Knock on Acceleration

[Willie66]

Recently replaced the primary chain on my 03 Ultra and decided to change out the compensator sprocket spring stack while at it and new bolt also. Trouble though at around 60mph, a lot of vibration from bottom of engine and when opening the throttle hard to accelerate I get a knocking like the big end bearing is going.

Have just dismantled again and compared to the old parts. Compensating nut is shorter than original and seems to be a tighter fit. Tried both on the shaft and the old one threads in further by about two threads.

My question, if anyone can help is: Is the new bolt not compressing the spring stack enough because it's a tighter fit and is this causing the problem? Should I go back to the original bolt & stack OR put a spacer (24033-70) which is recommended by HD (which I had ordered so have handy) on the new bolt and hope for the best?

Any advice would be appreciated.

Great site!

Willie

 

[Hoople]

because it's a tighter fit and is this causing the problem?

Going by what a 2002 touring manual shows me, absolutely yes.
It sounds like the sprocket cover is not seated and compressing against the crank. I would closely inspect the new bolt and determine why it does not want to thread all the way into the crank. (non-oem bolt,,old loctite in crank etc)

I thought the spacers were used for chain alignment? I would not use it to try and fix this problem.

 

[HDDon]

Willie I think I would go with the spacer and new bolt, see if that takes care of the knock.

 

[HDDon]

Going by what a 2002 touring manual shows me, absolutely yes.
It sounds like the sprocket cover is not seated and compressing against the crank. I would closely inspect the new bolt and determine why it does not want to thread all the way into the crank. (non-oem bolt,,old loctite in crank etc)

I thought the spacers were used for chain alignment? I would not use it to try and fix this problem.

Hoople I did not mean to contradict your post (posted at same time). I thought the spacer he was refering to went on before the bolt did not think he was refering to the spacer behind the sprocket.

 

[Hoople]

Hoople I did not mean to contradict your post (posted at same time). I thought the spacer he was refering to went on before the bolt did not think he was refering to the spacer behind the sprocket.

Never a problem Don. I am just wondering why the bolt won't thread in on it's own. The manual I am using is not for the exact year so you may be perfectly correct.

 

[Willie66]

Hi HDDon & Hoople, thanks for replies. This is a high output stator type so no spacers between the crank and conpensator assembly. Spacer I was referring to is according to Service bulletin TT122, HD recommend a 0.090" shim under the compensating nut.

Guys, there is a big difference in the fit of the two nuts on the shaft. The old one is very loose until the last few threads but the new one is tighter on the shaft and stops about 0.1" before the original. All OEM relacement parts.

The bike is uncomfortable to drive over 60mph. It used to be very smooth. It has already snapped one of the fairing mounting brackets so you might guess what I mean by vibration. lol

 

[Hoople]

The bike is uncomfortable to drive over 60mph. It used to be very smooth.

If the source of the vibration issue was in the engine or primary, I would think the vibration would repeat and be felt in every gear rather than a certain MPH.

Lets say at 60 mph when the vibration was maximum, your RPM was 2800. Then at 2800 in 1st, 2800 in 2nd, 2800 in 3rd, etc... the vibration would also be felt to some degree. Is this the case?

 

[Willie66]

Yes Hoople, you are correct but as I accelerate through the gears in that rpm range I get knocking rather than the constant vibration I get at cruise. I can feel it if I put my left foot against the gear shift. I assumed it was the compensator as it's the most recent mod. I hope I am right...hate to think it's the crank???????/

Just put new nut back with 0.09" shim, lots of oil on both nut and shim. Torqued nut to 75ft/lbs plus 45 degrees. Also checked sprocket alignment...difference of 0.0155" which is within the 0.03 spec.

Will ride tomorrow and see what happens!!!

 

[Willie66]

Still not happy after riding it today. Although the vibration has reduced it is still noticeable. Maybe I'm immagining it as worse than it was or maybe because I'm holding my foot against the gear shifter to assess it I'm feeling it more pronounced? The knocking has gone away on heavy acceleration though so al least it is better all round.

While examining the primary cover last night I noticed a few notches in the casting where it looks like the nut touched. Leads me to believe it had not compressed the spring pack even though it was torqed down to the right settings. Be interested to know if anyone has has similar problems after replacing this nut.

I think the new nut is a tighter fit than the original and therefore is skewing the torque readings. I might go back in and refit the old nut and see what happens.

 

[Willie66]

Just an update here on this issue.

Vibration getting worse over the last week or so and that was after taking off new compensator nut & spring set and replacing with old with no immediate difference.

I had previously checked torque on engine mounts especially the front with no problem detected. Today I decided to focus away from the compensator and again towards the engine mounts.

Took off the front rubber mount bolt and was surprised to see that the engine mount plate that is bolted to the rubber frame mount had a bolt hole that was oval? Don't remember it looking like that in the parts manual so I had another look in the parts manual and then in the workshop manual and they both show it as round. I wonder could this be the cause, surely so (I hoped).

Would this increase the vibration as the bolt hole was elongating. The hole is now about 50% longer than it is wide? Has anyone had this problem and what causes it?

Bigger question: Is this the problem or the result of a more serious problem with the engine?

Would appreciate any opinions!!!!