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Hey Guys,

I recently bought a 2003 DRZ400S and thought it would be a good idea to check the valves clearance etc . I timed the engine on TDC with the magneto mark aligned as per the manual but I find the cam timing slightly odd. The arrows pointing upward are on the 1st and 15th pin as they should but with the magneto timing mark aligned they are not perfectly straight. Same goes for the arrows that should be parallel to the cylinder head casing. Is this normal or should they be absolutely perfect ?

 

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Hi,

 

What you describe is indicative of a slight stretch in the CAM chain.  This is usually caused by the auto cam chain tensioner.  I would guess that the bike has a few miles on it?. I'm not sure how much performance  is affected but know it to be a common DRZ thing.

Eric has a nice writeup on why - and what to do about it here:

I changed my auto tensioner for manual one early on in the bikes life.  I hope this helps

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Thanks for that. The bike only shows 12K Miles on it but it looks as if it's done a lot more. I forgot to mention that it already has the MCCT installed but I noticed it was adjusted way too tight. Probably that in itself has worn the chain ???

As far as performance is concerned the bike starts/idles/runs fine but severely lacks top end power. It has a Pro Circuit T4 but no idea of the jetting just yet. I thought to check timing and valves first and then continue with the carb. It seems it was a good idea after all. Any other thoughts and/or suggestions before I start shopping around for a new chain would be great .

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2 hours ago, antonyp said:

Thanks for that. The bike only shows 12K Miles on it but it looks as if it's done a lot more. I forgot to mention that it already has the MCCT installed but I noticed it was adjusted way too tight. Probably that in itself has worn the chain ???

As far as performance is concerned the bike starts/idles/runs fine but severely lacks top end power. It has a Pro Circuit T4 but no idea of the jetting just yet. I thought to check timing and valves first and then continue with the carb. It seems it was a good idea after all. Any other thoughts and/or suggestions before I start shopping around for a new chain would be great emoji16.png.

The ACCS (Automatic Cam Chain Stretcher) AKA ACCT is known to cause early wear, add in a mis adjusted MCCT and yes, really early wear causing timing marks to not line up is a given. 

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9 hours ago, ohiodrz400sm said:

Is that corrosion on the flywheel and cam chain?

Tippex Marks on the Flywheel - Probably from the PO. Haven't checked the cam chain that closely but I don't think it's corrosion. I hope not anyway 😬

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9 hours ago, Erik Marquez said:

The ACCS (Automatic Cam Chain Stretcher) AKA ACCT is known to cause early wear, add in a mis adjusted MCCT and yes, really early wear causing timing marks to not line up is a given. 

How about impact on performance or fuel consumption ?

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On 10/10/2018 at 2:45 AM, antonyp said:

How about impact on performance or fuel consumption ?

Single cylinder 90-94mm bore motor, everything makes a difference but on their own each "thing" makes only a little difference positive or negative.

On a fully built motor, cams are timed to the desired setting spot on, 1, 2, 3, 4, 10 degs off would never be acceptable.
So would a new chain, MCCT, slotted cam gears, and cams degreed to spec better your performance and fuel mileage?  yes, no doubt in my mind...Would it be perceptible or worth the cost? Likely not on a build you are not trying to get the last 1 HP out of.
When you have reason to be in the motor, sure, replace the chain and set up properly a MCCT.
 

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I've not done it on a drz/ltz motor but there are several others that you can adjust one cam or the other 1 tooth advanced or retarded(depends which motor and how you want to move the power curve) and it would change the motors power characteristics quite a bit ,so ya, being just 1 or 2 degrees off effects power  . I've altered my cams 1/2º to play with it some and it was noticeable .

 

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Edited by jjktmrider

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Yamaha purposely retarded the cam timing on the original WR's to detune them. I wouldn't try the same with the DRZ. The only cam that you might get away with is the stock E intake as it reported is set a 117 LCA while most aftermarket are between 108-106. If one were to try it they would need to verify that there is sufficient piston to valve clearance. Just winging it is a good way to destroy the engine.

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That's why I had only gone 1/2 degree on this one , I knew there was clearance for that much but not sure how much more, didn't clay this one . My Wossener piston doesn't have deep enough valve pockets to start with as do several other brands in this motor ,  but many other models the cam(s) can be +/- 1 tooth with no issues, even 2 teeth some times (it'll run like shit though) . It's never done willy-nilly always verified before firing it up and reving it .

 

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Edited by jjktmrider
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That's why I had only gone 1/2 degree on this one , I knew there was clearance for that much but not sure how much more, didn't clay this one . My Wossener piston doesn't have deep enough valve pockets to start with as do several other brands in this motor ,  but many other models the cam(s) can be +/- 1 tooth with no issues, even 2 teeth some times (it'll run like shit though) . It's never done willy-nilly always verified before firing it up and reving it .

 

.

I know you're not winging it. I just wanted to add a bit to what you said. Who knows who is reading all of this.

 

 

I opened a package the other day and it had 4 warning symbols on the air filled packing balloons. 1st don't use as a life preserver. Ok, I get that. 2nd Not a child's toys. Sounds reasonable. 3rd not a babies pillow. Hmm, do people really need to be told this? 4th not a parachute. Wtf!!?? Who is the champion that parachuted with a 6" airbag that warranted this warning?

 

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I opened a package the other day and it had 4 warning symbols on the air filled packing balloons. 1st don't use as a life preserver. Ok, I get that. 2nd Not a child's toys. Sounds reasonable. 3rd not a babies pillow. Hmm, do people really need to be told this? 4th not a parachute. Wtf!!?? Who is the champion that parachuted with a 6" airbag that warranted this warning?
 


OMG - That's hilarious ! Can anyone really be that stupid ???

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