I wanted to get enough of these under my belt to make a determination that there is a real problem.

Out of 40 DBW S2000, 22 of them have had tight exhaust valves. A few had developed misfires from burnt valves, and the head had to come off for new valves.

I have found them as tight as .003-.008. For comparison, I have found tight valves on only 3 out 1000 or so cars, 2000-2005. Even those were no tighter than .009.

It appears the DBW cars run leaner, causing exhaust valve wear. This wear accelerates as the clearance lessens, and the valves begin to torch themselves.

I recommend getting the valves adjusted at 15k miles, no earlier. After that, I recommend 50k intervals. So if you are at 15k or better, now is the time.

I also recommend the exhaust valves be set to .012. You wont lose any power, create any noise, and you will add a large amount of reliability and longevity.

 

Did the valves have cracks in them ?, I've seen pics of cracked valves affecting DBW S2k's.

I always thought Honda's recommended valve clearance maintenance intervals were too long, it's always good to do the service earlier rather than later to keep clearances from getting too tight. Thanks for posting this info up Billman250.

 

For those interested in why the valves burn from tighter clearances if you don't know, less time sitting in seat = less time to transfer heat to the cylinder head = valve gets too hot and "burns"

 

 

Last time I did my valve adjustment I noticed that some of the exhaust valves were tighter then specified and backed them off into spec on my '06. Threads like these make me want to go do another valve adjustment just to make sure. Thanks for the heads up on this kind of stuff Billman

 

Yes .012 is for dbw cars only. .010-.011 is safe for 00-05.

 

Guess its time for another project on my 06. thanks for the heads up! As soon as I get time to do this/ ill report my findings also.

 

Great info! I adjusted the valves on my old 09 (27k miles), exhaust valves were tight. Did a friends 07, exhaust valves were tight also.

 

I guess your situation changes if you have a custom tune, right?

 

Wow, thanks Billman. I was already planning to do this, but now I will make it a priority to get it done ASAP. Already bought the tool from Amazon, and from the write-ups its very similar task to adjustment on my old Honda Interceptor bikes.

Car now has 85K miles and I have no idea if or when the PO ever had this done. So now a little worried what I'll find. At least I'm not getting any detectable misfires.

We should all update this thread with the initial numbers we find to give Billman more data points. Maybe year, mileage, miles since last adjustment if known. Billman, any other data you'd want or suggestions for how to consistently measure initial clearance so we are giving you comparable numbers?