TOMOS A3 70cc Performance kit ?

conway twitty /

I have a tomos what I believe is an A3. The original owner made some customization to the bike already. Mainly, he put dual exhaust pipes which is killing the power of the bike. Max speed on this guy is only around 22-25mph. My goal is to put on a performance kit but do not know where to start, bump it up to 70cc's to get some more power. Any recommendations? Also, how labor intensive is it, would like to not have to involve welding, using a lathe, etc. so any bolt on measures would be more appreciated. Thanks guys.

tomos.JPG

Re: TOMOS A3 70cc Performance kit ?

See how fast u can go on 50cc first. Widen and raise the exhaust port a couple of mm. Take the head off look at the wiki about milling the head for more compression. Look into a different non restricting carb intake set up. Also buying a exhaust for more torque or more top end depending on what u want. Look at gearing to.

Re: TOMOS A3 70cc Performance kit ?

Post a few pics of that custom dual exhaust set up .

Re: TOMOS A3 70cc Performance kit ?

Jimmy Cincinnati /

See how fast u can go on 50cc first. Widen and raise the exhaust port a couple of mm. Take the head off look at the wiki about milling the head for more compression.

He wants a bolt & go application.

Re: TOMOS A3 70cc Performance kit ?

conway twitty /

Thanks. Im not a mechanic, i dont have access to a mill lathe or weld. Trying to make as simple as possible before shelling out more than its worth to the chicago outfit to install it.

Re: TOMOS A3 70cc Performance kit ?

Tri-ped Dave O.D.B. /

Bah! Porting for a novice? No way. Just grab this:

https://www.treatland.tv/tomos-A3-70cc-45mm-cylinder-kit-p/tomos-a3-70cc-45mm-party.htm

it is a reed kit so you will need an intake, reeds and a carb 15mm-18mm is best for this cylinder. Then bolt on an estoril pipe and jet carb to match and go 50 plus

Re: TOMOS A3 70cc Performance kit ?

conway twitty /

Thanks guys. This is some good info to work with. Here are some more pics for reference. If anyone is interested in the dual exhaust let me know. I would love to trade for pipe.

a3 head.jpg
a3 rear.jpeg
a3 top.jpeg

Re: TOMOS A3 70cc Performance kit ?

I'll trade you a biturbo for that pipe. The mounting is the same as an a35 right?

Re: TOMOS A3 70cc Performance kit ?

conway twitty /

DEAL. let me see a pic of the biturbo, it should be same fitting. according to treats.

https://www.treatland.tv/tomos-A35-biturbo-pipe-p/biturbo-tomos-a35.htm

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