Hello everyone,
I am new here, but I am not new to mopeds or small engines. I am going to be upgrading my Tomos Sprint with a 70cc cylinder kit and biturbo exhaust. I am keeping the stock carb and gearing. The engine is an A35. I would like to know what size carb jet I should use.
No one can answer that for you. There's to many variables to consider.
Start by checking out the tuning spread sheet in wiki to get an idea where to start. Then pick up some jets in that range and trial and error until you have it running well.
I did look at the chart, but the jets people are using for the 70cc kit range from the 60's all the way to 94, and I read on here in another thread that someone intentionally tampered with the chart, so I really don't trust it. I was hoping someone here would have somewhat a better idea.
Id like to help but Vespas are all I know about.
Go high seventies and work your way down.
All right then, fair enough.
I was going to get both the 70 and 80 kits and work my way through those, seems a bit of a waste but since no one has any idea what size jet I should use it seems like the best solution.
i've also found the tuning spreadsheet to be fairly inaccurate and unreliable. I'm running a 78 jet in my 70cc A55 airsal with the stock 14mm PHVA carb, however it does seem to be a little rich. I think i'll downjet to a 76
Thank you for the response, I am just trying to avoid wasting money on carb jets I won't use, but I would rather run rich than run lean and risk damaging the engine.
Yeah I hear you man, I'm in the same position
The spreadsheet is totally all over the map. If I were you I would start in the mid 80's and go down to like 65, I don't think that you will end up in the 80's but it won't hurt to start there. Got a a35 65 cc performance pipe stock carb performance air filter and I'm at 65 with the plug looking good.
Allright, thanks for the info.
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