Newly kitted maxi.. Hot running issue?

Jay Nowakowski /

Hello all, well after trying for the last week to get the puch running well I've caved and decided to make a newb question thread ahahaha.. I guess what I'll do first is give a breakdown of what tue bike is at this point..

86 maxi sport LS

70 cc treat kit (kstar)

20mm Dell phbg

82 main

42 idle ( waiting for 45 )

W7 needle on top clip

Mild port work

Case matched


So basically what's happening has me pretty stumped, when cold the bike will start up and idle pretty darn good a smidge of 4 stroking at 1/3 throttle but revs out nicely. As it gets warm (about a minute or 2) it gets just a little shaky and then just shuts down. At this point starting the bike back up is a real pain.. It seems once it cools back down again is the only time it wants to fire back up. I have a few ideas but I'd love to hear what you guys think..

Also something I'm concerned about is I seem to be getting some noise out of the motor. Mind you before the kit it was smooth as butter.. It almost sounds like the piston is hitting something but from what I can tell there's no evidence of any contact anywhere. I shaved the little nub down in the case and the top of the piston looks unharmed too. Are there any other points of contact I should look at? Possible crank walk already? Again would

Love to here some ideas on this.

Thanks in advance for any help!

Re: Newly kitted maxi.. Hot running issue?

Overpriced Parts /

Not timed correctly

Not jetted correctly

Re: Newly kitted maxi.. Hot running issue?

stock head? 1/3 throttle thing is probably a needle/atomizer issue. give all you're carb stats

Re: Newly kitted maxi.. Hot running issue?

Jay Nowakowski /

Head is the treat high comp head..

As mentioned the needle is a w7 that is on set on the highest clip notch

Atomizer is the correct 2 stroke unit.

The four stroking I'm really not that worried about as I think it can be tuned out once I get my 45 idle jet in the mail. I'm more concerned about the way the bike seems to be running fine then just shuts off for no apparent reason. My first thought was possibly running a hotter plug?

Re: Newly kitted maxi.. Hot running issue?

I setup a puch last year.


Mikuni 20mm

High comp head

Just some thoughts.

You need to eliminate the 4 stroking or at least get a bunch of jets and determine which size "starts" it to 4 stroke... if you are a few jets into 4 stroking I have witnessed engine noises and so forth.

then forget about all the systems when the bike is just warming up.

Then the shut down issue. Check your head bolts and intake manifold. Mine did the same thing.. ran for a bit... then lost power and shut down.... happened faster on hills. the head bolts and my intake bolts loosened up all the time and then making the bike lean and hot then shutting down. The extra vibration or just higher RPMs was backing my head bolts out to about 5 foot/lbs and the manifold was also sucking air in.

Also don't rule out a crank seal going bad as this sucks air into the case. then leaning out the mixture and over heating....

My mikuni was a pain to adjust... and richening up the idle jet helped out after i fixed the head and intake leak problem.

good luck

Re: Newly kitted maxi.. Hot running issue?

Overpriced Parts /

Timing before jetting .

You will run cooler with correct timing then you can

Jet easer .

Re: Newly kitted maxi.. Hot running issue?

agreed! Can I say I assumed the timing was correct!

Re: Newly kitted maxi.. Hot running issue?

Jay Nowakowski /

Some good tips gents, thanks! Where would you set your timing? 1.5- 1.7mm before tdc?

I went on a wild goose chase Looking for the right ngk today after work but couldn't track one down. I did make a few calls and found some a couple towns over that I'm gonna go grab tomorrow. I'm hoping between my new idle jet options,adjusted timing and a hotter plug I'll see some good results. Fingers crossed!

Re: Newly kitted maxi.. Hot running issue?

Overpriced Parts /

1.7 is way too high that's like 20 some degrees. Run

1.1 mm in the plug hole or 16.5-17 degrees/mm on the flywheel.

A head temp gauge is a must nowadays so run one.

If you run cool then you can add timing.

#8 plug is fine

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account