As you guys know, kerry helped me rejet my bike. However i have found a few nagging issues.. i am assuming that its due to the main jet going lean.
Basically when im in 1-2-3rd gear it isnt that prominent, infact it pulls really fast to 9K. But if your on the freeway doing about 6000-6500 rpm its starts to feel like cutting in and out, not much but it wont kick in power. Around 7K plus it feel quite a bit worse.
I am thinking either the 137.5 jet is too small or the needles need to be shimmed up. The airmixture is at 3 turns if im right. Putting in new jets will be easier i think. I could go to 142.5 or something tells me that may not solve the problem. By the way im running the lunchbox k&n and the stock exhaust.
This weekend it was mighty cold in teh canyons but i still rode, though i cant figure out why i was bouncing so much. I actually got thrown up off the seat a few times on muholland hwy.
You did not mention your current needle height. But raise the needle first. If that does not correct it then go up one in the main and drop the needles back to where they are now.
http://www.factorypro.com/tech/carbtune,CV,high_rpm_engines.html
I actually got this surging behaviour when mine was running rich because of a float height that was way off.
Steady throttle issues are usually lean, lean surge or lean misfire (you may not actually hear it ... but it can lose a cyl on occassion and the next instant be OK) ... anyway 01+ carbs ...no clue, but I'll raise needle as Dgyver said...
Cool.
Srinath.
"....I am thinking either the 137.5 jet is too small or the needles need to be shimmed up....
You might try going up one size on the mid-main if you have not already. With stock exhaust and K&N pods I ended up at 142.5, one up on mid-main and #20 pilots. When I added a can it went up to 150 on the main
I had a similar issue after rejetting my bike (01). I noticed the problem had more to do with throttle position- Ie no matter what gear I was in, if I went from half to wide open throttle i would stutter and hesitate til I backed it off.
I thought it had to do with jet sizing and needle height and mixture- but in the end I wasn't getting enough gas. I ran a straight line from the tank to the carbs. I used a larger ID and made sure that the hose was as straight as possible (no big bends or loops). No more problem...
humm.. this means i got some playing around to do..
i want to ride, not fix.. oh well i will try shimming up a bit and just in case buy some 142.5's. My midmain are at 62.5 anycase (check my signature).
If its a fuel delivery problem - why would the effect be more prominent at higher speeds but similar rpm's. I mean i can do 7K in 2nd gear and it doesnt feel like it does 7K in 5th.
7 k in 2nd has a power demand that's quite different from 7 k in 5th. In other words, the position of the butterfly is way different (almost closed in 2nd, WO in 5th. Thus fuel demand is also quite different.
That's why they say jetting is dependant on throttle position ...
BTW With a kunch box K&N Manjul, I think you should be up higher on mains ... on the 33's without the mid mains I'll be at 145 with stock pipe, and 150 with slip on... you have 34's and a mid main ... :o ...so no idea... but go up on something ... you are lean.
Hi-T - Whacking open the throttle and bike behaves bad, open slowly and it behaves fine - dead giveaway the slides are comming up too fast. maybe that wasn't the case ... it behaved bad even when you opened slowly ... Then fuel flow is possibly choked ...
Cool.
Srinath.
Ahhhhh- I had a nice long post typed up and my browser crashed :x :x
Anyway- to go short- My problem was more predominant when I whacked the throttle. But in the upper gears, even with slow roll ons I still got a chugaglug.
I think your jetting is fine- The highest size I hit on the main was a 147 and that was with every mod you have listed and a full V&H. I don't think you've changed it enough to have that much of a problem. After I fixed the fuel problem I WAS lean but that was indicated more with back firing.
I'd say throw the stock air box back on- that should richen the mix back up without doing any rejetting. If the problem goes away - rejet again.
If it stays then I think it will indicate another problem- I'd bet fuel delivery... it could be a piece of rubber from the fuel line chunked off while you were working or you're just not getting enough gas.
I recommend getting some clear chemical rated tubbing (cheap at home depot) with a larger diameter. By pass the petcock (which I also had to do) and run the line as straight and short to the 'T' as possible. You will need a 2 vacuum caps- one for the reserve and one for the right carb.
Or maybe you need to adjust the valves and it just so happens that they went downhill at the same moment you were rejetting?? Boy- wouldn't that suck- spend all this time diagnosing carbs and it's not even the real problem... :)
Hi-T ... Is it on a 01+ you are talking about ... on the 89-00 a 147.5 main is probably the right size with K&N pod and pipe, I just recomend 150's for driveability especially when cold and humid, and helps start/warm up times and for a cooler running motor ... probably makes more power with 147.5 ... I know that 152.5 is lousy ... its a good step down from 150 ... Now between slip on pipe and stock pipe ... no more than 1 size jet difference and that too only in the mains ...
Cool.
Srinath.
My bike was an '01
Just wondering if you have made any additional tweaks... I have a 2001 that I will be rejetting...
I hope you get yours dialed in. That link from the first response i think it was has alot of good information. Sure wish i had my own private track outside the garage sometimes... like when it's time to rejet.
Suburbia... the joy.
The set-up I used.
Stock needles shimmed up 1/8"
#20 pilot
#67.5 mid-main
#147.5 main
4 turns out mixture
What filter and what mid-main are you running? Didn't we have this conversation around two years ago?
You said K&N in box right? try a bigger main, maybe a 140 or a 142.5. Shimming the needle will jus make it rich on the bottom of the power band. At 6500 that's right in between the mid and the main, how is it pulling up top? If it's good up there than go up one size on the mid.
I tsounds like you have it dialed in. We didn't talk two years ago thats for sure. Just got the GS.
I am going to use K&N lunchbox... so... I am just hoping to find someone with the same setup, Slip-on (Whileyco), and lunchbox filter that has it running sweet.
Thanks, J