Throttle feathering and bogging at quick WOT? Air leak?

We've checked for air leaks... set the timing properly via timing light and all those goodies.

The long and short of it is that we can't go WOT on it or the engine falls flat on it's face. It almost feels like it quick lean bogs out, and no four stroking.

This is a treats 64cc party pack burrito supreme with the treats cdi, and the crazy pietcard box/ht coil.

All timing is completely ruled out. We're on to the idea that it could possibly be a case leak... not 100% sure. My natural assumption is to think that this is an air problem.

If you feather the throttle, it will eventually get close to peak RPMS. Riding, if you gradually take it to about 1/3 throttle, it will eventually rev up and get to about 40-45 (estimated not gpsed, so probably more like 17-18 mph).

We don't have any more hair so we're ripping each other's teeth out with needle noses.

Re: Throttle feathering and bogging at quick WOT? Air leak?

Gruff "(OFMC)" - /

If you havent changed the bearing seals thats probably where I would look for an airleak? kitting seems always bring up the weak areas that normally wouldnt showup. if this was noobs I would say tuning problem but your not

Re: Throttle feathering and bogging at quick WOT? Air leak?

Richen up your idle and raise your needle setting.

Might have to go bigger on the main too.

Re: Throttle feathering and bogging at quick WOT? Air leak?

Needle is at full rich (lowest clip setting) and the main is reamed to 1.43mm... anyone know approx what size jet that is? I tried the dellorto stuff but couldn't find a translation from size to mm.

We haven't been able to replace the idle/pilot yet, that's the next step along with new seals.

Re: Throttle feathering and bogging at quick WOT? Air leak?

http://www.49ccscoot.com/jetdrill.html

That's a 143jet, mm=metric jet size

Seems awful rich, but what carb?

Re: Throttle feathering and bogging at quick WOT? Air leak?

amazing link! thanks man.

it's a 21 PHBG. The 65cc treat party kit comes with the 21mm PHBG and like an 18.5mm intake? We matched the intake to the carb to give it proper flow, and now it's just being a bastard. no air leaks on the top end, and the timing is like dead on perfecto...

this is the kit and party pack. we have the treats cdi with 2041? pietcard timing box

Re: Throttle feathering and bogging at quick WOT? Air leak?

That's too rich in my opinion.

Do you have other smaller jets?

If not, solder the jet closed and then redrill it with a smaller bit.

I'd try a 100-110 to start.

Re: Throttle feathering and bogging at quick WOT? Air leak?

I'm heading over there tomorrow to work on it. I have every jet from 95-120 so we'll play around with that and some new seals. I'll report back and let you guys know what we find.

Thanks for the words JBOT, you're the man!

Re: Throttle feathering and bogging at quick WOT? Air leak?

Overpriced Parts /

What atomizer?

What needle. ?

What pilot jet ?

AN or AU bushing/ carb

My treats 70 cc 21 mm set up ran a #9 needle, 50 slide and

87-88 jet

Re: Throttle feathering and bogging at quick WOT? Air leak?

W9 needle, 60 choke/starter jet, 50 idle/pilot jet, and it had a 92 main, which has since been reamed to a 140! exciting, i know. The atomizer is definitely AU, as for the bushing, I'd have to take a look to be certain.

It ran beautifully before it spun a gear bearing in the ZA bottom end. We rebuilt it, widened the exhaust port 1mm on each side, and opened/matched the intake to the carb/cylinder, and now... then well...

Now we have to feather the throttle or it won't rev up, just give out and "fall on its face."

Re: Throttle feathering and bogging at quick WOT? Air leak?

Overpriced Parts /

Try 40 idle high 80s low 92 main

Re: Throttle feathering and bogging at quick WOT? Air leak?

You jumped up almost 50 jet sizes!

That is the funny. You cray!

Re: Throttle feathering and bogging at quick WOT? Air leak?

The cray part was pulling it, reaming it, putting it back in, and testing it... I luckily was not there for that, nor do I want to know how many sizes they tried.

Re: Throttle feathering and bogging at quick WOT? Air leak?

you didn't mention which size atomizer you're using, and you can't mix au and an atomizers and bushings, so... if you have an au bushing , you have an au bushing. aside from that I agree with what Ken said about jetting

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