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Discussion Starter · #1 · (Edited)
yes, SHUDDER (or vibration), not the "chudder".....god knows I'm not looking to start one of those threads :green_lol: ........this quick shudder only shows itself when accelerating, and it's all the time, and in all gears. The motor smoothly pulls to about 3,700 at that point, the smooth power turns into a a much less smooth power (kinda like something spinning which is out of balance)...but smooths back out by 4,000. The actual power is NOT affected whatsoever....it's just the feel of the power pulses in that zone. No big deal....just wondering if everyone experiences this or what. The day I bought the bike, I think I mentioned this on the board, and we all thought it was "chudder"....but it's not.

* The "shudder" or vibration thing was present B4 I shimmed my clutch basket (5,000 miles ago) and after. Nothing changed, so it's not related to "chudder".
* The TB syncs don't seem to have an affect as it seems to be constant before and after.
* Doesn't seem to be fuel related, as it was there before and after adding a PC, and using various different fuel maps.
* The vibration is ONLY when accelerating. If cruising in that range, nothing unusual is felt.


Any thoughts on a quick vibration in the drivetrain from 3,700-3,900 under load?
 

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missing any bolts?

missing any bolts?

accleration = torque = load on mount
 

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With my 06 Vee, the roughness is completely related to throttle position and RPM. Motor can be smooth as silk at sub 3000 rpm with light throttle or it can be rough at 4000 rpm with too heavy throttle. Rider cannot be ham fisted and expect the big v-twin to always smoothly accelerate. My previous Wee strom was smooth at any throttle position or rpm but of course would not pull nearly as hard. So IMO just carefully keep rpm and throttle coordinated and Vee will run very smoothly.
 

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yes, SHUDDER (or vibration), not the "chudder".....god knows I'm not looking to start one of those threads :green_lol: ........this quick shudder only shows itself when accelerating, and it's all the time, and in all gears. The motor smoothly pulls to about 3,700 at that point, the smooth power turns into a a much less smooth power (kinda like something spinning which is out of balance)...but smooths back out by 4,000. The actual power is NOT affected whatsoever....it's just the feel of the power pulses in that zone. No big deal....just wondering if everyone experiences this or what. The day I bought the bike, I think I mentioned this on the board, and we all thought it was "chudder"....but it's not.

* The "shudder" or vibration thing was present B4 I shimmed my clutch basket (5,000 miles ago) and after. Nothing changed, so it's not related to "chudder".
* The TB syncs don't seem to have an affect as it seems to be constant before and after.
* Doesn't seem to be fuel related, as it was there before and after adding a PC, and using various different fuel maps.
* The vibration is ONLY when accelerating. If cruising in that range, nothing unusual is felt.


Any thoughts on a quick vibration in the drivetrain from 3,700-3,900 under load?
A lot of information in the quote above. Except what happens when you feather the clutch thru this rpm range you are having issues in. Feathering the clutch is the chudder test. It is a test that gives a definate result. Your description above is a classic chudder description. What process did you use to shim the basket? Are the shims on the "gear side" or the "basket side"? If on the basket side they may not help chudder much.
 

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* The vibration is ONLY when accelerating. If cruising in that range, nothing unusual is felt.

Any thoughts on a quick vibration in the drivetrain from 3,700-3,900 under load?
My bike does this also. I have done the FULL boat Realshelby clutch mod and got everything all sync'd up etc. It's not real bad and pretty brief as the engine goes through the rev range so I've just taken it as "normal" for the most part. I don't find it objectionable but I do notice it.

I have come to think it's just part of the engine/frame harmonics as every bike seems to have their own vibration periods, some more some less. I've never ridden a completely vibe free bike yet but I suppose something like a flat 6 Goldwing or the new BMW 1600 inline 6 might be as close as it gets.

I honestly believe the engine mounting preload adjustment has an affect on this and I would like to try adjusting mine to the factory procedure spec. The mounting points on these bikes involve a preload adjustment on the left side of the mounting points. If these are tighter or looser it can affect the vibration transmission and resonance throughout the bike. I think this is why some are smoother than others. I also think chain snatch vibration might play a part in it. I'm planning on going to a 530 chain next time as I think the heavier chain will be smoother.

At least that's my $0.02 on the subject.
 

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Discussion Starter · #6 ·
My bike does this also.

I have come to think it's just part of the engine/frame harmonics as every bike seems to have their own vibration periods, some more some less.


At least that's my $0.02 on the subject.
Interesting. That's what I've always kinda figured (it's normal harmonics).....but the other day, while testing different fuel maps, and thus really paying attention to the engine, I decided that I'd never quite gotten to the bottom of the quick vibration zone. Sounds like you have the exact same thing.

Realshelby- I shimmed mine on the gear side. I wonder how things are looking in there. Think I've got about 5,000 miles on it. What I thought to be extreme "chudder" was actually just extreme lean condition. The PC cured that, even though I shimmed the basket. I'll probably pull it apart soon to check on those welds.
 

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Realshelby- I shimmed mine on the gear side. I wonder how things are looking in there. Think I've got about 5,000 miles on it. What I thought to be extreme "chudder" was actually just extreme lean condition. The PC cured that, even though I shimmed the basket. I'll probably pull it apart soon to check on those welds.
The welds won't be a problem unless they did not have enough penetration. Depending on what kind of washer/shim you used they might show wear. BUT...unless you have a reason to be in there for something else I wouldn't worry about it. There are shim mod baskets out there with over 30,000 miles on them that don't have hardened washers still going strong...
 
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