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Would you reshim this?

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I checked my valve clearances again last night as I've recently had one of the intake seats and valve lapped, the bike is a 2012. The clearances are as follows (in):

 

Intake:

 

Left - 0.007

Right - 0.004 (this is the one that had the work done)

 

Tolerances as per the manual - 0.006 - 0.001

 

Exhaust

 

Left - 0.012

Right - 0.012

 

Tolerances as per the manual - 0.011 - 0.001

 

So the left intake and both exhaust are 0.001 out of tolerance on the loose side. The bike runs fine as they are currently. My question is - would you pull the shims out and sort it now? Or alternatively continue running it as it is, regularly checking it, until they move any further then do it? Are they likely to continue getting looser or will they tighten up back in to spec over time? 

 

Matt

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They've got a micro coating on the ti valves that lapping ruins. You should only lap ss aftermarket valves. Let me guess. A buddy did it or a local auto shop did it?

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The lash is fine except for the 0.004"

they tighten up over time.  so its better to leave them at the max tolerance vs minimum, it buys more time.

 

and lapping is a no no with ti valves,

its actually pretty wack with any valve imo.

permanently embeds abrasive into your seat....

Edited by EnglertRacing

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The lash is fine except for the 0.004"

they tighten up over time.  so its better to leave them at the max tolerance vs minimum, it buys more time.

 

and lapping is a no no with ti valves,

its actually pretty wack with any valve imo.

permanently embeds abrasive into your seat....

 

Why do you say except the 0.004? This is the only one actually within tolerance technically. 

 

I'll have a word with the guy who did the lapping for me. The reason it was recut was due to a tiny chip in the seat causing it to not fire. 

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Okay so had a chat to him, the valves weren't lapped, the seat was just re-cut. I don't know where I got the lapping from, I thought that's what he said... 

Edited by MJRacing92

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Might wanna take a closer look at your manual dude. It's not giving you a range of .006 to .001. Which is extremely tight btw. That's like the thinnest feeler gauge you got in your set.

It's telling you .006 plus or minus .001. Which means .005 to .007 is fine

.004 is too tight and is the only one that's NOT in tolerance technically. Not a huge deal right now. But in a few rides it'll tighten even more and be tough to start. Then you can shim it. And it'll be tight again in two rides. The. You'll try to shim again and find you don't have shims thin enough. Good thing winter is coming up because you're probably gonna need a little head work done if he lapped it. This time get it done by a professional crf head specialist. Even if that means shipping it away. Don't let your local garage mechanic, or automobile shop touch that head anymore. Send it to fastheads .com for a rebuild once it starts giving you more problems.

Edited by coryf89
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That's good that he didn't lap them. If it still starts fine let er be. When it starts acting up the check again and re shim if necessary.

Or if you're real bored and wanna fiddle with it. You can throw in one size smaller of a shim in it now. Not a huge deal. You're barely out of spec on one valve. Ride it a few more times and re check it

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Right I get it, I have misread the manual, thanks for pointing that out. 

 

I'm concerned that it has gone from 0.006 to 0.004 after the work he has done. It wasn't just any shop, he's got a very good reputation and a 4 hour round drop from me.   

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How many rides? Things could have settled. Or been a small error when checking the first time. Re shim it now and keep a close eye on it. If it stays. You're good. If jt moves again soon. You need head work done, again. Welcome to the crf world.

Not sure about doing just one valve and getting just one seat cut. If it was my bike id do them as a set. Not positive if that matters or not though.

Edited by coryf89

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I've done 5.5 hours since it was cut, it clearance was 0.006 before in went in, now 0.004 after those 5 hours riding. It was a tight 0.004 too. 

 

Not sure what's best to do, I've got a 3 hour enduro race on the 15th but limited time to work on it between now and then. I guess the safest bet is to shim it back to within tolerance then keep an eye on it? 

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I ran the tolerances closer as recommended in the FAQ pinned at the top of this forum.  The theory being that the cam lobe will lets the valve go into the seat more gently since it doesn't have as far to travel.  My valves had not moved in 200 hrs when I replaced them, the springs, cotters, seals, and recut the seats.

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I ran the tolerances closer as recommended in the FAQ pinned at the top of this forum. The theory being that the cam lobe will lets the valve go into the seat more gently since it doesn't have as far to travel. My valves had not moved in 200 hrs when I replaced them, the springs, cotters, seals, and recut the seats.

Yep, close is good on Intakes for sure!

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I ran the tolerances closer as recommended in the FAQ pinned at the top of this forum.  The theory being that the cam lobe will lets the valve go into the seat more gently since it doesn't have as far to travel.  My valves had not moved in 200 hrs when I replaced them, the springs, cotters, seals, and recut the seats.

what year is yours?

are you running the intakes at .004?

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Yes .004 on the intakes.008 on the exhausts.  My CRF is an 08. Shawn gets credit for this one.  His FAQ have a lot of great info. I am very anal with filter maintenance.  After cleaning in mineral spirits and soaking in Dawn dishwashing detergent. Backflushing with water, let dry. They are submerged in filter oil. Squeeze out excess, paper towel the rest. Let dispersant evaporate then install.  I run the Loudmouth intake for ease of installation with no posibility of incorrect seating.  I change the filter when its dirty/allmost clogged.  Properly oiled filter will not pass dirt just choke out engine. Probably more info than you asked for. :thumbsup: 
 

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