VIbrations at 4k RPM

[Lars]

Hello,

I have just gotten my CR back form the 72000 km service, yes, the big and expensive one. besides the fact that the chain was too tense ( howling, whistling noise, the bike even started to pull right when accelerating plus it was as tight as a solid steel bar when I sat on the bike ) It now has abnormal vibrations starting at 3k being most prominent at 4k.

After a bit of troubleshooting I found out that the vibrations are engine related as they appear even when standing still and in neutral. at 4k the mirros start to shake the vibrations are everywhere, handelbars, footpegs, tank, everywhere... the bike feels like sitting on a compactor.

I have ridden the bike for the last 72k km it never had anyhting like that and was as smooth as can be.

It is going back to the shop as in its current condition it is unrideable.

If anyone has any thoughts about that let me know.

Lars

[Skids]

Does the bike still accelerate as quickly? Is the power noticeably down?

[Lars]

Hello Skids,

the bike runs just as smooth and powerful as ever. VTECH works fine in any gear no power drops nothing

Lars

[Skids]

Definitely return it to the dealer, they should sort it.

[Crosspurpose]

Over-tightening the chain can damage the gearbox output bearing on a bike. This can cause vibration but would probably be present at most driven speeds. Not your problem to resolve though; as already advised, take it back to the dealer.

[Lars]

personal log of mysteries entry 3

A large portion of the vibrations were caused by a faulty front sprocket what in turn was caused by the overly tightened chain. riding about 50 km with a chain that tense is more than enough to cause serious damage just in case anyone wonderes.
more deail about that in my other post: https://www.honda-crossrunner.com/index.php/topic,2530.0.html

There are still vibrations left that are quite annoying. Honestly the bike was super smooth before the service. There - were - NO - vibrations - what - so - ever. what makes even the slightest vibration ever so annoying.

I seem to have found another clue.
The vibrations come and go and a sure way to get rid of about 80% of them is to revv the bike into VTEC above 6.5k rpm and keep it there for about 5 to 10 seconds or more whatever traffic allows.
This instantly stops it from vibrating at the lower revs, there are still some vibrations left but it is almost back to normal.

I have tested that. I drove for about 50 km with vibrations in full swing without going into VTEC range, the moment I revved up they were gone. It is reproduceable.

What I cant seem to get rid off is that when running the bike in higher VTEC revs starting at around 9k rpm there are suddenly extreme vibrations that definitely were never there before.
All the vibrations are what I would call high frequency vibrations, extremely uncomfortable, they make your feet go numb in seconds.

Other than that I  cant find any other faults, the engine does not sound differently, does not accelerate or pull differently no abnormal oil or petrol consuption, no fault lights on, no leaks, no strange smell nothing.

The fact that VTEC  has a noticeable effect on the behaviour makes me think that something went wrong during the valve check.

I guess for me the only way forward is to have the bike torn down to the valves again and done everything by the book.

I am going to have a talk about that with the shop and will see what they come up with.

Lars

[Crosspurpose]

I suppose that if one valve was adjusted incorrectly by some margin vibration would ensue. When the Vtech opens the other eight valves the imbalance is reduced ie one in so creen, not one in eight. Not sure why the vibration goes away after a spell in Vtech though...I think the answer probably lies with the valve adjustment. One wonders how good the dealer is if the drive chain can be so badly adjusted and nobody noticed..How accurately we’re the valves adjusted....