Kitted a3 performance. Where is it at

Matthew Fickett /

I have a bullet with a3 motor, treats 70cc airsal part kit. it has the high compression head 20mm Mikuni Vm20 intake...also Biturbo exhaust, 27/22 sprockets, a55 flywheel and parmakit cdi.

I’m hitting only 40/41 max. Gets there quick but a lot of people say it should be getting a lot more even on close to stock setup. I’ve done plug chops and it looks healthy golden brown. I had some gy6 jets laying around that fit the carb and tried going bigger and smaller with no real difference. (Yes I know the jet sizes between the Mikuni and gy6 are different)

I’m times to 2.8btdc and thinking about going down to 1.8 or trying something in between once I get my temp gauge in.

Also was thinking of doing a 30 and 20 sprocket for max full send. I’m not running a smaller magnito but everything I’ve seen 30 will clear the wheel with just some case grinding and the back wheel as well.

Am I at the bikes best or the engines best?

Top end and cases have all been redone and kit is new. Been putting on some nice break in miles.

Is the carb that came with the kit too big? Maybe run a more restricted air filter?

Again, when I got the bike it had the kit on it. Had to replace the kit from the previous owner improperly installing it. I’ve been trying to make the bike better and it’s getting there but I feel like it has a taaaaad more.

YES SIR YEEEHAAA!!

Thoughts?

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Re: Kitted a3 performance. Where is it at

A3 has different internal gearing ratio than A35 or 55. Go as large as you can on the front sprocket

Re: Kitted a3 performance. Where is it at

with the kit, did you port and polish at all? touch up the transfers?

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

I did not. This is a pic of the case with some bits in it when the wrist pin came out and destroyed the top end. Lol the transfers looked pretty good but I don’t have much experience with all this porting and stuff. It’s a a3 case with 70cc airsal

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Re: Kitted a3 performance. Where is it at

That looks like air leak city.

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

No leaks. Fresh gaskets and seals also did a spray down to check

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

His is the old kit that came off the bike when the previous owner installed wrong

Re: Kitted a3 performance. Where is it at

take a coupla inches off the exhaust header like 4.

Re: Kitted a3 performance. Where is it at

Are you running a piston port or Reed kit? Make sure that base gasket isn't blocking any of the case transfers, cut that gasket back on the bottom for sure

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

I ordered a new exhaust /)

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

Reed kit. The whole kit from treats that come with the vm20 carb

Re: Kitted a3 performance. Where is it at

A stock a3 with a biturbo and that gearing does over 40. I'd check the compression, it might be way too high with the hihi head. Jetting should be in the 135-155 range with a filter. As far as timing 2.8mm btdc is pretty hot for a tomos, unless you know what the retard curve of it is like. I've never used one of those myself. Usually with the fancier cdi you set them at max advance and it does the rest magically, but sometimes they're static and then retard from there at a pre designated rpm.

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

I have a better exhaust coming (estoril) and a temp gauge. I’ll start to see what compression and temps are and also the new exhaust should help with the top end

Re: Kitted a3 performance. Where is it at

Estoril has a lower peak and won't rev out as much as the biturbo. This is good tho, put the tall gears on it and ensure you won't blow out that bronze bushing in the crank.

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

Out of everyone I’ve talked to who run biturbo says they don’t have good high end and run flat. A week of researching made me order a different recommended pipe. Some people even suggested shorten the Biturbo by 4 inches from the header

Re: Kitted a3 performance. Where is it at

Nah biturbo hits.

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

Flat lines for me and a few others so idk. It’s got good mid range for sure though

Re: Kitted a3 performance. Where is it at

Josiah Radebaugh /

Last bike I rode with Bi-Turbo felt like a faster stock bike. No power band just had a little power everywhere.

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

Well besides the coating on the exhaust bubbling off (clear coat or something) and some slight figment adjustments, I’m pretty happy with the exhaust. Got a lot of power band throughout and good topend as well. At wot I’m only hitting maybe 350 and will go back down to 320 at a good throttle around town and even lower at low speeds. The cdi and timing I think is good. I might adjust a little.

I’m still wot at 42 and when backed off and then 1/4 throttle I’m still going 42 and then full throttle again it seems like it has more. Maybe jetting since I got the new exhaust. I was at 180+ testing with some off brand jets now. Will install a new plug and see what the color is from wot.

Progress!

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Re: Kitted a3 performance. Where is it at

Matthew Fickett /

Oh and the pedal hits on the right side. That was a given.

Re: Kitted a3 performance. Where is it at

You re-gear yet?

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

27/22

I was 26/22 then moved to a 27/24 that was nice but too much torque and lost some top. Maybe 37. I’m thinking maybe 28 or 29. I want this thing to be a rocket. Going to work on brakes tomorrow. Maybe fit a disk on the wheel

Re: Kitted a3 performance. Where is it at

Matthew Fickett /

Pedal delete for the win...testing out for a few and works great! Easy starting in the left side and once rolling, feet sit comfortably. got to paint but took the time dialing in the amps for the metal to melt and bond good. I don’t feel like my feet dropping on the road lol

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