CAN'T BELIEVE IT !!! I THINK IT HAS BROKEN AGAIN !!



5 replies to this topic
  • sm

Posted January 21, 2001 - 02:10 PM

#1

Hi Guys !

Remember me ? and my 426 Broken Gear Box ?

Well, this weekend I had a race and it was extremly muddy.

There were parts of the track where 2 smokes were using their clutch to pass through but our thumpers were doing just fine...

The mud was too deep and the bikes were pulling very, very hard.

That's when I heard some crack sound on my 426 engine. I thought: **** , That's a broken gear tooth...

I managed to finish the race and when I got back home, removed the oil and the oil filter.

The engine oil seemed to be clean (green like). The oil filter had some metal ... (sorry I don't know the word) "pieces".

I heard it is normal to have those metal ... in the oil filter but that sound...

I'm attempted to open the engine and make sure that there is not any gear tooth broken.

I wish I could do it without opening the engine.

Now, the bike's warranty is gone.

I have experience dealing with 4 strokes engines but I would prefer not to touch my 426's.

I also wish the crank case was transparent...

Well, sorry to give you bad news but I think she's done it again (furtunally this time less intensively - it didn't block the rear wheel and it didn't make so much noise - just the crack sound...)

  • Numpsy

Posted January 21, 2001 - 09:33 PM

#2

Did You use all five gears after that noise?
Any strange feeling?
If You remove the chain and rotate the drive sprocket, does it get "stuck" somewhere?
Since it was really muddy the crack noise could come from the chain.....
Some metal flakes will allways be in Your oil filter.
Maby You should test all Your gears in idle speed with the bike on a workstand!?
Please keep me posted of Your progress

  • Boit

Posted January 21, 2001 - 11:09 PM

#3

If running the engine to check for the problem is not desirable, you could remove the spark plug, or zip-ty the compression release lever in, and with the bike on a stand, spin the rear wheel forward as you move the shifter through the gears. This way, you can spin the engine slowly and try to feel anything unusual with your hand on the wheel as you check each gear. Maybe if you have a broken gear tooth, you will be able to feel it as a notchy feel. It's worth a try. Releasing the compression will allow you to spin the engine with little effort.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • MrMXer

Posted January 22, 2001 - 01:15 AM

#4

Ditto on what Boit said... I've heard some strange noises on muddy days that I have deemed nothing more than a small rock lodged between the chain and sprocket making the sound you described. Still a good idea to try what Boit said though.

  • sm

Posted January 22, 2001 - 12:04 PM

#5

The chain guide (drive sprocket) was a little bit bent.

Maybe the theory of some rocks in the chain is true (I hope).

I'll only be able to try what Boit said next weekend.

Then, I'll post a reply on this thread of what I have found.

Thanks you all, guys, I feel more confortable now.

(S.M.)

Portugal - Europe
s_m_c_m@hotmail.com

  • sm

Posted January 22, 2001 - 12:08 PM

#6

Originally posted by Numpsy:
Did You use all five gears after that noise?
Any strange feeling?
If You remove the chain and rotate the drive sprocket, does it get "stuck" somewhere?
Since it was really muddy the crack noise could come from the chain.....
Some metal flakes will allways be in Your oil filter.
Maby You should test all Your gears in idle speed with the bike on a workstand!?
Please keep me posted of Your progress


Yes! I did use all the gears till the end of the race.

I did not find anything strange nor did I found any weird noise...

I don't know if it is possible to ear something wrong with the gearbox when the engine is running...

Anyway, I'll check that next weekend.





Related Content

Forums
Photo

Megabomb Fitment by 288yz450


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
Forums
Photo

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F


Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies
Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
Forums
Photo

YZ450F 03 Sparks driving me crazy by SirAttard


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.