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Discussion Starter · #1 ·
can anyone tell me what jetting(pilot,needle position,main) they have used on 38mm mikuni flatslides.
engine is stock with vance & hines exhaust.
 

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It would be good to know what your putting them on when you ask a question like that dont you think?

If I remember right, you have a 91/92 1100.

On my 91 1100 with those same carbs I ran a 135 MJ with the needle on the 3rd clip, and with individual filters. Used stock air jet and idle mixture was 1/8 turn past what they come with, which I think was 1/4 turn open (yes very different from CV's)

How do you like that manly throttle return spring? Makes longs rides a bit more tiring.
 

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Discussion Starter · #3 ·
Cheers harpee,
Yeah it is a 921100,when I got the carbs we put them on and ran it on the dyno and it only made 107hp it ran 130hp with the standard carbs.
we pulled the carbs apart and they had a 132.5 main jet,a huge 32 pilot jet and the clip on the needle was at the top.
we then put in a 134 dynojet main and it made 132.9hp but ran like crap below 4000rpm on a constant throttle,so we balanced the carbs and changed the pilot for a 20 and it cured that.We also put the clip on the needle in the middle.
I will be taking it back to the dyno in the next couple of days to see the results but it feels alot better.
The throttle is a lot heavier than the standard one,we are having trouble with it returning to idle.If you open the throttle then shut it off with your hand at the carbs it returns to idle fine but if you use the throttle at the grip it hesitates on the way down.
 

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Sounds like the cable is not adjusted or rounted properly. If you went to a dual cable set-up like your suppose to with those, make sure they arent fighting one another. That should fix the hanging up.

Sounds like the last tuner was a bit off. There is no reason to run those needles down that far, so your probably close. But they did a good job picking the stock pilot, so check the mixture screws. I have seen many guys who have never had those carbs think they are like CV's and the screw should be 2 full turns out, and run like crap down low and fowl plugs.

That would explain why they ran the needles down and why you could lean it out so much and it works. I have to see if I have my Mikuni stuff about to tell what the stock pilot jet was, but I do recall you run the screw at very small openings of 1/4 to 1/2 turn. So if the other is correct, I would go back to it and set the mixture screw accordingly. It will transition better from pilot circuit to the needle.

Should be Ok to use the DJ mains even though they are different than the large rounds used stock. Tapers are close and you dont need the larger area for a stock motor, even if it makes a difference, which it probably doesnt.

Good luck with fidling with them.
 

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Discussion Starter · #5 ·
thanks again harpee,
I have ordered a push/pull throttle should be here in the next couple of days.
The stock pilot jet for the 38mm flatslides is 17.5.
I'll post how it goes on the dyno
 

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Kiwi, I'm running RS38's on my Bandit1216; when I was running the GSXR cams it was happiest with a setup pretty much like Harpee's... 132.5 or 135 mains, 17.5 pilots, 9CHY03 needles (usually set at #3 or #3 with a 0.5mm shim), floats at 17mm.

I've got the accelerator pump set so that it begins delivering fuel through the nozzles at about 1/4 throttle and then hits the stop at around 3/4 throttle.

Bike is set up with K&N RU-2922 filters... YMMV if you're running something different.

By all means get a push-pull throttle on there... my carbs are very sluggish to return to "closed" by themselves under high (decel) vacuum conditions, it has been pretty exciting once or twice to get on that bike after getting used to the response of the CV's on my 1100w


Ed

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