weird jetting

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scheckaet
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weird jetting

Post by scheckaet »

would cleaning the pipe and repack the silencer change the jetting that much???
The bike doesn't pull right off throttle like it used to, then it's good once you're in the powerband.
fiddling with the air screw help a bit but it's still there.
My air filter was a clean one, gas was new and temp was around 32F.
(I did not find too much carbon build up in the pipe, but the packing was really nasty looking, I'll post a pic tonight.)
Any comment?
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Post by skipro3 »

Unless the S/A was restricted with carbon, then I don't see how it would affect jetting.

I switched to race gas just to get consistancy with my fuel. It's been my experiance that each can of gas I got out of a pump was different. Very hard to jet when fuel quality keeps changing from tank to tank. Race gas is very consistant. I could jet to a razor edge. So, if nothing else has changed, I would try another brand of gas, add an additive like CC and Wib do, change to a fresh plug, (It DOES make a difference!!) try some fresh race gas, (I used VP C-12). In any case, a change would warrant a plug chop to check jetting correctness.

Also, take the carb off and blow out all the passages. Just a minute' bit of gunk can cause symptoms. Check for brake pad drag. Calipers get worn and can hold back a bike.
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Post by canyncarvr »

'Cleaning' the pipe could well require a jetting change. Jetting changes from the -30 to the -35 (did for me..easily noted), so it stands to reason that somewhere in there is enough of a change in pipe 'tune' from carbon that could change jetting requirements.

Re: 'Calipers get worn and can hold back a bike.'

So can bad wheel bearings. So said Wibby this weekend anyway.

Do you have to use oxygenated fuel in the winter? There's a big deader performance-wise.

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scheckaet
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Post by scheckaet »

Thanks ski.
The S/A was NOT really restricted with carbon, I used a wire brush to remove most of it. (t'was almost shinny when I was done)
BUT I did use a different gas station :?
Haven't check the pug yet cuz I lost the damn wrench :sad: I'll clean the carb this week and try it next week end. if still the same, then it HAS to be the gas.
Thanks again :prayer:
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Post by scheckaet »

oxygenated fuel in the winter
oxywhat??? I get whatever they sell at the pump, 91 or sumthin...

My bearings are new ones so I'm thinkin maybe gas is the issue, on the other hand,
Jetting changes from the -30 to the -35 (did for me..easily noted), so it stands to reason that somewhere in there is enough of a change in pipe 'tune' from carbon that could change jetting requirements
makes sense too. I'll find out this week end
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Post by scheckaet »

Image
Is that supposed to look like this after 6 months?
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Post by skipro3 »

Not too bad!! Hardly any spooge, just a little cooked.

Carvr's comment that carbon could affect jetting is technically correct as he pointed out the volume difference in a -30 compared to a -35 pipe. But those pipes differ by INCHES in circumference. I wouldn't think a lifetime of carbon buildup could add more than a 1/4" of carbon build-up. Needless to say, so I'll say it anyway, I don't think carbon in the pipe is going to cause you to need to rejet.


Oxygenated fuel is gas that has Oxygen added to it to cut down the bad emmissions due to the colder weather. There will be a sticker on the pump. Also, alcohol is an additive that will affect performance. Avoid any station that sells it if you are planning on using it for your bike. Alcohol will also seperate out of your fuel with just a tiny bit of water as well. 1 teaspoon of water could pull all the alcohol out of your tank of gas. It settles to the bottom of the tank where you could send a big slug of it to your motor. No premix, just alcohol. It has been known to seize a motor.

CC, I thought you were going to give Wib a set of bearings and he was going to replace them with a new set for you. What happened?
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Post by Mr. Wibbens »

That packing looks GREAT, looks more like my packing on the DR than from a KDX


Bearings were not bad just goobered

Fronts this time, changed my front tire and noticed I could not turn the bearings with my finger. Took em out, removed the seals and cleaned/repacked. Bike just glides now! Even easier pushing it up the ramp to load into ol' yeller

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Post by skipro3 »

CC is my hero! He always has a beer ready when I see him. Do you think he could pick up a bike for me like he picked up a tire for you? I'll even pay for the pizza! If you or he come across any good leads, let me know. That would be the perfect excuse to drive up and visit y'all!!

Wib's point is well made; there are things that can make a motor feel like it's less than optimal.
Jerry

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