Tomos not idling, not revving high either.

James Boehnlein /

I have an a35 engine with a 70cc alukit with a puch high compression head, the intake is 19 mm on the inside I think, the carburetor is a 21mm Dellorto with a 104 jet, Malossi high flow airfilter, idle screw turned all the way in mixture screw turned all the way in, it won’t idle at all and it won’t revv high as a moped should either. It also takes a bit to revv as high as it does. Believe it or not I think it might be running lean because when I made the mixture richer It revved higher. Should I upjet? I do not want to run it long incase it’s too lean.

Re: Tomos not idling, not revving high either.

James Boehnlein /

Is it possible that there is too much oil?

Re: Tomos not idling, not revving high either.

James Boehnlein /

Wait it might also be too rich.

Re: Tomos not idling, not revving high either.

Hepatitis J [OFMC] /

Your air mixture screw should never be screwed all the way in. It should typically be 2 to 2.5 turns out from all the way in. Any less than that and you need a bigger idle jet.

Re: Tomos not idling, not revving high either.

What slide, needle, idle jet do you have in there?

I’m doing my first PHBG tune right now. It seems like it’s very easy to have it too rich at starting throttle and too lean at WOT.

You cannot correct that with the mixture screw all the way in and idle set max in. It needs to be done with a bigger slide cutaway (mine has a 30 gonna try 40 next), needle position or fatter/later needle and smaller idle jet.

Don’t want to say too much since I’m a noob to this carb. But, the PHBG wiki is amazing. If you read, and understand that whole thing m, you will get it right.

Re: Tomos not idling, not revving high either.

what happens when u run it w choke?

Re: Tomos not idling, not revving high either.

James Boehnlein /

Well remember how I said it wasn’t revving high I think it’s actually four stroking because the jet is too big so I'm going to go back to the 86 stock jet, last time I had an air leak so I kept putting in a bigger jet because I didn’t know I had an air leak.

Re: Tomos not idling, not revving high either.

James Boehnlein /

When I turned the one screw in I don’t think it actually revved higher.

Re: Tomos not idling, not revving high either.

Hepatitis J [OFMC] /

> James Boehnlein Wrote:

> -------------------------------------------------------

> Well remember how I said it wasn’t revving high I think it’s actually

> four stroking because the jet is too big so I'm going to go back to the

> 86 stock jet, last time I had an air leak so I kept putting in a bigger

> jet because I didn’t know I had an air leak.

Yeah, I tried to tell you you were way too rich in the last thread. Don't just throw in the 86 and call it a day. You'll have to dial it in once you're in the correct range with plug chops. Plus your kit looks pretty new so you're probably still breaking it in so take it easy. Your bike is probably going to run and feel much better with the smaller jet , but that doesn't mean it's tuned correctly.

Re: Tomos not idling, not revving high either.

James Boehnlein /

Yea I’m not just gonna throw in the 86 and call it a day I’m going to adjust the needle to get a good power band and adjust the mixture screw so it’s a bit on the rich side because it’s still breaking in. Eventually I might upjet a bit and get a cone filter to get the most power out it as I can.

Re: Tomos not idling, not revving high either.

James Boehnlein /

Last time I had this kit running I didn’t have it tightened right and there was a leak in the bottom gasket. But I’m all about tuning and I try to spend a lot of time to get it just right.

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