[JRWalker]

dealer said it sounded like a main bearing..... Now, any one else have this issue, and what does it sound like

i never had this problem with my bike but i had a car do something like that once and it was piston slap. IOW's worn out cylinders. once engine warms up, pistons expand due to heat and noise goes away. before tear down, do a compression check. if compression checks out ok then, probably not worn out. g-luck

 

[Scott E. Bonds]

Sounds like piston slap or rod knocking. Once oil pressure comes up, rod will quiet down some. A mechanics stethescope will tell you whether its top end or bottom end, need to listen right at start up.

My experience is rod knock will quit sooner than piston slap upon start up as oil pressure comes up quicker than piston heat. As you have guessed lugging an engine is bad for lower rod bearings as the rod force is very high and the oil pressure is low and oil film layer is thin.

 

[Gary]

Thanks for the reply's, I have a stethascope somewhere, will dig it out and give a listen and see if I can pinpoint where its coming from. I've parked it for now..... the tears are falling......

Gary

 

[ockerstrom]

Thanks for the reply's, I have a stethascope somewhere, will dig it out and give a listen and see if I can pinpoint where its coming from. I've parked it for now..... the tears are falling......

Gary

Long screwdriver.

Place screwdriver tip at different points on the engine, place ear against handle butt and listen to the noises.

This is a highly effective way to pinpoint and identify internal engine noises.

Over the years I have identified bearing noises, tappets, lifters, water pumps, distributor shaft wear, bearings and numerous other faults inside engines [mainly cars but on bikes too].

 

[realshelby]

I will be surprised if it is a main or rod bearing. If it is that loud on start-up then once the oil warms up there WILL be some noise then also.

Double check the cam chain assembly.

 

[Gary]

I will be surprised if it is a main or rod bearing. If it is that loud on start-up then once the oil warms up there WILL be some noise then also.

Double check the cam chain assembly.

Will do, thanks.

 

[Starfleet]

If your bike is making lots of noise on startup, as Shelby says, check for problems with the cam chain tensioners. They make a heck of a noise at start up if one is failing.

The other thing to consider is a duff oil pressure relief valve (oil pressure regulator). This may not be working for a variety of reasons (usually dirt or muck sticking it up) and it allows the oil in the engine galleries to drain away completely so you start up pretty dry of lube. It may also prevent the engine from reaching normal oil pressure so maybe a check of the oil pressure is a good idea. I doubt your engine has come to any harm though. Not yet seen a Vee with rod or bearing problems.

 

[SittingDuck]

Just out of curiosity (and this might be related to your problem), what kind of oil are you using?

In my experience, shot bearings knock all the time, not only after you start the engine.

Piston slap, in my experience, has also been constant, though it is more audible under load.

 

[Gary]

Morning!! Long weekend, I go off the grid when I'm not at work... anyway, problem solved, or at least found, not even in the engine. Once seat was removed, plastic under tank pcs, and bike on center stand in my shop, sound was not even coming from engine..... now I had upteem people, and some claim to be mechanics, listen to my bike, and they all went, ooooooooh, that's gonna be bad..... but the sound was coming from an exhaust leak... rear cylinder exhaust header, where it fits into the exhaust system, could even stick my face down next to the battery and smell and feel exhaust coming up, actually, just tightened it up, and the sound is gone...... never at any time did this sound like normal exhaust leak. Anyway, appreciate all the input, rode in to work this morning, and the bike rode exceptionally well!!! Thanks again!

Gary

 

[Starfleet]

Gary that's brilliant news. Enjoy the bike!:thumbup: