Nice job! Ill be doing that too soon enough.

Excellent work Pete! Those things are well stuck with some kind of badass locktite aren't they!

The grinding approach is a backup. I'm glad you didn't have to resort to that

A note on jetting. I started the bike yesterday in freezing weather. It barely needed a momentary choke. Stalled, and then it started without choke, bone cold. I think I am a bit rich on the pilot jet.

The other think it did was it started to drift up to a high idle. I am pretty sure this same behavior happened to someone else recently. I thought maybe it was leaning out from a intake spigot leak (the rubber connector between the carb and head). But this really makes no sense since it didn't even need choke to start at 32 degrees cold!

I put the bike back under the tarp. Too cold to ride. This doesn't affect performance, but I would sure like to know what is causing this :hmm:

Mine would idle high sometimes, as well-and occasionally stall. I didn't ride mine for about 4 days last week, and I pulled it out of the garage. It started, died, and wouldn't start again. I've only run non-eth in it, so I know it didn't clog up with corn syrup. :D Checked fuel filter and flow, checked for spark-good. New NGK plug for a laugh. Nothing. So I did what all real men do, and pulled the boot...and blasted it with starting fluid. Started, ran out of laughing gas, and died. I could likely figure this carb out, but I don't have the patience right now. I'm in the middle of a street tracker build, so I'm looking for my other bikes to be runners. I ordered a Nibbi PE28 for it, and I'll give it a shot. If that fails, I'll get a real PE28. They're really not expensive, and I know they work. Some of the Chinese carbs are a real crapshoot.
I used to commute on a 2012 CCW Misfit. It was 5 years old with 9k miles when I bought it. Aside from a clogged emission mess once, it was dead reliable. I fixed all of that,and cleaned/rebuilt/rejetted the carb. It ran great. I sold it to a friend of my wife who's my age three years ago (I'm 52 now) who always wanted to learn how to ride. I clean the carb for her at the beginning of every spring, because she doesn't understand that "premium" doesn't mean non-eth. Literally emptied syrup out of it this year. Carb cleaner, compressed air...BOOM! Runs great. Carb looks like absolute cheap trash, but the bike always runs fantastic (when clean!!)
Might buy the bike back just for the carb. :D

Ohhh...but I really like the bike. It's fun, torquey enough, handles pretty well, suspension's OK, competent. I also have a Kayo 230. The Kayo is fun, kind of a "poor man's KTM Freeride" with a dogbaby of an engine. It's small, so it's easy to throw around, and it's a climber. Forks are decent, rear shock is way soft for my fat arse. The X dogwalks it, though-and it's plated. The Kayo is going away. Only rode it once, bought it with @ an hour on it from a rapper. :D

I put the oem jets back in the carburetor when I reinstalled mine so I could experience first hand what the jetting is like out of the box since no two carbs on identical bikes will be exactly the same.

I made the first run video faster changing out the shipping oil for Rotella T4 so you can hear what the default carburetor is like.

https://youtu.be/dhAYEKH-jFQ

I then spent a good seven to ten minutes going through 5k rpm on the digital dash and below varying up and down. Tossed in a few fistful of full throttles. And here’s what the running conditions were. Temperature: 3.8C / 39F, Elevation: 182m / 597feet. On some acceleration runs bogging. One full fist of throttle single bog and quit. On some deaccelerations popping. I found the idle screw and adjusted idle RPM. I didn’t find the pilot screw yet or know if this carb puts it on the air intake side or on the fuel side but I will need to find that next.

The engine has the potential for making more torque and hp. If I can find the time this Winter, I will work on the head. I got a bit set for the Dremel to do the porting. It has been sitting there for 6 months!

I have also been looking for a compatible headpipe with a resonator (and no cat). They make them for the CG clones (ZS167FMM). I don't think these will fit the ZS172 clones.

Megadan and many others have install 4 degree (or other) timing advance key as well. KTM and Husqvarna engines are already significantly advanced, and lower advance keys are available for them (1 degree, 1.5 degree, etc). I have a timing light somewhere. I'd like to shoot the timing on the Temp X and find out what the OEM advance is. I had installed a dyna2000 on my first gen bandit so I could select advance settings. This kind of setup would be much easier than changing timing keys to explore the effect of advancing timing. I would like to use timing advance, but no more than needed to get a boost in power to complement the porting/exhaust mods. A new carb might make sense at some point as well, but the OEM smoothbore Youall has been adequate for the unmodified engine.

Finally, you can buy the 5speed and 6speed versions of this ZS172 for about $500. Maybe the best approach is to swap in a new stock engine and get it working, then begin all of the modification on the partially broken in, proven good engine I got with the bike. Or just modify the virgin new engine. Not sure which approach would be best.

If I recall, Megadan used the method of order a new head and work on porting that. Once you have success just unbolt the old and swap in the new. Lower risk that way.

I have considered that (just buy the head). But the difference between the price of an OHC head and the compete engine is just a few hundred. And you get all of the parts and a CDI unit with a complete new engine. Think about it... a spare transmission, clutch, stator/rotor, cylinder/piston/rings, all new seals/bearings, sprocket, and its a working replacement unit.

So you can plod along building a complete engine while enjoying a working motorcycle:clap:

Thats definitely a better deal with a full set of current parts to use as spares when doing any engine rebuilding or repair.

I like the ZS172FMM-3A (5-speed) for it's simplicity, and for a dedicated offroad bike, it's adequate. But the 6-speed version with counterbalancing is also available for about the same cost. Amazon has at least one source for the 5-speed, and ebay has a few sources including the 6-speed.

I can hear the counterbalancer linkage in the 6-speed (not loud, but audible). I am sure it is normal. That extra gear is useful, and the counterbalancing is nice for road use, but the 5speed might be a better choice for an offroad build. The choice is not that easy for me :hmm:

As you can tell by the triangular right case shape, and the absence of a kick starter, this is the 6speed. It even comes with a gear shift and a starter. The real benefit of paying the additional ~$450 (more than the cost of a head) is that you can do a complete bench build and swap it in when you are ready. And the head in the complete engine includes the cam/rockers/camchain sprocket/camchain...

Attachment 27891
Attachment 27892

I definitely see your point Thumper. And that’s just a darn good deal on both those engines! I really don’t see how they can make, market and sell those engines that cheap. Hell a comparable Honda engine would be 4 times that amount.

Other engines
 

AJ1 (https://aj1moto.com/) has a variety of engines, including the twin cam ZS NC300 liquid cooled engines (280cc) shown here. They do have the ZS174FMM-3A (OEM 5-speed on the original Temp X and now on the Temp M). It is a great engine for off road, no counterbalancer, but easy to work on/mod.

This NC300 won't fit and you'd obviously have to add a radiator!! But at the moment, a TempX frame conversion would be one way to own a Zuumav NC300!

The K8 motorcycle is offered on the AJ1 website for $3900. It seems like you can equip it with the NC300 engine!

Attachment 27938

I’ve been kicking around the idea of adding dual oil coolers where a radiator would bolt up to the Templar frame. I would have to lose the louvres. Do you think the addition of dual oil coolers would cool the engine better? Even with the loss of air flow from the louvers? Looks like the shrouds themselves catch a lot of air.

An oil cooler mounted on one side, or twin oil coolers mounted there would definitely cool the engine, not cause any overheating problems.

lowering-Rear Shock mod
 

I pulled the rear shock to drill new lower mounting holes to lower the bike. While I have it off, I made some measurements.
Attachment 28148

The top and bottom mounts are BOTH secured with bolts that have 10mm center sections. The upper bushing is 22mm wide. It mounts just under, and in front of the battery cradle, behind the fuel tank. Both upper and lower bolts have M10-1.25 threads and locking nuts.

Attachment 28149

The distance between the upper and lower mounting positions is ~460mm (sorry about the poor photo, but the measurement is ~460mm).

Attachment 28150

The spring shows 350 pounds per inch rating.

Attachment 28151


I am waiting for a pair of 10mm high speed metal drill bits to make the new lower mounting position. I'll post photos after I drill them.