Jet Kit for 79 xs1100F

[IanDMacDonald]

So i pulled my main jets yesterday and I can't tell what size they are. Is there a special number I should be looking for? If so where should it be? I can't see any numbers on these jets. Perhaps they wore off.

On the face of the jet, u should see the number with the Mikuni swirl logo. If u do not see it, they're not Mikuni's. See my link for jets for cheap in my thread.

[TheRev]

Thanks Ian

Are those jets in your link genuine Mikuni's? You suggest starting with stock and moving up one size on the main, correct?

On the face of the jet, u should see the number with the Mikuni swirl logo. If u do not see it, they're not Mikuni's. See my link for jets for cheap in my thread.

[DiverRay]

Rev, Go back a a bit and look at my post. I've set up a '79 with the '79 carbs, and I went up 1 jet size with stock air box, K&N, and turnout MAC exhaust. I would start there, and tune as needed. JMHO

[TheRev]

Thanks Ray

You went to 140 on the main? I will start there. Thanks

Rev, Go back a a bit and look at my post. I've set up a '79 with the '79 carbs, and I went up 1 jet size with stock air box, K&N, and turnout MAC exhaust. I would start there, and tune as needed. JMHO

[TheRev]

Are these the jets i'm looking for.

http://www.mikesxs.net/product/48-0121.html

I want to go up one jet size so that would be 140.

[jetmechmarty]

Are these the jets i'm looking for.

http://www.mikesxs.net/product/48-0121.html

I want to go up one jet size so that would be 140.

Read that again! "Main Jet #140 - Large Round Mikuni Type Yamaha XS650" You aren't going to get Mikuni jets. You're going to get jets that fit in your Mikuni carburetor.

[TheRev]

Good point. I think I want Mikuni. What about these

http://www.amazon.com/Mikuni-Main-Je...n+main+jet+140

Read that again! "Main Jet #140 - Large Round Mikuni Type Yamaha XS650" You aren't going to get Mikuni jets. You're going to get jets that fit in your Mikuni carburetor.

[TheRev]

I'm not sure if our jets are round, small round or large round.

[IanDMacDonald]

Hey Rev- I also have 140's in my bike, with a modified airbox I've , and at the time Mac exhaust. The bike runs great! However, my mileage is not great, and I attribute that to my engine modifications and possibly the jetting. So . . . I experiment with a smaller main jet (stock 137.5), and if I don't see a correct tune, I'll resort back to the 140's.

If you see my link, the jets are three dollars cheaper. However, as Nate/Moto pointed-out, the pic shows EBC RD jets, yet the description says "Mikuni" under brand. I'll let you know when they arrive. I'll probably be doing my carbs a week or two before you.

LARGE ROUND

[TheRev]

Sounds great Ian. I don't ride the bike enough to worry to much about mileage. I just want the bike to run likes it's supposed to. I can't wait to ride it when she is tuned right. I spent the entire season last year trying to tune her. I just hope going back to the air box will solve my problems. I have way to much money invested in these carbs to not have the bike run properly.

[IanDMacDonald]

Yes, I suppose. But, it'd be nice to see 150-160 miles to the tank + reserve, as opposed to the 130 I currently get.

[jetmechmarty]

I get mine from Jets R Us. They have removed the guesswork

http://www.jetsrus.com/a_jet_kit_street/yamaha_1100_XS1100F_1979.htm

Good luck!

[TheRev]

So i pulled the jets out of the carb today just to see what size they were. I don't want to purchase jets I already have. The jets say 135 and have a symbol of a box within a box. So my guess is that these arn't Mikuni jets. Is 135 close enough to stock Mikuni jets? If so then I will start with them. If I need to go up one jet size then I will go to 140. Does that sound correct.

[TheRev]

Never mind. I guess the symbol of a box within a box is Mikuni. So 135 is too small. I am going to order stock 137.5 and start there. It's interesting that the jets that were in my carbs were smaller. Perhaps that was the main problem. Is there any reason my mechanic would drill the slides and then put in a smaller jet?

[red bandit]

A symbol of a box within a box, they ARE Mikuni jets. 135 is too small for stock 79 carbs. Stock is 137.5