P
Phaedrus
Guest
Update
Update
Alright, so the 137.5 mains finally came in and I was able to tune a bit more. Much closer, but still no dice.
- With the needle @ notch 4, as suggested, 1/8 -/1/4 was solid, but 1/2 -3/4 was too lean, and full throttle seemed strong enough to pull through redline.
- I was able to remove all hesitation 1/4 - ~3/4 throttle by richening the stock needle all the way to max + a washer. Now, the hesitation is gone, but the bike doesn't want to pull ~<3/4 through full. It seems that the last bit of the taper on the needle is just a tad too rich. My conclusion is that the 137.5 main is very close and with the proper length/tapered needle, this bike could ride smooth as butter.
My last swing at this will be to remove the stock needles and compare their length/taper to the dynojet needles. The dynojet needle's taper is far less severe (leaner) and the needle itself is much shorter. I'll try to see if I can line up the current notch on the stock with a sweet spot on the dynojet needles. If that doesn't work, I'll have to measure the stock needles and try to find some shorter, slightly leaner needles.
This has been glacially slow progress, but it's getting closer with every little adjustment. Thanks John Kat for the recommendation of trying 137.5 Mikunis and a different needle. Definitely on the right track
[Edit: A Few Hours Later...]
Dynojet needles are way too lean at WOT for a 137.5 Mikuni. A few people have expressed their surprise that the Dynojet kits provide such "large" main jets. It turns out that this is because of the needles that they supply with the kit. They're so lean at WOT (about the same as the root diameter of a stock needle), that they need a gigantic main jet in order to balance the mixture. It's a main-to-jet needle taper ratio. Stock needles require much richer tapers in conjunction with the smaller Mikuni main jets.
Now I just need to find the right jet needle....
Update
Alright, so the 137.5 mains finally came in and I was able to tune a bit more. Much closer, but still no dice.
- With the needle @ notch 4, as suggested, 1/8 -/1/4 was solid, but 1/2 -3/4 was too lean, and full throttle seemed strong enough to pull through redline.
- I was able to remove all hesitation 1/4 - ~3/4 throttle by richening the stock needle all the way to max + a washer. Now, the hesitation is gone, but the bike doesn't want to pull ~<3/4 through full. It seems that the last bit of the taper on the needle is just a tad too rich. My conclusion is that the 137.5 main is very close and with the proper length/tapered needle, this bike could ride smooth as butter.
My last swing at this will be to remove the stock needles and compare their length/taper to the dynojet needles. The dynojet needle's taper is far less severe (leaner) and the needle itself is much shorter. I'll try to see if I can line up the current notch on the stock with a sweet spot on the dynojet needles. If that doesn't work, I'll have to measure the stock needles and try to find some shorter, slightly leaner needles.
This has been glacially slow progress, but it's getting closer with every little adjustment. Thanks John Kat for the recommendation of trying 137.5 Mikunis and a different needle. Definitely on the right track
[Edit: A Few Hours Later...]
Dynojet needles are way too lean at WOT for a 137.5 Mikuni. A few people have expressed their surprise that the Dynojet kits provide such "large" main jets. It turns out that this is because of the needles that they supply with the kit. They're so lean at WOT (about the same as the root diameter of a stock needle), that they need a gigantic main jet in order to balance the mixture. It's a main-to-jet needle taper ratio. Stock needles require much richer tapers in conjunction with the smaller Mikuni main jets.
Now I just need to find the right jet needle....
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