4 stroking out up top

so my setup:

1995 tomos A35

Treats People 70cc Puch piston port kit (non-reed)

Mikuni VM20

stock tomos 50cc head

no port work, just threw the kit on

bi-tubo pipe with gutted silencer

brand new cdi coil from tomos

10w-40 in crankcase

diagonal slits cut into clutch cork

8 heatrange NGK plug

109octane gas

32:1 ratio blendz-all green castor oil

stock gearing

so, we've been dicking with this thing for a while trying to get it dialed in JUST right and its really getting old

ive got a 140 main jet and my needle clip is at the top (needle all the way down)

with the air filter on, up top it starts to 4-stroke out... almost like a revlimiter type deal, but if i back off the throttle a little bit, the 4-stroking goes away and the bike continues to accelerate. it takes a while for sure... its a slow acceleration, but you can hear it.

i thought at first that maybe i was actually too lean and the backing off the throttle was restircting the amount of air getting in, thus richening the mixture, but when i jet up.. even just to a 145, it worsens. alot.

i think whats happening is when i back off, im actually just letting the needle down and helping to lean it out.

when i pull my airfilter off, i get virtually no 4-stroke (just the occasional pop here and there) and the bike hits 46mph with me in full tuck.. mind you, i also weigh 209lbs.

i mean really... 135 jet? that sounds super lean to me. the plug always looks fine, never lean.. even so, i could get away with it abit with the 109octane i think.


Re: 4 stroking out up top

wow 109 octane? damn thats quite a bit overbaord if you ask me. i would go down the a 135 and rasie the needle to the middle notch, read your plug and adjust from there. you should be getting more than 46 in a full tuck. im getting 43 in a full tuck on a 94 sprint with estoril and reeds. no kiit, no porting.

Re: 4 stroking out up top

this is a toy for me and i wanted to take the aromatic castor and splash in a spice of race gas to tingle the senses... and 109 was the lowest octane the local parts place carried.

i intend on insane compression and ridiculous porting in the near future, but first, i want to RIDE.

Re: 4 stroking out up top

taylor: advance the timing and run the 135 jet.

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