Tomos noob, need tuning help

Picked up a 2005 a35 that needed throttle screw. Put screw in it and it ran reasonably well, but seemed to sputter some on top end. After test run put cleaned and oiled stock air filter and housing back on and it has no top end. Starts fine and accelerates for a second then bogs. I have tried the following one by one after researching but still same result...

Took air filter and paper towel "dried" excess oil (none to speak of)

Removed and cleaned carb (minimal debris on screen, good otherwise)

Ensured rubber boot between AF housing and carb was aligned (it wasnt but no difference)

Took carb apart again for main jet # (its 53 and that seems to be stock sizefrom what I found)

If I take the air filter off it will get up RPM, I dont think it's singing yet but it goes... Just looking to get a good running stock (as far as I know) bike before any modifications.

What would be my next steps?

Seen something about burning out clogged exhaust

Maybe adjust timing

Re: Tomos noob, need tuning help

Forgot to add the carb is the dellorto sha, the stock piece from what I find...

Re: Tomos noob, need tuning help

Probably Fred /

Leave timing alone

You air fuel could be off make sure you have full airbox if your running stock pipe. Your pipe may be blocked .

Make sure fuel line, filter, petcock etc not blocked .

If oil injection make sure it's working/lines not crimped

Re: Tomos noob, need tuning help

Airbox is unmolested stock piece

Checked fuel flow and it is good, left cap on for this to make sure it is venting as well.

While checking flow, drained the whole tank and refilled with fresh gas.

Also pulled plug, it is b6hs gapped to .7mm assuming thats OK since I see references betweeb .5-.8

Oil injection lines not kinked, is there a way to test operation?

Muffler has tomos #'s stamped on it so assuming stock piece.

It does seem to be missing something in the end as theres an empty screw hole.

I can take pictures of anything if needed...

While looking up plug gap info found a manual to download :- )


Re: Tomos noob, need tuning help

check for air leaks

Re: Tomos noob, need tuning help

No air leaks I can find, carb has the plastic shim and the oring at mount and intake is tight.

I pulled the muffler off and some oil came out standing it on end.

Not keen on burning the muffler (ruining finish) but will if it's necessary.

Is a stock bike normally jetted rich?

Maybe I need to lean it out?

Re: Tomos noob, need tuning help

Could be rich if it's four stroking at top end or won't run with air filter. I'm having the same issue except I can't even get it past an idle without it bogging or dying. If it's oil injected I'd try emptying the reservoir of the old oil (mine had actual motor oil in it) and refilling it with some better quality oil

Re: Tomos noob, need tuning help

Thanks for the reply, I keep coming up empty...

It does seem rich to me, but having the stock jet confuses me

I will try changing out oil, good idea

To update efforts

I put kerosene in muffler, plugged ends, and shook around alot to clean out.

Also tried new plug, and changed out trans fluid. Still rides same.

Was thinking it's early shift into 2nd was putting it in a bog killing motors top end

This is my thinking at the moment, may try spring mod, not sure :-( (edited)

Re: Tomos noob, need tuning help

ephraim zimbalist jr /

whats your top end speed and shift speed?they cant tell you whats normal without those two factors

Re: Tomos noob, need tuning help

Do you have the stock airbox or the metal mesh screen for an air filter?

Re: Tomos noob, need tuning help

Stock box now with the straw sized inlet enlarged

Drained tank, blew out line, and changed oil but no difference.

Just took gps for a ride, 2nd seems to hit between 12-15mph and 15.6 was top speed.

Re: Tomos noob, need tuning help

Just did a compression test, not sure of the proper method but

with one swift kick it'll go just shy of 150psi

If i do not relieve pressure it'll go up a hair over 180psi with 2nd kick

Re: Tomos noob, need tuning help

To follow up...

Ordered 50's jet assortment since it appeared to run rich even with stock #ed jet.

When looking at new jets the holes appeared smaller than I remembered the other one looking

Thought I ordered wrong range, but searched and 53 is stock.

So pulled carb and jet, and using a small straight pin as a feeler guage the 53 is roughly a 60.

It was loose in the jet removed, but was slightly to big to fit in the 59 from new assortment.

Slapped a 57 in there on a guess an she runs good (I think anyway)

Got 28.8 on gps...

Guess the other jet was drilled out or was for something else (said "53 inc")

Now that it's running well stock how big can I go on front sprocket?

Currently 26f & 22r

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