Scratching Head...upgraded bing 14 to 15

My puch free spirit was doing nice with a proma gp, bing 14 (72 jet) and a high comp cylinder head - i was doing around 32-34ish with a slow low end...well, i ordered a bing 15 (82 jet) w/intake and now it bogs/chokes at 27ish...i tried even with out my high flow filter same thing. I haven't messed with jets just yet, does it sound like i need to go down in jets in the new carb? or should I slap the 14 back on? I thought the bing 15 would give me more air allowing a better low end.

Re: Scratching Head...upgraded bing 14 to 15

thats a huge difference in the jets. jet down gradually until you find what you need.

Re: Scratching Head...upgraded bing 14 to 15

downjet. probably a 72 or 74

Re: Scratching Head...upgraded bing 14 to 15

people should learn the basics of upgrading before just buying stuff thinking its bolt on.

downjet and you'll be fine.

Re: Scratching Head...upgraded bing 14 to 15

dude, come on. everyone has to start somewhere. not saying you arent right, but i can remember when i posted that same question about my dellorto when i first got it. thats how we learn.

Re: Scratching Head...upgraded bing 14 to 15

well, i did, 72, 70, and now a 66...still same problem....if i gass it all the way, it really bogs, but if i go 3/5ths of the way, it will go up to about same speed as before....i did a shitty plug chop on the way home - i got it to top speed on 1 block then killed the engine, darker mocha color on spark plug (not a new plug) - should i keep going down?

I thought going with bigger bing would mean going to a bigger jet?

Re: Scratching Head...upgraded bing 14 to 15

62 was the worst, 64 improved and 66 was good

the 62 felt like not enough gas is getting in....i don't have a 68 jet but i have 66 70 - could that 68 be crucial? could my needle have something to do with not getting the gas when i throttle it fully (its all the way down!)?

Re: Scratching Head...upgraded bing 14 to 15

well, i put the 72 again, it seems better then 66 now that i think of it...but my needle only run the moped if it the jet needle is on first setting making the needle sit higher up

Re: Scratching Head...upgraded bing 14 to 15

do a plug chop with a brand new plug. thats the only way you can get a good reading. once you do that you should have a better idea of whats going on and go from there.

Re: Scratching Head...upgraded bing 14 to 15

nice work keep it up.

Re: Scratching Head...upgraded bing 14 to 15

air leak?

Re: Scratching Head...upgraded bing 14 to 15

i should check it....but my compresion was originally 120ish....i threw a high comp head on it, and it went to about 175ish after one crank, and went around a couple times and almost hit 190-200ish...

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