Project 90 (Stock 89cc And Beyond)

[2strokd]

Thats gotta be the cleanest stock carb ever lol. You try any of the dumb shit? Like changing the plug? hhhmmmm?

[190mech]

Do you have another air filter element you could try in the airbox?

[90GTVert]

I have changed the plug. I checked the filter, but never changed it. It had the typical smudge on the yellow side that all of my filters seem to get, but was otherwise clean and clear as far as I could tell. If the float doesn't do it, I'll swap the filter with another one.

[90GTVert]

I set the float a little lower. Didn't change anything. Pulled the bowl off without draining and the level sure doesn't look so high as to cause problems to me. A little low if anything now.



Put the stock airbox on with no filter in it. Same thing. Took the snorkel out and it will run. Now there's no way that this thing has suddenly changed so much that I have to remove the snorkel just to get it to rev. I removed the snorkel before because it was too fat down low, but it would rev fine with it. The only other thing I can think of is compression and sealing maybe causing it to run funky, but it's obvious that it has normal power when it's got enough air and it feels like there's plenty of compression. If it were some weird ignition issue, I wouldn't think it should run decent upon the introduction of more air.

That makes me think this cheap carb has something screwy going on now. I've cleaned it as thoroughly as I can. Air and carb cleaner seems to come through all of the passages. Looks about spotless.

Stupid thing has already stripped the threads that hold the cap on a while ago. I had to rethread it to M6x1.0 to fix that. I never even screwed it down with much force. This stock carb is truly craptastic.

[2strokd]

Time for a carb. Maybe just try another to see if thats it?
That is weird! Maybe, hell i dunno?

[90GTVert]

I was thinking about putting the Arreche on long enough to be sure. It's the only carb I have (not in use) that will fit in a stock intake. Just need to build some patience back up. lol This is supposed to be easy. If it is the carb, I'll probably pull the pipe off and let this sit for a bit so I can get the Venus setup for the PG pipe again. Tired of having no scoots to ride already.

[2strokd]

Dont blame ya! This is supposed to be fun. Go ride!

[90GTVert]

It was not right but ran on the rich side of OK with the Arreche swapped on with no changed from whatever I used it last with. Gonna have to get another stock carb when I can.

[lshigham]

I've had that before with a 17.5mm delly, couldn't make it run right no matter how much I adjusted and cleaned. Swapped in a 21mm PHBG and was fine.

[90GTVert]

190mech was kind enough to send me his old CPI carb to keep things moving. It's in a bit of rough shape, but it seems to be working. Thank you John!





I cleaned it up and then added a new fitting to the cap to work with my throttle cable.



My jetting is still small. I was using an 85 main in the last stock carb. A 78 was the previous carb's stock jet and it seized with that. I was quite surprised to see this carburetor working well with only a 75 main jet. I went with a 78 just to stay a little more on the safe side. Needle clip in the center position. On a ride, I did discover that the midrange had a lean spot that was kind of dead, so I think the needle should have been raised a bit more. This is with the stock exhaust and airbox again to get a good idea if this carb changed anything.

I went for a 28 mile ride and got 44.7MPG. Max speed was 50MPH. I think I could have squeezed out the extra MPH to equal what the other carb did with the same setup otherwise, but I had traffic to deal with when I tried to stretch it out. At any rate, it appears that the carb is not going to change performance so it should be fine for future comparisons. I would have liked to stay with the other carb and jetting that was working so my results for upjetting and other tuning for different mods would have been most relevant, but what can you do?


Now my next problem. The rectifier/regulator I used doesn't work. I'm not getting any charging and my low beam keeps blowing. I'm not sure why, but the high beam hasn't blown. It seems the only ones that will just swap in are labeled with QJ 125.... I've tried PFS and one from Scrappy that I had around. Neither are right. I'd like to find the correct ones that just plug in, but I suppose I could try swapping wires around. I had the same trouble when T1's rectifier went bad years ago. I ended up ordereing from Vento to get the correct part. Now there's no Vento to order from. If anyone knows a place that carries the correct regulator, please share.

[2strokd]

So you switched carbs with John old one and it ran fine? Thats the only change? Just making sure i didnt miss something.?
Ive gotta few regs, lemmi see if any have QJ125 for ya?

[90GTVert]

I had to downjet it too, but yeah. I'm at 78 (actually 78.7) and it's OK and with as low as an 80 in the last carb it would just sputter and smoke if I tried to rev it. Maybe the difference here is just something with the two styles of carburetor? Either way, the style like John's that is considered the better one is proving why. Look at the thing, and it still works. The shiny, pretty new, other style carb is screwed up.

[2strokd]

Good point! Is the ugly one a Mikuni?

Edit, nevermind. Lol, i should read and look more before asking :lol:

[90GTVert]

I was just looking at the 10 day forecast. If it's right, I don't think I'll be doing much with this or any scooter project. They're saying rain starting later today (Friday), Sat, Sun, Mon, Tues, Wed, Thurs, clearing Fri, then rain again Sat, and Sun. I hope they're wrong or it's scattered.

[190mech]

I ran into the same rectifier trouble with my CPI when replacing it,turns out the replacement unit was wired different than the CPI.I had to move a couple wires around,now it works well.I'll check tonight for the new pin out and post it...