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Discussion in 'Modifications' started by scott s, Feb 12, 2019.
Thanks. These are for the 22mm carb that comes with the 140cc?
To ensure you buy the correct pilot search VM26/486/22.5 on ebay. The seller has a picture of the actual jet they sell.
Yes, that carb uses Mikuni jets.
OLDCT, do you know if you had to change the needle clip position?
It's been a long time Scott. I didn't keep notes. Start out in the middle and try the 110 main first. After any jet change/clip adjust make sure to re adjust the air bleed screw.
Im still in the building phase so when i had the stock 95/15 combo it would only run on choke, then die out after i took the choke off. I had actually only attempted to start it a few times when this thread came out.
I put in a 22.5 and a 110 just like OLD CT said to. Took a hell of a lot of kicking and cursing but she fired up. I got it to idle around 1800 with the choke off, but oh man does she wail like I said her sister was better in bed when i had the choke on.
Im still tinkering around with the air screw and I have the needle in the center position. The bike will idle with the air screw all the way in. I can also turn it out at least 2.5-3 turns. Its the optional air screw with the numbers on it. Seems to be more difficult than a z50 but maybe its just a learning curve.
With the bike fully warmed up ''lower'' the idle till it almost stalls. A really low idle. Turn the bike off, then turn the air screw in till it's ''lightly'' seated. Then turn it out 1 1/2turns out and start it. Then turn the screw slowly in either direction slowly till you get the highest smoothest idle. Then turn it clockwise 1/4 turn in. Re adjust idle. Done. Normally the bike by rights should stall with the air or mixture screw turned all the way in. Be careful not to crank on it when you turn it in. Very ''lightly seat'' these screws on a carb.
Got those new jets installed in the 22. Just need some time off work and a dry day to swap carbs.
Got the VM22 swapped over today. I used a 22.5 pilot and a 110 main. I set the mixture screw at just over 1.5 turns out; about 1.5 turns and then the width of the slot on the screw. I used a UNI filter and I oiled the inner filter and left the outer dry.
I was able to use the throttle cable I had and just adjust it with the barrel adjuster and the one up at the grip.
This was a bone dry carb, never had gas in it before. I kicked it over twice with the key off and then about 5 or 6 times with the key on, choke on. It fired up and held an idle on its own, even after I lowered the choke lever.
The bike runs every bit as good as it did with the VM26 and has MUCH better throttle response and control, especially in the mid range and coming off a rolling stop. After it was fully warmed up, I was able to lower the idle a good bit. I don't have a tach on the bike but now it just "sounds" right. It was idled way too high with the other carb, just to keep it running.
I'm really happy with the swap so far. I have no doubt that I have all of the performance I had before and mileage should be substantially better.
I would like to try adjusting the mixture screw for best idle, but it's pretty much impossible to get to without removing the carb from the manifold.
The only other thing I would like to do is fab up a bracket to lower the petcock. I'm using one of those aftermarket petcocks mounted to the frame and the fuel actually has to go UP a little bit to get to it. When I go on reserve there's still a good bit of fuel left in the tank and I've actually ran out of gas with a little bit still in the bottom. Should be easy enough to fab up a drop bracket to get the fuel outlets on the tank inline with the inlets on the petcock.
I got some time today between rain storms to toss in some fuel and monkey around a bit. I put the new jets in a while ago. Then needed to take a few days off as my right ankle was killing me and my left leg was sore from kicking it over too. I ordered up a race cdi that has less timing in it at low rpm, and a different kickstart lever. The pos one it come with was too close to the footpeg.
I got it up and running, but everytime i tried to give it gas it would pop, hiss, and gurgle. The lightbulb finally went off and i messed with the rev limiter screw on the cdi, and BAM. Give it gas and off she goes.
So i had to start over with OLDCT's instructions. Its idling at about 1800 right now. I didnt notice much difference +/- a quarter turn to a half turn on the fuel screw with idle speed. I put it at 1.5 out and called it a day. I'll take it out tomorrow maybe.
Yes the mixture screw is in a bad place, I use a hex bit with a tiny piece of vacuum line on the hex part for finger grip.