Tomos A35

Robert Phipps /

Needing some help with my bike what does the mm stand for on the carbs wanting to get bigger carb but not sure on how this works can I get any help

Re: Tomos A35

Beach Club Nick /

Upgrade carb last. Stock cylinder and pipe? Bigger carb won't do anything except make you get shittier gas mileage.

If you're buying a bigger carb you need a bigger intake too. There's little point in putting a 15mm dellorto on the stock 12mm intake

Re: Tomos A35

Robert Phipps /

I got new exhaust an intake kit coming 70 cc 45 mm an new jets just my card leaks like crazy so was gonna get new one so figured to go up in size but not sure on how to read them don't understand it

Re: Tomos A35

Robert Phipps /

An I heard u can get better top end speed by changing the sprockets how does that work as well

Re: Tomos A35

Whooooo buddy you’re firing right in from square 0 huh? It seems you don’t have much knowledge of building or tuning engines. I wish you the best of luck. For a 70cc kit go for a 19-21 mm carburetor. You’re going to need to learn how to tune as well. The Mikuni carbs tend to be forgiving from what I hear, I’m a dellorto PHBG man myself. There’s a wiki page here on the site (the wiki is a great resource) that tells you step by step how to tune a PHBG, but could be applied to a mikuni as well.

***PHBG TUNING GUIDE***

If you’re not planning on rebuilding your engine you may run into some issues down the line depending on how old your tomos is, I know the a35 was used pretty early on, and those bearings and seals could easily be 25-30 years old.

Some tips though, make sure you get ALL old gasket material off of your old cases when you put your new cylinder on. Don’t use a razor to remove stuck on gasket, if you gouge the metal mating surfaces it will suck in air and make it run like poop. This is called an air leak (by your question and wording I’m assuming you know none of this or most terms so I’m trying to explain things thoroughly.)

If you don’t know, the bottom end of the engine is the transmission part. The block with all your gears, and clutches. The top end is the crank, cylinder, piston, reeds, and head.

Changing sprockets is tricky. You have to balance take off power, and top speed, if you hear for more speed, your bike will be slower off the line. If you hear super low, you’ll have a slower top speed. Honestly 70cc bikes on stock gears can be kinda fun because they usually rock off the line but might max out at 40ish. Bigger front OR smaller rear will get you more top speed and the reverse, smaller front or larger rear, will get you more low end grunt. Try stock gears fist, maybe but a front sprocket with one extra tooth to try down the line (you’ll need another chain) or a rear with a few teeth left, don’t go too extreme or you’ll take forever to get into the power, too extreme and you won’t get to the power at all.

Good luck homie. Watch a bunch of YouTube videos and read read read. All of us here did it (I started on here when I was 16, 11 years ago with zero motor knowledge. But it’s just mopeds homie. You have the resources done be afraid to read first you’ll usually find your answer.

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