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t500 needle jets

Posted: Thu Jul 19, 2012 6:37 pm
by joewillybob
Now I've gone and done it. I buggered one of the needle jets on my T500R, 1971, 32mm spigot mt. carbs. 188 needle jets The jets I need are no longer available anywhere I've been able to find. Will a series 159 needle jet with the appropriate main jet work? I can find the 188 series jets in either P-0, or P-8. Will either of those work? The more I look into this, the more confused I get. Thanks.

Re: t500 needle jets

Posted: Thu Jul 19, 2012 9:23 pm
by tz375
#159 is essentially the same needle jet. replace both needle jets with 159 series and replace main jets with equivalent flow (bigger number) hex main jets. Start one or two sizes larger than teh chart just to be on teh safe side

Re: t500 needle jets

Posted: Sun Jul 22, 2012 12:17 pm
by joewillybob
Looks like I need to use around a 270 or 280 main jet. Does this sound about right? Also, do I use the same needle?Thanks again

Re: t500 needle jets

Posted: Mon Jul 23, 2012 9:06 am
by tz375
What size are the main jets and are they correct for your bike? There were significant variations in size over the years with different intake designs.

Re: t500 needle jets

Posted: Mon Jul 23, 2012 10:05 am
by joewillybob
main jets are 150's. According to my admittedly crappy shop manual, that's the correct size. They are the round type. Pretty sure that the entire intake system is as stock.

Re: t500 needle jets

Posted: Mon Jul 23, 2012 11:56 am
by tz375
If the bike ran fine with a #150 round, then it should be close with a 280 hex.