RockyMtnMark

Valves: To Adjust or Just Ride?

31 posts in this topic

Good Morning,

  Last night I measured my valve clearances for the very first time (I know...) on my DRZ400S.  It's a 2002 and I've owned is since 2011.  I bought it with t's got about 15,000 miles on it and most of it's miles these days are on dirt.

Intake specs are 0.10-0.20 mm.  Exhaust specs are 0.20-0.30

My intake valve clearances are in spec, forgot to write them down.  My exhaust valve clearances are between 0.1778 and 0.2032 which is slightly out of spec.  They are no more than 25 microns out of spec.  My question is, do I really need to shim these?  Will this kind of out-of-spec cause performance, mechanical, or other losses?  As far as I can tell, I'd have to buy a whole shim kit which is like $80.  Thanks!

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Bring your shims to a mechanic or dealer, often times they are willing to exchange them with you for free. 

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21 minutes ago, LuckyLucky said:

Bring your shims to a mechanic or dealer, often times they are willing to exchange them with you for free. 

Interesting.  Thanks for the tip, I'll call around this afternoon!

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So then is it safe to say that everyone thinks I should re-shim rather than just let it be since the numbers are right on the fine line of in/out spec?  Anyone think I'd notice poor performance or do harm to engine components running them at the edge of in/out spec?

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I'd re-shim as well. You did measure with the cam lobe facing away from the bucket and did not 'force' the feeler in, right? It is odd the exhaust were tight. Usually, it is the intakes, hence my skepticism.

Leaving them be can cause poor hot starting, decreased performance. You do not have to do it today but certainly in the next month or so. Then after 1,000 miles, I'd recheck to see if they closed up more. If so, it is time for a valve job.

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5 minutes ago, William1 said:

I'd re-shim as well. You did measure with the cam lobe facing away from the bucket and did not 'force' the feeler in, right? It is odd the exhaust were tight. Usually, it is the intakes, hence my skepticism.

Leaving them be can cause poor hot starting, decreased performance. You do not have to do it today but certainly in the next month or so. Then after 1,000 miles, I'd recheck to see if they closed up more. If so, it is time for a valve job.

Thanks.  I guess I came here to find the peer pressure to do the job properly. Too bad I didn't record the actual measurements and just ranges... :banghead:

I did measure at TDC on the compression stroke if that's what you mean.  I believe the lobes were facing toward the exhaust rather than toward the center, for exhaust at least.  Can't remember where the lobes were on the intake but I think they were facing away from the carb.

I'll repost after I get to doing the work on this.  I appreciate the help everyone!

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Well only one of your EX valves is too tight, the other is still technically in spec, but getting tight, so I would adjust both. I like to set them right in the middle, at .25mm clearance. 

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Adjust them before riding.

The Min spec is there to ensure when the engine is at operating temp, the valve will still close and seat completely. 

If you have an EX valve at 0.1778 you are .0222 mm to tight, yes re shim or risk valve and head damage as well as hard starting hot.
Additionally, if the clearances are moving tight, chances are they will continue to decrease as they wear more after you adjust at an accelerated rate. As you have no base measurements, cant really say if they are moving lately or always been this tight

 

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I'm With Erik, you've taken the time to pull the lid off and have a measure.  Now note the clearances and find what you need to change.  I'd try the local bike shop or Suzi dealer for exchange or some right size specific shims.  I asked the dealer shop that my bike came from I did the cams last weekend what the availability of the shims is. The answer was overnight and any of the standard sizes for not much money.  I was fortunate that mine came back within spec so no intervention was needed.  

I would also check again at the next service (even if you have shimmed them to spec this time) to see if you have any movement suggesting a freshen up of the head is required.  It is better not to bury your head in the sand over this as the catastrophic result is way harder and more costly to fix than a timely freshen up 

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Rocky, to deal with valve clearances tightening, you don't need to buy shims, just get a piece of plate glass and some 320 grit wetordry and lap yours down. Having a micrometer helps, or you can just trial and error it.

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If you do this make sure that the refaced side is facing upwards towards the bucket. Otherwise the valve may wear at the unhardend surface.

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Thanks QB and Broady for the ingenious idea of lapping these down.  I've got a micrometer so it should be easy enough.  Bike's already back together but I'm going to plan to do this soon and then check at my next oil change to see how things are moving (or not).  Big ups to everyone for the help here :ride:

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16 hours ago, Broadie said:

If you do this make sure that the refaced side is facing upwards towards the bucket. Otherwise the valve may wear at the unhardend surface.

The amount of work and or chances people take to get it wrong,  just to earn the chance at doing again a second time always surprises me.

Why is it, no one has the time or money to do it right the first time, but finds enough of both to do the job a second time. 

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Why is this even a question?  If it’s not in spec, fix it!

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The amount of work and or chances people take to get it wrong,  just to earn the chance at doing again a second time always surprises me.

 

Why is it, no one has the time or money to do it right the first time, but finds enough of both to do the job a second time. 

Completely agree. Wouldn't do it myself, maybe on a Ducati (no valve spring resistance) if I could be sure of consistent thickness.

For me a shim kit is a no brainer. I payed £50 for it and shims are changed in 30 minutes. No leaving the bike in bits for a week.

When I finish with the shim kit it will probably still be worth £50

 

I'd keep an eye out for a 9.48 shim kit :-)

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57 minutes ago, Broadie said:

Completely agree. Wouldn't do it myself, maybe on a Ducati (no valve spring resistance) if I could be sure of consistent thickness.

For me a shim kit is a no brainer. I payed £50 for it and shims are changed in 30 minutes. No leaving the bike in bits for a week.

When I finish with the shim kit it will probably still be worth £50

 

I'd keep an eye out for a 9.48 shim kit :-)

I was a little too harsh ...Its not that it could not be done and work....but removing the hardening which is only microns deep is not a great idea, no mater if you put that surface towards the valve tip of the follower cap.

Expecting the hand sanding of a shim to be even, and keep both sides flat and parallel is simply unrealistic.  Close enough for the intended use? Probably with only additional wear to the valve tip of follower cap the only likely downside...  
And then there is the time involved.....

All that said, yup Ive done it...Friday night when I only had 1 of size X.XX and needed 2....with a ride departure time of just a few hours away... darn right I've sanded a shim to make the ride...then replaced it with a proper one when parts came in next week.
Other than that..go see your local shops and ask to swap shims, so will, some wont. I might if it did not deplete my sets to zero of the requested size.

Or order them on line, and wed or so of the following week install them. 
 

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21 hours ago, Erik Marquez said:

I was a little too harsh ...Its not that it could not be done and work....but removing the hardening which is only microns deep is not a great idea, no mater if you put that surface towards the valve tip of the follower cap.

Expecting the hand sanding of a shim to be even, and keep both sides flat and parallel is simply unrealistic.  Close enough for the intended use? Probably with only additional wear to the valve tip of follower cap the only likely downside...  
And then there is the time involved.....

 

Exactly! Glass is not flat, and you will get the edges rounded first no matter how good at lapping you are. On a granite plate with good lapping skills, you will at least get the edges rounded evenly.

Motors cost thousands, shim kits cost under $100. I'd rather have a shim kit I've never used (and I do) that grenade an engine.

FWIW, running at the bottom of the spec is not only better for performance, it's easier on the valve train. :thumbsup:

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I'd re-shim as well. You did measure with the cam lobe facing away from the bucket and did not 'force' the feeler in, right? It is odd the exhaust were tight. Usually, it is the intakes, hence my skepticism.
Leaving them be can cause poor hot starting, decreased performance. You do not have to do it today but certainly in the next month or so. Then after 1,000 miles, I'd recheck to see if they closed up more. If so, it is time for a valve job.
My exhausts are tight too, both right at .02 but i left them and kept riding because thats still in spec and I'm scared to reshim them myself.
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2 hours ago, HeavyRotation said:
On 3/15/2018 at 0:18 PM, William1 said:
I'd re-shim as well. You did measure with the cam lobe facing away from the bucket and did not 'force' the feeler in, right? It is odd the exhaust were tight. Usually, it is the intakes, hence my skepticism.
Leaving them be can cause poor hot starting, decreased performance. You do not have to do it today but certainly in the next month or so. Then after 1,000 miles, I'd recheck to see if they closed up more. If so, it is time for a valve job.

Read more  

My exhausts are tight too, both right at .02 but i left them and kept riding because thats still in spec and I'm scared to reshim them myself.

Just for clarity sake...If they are at .020mm they are a LOT too tight...
If that was a typo (likely) and they are 0.20mm clearance your IN spec, nothing to change...and in  a perfect world where you check and adjust valves every ride, you would WANT them set to 0.10mm intake & 0.20 Ex to get best performance from the valve train 

Read though the FAQ page on checking and adjusting valve clearance 

 ....It really is doable by most with some help along the way    

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