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Serious Engine Problem

Started by Kee, October 16, 2003, 08:34:14 AM

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Kee

Well my bike crapped out on me last week on the way to work. Something in the engine, according to the shop, and they want $800 just to take it apart and put it back together again, and thats without knowing what exactly to fix. There is no way in hell I am paying that, and even though I know nothing about motorcycle engines, I figure now might be a could time to learn. I figure the worst thing that can happen is that I won't be able to fix it and I could sell off the good parts.

Now for my question: The engine will start up, but when you get it to 4-5000 rpm, there is a loud clicking noise in the engine and really shtty performance. It will change gears, but that doesn't solve anything. Does this sound familiar to anybody?
If I am going to tear it down myself, it would be nice to have a starting point. Thanks.


Does anybody have any idea what I could sell a 96 gs parts bike for?
I love YOU goes to college.

Moose

I know this is probly a question that will come up is it in the top of the engine or the lower part of the engine that you hear the noise from?
Of All The Things I`ve Lost I Miss My Mind The Most

Kee

The mechanic at the bike shop says it is coming from the lower end. To me it sounds like the top, but I have to defer to the experts, hoping they aren't trying to rip me off.
I love YOU goes to college.

JasonB

crank/rod bearings for bottom

Timing chain tension, valve clearences top end.
"Hairy Gutter" The Spot Behind Pantablo's Knee.
"Dirty Gutter" The Space Between Pantablo's Ears.

The Buddha

5K clacking... I'd bet Cam chain tensioner. But more info will help. On leading throttle if its silent, but comes on trailing throttle... Bottom end... get a new motor... 2-400 bux and put it in.
If its making compression (atleast 100 psi - thumb test) then its not upper end.
Have you tried riding it... loss of power and poor running (well it be hard to strat as well) will mean timing is off possibly as a result of the cam chain tensioner.
In short its easy to fix even it you have to get a whole new motor.
BTW did you run it low on oil or hydrolock it or somehting else stupid.
Cool.
Srinath.
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Kee

I have tried riding it and it has hardly any power. It will start but it was harder than usuall. Took a couple of trys.

Where can I get a new motor?
I love YOU goes to college.

The Buddha

Its top end... Valves probably. You know if its runnig on 1 cyl or both. Try the flash light test for valve actuation, and try the thumb test for compression, and look at the timing of the valves opening etc. I believe bottom end almost can be ruled out, as can any serious valve - piston contact. Cam chain is making noise and the cams have gone off 1 tooth is all I am left with. Or a big exhaust leak... But over 5K only... I guess its possible.
Cool.
Srinath.
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I run a business based on other people's junk.
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Kee

You will have to forigve me for knowing next to nothing about bikes, but I am not familiar with the tests. Are they in the repair manual?

I am guessing that having a problem in the top end is better than the lower end. Is that right?

Thanks for all the help so far.
I love YOU goes to college.

The Buddha

Top end is better than bottom end but yours is not a problem at all IMHO.
Thumb test for compression...
Take out both spark plugs, pull the clutch in and zip tie it to the handle bar. Hole throttle WFO and crank motor with starter while holding your thumb pressed hard against spark plug hole. It it blows your thumb off and escapes around the sides... you have 100psi + You are ok. repeat for other cyl.
Take off tank, seat, side covers (optional), airbox, carbs, valve cover, round engine side cover, spark plugs and exhaust. bring right cyl to top of compression stroke (manual). Shine light in intake port and look in spark plug hole, repeat for exhaust port. Then bring left cyl to TDC top of compression stroke. Shine light in both ports and look in plug hole. In both cases the plug holes should be dark.
Then bring right cyl to middle of intake stroke and repeat flash light but this time you should see light, then repeat exhaust and other cyl. Trust me this is easier than any other method for checking for bent valves etc. Also when the right cyl is at TDC top of compression stroke look for cams being in the right position. Get a small powerful flash light. Really helps.
Cool.
Srinath.
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I run a business based on other people's junk.
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Kee

Picked up the bike at the shop today and the mechanic said he was sure it was the bottom end - used some type of stethascope to determine where the noise is. What do you suggest now?
Is it difficult to find a new engine?
If I wanted to cut my loses how much do you think I could sell it for as a parts bike: 96, no add ons, pretty good shape, except for the engine (obviously).
I love YOU goes to college.

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