big bore vs stock reliability

Hello got a prob rode my qt into the ground always wide open, 40 miler a day and need to do high 30's atleast. Put a uni filter on my qt50 and three days later bam, now I need a new cylinder and was wondering what the feed back is? yamaha part vs. brandx. I need to go fast, but not break, was going over 30 really wanna do 35 consistant. Did my uni filter have something to do with that, because i had to put the air screw in all the way.

thanks sam

Re: big bore vs stock reliability

if you put a hi flow filter on and didnt upjet thats why you siezed. you should do a little more reading before you think about getting a kit.

Re: big bore vs stock reliability

well....

Did you upjet your carb at all when putting on that airfilter?

More Air = Needs more fuel/oil.

Did you seize? what happened to the cylinder?

Re: big bore vs stock reliability

the cylinder got scared by one of the rings coming apart. did not know I needed to upjet. shit.

Re: big bore vs stock reliability

i was told by someone to adjust the air-flow, did not really know enough about jetting. Also the yamaha dealer did not have a listing on qt50, where can i get some jets. would like to get my ped together asap, but know im worried i dont know enough and dont want to waste anymore money.please help..newbie

Re: big bore vs stock reliability

I think most yamaha nopeds ran kehin carbs. I'm not sure what brand of jets those take. I think maybe regular dellorto jets? Maybe?

Re: big bore vs stock reliability

yamaha runs mikuni carburetors, not kehin.

any competent yamaha dealer should have no problem getting you parts.

pretty much any motorcycle dealer should be able to get you mikuni carburetor jets

Re: big bore vs stock reliability

jon whats a good starting point as far as sizes go? sorry i dont know shit.

thanks for the help you guys.

Re: big bore vs stock reliability

A good starting point would be checking to see what size jet you have in there now. Sorry about the bad direction with the kehin comment.

Re: big bore vs stock reliability

assuming the carburetor has the stock jet in it, you should have a 70 in there now(you should check to be sure). the mikuni jets come in 2.5 increments. assuming you have the 70 in there now, get yourself a 75 and a 72.5, do some plug chops, and see how the bike performs.

Re: big bore vs stock reliability

jon thanks for the starting point still dont even know what a plug chop is. i am real new at this and trying to learn. thanks for being cool

Re: big bore vs stock reliability

not everything here is applicable to the qt, but this is "fred's guide," a good primer for moped repair:

http://www.mopedarmy.com/resources/articles/fredsguide/

here's a link for the owners manual for the qt50:

http://www.mopedriders.org/article_view.php?faq=2&fldAuto=41

also here's a link to the service manual for the qt50:

http://www.mopedriders.org/article_view.php?faq=2&fldAuto=45

« 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