KZ550 powered YZ125 project

videos.streetfire.net/video/YZ125-with-s...t-bike-up_705748.htm



Needs jets and the carbs need to be sync'ed.... #2 cylinder is not firing, i think the pilot might have gotten clogged again.

Hell yeah! The neighbors must love that thing by now!! :laugh:

The stock main jets are 92. With pods and less restrictive exhaust, you may have to go somewhere from 98 to 102 or even 104.

The stock pilot jets are 32. After some tuning and time, if the bike hesitates and takes too long to warm up, you may want to bump the pilots to 34, maybe even 37, but I wouldn't into that right away.

The stock needles are not adjustable. You can get adjustable versions of the stock needles in the K&L rebuild kits. Or you can get the Dynojet kit which has different adjustable needles. You might be able to get away with just raising the needles with shims.

Obviously, the first thing is to find out what is up with #2. Then compression test, valve lash, ignition, etc. Then jetting. Oh, and an exhaust system of some sort

I think compression on #2 is fine. When i sprayed some penatrating oil in there you can hear her wake up and the exhaust pipe would warm up. I noticed when i first put gas into the carbs #2 was spitting out gas from the over flow???? I'm trying to ride this beast up and down the street a few times to make sure every thing else is good before i spend the $$$ on the finishing touches. I'm going to pick up some main jets this week and make that home made sync tool.

I checked the valve lash when i first got the engine (.004 on the exhaust and .003 on the intake). Over the winter i'll pull the motor and get all of them up to .005 (best to be a little loose from what i've read). I'll go with the 102's for now and see where that gets me. I saw in one of your vids that you are running the mini tach....how did you wire that up with the waste spark system? I emailed the company and they said it wouldn't read the correct rpm.

I hope i can get her to idle so i can ride it up and down the street a little bit next weekend. She didn't take well to opening up the throttle today (just died when i did).

Exhaust...the exhaust is done :laugh: . Its not that bad once she is out of the garage.

I love it. Do the neighbours have ear protection also? I think they might be needing some.

nelson8708 wrote:

I think compression on #2 is fine. When i sprayed some penatrating oil in there you can hear her wake up and the exhaust pipe would warm up. I noticed when i first put gas into the carbs #2 was spitting out gas from the over flow???? I'm trying to ride this beast up and down the street a few times to make sure every thing else is good before i spend the $$$ on the finishing touches. I'm going to pick up some main jets this week and make that home made sync tool. .

Looks like the carbs will have to be cracked open. Hopefully the gaskets are not cemented on. I use a little antisieze on the gaskets to keep them from sticking.
I would just do a preliminary sync by looking at light through the bottom of the slides. I have a lot of notes on sync tools, and some of the home made ones have a few problems. Here's my notes:
home.comcast.net/~loudgpz/ManometerNotes/ManometerNotes.html
The most important thing is to make rigid restrictors and put them as close as possible to the intake manifolds. Plastic or wood restrictors are not ideal since they can act like mini-check valves. The restrictors should have the smallest hole possible so the manometer won't affect the vacuum inside the manifolds, but merely read the vacuum.

nelson8708 wrote:

I checked the valve lash when i first got the engine (.004 on the exhaust and .003 on the intake). Over the winter i'll pull the motor and get all of them up to .005 (best to be a little loose from what i've read). .

Oops, sorry, I think we covered that earlier.

nelson8708 wrote:

I'll go with the 102's for now and see where that gets me. I saw in one of your vids that you are running the mini tach....how did you wire that up with the waste spark system? I emailed the company and they said it wouldn't read the correct rpm..

I responded in that thread you started on the subject:
kzrider.com/index.php?option=com_kunena&...ew&catid=4&id=314093

nelson8708 wrote:

I hope i can get her to idle so i can ride it up and down the street a little bit next weekend. She didn't take well to opening up the throttle today (just died when i did)..

Probably just way too lean or clogged jets.

nelson8708 wrote:

Exhaust...the exhaust is done :laugh: . Its not that bad once she is out of the garage.

Keep those headphones handy. :woohoo:

Cool you got it running! I'm impressed! You may be able to fix that #2 carb by just tapping on the float bowl with the handle of a screw driver. Keep banging on it until the gas stops dribbling. If this dosent work then you'll have to take the bowl off and clean the needle/seat.

TerryK wrote:

Cool you got it running! I'm impressed! You may be able to fix that #2 carb by just tapping on the float bowl with the handle of a screw driver. Keep banging on it until the gas stops dribbling. If this dosent work then you'll have to take the bowl off and clean the needle/seat.

It only leaked fuel out of the over flow when i first put gas into the carbs. It stopped after a few seconds. The carbs are going to come off this week anyway so i can put the bigger jets in so i will clean the out when i have them apart.

Great job on the conversion! Looks really sweet... Are you going to title as the 550 to keep it legal on the street or use for supermoto?

aaron3874 wrote:

Great job on the conversion! Looks really sweet... Are you going to title as the 550 to keep it legal on the street or use for supermoto?

Defintally wont see much off roading now. The engine weights to much to be competitive in super moto....She will be titled under the 550 title and road on the street. Taking her to the dragon in the spring

I'm going to pick up some jets tomorrow but, i can't seem to find any thing for TK carbs..... what jets would work (MIKUNI, KEIHIN, Hitachi)?

nelson8708 wrote:

aaron3874 wrote:

Great job on the conversion! Looks really sweet... Are you going to title as the 550 to keep it legal on the street or use for supermoto?

Defintally wont see much off roading now. The engine weights to much to be competitive in super moto....She will be titled under the 550 title and road on the street. Taking her to the dragon in the spring

I'm going to pick up some jets tomorrow but, i can't seem to find any thing for TK carbs..... what jets would work (MIKUNI, KEIHIN, Hitachi)?

Small head Keihin's work.

You will probably want the Dynojet kit #2305 since you are going pretty extreme with the exhaust and pods. The Dynojet needles are more friendly than the stock ones. It comes with main jets too.

The K&L rebuild kits come with stock mains that you could drill out. I've always drilled my own jets. You may want to read this thread:
kzrider.com/index.php?option=com_kunena&...ew&catid=3&id=306842

i ordered a mini drill bit kit so i can drill my own jets after reading that thread you suggested...So no action this weekend but, hopefully next. While i'm waiting i was wondering whether or not you guys run the stock pcv system or if i'm better off putting breathers on it?

-Nelson

nelson8708 wrote:

i ordered a mini drill bit kit so i can drill my own jets after reading that thread you suggested...So no action this weekend but, hopefully next. While i'm waiting i was wondering whether or not you guys run the stock pcv system or if i'm better off putting breathers on it?

-Nelson

I'm not sure if we covered it in this thread, but you can eliminate the air injection system. That's the two big ports on top of the valve cover. Just plug them. If they leak air, you will get backfiring in the exhaust. Also plug the ports on the intake manifolds.

The PCV is the round cover on the trans with the port sticking up. It will spit out water vapor and oil mist. Some people just put a breather filter on the port. I tapped the port and put in an elbow so I could run a hose down to the ground.