07 YZ450 Engine Noise?



69 replies to this topic
  • CPD305

Posted August 02, 2015 - 09:27 AM

#61

Hey guys! After a LOOONNNGGGG absence from the dirt world I've purchased an 06 yz450.  I was really worried about the chatter(been riding Harley EVOs for years, USED to that noise) I'm glad to know my new toy is "healthy".  Thanks for the input



  • mixxer

Posted April 23, 2016 - 02:33 PM

#62

I have owned quite a few 450s... Honda, Yamaha, Suzuki quads... KTM and Honda dirt bikes...
I made a good trade on a gently used 04 yz450... The noise it makes is when in neutral with the clutch engaged... Pull the clutch Iin to disengage... No noise...

The noise is like marbles whirling around in a tin can...

So I have never heard a bike or quad that makes that noise unless something is wrong with bearings...

Next up I buy new tranny bearings and main bearings because I figure what the hell, as long as im in there...might as well...

Engine comes apart and everything looks great...piston..cams...clutch basket...timing chain... All showing little wear ...looks like maybe 30 hours on all original..

Bearings out and they are all in great shape...smooth..no noise..

Is it really that the Yamaha tranny just sounds like that when all is good?? I pulled it all down for nothing???

  • knuckleduster271

Posted April 23, 2016 - 03:04 PM

#63

I have owned quite a few 450s... Honda, Yamaha, Suzuki quads... KTM and Honda dirt bikes...
I made a good trade on a gently used 04 yz450... The noise it makes is when in neutral with the clutch engaged... Pull the clutch Iin to disengage... No noise...
The noise is like marbles whirling around in a tin can...
So I have never heard a bike or quad that makes that noise unless something is wrong with bearings...
Next up I buy new tranny bearings and main bearings because I figure what the hell, as long as im in there...might as well...
Engine comes apart and everything looks great...piston..cams...clutch basket...timing chain... All showing little wear ...looks like maybe 30 hours on all original..
Bearings out and they are all in great shape...smooth..no noise..
Is it really that the Yamaha tranny just sounds like that when all is good?? I pulled it all down for nothing???


Both my 5 valve yamahas made the clutch noise as well as other "noises" before and after rebuilds.
Its just the nature of them..
Makes them somewhat hard to diagnose when you actually do have a bad bearing- trying to listen to one of these through a stethoscope is almost pointless.

  • grayracer513

Posted April 23, 2016 - 03:26 PM

#64

.

Is it really that the Yamaha tranny just sounds like that when all is good?? I pulled it all down for nothing???

 

Yup.  It was fun, though, in its own way, wasn't it?



  • mixxer

Posted April 23, 2016 - 03:55 PM

#65

Thanks gentlemen! I wonder why the quad models don't make that sound!?

And lol... no Mr Grayracer... No fun at all... I'm sort of grizzled and a bit of a princess now at 55.... I love modding the bikes, always have, but the repair stuff isn't so fun anymore...

I have 2 teenage boys now... Never interested in riding with dad until I got a KTM 450 as a bike I could loan if a buddy was down when a ride was planned...

Something in the orange worked like a fishing lure to the boys , who thus far had put no effort in Learning off road skills... I told them they could try it, but it was too violent for their skill sets..

Pure addiction on ride number one...

And now I have spent 2 years of shopping used bikes, putting cranks in 2 strokes... Putting exc six speeds in sx engines...all while they suddenly want to know all they missed so far and figure out what they really liked....

I'm so sick of wrenching !!! I was ready to throw the 450 in the pond this afternoon...

There... Tantrum thrown... Gonna get a moosehead and chill....

Thanks for the answers again... At least I won't search for the marbles in the tranny anymore...
Thanks gentlemen! I wonder why the quad models don't make that sound!?

And lol... no Mr Grayracer... No fun at all... I'm sort of grizzled and a bit of a princess now at 55.... I love modding the bikes, always have, but the repair stuff isn't so fun anymore...

I have 2 teenage boys now... Never interested in riding with dad until I got a KTM 450 as a bike I could loan if a buddy was down when a ride was planned...

Something in the orange worked like a fishing lure to the boys , who thus far had put no effort in Learning off road skills... I told them they could try it, but it was too violent for their skill sets..

Pure addiction on ride number one...

And now I have spent 2 years of shopping used bikes, putting cranks in 2 strokes... Putting exc six speeds in sx engines...all while they suddenly want to know all they missed so far and figure out what they really liked....

I'm so sick of wrenching !!! I was ready to throw the 450 in the pond this afternoon...

There... Tantrum thrown... Gonna get a moosehead and chill....

Thanks for the answers again... At least I won't search for the marbles in the tranny anymore...

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  • mixxer

Posted April 23, 2016 - 04:12 PM

#66

I should have just called and asked you, James....

  • mixxer

Posted April 24, 2016 - 05:28 AM

#67

I have always been a fan of heavier flywheels on torque laden big modded thumpers.... Love the change to controllability of the powerband...

And it moderates the "snap & slack" of the valvetrain and timing chain from a thumpers inherent non steady gait , especially at lower speeds..

It seems as though this yz already has a Yamaha weighted flywheel already on it... Cone shaped weight welded at 3 points... So it's not a TT single piece flynweight... Or a steahly bolt on weight...

Anybody know what amount is added on what must be a 04 gytr fly??

All the added weight is periferal, so whatever is there will do the most good...

Might have to buy an OEM fly so I can fit whatever is the biggest bolt on weight I can find...I know I like the powerbands and I am going to mod it a bit for more midrange..

Want to see if a bigger fly will moderate the marbles whiling in a tin can... Of as some else said ...nails spinning in a bucket...neutral with clutch engaged..

Curiosity running amok....lol

  • grayracer513

Posted April 24, 2016 - 06:05 AM

#68

The welded weight is likely either a DRD or a GYT-R (which may both be from the same source).  It physically adds 9 ounces, and nearly doubles the inertia mass of the flywheel.

 

IF you can find one, Steahly used to offer a 12 ounce, but that won't cure the gear rattle in neutral.



  • mixxer

Posted April 24, 2016 - 06:56 AM

#69

Thank you again Mr Grayracer...

You are like a walking encyclopedia..

If the weight is 9oz and all periferal .... It will have as much or more rotational inertia than me bothering with a bolt on 12oz with some of its weight closer to the center of rotation ... Plus this one isn't going to come loose with those welds... Lol

So since it was making plenty of noise with this weighted fly already.. I'm sure you are right that I'm not going to cure the snap and slack of a thumper with a few ounces more...

If the yfz quad 450s I had had made a noise like this, I would not have been pulling this one apart...

I'm shaking my head at the waste of time while I'm putting it back together today... 4 speed gears are pretty beefy... Also, zero wear on gear engagement dogs... I have never pulled one this far apart for nothing before...

My main reason for looking for my first 5 valve dirt bike 450 is that I have been doing porting and valve work on the quad models for 12 years now... And without question that 5 valve Yamaha valvetrain is by far the best I have ever seen in an off road performance thumper...

Small light valves , quality hard coated titanium valves with back cut /flow producing profiles, perfectly matched light springs, awesomely engineered cam profiles...

A work of art ... And the most immortal of them all... Rarely needs shimming adjustment and outlives everything else on the market...

A cam and valvetrain setup right from the factory that needs nothing for either performance or longevity modifications.... A blessing in the expensive 4 stroke performance world...
 



  • grayracer513

Posted April 24, 2016 - 04:30 PM

#70

 

If the weight is 9oz and all periferal .... It will have as much or more rotational inertia than me bothering with a bolt on 12oz with some of its weight closer to the center of rotation .

 

I don't know if anyone ever produced numbers for the Steahly 12, at least not in directly comparable terms.  Just guessing, I'd say it would be like the difference between your 9 ounce and a 10 ounce.  That's guessing that the DRD used up all the available space around the perimeter, and the additional mass in in the circle inside that.  That may not be the case, though.  If they managed to make the outer ring portion larger than the DRD, then the increased effect would be more. 

 

Worth it? I'm the wrong one to ask.  I'd love to have the extra inertia, but I'd rather it was welded.







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