I re shimmed the exhaust valves on the front cyl. When I measured it was .011 inch (.012 would not go in.) In spec but at the lower limit. I figured since I had it all open I would put it back to spec, so I won't have to open it up for a long time.
the old shims measured 182 and 180. I did the math and my dealer said round down, they will wear in. The Honda dealer only carries sizes by 5 (170, 175, 180, 185, etc.)
I put in 175 in each, going down 1 size. This must be what they would use.
After turning engine a few times by had a measuring I can slide a .014 in wach, not a 0.15. So it is out of spec. too much clearance. The mechanic said it would wear in to be within spec.
Should I leave it? or go back to the orig. I took out? and leave it at 0.11?
Thanks.
Darren

 

this thread might answer a lot of your questions. you're in there now, so might as well get them as close to perfect as possible. I can't remember from your prior posts but I think they are (mileage-wise) past the point of 'wearing' in much in the anytime near future. they make shims in between what your dealer may have on hand (like your 172 for example)

https://www.superhawkforum.com/forum...ad.php?t=16497

 

They have a min and max spec for a reason. In time all things wear.

How many miles do you have on the shawk? I checked my valves at 12K and none needed adjusting.

 

8700 miles. I am using Feeler guages that change at 1/1000th of an inch. Using the go-no-go method. So nothing is exact.

 

Darren,
The valve clearance typically does not change very quickly. I would guess that the exhaust valve clearances were always toward the low end of the clearance range.

Like Bill said, I think there are 172 shims available. The shim thicknesses are listed in the manual. RC51 shims are the same, if that helps. Going from a 1.80 to a 1.75mm shim thickness should be about .002" adjustment. It sounds like you got more than that. Was everything super clean when you reassembled?

 

It was very clean. But I may try moving the old shims around. They did measure different, very slightly, than what was stated. No shops around have the 1.775, I could order through Honda, I did see a part number listed.
I could insert the .011 originally, definitely not the .012. Now .014 goes and .015 does not. It does seem like I got more.
Since the shops dont stock - I am really wondering how they would leave it. It would seem crazy not to adjust at .011. I think. But they get paid to do it and it isn't their bike.
I also tried to reason the percent, if comparing exhaust to intake, would be the same at .002 varience for the exhaust. I know that isn't how it is done, but I think I was trying to make myself feel beter.

 

There are only 3 digits on the Honda shims. You won't find a 1775 but you will find a 178 just as you won't find a 1825 but you will find a 182. As cliby said, you might as well get them as close to perfect as possible. On the other hand, your motor won't become a hand grenade if the clearances are barely in or barely out of spec.

 

Agreed. It sounds like you have taken all the right steps.

You could go either way. You could order the proper shim, if you want or feel the need to. I probably would. It's probably better to be just on the loose side with the exhaust valves, because they get longer as they heat up - more so than the intakes.

 

I think the more perfect the valve train the longer the whole engine will last. The valve train and the mechanisms that operate it are the most over-worked parts of the engine and have the most moving parts. 8700 miles seems low to me to be very deep in there unless there have been other problems with the engine. Don't believe everything you hear at the Honda shop.

 

Agreed, you want to get the clearances within spec now, don't wait for something to happen that will magically get it there. Intake valve clearance generally tighten up over time due to valve seat degradation. Exhaust valves build up carbon on the seat so the clearance will either stay constant or maybe open up a bit. Personally I've never had to replace shims as a service task, the only time I do that is when installing new parts in a used engine.

 

There is a difference between wear-in and wear... Wear-in has already occured in your case... now we are down to normal wear, and unless there is something else wrong with the engine that's a very, very slow process... If I had taken the effort to take it apart I'd spend the extra time and effort to make it within spec, no doubt...

 

I tried moving some shims around last night and remeasuring. Still not as good as I think I can get.
I ordered the shims from Honda. $7 per instead of $2. Not worth doing it incorrectly, not the best I can get, as long as I am in there. It really isn't bad at all re-shimming and measuring - you just have to take your time.
I can post the results after I do it if anyone is interested.
Thanks for all of the info. It sounds like most of the wear has taken place. I did not know it wasn't usually a constant over time. Thank you.
I really only did it at this point because I had the carbs off for another reason, and the 1 intake was slightly out of spec.
Darren

 

Hot cmas has shim sets that are cheap. If you are purchasing 8 honda shims, you can easily pay for the set. My boss is really cool about shims, he will exchange them with customers for nothing. If you bring in your shims, he gives you the ones you need. Same with when we make adjustments, he just charges for the labor if we have the shims. The shims don't wear.

As for the clearances, the min is so the valves are not held open even when its closed, the max is so the lobe is punching the buckets. If you are .001 over the spec for max, its okay. If you are more, you want to find the correct shim. if you are under the min., you definitely want to get the shims changed. Loose is always better than tight.