carb work recommendations

[rideOn]

Here is a link on needle shimming from BassCliffs website.

http://members.dslextreme.com/users/...at_height.html

looks easy enough, maybe some experimenting. thanks. i'm not the brightest person, but i just realized, each carb may need adjusted to different characteristics than another. is that too far-fetched.

[Steve]

... when i'm in that 3-4k range, i push the choke over about 1/3 and it smooths out nicely.

Good troubleshooting.

That shows you that it's running LEAN. You still want to check your valves to make sure the engine is breathing right, then you can adjust what it's breathing. You will need to make sure there are NO air leaks, especially between the carbs and the engine. Does your bike have o-rings in the intake boots? What shape are the boots in? ("Round" doesn't count.) If they are not soft and pliable, they could be the source of your air leak.

Now, concerning that "3-4k range", ... what is your throttle position when you are doing this? What I mean is, is it just barely open, as in cruising down the road? Is it open about 1/4, 1/2 or even full open? Diagnosing jetting problems has more to do with throttle position than it does engine speed. Example: going down the road at 25-30 mph in fifth gear (about 2k rpm) will take more throttle than sitting in your driveway, in neutral, and going for 5-6k rpm. Especially for repeatability when doing your plug chops, you should mark your throttle so you can SEE where it is, and you don't have to guess.

Here is how I marked my wife's throttle when I was working on it:


The marks are:
Idle
1/8
1/4
1/2
Full

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[rideOn]

Good troubleshooting.

Now, concerning that "3-4k range", ... what is your throttle position when you are doing this? What I mean is, is it just barely open, as in cruising down the road? Is it open about 1/4, 1/2 or even full open? .

not sure. i'm fixin' to ride it 15 miles to the house. i'll make notes....but not while i'm driving!

[rideOn]

Good troubleshooting.
Now, concerning that "3-4k range", ... what is your throttle position when you are doing this? What I mean is, is it just barely open, as in cruising down the road? Is it open about 1/4, 1/2 or even full open? .

in any gear, under 3k rpm, no problems that i've seen up to about 40mph. at 40-50 mph, 3-3.8k rpms and 3/8 throttle (best estimate per your diagram) very uneven with popping on decel. any thing above 50mph, 4krpm and 1/2 throttle up, runs great. good pocket about 60mph. there is decel pop at this level, also.

[Steve]

You are still pretty much on the pilot circuit at those low throttle openings. How far out are your mixture screws? They should be somewhere in the range of 2 to 3 turns out from lightly-seated on a stock bike. Try that and report back.

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[rideOn]

You are still pretty much on the pilot circuit at those low throttle openings. How far out are your mixture screws? They should be somewhere in the range of 2 to 3 turns out from lightly-seated on a stock bike. Try that and report back.

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i'm either blind, an idiot or both. i can't find any mixture screws. i've gone through my clymer manual and basscliff's BS32 manual to check if i'm missing something...nothing on mix screws

[twr1776]

Here is a link to the mixture or "air" screw. If your carbs have never been adjusted there is a cap over the top of them from the factory. You will have to drill out the cap but be VERY careful so you do not go too far and get into the top of the mixture screw. There is an o-ring under this screw that should be replaced but it comes with the o-ring kit from Robert Barr.

http://www.thegsresources.com/images/carbs/025_Prepare%20to%20remove%20air%20screw.jpg

[rideOn]

well crap, i am blind. i see them. i also did plug chops in two ranges this morning. all plugs are the same color except for #2. at low speed, in the trouble range, it was gray. at wide open, it became lighter gray, almost white. what does this tell me, rich up # 2 a fuzz?

the 'trouble' range starts at 35mph and she runs unven (spits and sputters). past about 45-50mph, she evens out and is fairly responsive.

[twr1776]

Yes, I am not sure if I missed it but have you already done the valves and intake o-rings? If you airbox is sealed up properly your air mix screws should be pretty close to each other in turns.

[rideOn]

looks like some seepage around the intake and boots, especially #2, so the o-rings may need replacing. valve shims are waiting for middle of november pay day

[rideOn]

after the readings i took yesterday, i adjusted the mix screw on #2 from 2.5 to 3. there is just the slightest roughness, but much improvement. no more loss of power and no more surging. this in only a temporary thing. i'll re-work the carbs with new o-rings, a cleaning and boot/intake o-rings over thanksgiving. i'll see what happens and go from there. oh, and valve shims. thanks for the help! i'm sure i'll bug everyone for more info soon.