Oh boy... more jetting issues.... getting desperate

[nmh5028]

I've been "fighting" with my jetting setup for way too long now, and I'm beyond frustrated with this bike (almost to the point of just selling it for something with EFI). Hopefully someone here can point me in the right direction and I can finally just enjoy the bike instead of tearing the carbs apart every weekend.

The vitals:
2001 GS
full V&H exhaust
K&N Lunchbox air filter
Bob B ignition advancer
Riding at or pretty close to sea level all the time

I've been everywhere from 20/62.5/147.5 to 22.5/67.5/152.5 and 0 to 3 washers and most every combination in between. There are always issues somewhere, but I have narrowed my smoothest setup down to this:

20/62.5/152.5 with 2 washers, 2.75 turns out.

This issue here is in the (surprise!) 5-6k region at or going to WOT. When pulling from 4k at WOT, the bike stutters and skips through the 5-6k region, then pulls hard from 6 to redline. If I'm cruising between 5 and 6k and I jump on the throttle, it stutters and eventually goes once above 6k.  I popped a 65 mid jet in today (left the 2 washers in) and this area got worse.

I have only come across a few posts with a 2001+ bike with ignition advancer, and I think the setup that they came up with was 20/62.5/155 1 washer. I don't have any 155's yet (because nothing on this site points to jets that large). Is there that big of a difference with the advancer, or am I just way off?

Like I said before, I'm almost at the point of just giving up (though I enjoyed the GS before I had to replace the exhaust and started all the trouble). ANY suggestions or help would be awesome. Thanks!

[Nighthawk016]

sounds like you are lean on your needle, could be the diaphragm possibly not actuating the needle, or a general fuel starvation issue do to improper float height. Check your float height, make sure your carbs are clean, inspect you diaphragms, then verify your carbs are sync'd properly.

[nmh5028]

sounds like you are lean on your needle, could be the diaphragm possibly not actuating the needle, or a general fuel starvation issue do to improper float height. Check your float height, make sure your carbs are clean, inspect you diaphragms, then verify your carbs are sync'd properly.

Floats are spot on (fuel level is right at the gasket using the U tube method). Carbs have been cleaned and synced almost every time I take them apart (recently it has been about once per week). I don't see any issues with the diaphrams, they are nice and flexible with no visible damage.

[The Buddha]

No you sound rich on the needle.
Remember these 2 things -
1. Carburetion is related to throttle position, not to rpm.
2. Problems opening the throttle and lack of power - stuttering etc are rich. Steady throttle problems are lean.
Cool.
Buddha.

[nmh5028]

No you sound rich on the needle.
Remember these 2 things -
1. Carburetion is related to throttle position, not to rpm.
2. Problems opening the throttle and lack of power - stuttering etc are rich. Steady throttle problems are lean.
Cool.
Buddha.

So if I am rich on the needle with no washer, I should probably drop a size or 2 on the mains? Where do the mids play into everything?

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[The Buddha]

I thought you had 20/62.5/152.5 with 2 washers, 2.75 turns out.

You still rich with no washer (BTW you have to observe if it got better or worse when you went from 2 washers to 0) then drop 1 size on the mains.

How do the mids figure into all of this ... he he, that's what I want to know too.
Hey drop to 60 on it if 150 mains are rich in the 1/2-3/4 throttle range.

Cool.
Buddha.

[nmh5028]

I thought you had 20/62.5/152.5 with 2 washers, 2.75 turns out.

You still rich with no washer (BTW you have to observe if it got better or worse when you went from 2 washers to 0) then drop 1 size on the mains.

How do the mids figure into all of this ... he he, that's what I want to know too.
Hey drop to 60 on it if 150 mains are rich in the 1/2-3/4 throttle range.

Cool.
Buddha.

I was at 2 washers. I took them off and noticed no real difference. I know for sure that the 65 was worse than the 62.5, but I'm seeing no difference with 2 washers vs 0 washers. I'm going to drop the main a few sizes (making it 20/62.5/147.5) in hopes of a drastic change. If it is still rich in the 1/2 to 3/4 range then I'll probably step down the mid.


Another question, what is the maximum suggested number of washers? I tried 3 a few times and it seemed like a lot of lift. Is 2 the max or is 3 OK if needed?

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[Nakedguy]

Get some factory pro kit adjustable needles. It helps. I feel your carb tuning pain. It took 2 bike mechanics, myself and 5hours to figure out I had a weird carb boot leak.

[The Buddha]

On a 01+ 2 is about the max. That spring pushing down on the thing has too much preload even @ 2.
You try dropping to 147.5, 62.5 could be perfect. I sell 65's only as a special case to those who are lean after 2 washers on the needle. 62.5 will be fine ...

Cool.
Buddha.