GTR engine problems

[Sno Jet]

Hi everyone, I thought I would share my recent motorcycle hardships with all of you.  Don't want you to feel it only happens to you.

I have a GTR, 6K miles.  A bike in overall good shape but not run frequently during its lifetime.

I was hoping I could get it running and enjoy it a bit this summer.  Well when I got it running this weekend, I noticed that that it started to make more and more noise, from crankcase area. 

Upon hard acceleration, I  heard a metallic sound in the right muffler.  Sort of sounded like  small piece's of metal coming through the exhaust.

I shut it down in fear of causing damage.  I ran a compression check and found that compression was unchanged at 125 in each cylinder.

I assume that the bearings are what is making the noise.  I also noticed that there is a small leak from the crank halves.  Doesn't look like I will riding any where soon.  The good news is it was starting on the first kick!

I am a little disappointed but accept that there are going to be problems when running a 40 yr old bike.  Appreciate any advice or comments from someone who has been here!  Thanks!  Harry

[BS Mechanic]

Wise to shut down till the noise source is found.  I've seen minor problems completely destroy an engine by continuing to run it.

A few things to look for that can make noise that may be fixed without splitting the cases:
Exhaust gasket to header pipe leak
Head gasket leak
Pre-ignition, can be caused by a variety of issues
Loose primary drive gear on the end of the crank
Loose connection between crank and rotary disk

Hope it isn't too serious!

[Toystoretom]

I would try and chase down the noise. The problem might be in the right muffler itself. Pull the muffler off and shake it and see if something internal rattles. Pull the baffle and check that. It's not too hard to do that.

If that checks OK try pulling the spark plugs out and kick the bike over and see if the noise is still there. Maybe put the bike up on the center stand and have someone spin the rear wheel while the bike is in gear to turn the engine over. Is there a noise? Feel any roughness?

You could go beyond that and pull the heads and cylinders and check the piston wrist pin bearings and the rod bearings. It really isn't all that hard.

Could the noise be coming from the clutch or tranny?

Maybe before you tear anything apart start the bike and see if you can duplicate the noise with the bike running on the center stand. Use a mechanics stethoscope to try and locate the general area of the noise.

These are just some thoughts. My GTR makes a bunch of goofy noises and most of them come from the dry clutch. I think most of that is normal.

Also check you ignition timing and make sure it is not too far advanced. You can get some nasty spark knock if things fire too early.

You could sell it to me... I need more GTRs!!!   

Tomo

[reed]

Harry
I would start by removing the top end and check pistons, rings, small end bearings and the con rods etc.
That where i would start if you need any help give me a e mail or a call.
Thanks.
Steve.

[Sno Jet]

Thanks everyone for your input.  Gives me some things to think about.  This Forum makes it a little easier when things like this occur.  I was a bit rattled the other day.  Asked myself a few times why I did not buy a new bike!  I don't regret anything yet though.  Someone has to bring these bikes to life!!

The noise is also happening when sitting at idle, so I assume that rules out tranny and clutch noise??

Also have that small leak coming from between the cases.  I am being extra cautious here.  Don't want to cause more problems.  Piece of mind is my goal.

I will let you all know how it ends up working out as I(we) go along.  Harry

[OldSwartout]

When mine had a loose nut on the end of the crank, it made some nasty clattering noises at idle.  However, that went away as soon as the RPM was increased and it was put under load.  However, the nut can back off until it chews into the side case, so that can still be the problem.  I also had a baffle in the muffler come loose years ago; it's been held in place with three sheet metal screws since.  Just saying, there have been some good suggestions so far, methodically go through them.  I'd start with the basics and the easy stuff - check timing, listen with a stethoscope, pull plugs and listen while it's spun over by hand, etc., to try to narrow it down before tearing things apart.