Author Topic: Engine Vibrations (Read 5207 times)

catastrophe · **on:** November 16, 2010, 02:03:22 am

Hello Hello,

My 09' Avl engine vibrates heavlly between 3000 - 3500 rpms. My bike has 5536 miles on it.
Question: Is this normal?... Anyone know.

REpozer · **Reply #1 on:** November 16, 2010, 02:21:28 am

That's tuff to tell, I think what your asking is when does" normal vibration" turn into "unusual vibration". That's the key.....would you consider this to be unusual?

You could take a spanner and turn a few fasteners, also take a cloth and WD-40 and start wiping parts down,, you might discover a lose or missing piece. Could also look and listen at idle for "unusual "things.

catastrophe · **Reply #2 on:** November 16, 2010, 03:02:52 am

I think the vibrations are abnormal. The bike is kept clean. I've run the bike on the kickstand to pin point the vibration and it is the engine. I can look over the the bolts on the frame again but it doesn't explain the rpm specific vibrations that I feel.

REpozer · **Reply #3 on:** November 16, 2010, 03:07:53 am

At 3500 rpm, does it make unusual vibes in all gears?

Cruising at 3500 rpm (5Th gear) pull the clutch, does it stay or go away?

UncleErnie · **Reply #4 on:** November 16, 2010, 04:36:24 am

Yeah- what speed is that?

Did you check what's called the "head stay"? That's a tube that's been crimped on both ends and one end bolts to the top of the jug (somewhere) and the other end bolts to the frame. It should be to the immediate top left of the carburetor. This bit is famous for working loose at the frame bolt.
There shouod be a picture somewhere- it's come up before. Mine is a sort of odd coulour- gold-ish, maybe 3 or 4 inches long.

Believe it or not, your engine is still breaking in. It facinates me how these lumps keep smoothing out.

PhilJ · **Reply #5 on:** November 17, 2010, 05:47:52 pm

Quote from: UncleErnie on November 16, 2010, 04:36:24 am

Yeah- what speed is that?......

On my AVL it's 58 mph with an calibrated speedo, gps verified. Top gear is right at 16 mph per 1K rpm.

catastrophe · **Reply #6 on:** November 18, 2010, 02:29:22 am

Yes to it happens in every gear it starts at 3000 rpms.

The vibrations disapear when the clutch is engaged.

The headstay I will check tomarrow.

UncleErnie · **Reply #7 on:** November 21, 2010, 02:43:47 am

Well?
How long does it take to check the tightness of one nut?

Ice · **Reply #8 on:** November 21, 2010, 04:06:16 am

When my Bullet vibrates like that it is indicating a nearly empty fuel tank,, no kidding.
Took me a while to figure that one out.
No two Bullets are exactly alike. YAMMV yadda yadda yadda

Gordon · **Reply #9 on:** November 21, 2010, 06:51:47 am

-Try a higher grade of petrol. I've found a major difference in using differenct fuels with additives. The one I'm currently using is actually giving me a better pickup and mileage, even a smoother ride with less vibration.
-check the intake manifold for cracks or tears
-clean spark plug and carb
-check electricals for any shorting

UncleErnie · **Reply #10 on:** November 21, 2010, 12:19:11 pm

What's this amazing gas?!

Gordon · **Reply #11 on:** November 21, 2010, 03:56:28 pm

Petrol is available with different octane levels. Unleaded fuel is the most basic fuel. In higher octanes, fuel additives are added that help in cleaning and lubrication of the intake valves, jets and injectors. It also depends on the company, because I tried two different brands and the current one (Bharat Petroleum Speed) is giving me good results.

UncleErnie · **Reply #12 on:** November 21, 2010, 08:17:47 pm

Uh...
Oh. You're not in the 'States. I didn't realize.

here, I use 89 octane and use Marvel Mystery Oil in the tank. Keeps things clean and provides a little top-end lube.

Ice · **Reply #13 on:** November 21, 2010, 08:44:24 pm

U.S. Spec fuels are a gamble as to burning qualities.

Computer managed engines continuously adjust hundreds of times per second in order to run acceptably on crap gas.

Its difficult for the manufacturers to keep the octane levels up with the even less desirable dilutants, fillers and extenders.

I have found my low compression carburetted engines do start easier and tick over/run smother on the higher octane stuff.

They go no faster and jump no higher, just run better is all.
The higher compression engines are a bit more responsive.

bratchat · **Reply #14 on:** January 12, 2011, 03:51:38 pm

Hi,
i am having the same problem here...!!
tried everything in vain from fastening the nuts to checking the clutch case...!!
did anyone here find a way out??

1Blackwolf1 · **Reply #15 on:** January 12, 2011, 05:26:51 pm

Did you open the primary? Loose primary chain will cause LOTS of bad vibes. While your in the primary check your alternator and stator mount bolts as well as the clutch basket components. Sounds like a likely culprit to me if it happens at approximately the same engine rpm and goes away when the clutch is engaged.

Ice · **Reply #16 on:** January 12, 2011, 05:48:30 pm

Also dont forget to check the final drive chain tension.

bratchat · **Reply #17 on:** January 12, 2011, 06:58:19 pm

@ 1blackwolf1 i checked the startor even temporarily disabled the starter by replacing the starter gear.and there seems to be no problem with the clutch basket...as soon as i re assebled the old starter gear there is a bit of rubbing and a sound like tak tak coming from the primary case.mine has run about 15000 miles i get the vibration very heavily...like my watch starts vibrating around my wrist..!!

@ ICE the final chain is according to the prescribed tension.

Please help me out guys..!!

1Blackwolf1 · **Reply #18 on:** January 13, 2011, 12:04:09 am

  Sounds like something in the clutch to me then. The split type basket and the retainer ring aren't awe inspiring. I had quite a bit of squawking after a sprag clutch was replaced..I disassembled the whole works and cleaned up the disks and friction plates. And also installed three heavy and three normal springs. I get the noise once in a great while now. Like when I need to change the primary fluid. You may also have a loose bolt behind the primary drive pulleys (alternator/clutch) and that could cause the noise/vibes you are feeling.

  Let me know if this helps.

  Will.

Gordon · **Reply #19 on:** August 20, 2011, 02:21:38 pm

I've noticed that when the revs build-up I can hear sharp vibrations from the rear suspension springs. Did anyone else notice this?

I shall take a video if possible to demonstrate.

Arizoni · **Reply #20 on:** December 02, 2011, 02:53:17 am

BOY! I WAS JUST THINKING ABOUT MY WEDDING DRESS THE OTHER DAY!---------NOT!

The stupidity of these SPAM'ers that sneek in here amazes me.
One would think that they would at least look around to see who they are SPAMMING to before they post their crap.

Mr. Moderator: Feel free to delete this comment when you blow that thing away.

kodai · **Reply #21 on:** December 02, 2011, 04:40:38 am