Tomos won't max out

So here is my situation:

I have a very low top speed. Maybe 25 mph

I can't really feel if it's 4 stroking (atleast not how my maxi feels, which is very obvious)

I'm working on the jetting now.

When I look at the wiki, everyone has a way higher jet then what I have now.

My plug is dark, which is telling me to down jet.

I figured I'd post what I have and see what some people think.


malossi 4p

polini phbg

tecno circuit

no air leaks, timing set correctly

ngk b7hs plug

I have a 78 jet in now.

I started at 90 and worked down this far.

Everyone in the wiki is like 88 or sometimes higher for this setup.

What am I doing wrong, or what should I look at changing?


Re: Tomos won't max out

You left out the size of the carb this on a tomos? (edited)

Re: Tomos won't max out

Sneaky Pure /


phbg 19mm

Re: Tomos won't max out

This was verrrry helpful when I finished kitting and upgrading the carb this past spring:

Re: Tomos won't max out

Steve Dethrow /

I'm having a similar issue, I'm gonna try puttin a better throttle assembly on there.

Re: Tomos won't max out

Zeke Rigg /

do you have a restrictive air filter on there?

Re: Tomos won't max out

Sneaky Pure /

malossi, the squareish one.

use the same one of my maxi/polini and was wonderous.

Re: Tomos won't max out

I have your same setup..exactly, but on a za50. I am doing 45'ish..gearing 18x40..don't know how it compares though..78 jet also..

Re: Tomos won't max out

Sneaky Pure /

problem solved.

The gun I was using to try and set the cdi had to be funky.

whether i put the cdi at full advance or retard, all my marks always showed in same spot.

Got timing right.

80 jet in.

oh my god fast (i have a polini geared tall and am not used to all the redic low end)

Re: Tomos won't max out

the circuit pipe is wicked for low end on a tomos... best cheap pipe for tomos ever! my next build is another polini on a a35 with a circuit and phva 17.5.... nice everyday rider

Re: Tomos won't max out

Sneaky Pure /

I've been riding my maxi for sooo long.

It's a slips up until like 20 mph

this tomos has some torque.

pullin wheelies style.

Re: Tomos won't max out


Does the engine have new crankshaft seals? both sides.

Are you using the stock voltage reg. ?

Re: Tomos won't max out


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