0yGcQhDn3bY#hl=en&tbm=isch&q=gy6+air+filter+intake+tube).

[fratermus]

Airbox snorkel . . but the TaoTao Evo 150 port (http://beastparts.com/products/air-box) appears to be missing on many vendor images (https://www.google.com/search?hl=en&site=imghp&tbm=isch&source=hp&biw=1129&bih=562&q=Air+Filter+Intake+Tube+for+gy6+150cc+&oq=Air+Filter+Intake+Tube+for+gy6+150cc+&gs_l=img.12...1223.7676.0.9313.5.5.0.0.0.0.68.322. 5.5.0....0...1ac.1.64.img..0.0.0.0yGcQhDn3bY#hl=en&tbm=isch&q=gy6+air+filter+intake+tube).

Great information, thanks.

Since the port has already been problematic I think I'll get one without. From memory, I think it was connected to PCV system line. I can handle that some other way. I've temporarily patched the split with E6000.

Today's progress: EGR delete, exhaust header nuts came in and got installed, exhaust hangers secured with generic bolts from the hardware store.

Got in the Gates kevlar belt and installed it. Engine started fine but didn't want to rev, seemed out of balance, and rear clutch engaging at low engine RPM. Wha-a--aa--a-t?

Ok, experienced folk probably figured out there was something wrong at teh variator end, but I'm still learning this stuff. :-) . I hadn't taken the inner plate off (the one with the rollers and ramp) to see if any belt chunks had ended up in there. . I spun the variator around and looked in the holes; one of the rollers was stuck in a weird/outward position. I think this was pushing the belt outward as if the engine were revved, increasing the belt RPM and engaging the rear clutch. Since only one was out this could also explain the increased vibration.

I ordered a set of 18x14 13g sliders and some of those little v-shaped "variator slide" pieces that fit on the ramp. One was missing, or I dropped it, or it turned to dust with the belt.

At this point I think I am a week out from the traditional Highly Illegal Test Ride. :lol:

[Weldangrind]

I'm curious to learn about how the 13g sliders work for you.

[fratermus]

I'm curious to learn about how the 13g sliders work for you.

They work, although I have no baseline to compare them to. Never rolled the scoot with the damaged stock rollers. I got the sliders in 13g because the stock rollers were 13g. Since I hear you are supposed to go up +1g with sliders I figured it would be an incremental net lightening.

They came in today and I dropped them in the variator a few minutes ago. Generic eBay sliders, "ForExtreme", $14 shipped.

http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160404_230924_zpso2146x4q.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160404_230924_zpso2146x4q.jpg.html)

Put some air in the tires, cranked it up on whatever gas was still in the tank from god-knows-when the P.O. put it there. :-) and took it for the first test ride. Since the headlights don't work yet and it's dark on this farm-to-market road I didn't go too crazy. :D

Motor seems seems strong and willing. I've never ridden a 150cc scoot before and the acceration was surprising. Idle is too low. Ran it up to indicated 50mph before I got scared running on the marker lights only on the unlit roadway. :hehe:

CVT is smooth and holds a steady indicated 4k rpm on the dash tach under load and readjusts appropriately at neutral throttle and decel. The wikipedia page suggests the max HP is at 7k so if the tach is correct there is plenty of headroom. I'll leave slider weight where it is while I learn how the rescued beast likes to run. After that it sounds like I could lighten them up. I'm not chasing performance though. It's an around-the-village explorer.

Maybe I'll make a video tomorrow and y'all experienced folk can tell me if it sounds like 4k rpm to you.

[Weldangrind]

There's a song lyric in there: "I ain't scared; brakes are good and tires are fair."


I'd only be guessing what 4000rpm sounds like. It's really cool that you've made the scoot run under it's own power already.

[fratermus]

It's really cool that you've made the scoot run under it's own power already.

Thanks for the encouragement.

Today I put fresh gas in it (gauge works, yay! and took it out for a backroad run of a few miles. Some smooth oiltop, some rougher oiltop, some dirt, some gravel. The gravel wasn't much fun.

It was a good ride. The odometer worked. When I was trundling around slowly the revs dropped down to around 2500. Under max load it it was 4500-5000. I liked the CVT's adjustments and may just leave it there.

I got it up to an indicated 55mph. The variator must have been topped out because rpm finally climbed to 6000 at that top speed. I could get a little more in that straight but just after 55mph the chassis started to feel unsettled/squirrelly so I backed down. It could have been the uneven road surface but I didn't want to go any faster.

The tires on this thing are kind of a sporty low-profile look. It makes for odd inputs on cambered surfaces. When I replace them I might go for a more traditional round tire profile. I had a similar issue on my street bike; the OEM rear had a shape that made the bike want to "fall in" on cambers/turns. When I replaced the rear with Conti Motions that tendency went away completely.

Working on headlights tomorrow.

[Weldangrind]

55mph is impressive. It sounds like you have it dialed right in.

[fratermus]

Two setbacks in this little adventure that have pushed my inspection/registration back another week.

Headlights

This machine uses HS1 35/35w bulbs but the more-common H4 bulbs are backwards compatible if they are 35/35w. I couldn't find any HS1 or any low-wattage H4 at auto parts stores or Wally World. They are available online from Amazon and elsewhere but won't arrive until tomorrow when my 4x10 workweek has started again.

I hadn't ordered them before because I didn't know if the bulbs were blown or if it was something else (switch? wiring?). I took the front cowl off yesterday and tested the power to the bulbs; good, and not overvolted. I pulled the bulbs and the filaments were broken.

While I was in there I checked the existing rectifier/regulator against a new spare I bought. Both gave the same output at idle and when revved so I think the OEM is still good. I left it in place.


Keys

I had tried calling around to check for the HS1/H4 bulbs but had more faith in my own eyeballs looking at the shelves. So I went on a little errand trip to a couple of nearby towns.

At some point in that trip I lost the scooter key. :-( I think I had it loose in my pocket and it got tangled up with something I pulled out. I ordered a replacement lockset ($25) and they are supposed to be easy to install but it's still frustrating.

[Ron B]

any updates?

[fratermus]

The headlight bulbs and lockset came in yesterday but my next day off isn't until Tuesday. :-(

[fratermus]

My day off came and I got the new locks in. Unfortunately I ordered the wrong kind. >:(
I matched up pics of the current one to one on eBay and the correct one is on the way now.

Today I thought what if I I disassembled the current useless ignition lock so I could manually turn the switch? That works. I got the scooter started and the headlights work great.

I doublechecked all the required stuff and headed down to the insurance office to pick up the papers. It was going to be close but I could make it to the nearest bike inspector about 10mi away, then to the licensing office.

The bike was really running great. I loped along on the back country roads at about 45mph since they were a little rough. I managed to get the chicken strips down to about 2cm in some of those curves. :yay:

About 7mi out I was bopping along when the engine died. I checked my rearviews, checked the kill switch, and found a place to coast off the roadway. Cranked but didn't even try to run. I suspected the CDI died or maybe some wiring popped loose.

I called my Dad who lives in the town I was riding to; we threw it in the back of his truck and brought it back to my house.

I tried a spare CDI. Nope.
I tried a spare spark plug wire. Nope.
I pulled the plug and looked at it; good.
While I had the plug out grounded on the block and cranked; no spark at all.

I spent about an hour with the multimeter and YT videos. Worked my way back to the stator outputs. Checked the wire taking ignition power from the stator to the CDI and it had less than 1v when cranking. If I understand correctly that should be considerably higher.

Of course I don't know what kind of stator is in it until I see it, and I don't have a puller. There are two barrel connectors and one 3-wire connector. The only ones I have seen with those connectors have been 6-pole stators which I understand are more common on 50cc scoots. Hmmm. They look like this (screenshot from a YT vid):

http://i722.photobucket.com/albums/ww222/fratermus/scooter/typeAStator_zpsja30d16e.jpg


I could Amazon Prime a puller and 6-pole stator with the connectors as shown but I don't know if the stator would be right. I'm googling my brains out but can't reassure myself what stator comes on a TaoTao Evo/ATM150.

There are a couple of brick-and-mortar chinese bike shops in the nearest big cities (Dallas, mainly). I think I will call them tomorrow and see if they have a puller and 6-pole in stock. If no one has them I'll mail order the parts in and punt until next Tuesday. <sigh>

At least I got a short jaunt on her today. Light at the end of the tunnel and all that.

[fratermus]

A pic from the stranding...

http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160414_153250_zpskcrcjsjl.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160414_153250_zpskcrcjsjl.jpg.html)

[humanbeing]

https://img.alicdn.com/imgextra/i4/389662530/TB20zr4aFXXXXXOXpXXXXXXXXXX-389662530.jpg
GY6 family had "half/ full" http://mastercircuits.blogspot.com/2011/06/half-wave-stator-to-full-wave.html ... "twin" or no source (needs DC-CDI) ... 6/8/11... http://www.chinariders.net/images/icons/smiley-gag-green2.gif

[humanbeing]

Ref to datas of these [光阳 Kymco 豪迈125 (REAL gy6) | 三阳 SYM Duke125 | 本田 Honda CHA125 (engine family: JF04) ] early 2-valve air-cooled scooter will solve chinese headacne...
http://s9.postimg.cc/m82bobsaz/image.gif (http://postimg.cc/image/m82bobsaz/)http://s9.postimg.cc/h6uxmykuj/image.gif (http://postimg.cc/image/h6uxmykuj/)http://s9.postimg.cc/ylf5v8hzf/image.gif (http://postimg.cc/image/ylf5v8hzf/)
===
In modern Honda manual
Source >=100v (40+ is enough to see spark, these often failed. DC-CDI is a quick fix) | P.c >=0.7v (trigger is RARE to fail)

[tortoise]

There are two barrel connectors and one 3-wire connector.
It is somewhat awkward, but you can count the number of stator poles through one of the fan mounting bolt holes as you rotate the flywheel and use a flashlight for a backlight.

If just the trigger pickup coil is deficient . . resource (http://www.chinesescooterparts.com/GY6-ignition-trigger-pickup-0122-08.htm?categoryId=-1).

https://www.youtube.com/watch?v=q9-mr7BXIho

[fratermus]

Thanks, I had forgotten about full/half wave.

After reading the reminder about trigger voltage I went back to make sure I wasn't confusing my trigger and power voltage readings. Nope, it really was the power to the CDI that was <1v.

I ordered the puller from Amazon and it will be here on the 19th.

I made some progress on identifying the stator. Taotao.us points to Eagle ATV for parts. Eagle lists this 8 pole stator (https://www.eagleatvparts.com/product_info.php?cPath=50&products_id=10552&osCsid=526a1c366b15c644ed97905ef1926337) for the Evo 150 and most other Taotao 150s. It does have the correct 3-pin connector + two barrel connectors like mine.

[fratermus]

It is somewhat awkward, but you can count the number of stator poles through one of the fan mounting bolt holes as you rotate the flywheel and use a flashlight for a backlight.


I just tried but don't have enough practical experience to know what I am seeing. I can see copper sometimes but not well enough to count.



If just the trigger pickup coil is deficient . . resource (http://www.chinesescooterparts.com/GY6-ignition-trigger-pickup-0122-08.htm?categoryId=-1).


I think the pickup is ok because a because a <1v signal comes through on that lead. I am beginning to suspect when I get the stator out I will see physical damage, like a wire or winding popped loose and shorting to something it shouldn't.

[tortoise]

I can see copper sometimes but not well enough to count.
Might try counting the number of spaces between the poles where the backlight shines the brightest through the bolt hole . . 8 spaces = 8 poles.

[humanbeing]

...just tried but don't have enough practical experience to know what I am seeing...
It's normal cuz we aren't voyeur yet
---
What's a GY6 http://www.microsofttranslator.com/bv.aspx?from=&to=en&a=http%3A%2F%2Fforum.gamer.com.tw%2FCo.php%3Fbsn%3 D60545%26sn%3D28112
Source fail = http://fanyi.baidu.com/transpage?query=http%3A%2F%2Fwww.chyangwa.net%2Fth read-177056-3-1.html&source=url&ie=utf8&from=zh&to=en&render=1###
Re-wound experiment: http://fanyi.baidu.com/transpage?query=http%3A%2F%2Fwww.chyangwa.net%2Fth read-374439-1-1.html&from=zh&to=en&source=url&render=1

[fratermus]

Got in the flywheel puller (note to newbs, they are reverse threaded) and popped it off. The stator identification mysteries are revealed:


http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160419_145701_zpsyvwhk9ok.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160419_145701_zpsyvwhk9ok.jpg.html)

8 pole, 5 wires (2 loose + 3 in a 3-wire connector). The 3 are in a 3-wire connector (see pic in earlier post (http://www.chinariders.net/showpost.php?p=211947&postcount=21)) rather than the more common 3 wires in a 2x2 connector with one left empty.

I ordered the stator and should have it in by next weekend.

[fratermus]

Got the new eBay stator in. Aaaaaaaaaand one of the wires isn't soldered down.

http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160422_231125_zpsziszg4so.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160422_231125_zpsziszg4so.jpg.html)

By looking at other pics it looks like it should be soldered where the coil to the right is anchored. On my OEM stator the white wire dives down somewhere I can't see to tell if it's soldered in. And the loose wire doesn't seem long enough to reach, anyhow. Maybe that's why it's not connected...

I emailed the eBay seller for their input. I will wait to hear back from them before I try to force it over to the apparent solder point.

[Weldangrind]

Odd.


I can't see where it should be going. I hope the seller cooperates.

[fratermus]

Yes the seller saw the pic and shipped a replacement the same day. I should have it Monday, and will install it Tuesday (lord willing and the creek don't rise).

[Weldangrind]

Do you have to return the defective unit? If not, maybe you can repair it when you have a good one to compare with.

[fratermus]

The seller shipped the replacement and didn't require me to send in the bad one:

http://i722.photobucket.com/albums/ww222/fratermus/scooter/20160427_212617_zpsrazbxyfc.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/20160427_212617_zpsrazbxyfc.jpg.html)

I will mess with the broken wire one and see if I can get enough slack to solder the white wire back down. Keep it on the shelf as a spare, I suppose.

The good stator is installed and produces a nice dancing spark like I am used to seeing. Scoot is up and running again! I could be imagining things but it seems to be idling a bit better.

While I was in there I put an "upgrade" fan in it. Didn't weigh it but it is lighter and the vanes appear to be more aggressive. In Texas any extra moving air across the engine will be welcomed:

http://i722.photobucket.com/albums/ww222/fratermus/scooter/fan_zpsrfij9chz.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/fan_zpsrfij9chz.jpg.html)

I've got some errands to run tomorrow but will try to get it inspected and registered if time allows.

[tortoise]

put an "upgrade" fan in it . . any extra moving air across the engine will be welcomed

http://i722.photobucket.com/albums/ww222/fratermus/scooter/fan_zpsrfij9chz.jpg

Performance fans typically flow LESS air (reduced parasitic drag) . . review (http://www.amazon.com/NCY-1100-1258-Orange-Turbo-Scooters/dp/B00CMU8A3U#customerReviews).

[fratermus]

Performance fans typically flow LESS air (reduced parasitic drag) . . review (http://www.amazon.com/NCY-1100-1258-Orange-Turbo-Scooters/dp/B00CMU8A3U#customerReviews).

Interesting. I didn't take any IR temp readings before the change. Maybe I'll take some now and swap back at some point and compare readings.

Most of the reviews I saw were positive but no one mentioned taking measurements.

[fratermus]

Here is a victory photo with spanking new plate:

http://i722.photobucket.com/albums/ww222/fratermus/scooter/2016-04-28tags_zpsdodvikfc.jpg (http://s722.photobucket.com/user/fratermus/media/scooter/2016-04-28tags_zpsdodvikfc.jpg.html)

I rode it about 10miles to the inspection point then to the DMV. I think I have found an objective downside to letting the RPM stay down in the 4.5k range with the 12g sliders. The area was slightly hilly and the scooter lost RPM on the hills. I think at 4K RPM it doesn't have enough torque to get the contra to drop the gearing.

I do have a roller weight tuning kit now and likely start playing with it. I think 10g sliders are in my future.

[fratermus]

A couple of interesting developments. Got a refund from Dairyland insurance when they combined the scooter liability with my road bike's full coverage. The NC by itself was $400/yr and after adding the scooter it dropped about $20. I guess they count on me crashing the cheap scoot 50% of the time. :-)

Turbo fan test: I did a test route then tested the heat at the valve cover (it was accessible) with the 'turbo' fan. Average 156F in a few different spots. I did some other stuff, swapped back to the OEM fan and tested: 158F average. So too close to see a difference with my unscientfic method. I'm calling it a wash for now.

Did a couple of roller weight test runs and noted RPM:
12g sliders from before = 4.5K WOT
test kit average 10g rollers = 5k WOT
test kit average 8g rollers = 6k WOT
test kit average 6.5g rollers = 6k WOT <--- interesting

I assume the RPM should have gone up with the 6.5, but maybe my machine is not running optimally (fuel/air?) or something else keeping it from going over 6k. Pickup is noticeably stronger at 6k.

I also installed the new keyset. Ignition was trivial, the glovebox was a pain to get to. I can't get the seat release to pull far enough yet; might have to tweak the bracket.

[Ron B]

so hows the scoot doing?

[fratermus]

Good, I've been putting a lot of miles on it until recent rains.

I have been investigating a puddle of oil under the carb. Looks like I got carried away when I started ripping out unneeded components. In think one of them was an OEM oil catch can that was holding and returning oil to the valve cover area.

I tried using a longer run of tubing with a filter at the end to see if that would hold the excess while running. I revved it out on the stand and it seemed to work fine, but when I rode it at WOT it puked out the filter. So I think I will try the hamster bottle catch can mod as described on prodawg.

[tortoise]

puddle of oil under the carb
If originating via the valve cover vent . . usual suspects are too much engine oil, or excessive piston ring blow-by. Consider experimenting with adding 1 tablespoon (½ ounce) of 2-stroke oil per gallon of gas, unless you are already using 1 ounce per gallon of Seafoam. The supplemental top end oil may, or may not, reduce blow-by.

Material Safety Data Sheet comparisons . . .

Seafoam per MSDS:
Pale Oil 40-60%
Naphtha 25-35%
Isopropyl Alcohol 10-20%

Berryman's B12 per MSDS:
Toluene 40-50%
Acetone 20-30%
Methanol 20-30%
Methyl Ethyl Ketone <5%
Isopropyl Alcohol <5%
2-Butoxyethanol <5%


If origination is unclear, another scenario . . .

http://www.youtube.com/watch?v=ttD9zE2791E

[fratermus]

I may have also messed up when I was deleting the PCV (?) setup. I watched some YT vids on vacuum line simplification and may have misunderstood. I routed what I took to be the crankcase vent (in the right in this pic):

http://i722.photobucket.com/albums/ww222/fratermus/scooter/Screenshot%20at%202016-05-20%20071916_zps6one6afd.png

... back to the airbox snorkel running from the filter to the carb, not realizing oil could get in that line. I think the oil was pooling in the snorkel and dripping out of the tube/snorkel interface onto the top of the case. Which would imply a leak there. [also, I just rewatched that video (https://youtu.be/2JTi_5UJbc4?t=42s), and he ran from the PCV port to the air filter, not the snorkel. Perhaps that would result in less vacuum pulling on it.]

I pulled that end of the snorkel, observed oil in it, cleaned and replaced/tightened. I have not run it since I made that observation as it's been raining and I have been researching.

I'll drain and refill the case with a known amount of oil so I will have a good baseline. In the meantime I ordered a catchcan. I will also try the oil additives you recommend. I assume that would show improvement if the problem were with the piston rings.

[fratermus]

Next day off is Tuesday, so I will work on the oily issue then. I am suspecting overfill since I tend to fill to the top of dipstick crosshatches, and my recent reading suggests GY6 engines like about halfway up the crosshatches.


Thanks for everyone's input and interest.

[Weldangrind]

What did you find on Tuesday?

[fratermus]

What did you find on Tuesday?

Confusion.

I drained the case and added a measured 800ml. This took it to near the top of the hatchmarks on the unscrewed dipstick. Nothing foreign in the strainer or on drain plug.

Installed the catchcan on a dipstick adapter for testing; if it worked I'd move it to the valve cover breather.

At idle (and with the valve cover still vented with a 2' tube) there is so much pressure that oil was pushed up about 1.5' up the new dipstick-attached tube, just short of the catch can itself. I revved it and oil blew out of the top of the catch can like a water hose. I would say at least 400cc was ejected in a couple of seconds.

Could blow-by really be causing this much pressure? Maybe there is a blocked oil passage and the oil pump is forcing oil out some other path of less resistance?

If blow-could cause monster pressure like this I guess I need a compression tester to see how the piston is doing.

[Weldangrind]

You could also try a fitting that screws into your spark plug hole, and accepts an air chuck. When you pressurize the cylinder, any leakage will be evident. You need to turn the crank to TDC to perform the test. Air rushing out the muffler is a leaking exhaust valve, air blowing back through the carb is a leaking intake valve, air coming out of the dipstick hole is rings. Expect some air to come out of the dipstick hole, because of the ring gaps.


You can make your own adapter by breaking the ceramic off of an old plug, and then welding or epoxying an air chuck fitting to the threaded body of the plug.

[MICRider]

Some bikes do generate quite a bit of crankcase pressure. I recall someone forgetting to put their oil cap back on a KLR only to get a leg full of oil... Unless that's because the clutch is right there on a KLR?

[fratermus]

I ordered a compression tester and will let everyone know what I find out.

[fratermus]

Ok, I got a compression tester with 10mm adapter and an attachment that will allow me to blow air into the sparkplug hole. So some new pieces of information.

1. Cold engine has 125psi of compression.

2. adding .5ml of oil manually bumped it to 128psi or so. Certainly not a big jump.

3. blowing into the spark plug hole with 60psi caused the engine to turn over

4. when it came to rest from #3 the air came out the exhaust

5. when I put my hand over the exhaust while injecting air I got some oil to rise up the catch can line. Releasing my hand dropped the oil again.

Am I any closer to a diagnosis?

[Weldangrind]

Try turning the motor to TDC and holding it there with a socket and breaker bar; repeat the compressed air test, and see where the air goes. My guess is out of the dipstick hole.

[fratermus]

Correct, out the dipstick hole which is currently holding the catch can tube.

Does this narrow it down to a compression issue?

I ran a little camera-on-a-wire thing down into the cylinder. It looked like there was still crosshatching on the walls and no other scratches. Piston was carboned up, probably from the oil dumped into the airbox before I figured out there was overpressure.

[Weldangrind]

Save me from going back through the thread; could there be a blockage in the vent tube?

[fratermus]

No, because it was originally blowing oil out that vent tube. That's why I got the catch can and mounted it on the dipstick side.

I haven't pulled off the valve cover since this started happening. Maybe I should do that and look for broken parts and repeat the pressurization test.

[Weldangrind]

I expect pressure to leak past the rings and blow into the crankcase, but a minor amount. Maybe a ring was broken on assembly, which explains the decent crosshatch.