Baja / Zhejiang X250 Upgrade Thread

[KirkN]

Hi, all,

I posted a bit about myself and my 2007 Baja / Zhejiang X250 in an Intro thread: http://www.chinariders.net/showthread.php?t=14247

I haven't done much else with the bike since that first race outing back in November except ride it around my yard and around the neighborhood.

I've decided that I'm more of a dual-sport guy so I've decided to convert the ol' girl to at least the appearance of street legality. I've got a dual-sporting trip planned up to Suches GA in 3 weeks and this bike will be going along. I thought I'd do a bit of a thread on the project.

Here's where we started:












So, there a fair bit of stuff to do to make this look like it's street legal. Plus, there's a bit of maintenance stuff to do as well.

More to follow...

[KirkN]

Well, since the tires are nearly new, I'm not going to replace them yet, even though they're not DOT-legal. Gonna have to take my chances there. Gotta go careful around the corners on the street as well.

Equipment I'll need is lights, blinkers, horn, mirrors. Some other stuff will be valve clearance check/adjust, gearing changes, carb upgrade to Mikuni, oil change.

Here's the 'universal' headlight I have. My son picked this up somewhere and he gave it to me. It has a high/low beam, and even has integral blinkers. You can also just catch a glimpse of the tail / brake / license plate assembly I'll be using sitting on the bike to the right in the background.






I ordered a universal headlight/hi-low/blinker/horn switch off ebay, and while I wait for it to show up, there's other stuff to do. This bike, for some reason, came with the kill switch / e-start button assembly mounted on the LEFT handlebar. Now that I've got the light switch assembly coming, I decided to swap sides so the switches will all be in their "normal" places.




On this bike, the front brake lever assembly had what was a safety switch. You were supposed to have to squeeze the brake lever for the e-start to be able to work. I bypassed that, but it left a perfectly nice switch available for use as a brake light switch. I'll maybe one day add a rear brake light switch. I've seen hydraulic switches that install right at the banjo bolt in the system. It's not top priority, since I'll at least have a brake light off the front brake for now.

[KirkN]

I decided to check the valve clearances while the tank was off. This bike was ultra-quiet from the top end. Plus, it never did like to kick-start.

Good thing I checked, too. Intake and exhaust had basically zero clearance. Couldn't slide the 0.002" feeler gauge in at all. So, I reset 'em to 0.003" intake and 0.004" exhaust. Slappy valves are happy valves and all that.

I was surprised at the difference - it will kickstart right up first kick. I use the e-start, but it's very nice to know the kicker is an option now.

[KirkN]

The bike also needs a gearing change for street riding. It came with 15/48 gearing with a 420 chain, and it tops out at about 35 ~ 40 mph in 5th. I've got a 16-tooth front sprocket on the way. I bought one for a Honda SL125, since they're interchangeable.

The rear sprocket, though, is a mystery. I've read other threads that talk about measuring the center hole diameter and the bolt circle dimensions and ordering based on that. I did an on-the-bike measurement and got about 2-1/16" for the center hole. Bolts are 2" apart and about 2-7/8" apart on the diagonal.

Anybody have any details or interchangeability hints?

I'll make a decision on number of teeth based upon how it drives with the 16-tooth up front. I'm thinking 45 or even 42 or so.






And that's about all for now. More updates to come when parts start arriving. Woo Hoo!

Kirk

[JTHSPACE]

Nice posts and pictures. Are the hand guards fitted with LED's to act as indicators? Odd sizes on the rear sprocket you are getting is probably because it's metric so you need to measure in mm as any replacement will almost certainly be in mm's.

Jeff

[KirkN]

Thanks. Good point on the measurements. I'll wait and see how the bike rides when the 16-tooth front sprocket shows up. If it still needs to be geared taller, then I'll take the rear wheel off and measure more accurately before I order something.

The handguards don't have anything but stickers on 'em. I had been thinking about mounting some kind of indicator on them until my son came up with the headlight with those integral blinkers.

I picked up a $20 pair of generic mini-blinkers to use on the back. They'll get mounted directly on the tail light assembly.

I'll pick up an electronic blinker flasher from the auto parts store.

Gotta figure out something for a horn, too. I might have a spare laying around. Otherwise, something generic will do.

Then mirrors.

For now, I don't have any speedo / odometer. The biggest hurdle there is going to be a drive assembly from the front wheel. The bike currently has nothing, so I'm not sure what to do there. We'll see.

[JTHSPACE]

Speedo - get an electric one - stick a magnet to the disk and the sensor on the fork and then you dont have to worry about speedo drives etc. Also, it can be configured to your wheel size so you can get fairly accurate reading.

Interestingly, in the UK, you are not legally required to have indicators on your motorcycle. However, once fitted it is a legal requirement that they work properly.

This is from eBay UK, but a search on eBay US will find similar

Digital Speedo

There are lots of different types, cheap to "how much!?"

Jeff

[Weldangrind]

Excellent write-up and pics.

Interesting that your bike came with a Keihin clone and a 420 chain. The Canadian version of that bike had a Mikuni and a 428.

Do you have a cat in the exhaust header?

[KirkN]

D'oh! My mistake - it IS a 428 chain, not a 420.

As for what carb the bike came with, I don't really know for certain. When I got the black bike, it didn't have a carb at all. When I got the silver/red parts bike, it had the Keihin clone PZ30 carb, but since so much was missing from that bike in general, I wouldn't swear at all that that's the carb that IT came with either. The owner was just a 19-year old young guy who had been hacking around at it. And HE wasn't the original owner either...

I don't THINK the header has anything in it. The bike didn't have a header pipe, so that one came off ebay. Was brand new, not used. It has a bulge in it like some of the aftermarket manufacturers use. Power Bomb or something like that...

Kirk

[ripcuda]

Very cool. I love the split rail frame on your bike. Getting to the top of the engine and carb looks so easy (once the tank is off).

So with 15/48 sprockets... and 5 speeds... you can only reach ~ 40mph? Wow... those must be super low gears... which I guess makes sense if it is an offroad dirt bike... not an enduro. Mine with 15/46 sprockets and 5 speeds... can reach ~55mph.

Your header has the looks as though it might have a cat in it. It's the same size and location as the one on my header. Perhaps it does...

Cheers!

[KirkN]

Well, the top of the engine is easy to reach that's true, as is the top of the carb. Overall, though, the carb is a real PITA to access. It sits right between those frame rails and it wants more delicate hands than mine to reach in there. Sigh.

The bigger frustration, as far as I'm concerned, is that frame design makes it dern near impossible to swap on a larger tank. Almost all tanks around are meant for a conventional backbone type frame or are fit very specifically for some other frame rail dimensions. And at 0.8 gallon capacity, that tank REALLY needs to be changed out.


Well, I don't know exactly how fast I'm going, and I don't know what RPMs its turning. It just feels and sounds like its really wound out in 5th and I'm not really going that fast thru the neighborhood. And second gear is barely above walking speed!

Interesting about the possibility of a cat. It never occurred to me to look or check. Huh.

[Weldangrind]

Originally Posted by ripcuda

So with 15/48 sprockets... and 5 speeds... you can only reach ~ 40mph? Wow... those must be super low gears... which I guess makes sense if it is an offroad dirt bike... not an enduro. Mine with 15/46 sprockets and 5 speeds... can reach ~55mph.

The gear set is identical between street bikes and dirt bikes with these motors; there's no distinction made at the factory level. I suspect it's going faster than Kirk realizes.

Kirk, a 17 tooth on the front would wake it right up. That's easier and cheaper than a rear sprocket.

[Weldangrind]

Originally Posted by KirkN

Well, the top of the engine is easy to reach that's true, as is the top of the carb. Overall, though, the carb is a real PITA to access. It sits right between those frame rails and it wants more delicate hands than mine to reach in there. Sigh.

The bigger frustration, as far as I'm concerned, is that frame design makes it dern near impossible to swap on a larger tank. Almost all tanks around are meant for a conventional backbone type frame or are fit very specifically for some other frame rail dimensions. And at 0.8 gallon capacity, that tank REALLY needs to be changed out.


Well, I don't know exactly how fast I'm going, and I don't know what RPMs its turning. It just feels and sounds like its really wound out in 5th and I'm not really going that fast thru the neighborhood. And second gear is barely above walking speed!

Interesting about the possibility of a cat. It never occurred to me to look or check. Huh.

Back when these bikes first came out, there was a competing China bike that was called a Hummer, and it had a much larger capacity. There isn't much that can be done about your tank, unless you're prepared to graft a conventional back bone in.

I'm now starting to wonder if your clutch is slipping; that may be why it's screaming but not actually going that fast. If the PO put regular 10W30 in it, the friction discs might be slipping. The good news is that the friction discs are cheap.

I'd run something through the header to see if there is indeed a cat in there. If there is, there's horsepower hiding in it.

[humanbeing]

Originally Posted by Weldangrind

...The good news is that the friction discs are cheap...

U need a tool like this http://www.ebay.com/itm/151294063048 & ensure which type 1st http://chinariders.net/showpost.php?...3&postcount=13

[KirkN]

Yeah, I'm probably going faster than I realize. Or, it could be lower in the rev range than it sounds. I never really held it for any length of time in 5th. When it's back together, I'll have my son ride alongside me on his bike, and we'll see what it's really doing.

I've just ordered up a 17-tooth sprocket as well. At first, I didn't see a 17-tooth available anywhere, so that's why I got the 16. After a bit more digging, 17s are indeed available. Don't know how I missed 'em. D'oh.

Anyway, the lights/blinker/horn switch arrived yesterday, so I installed that, and have been working on all that wiring. Picked up a flasher at the auto parts store and that's working and the headlight is working (all with temporary wiring yet). Gotta do the rear light setup including the rear blinkers. I think I have a spare horn somewhere, too.

Chugging along, chugging along.