Polini exhaust on a kinetic TFR

My Polini exhaust finally came. It is suppose to be for a Vespa Grande but it fits on the TFR and all the specs for the grande and TFR seem to be the same from the research i have done. The pipe is on there secure and the plug chop i did this afternoon showed light brow/dark tan. My problem is the acceleration really sucks ass now, the top end rocks though. Another thing to factor in is that my piston has scorching marks on it from the previous using straight gas not oil. This never hurt the perfromance before, although the acceleration has always been a little slugish but thats usually normal for kinetics. Anyways if decreation in acceleration is normal with tuned pipes then is there anything i can do to bring back up to spec or if this is not normal then hopefully u guys can give me some clues to the problem. Thanks alot in advance.

Re: Polini exhaust on a kinetic TFR

HI THERE, I READ SOMEWHERE THAT SHORTEN A PIPE GIVE BETTER LOW END (TAKE-OFF) AND LENGTHEN A PIPE FOR TOP END, AND THIS WAS ON 2-STROKES. i GUESS THIS MIGHT MEAN YOU MIGHT NOT HAVE BOTH, BUT I`M SURE SOME OF THE GUYS WILL HELP YOU WITH A HAPPY MEDIUM. LATER....DOUG D. IN VA.

no no no

That is backwards Doug... in general.. if you want more low end and less top end... you lengthen the header pipe.

And conversely... if you want more top end and less low end... you shorten the header pipe.

However Rasta... Yes ... I am afraid that a tuned pipe will usually take away some low end and give more top end.. so what happened to you is kind of normal.

The only way to get some of that back without altering the pipe will be to raise the compression... you can do that by removing the head gasket (if you have one)... or by shaving the head some.

If you want to do that... you need to let somebody with a lathe or mill to do it (dirt bike shops usually can do it... or tell you who can)... look closely at how close the piston comes to the head... and make sure not to remove too much (maybe .030").

Raising the compression might require different ignition timing... or a cooler spark plug... because the engine will run hotter.

Always check the plug color again if you make another change.

Re: OOPS! Wrong......again!

HA! THANKS FRED, I GOT IT BACKWARDS, I HAVE USED CLAY TO CHECK PISTON/HEAD CLEARANCE ON CARS. Have you ever used mopedwarehouse on machine work? I have and got nice work back, porting, polishing,heli-cores, ect. A hell of a lot better priced than here in VA.and there are a lot of shops here. Chris, will cut you some slack. Thanks Fred for the correction. Doug D.

Re: OOPS! Wrong......again!

Thanks guys. Yea i have already removed the head gasket, so i think this is as good as it gets. Its not that bad just a little slow off the start. Oh well, thanks again guys.

Re: Polini exhaust on a kinetic TFR

Reeperette /

>>Another thing to factor in is that my piston has scorching marks on it from the previous using straight gas not oil. This never hurt the perfromance before, although the acceleration has always been a little slugish but thats usually normal for kinetics.<<

Umm...I hope your not still using straight gas ?

And I would check and replace the rings, if the piston is scorched.

-Ree

Re: Polini exhaust on a kinetic TFR

Oh no, it was never me using straight gas. The rings didn't look to be bad shape when i took her apart.

Re: Polini exhaust on a kinetic TFR

You had us worried about you ,RASTA,with that gas but no oil thing! Gasoline has good additives these days but not that good.BYE!

Re: Polini exhaust on a kinetic TFR

Yea i have made a few mistakes but not any such as that, i really don't know what compelled the previous owner to do that when it even stated on the gas cap to mix oil with gas.

Re: Polini exhaust on a kinetic TFR

Well,I hope you rescued the poor thing before the damage was done `cause I've heard that it only takes a few miles to mess it up bad that way.BYE!

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