'08 TE510 MYSTERY: intake valve clearances WAY too large

I just put a new piston in my 2008 Husky TE510, and was checking the valve clearances before closing up the engine. (I bought the bike used, it has 4,000 miles on it, and this is my first valve check.)

Both exhaust are in spec at 0.20mm (range is 0.15 to 0.20).

Both intake are at 0.66mm -- and range is 0.10 to 0.15!

That means that if I put in the thickest shim Husky uses (2.6mm), my clearance is still too large by 0.26mm. That's equivalent to over five shim sizes!

The intake cam is not worn; the bearings are fine; the shims I removed (2.30 and 2.35) are not squished; there is no carbon buildup holding the valves open, as this is the intake side; and it can't be a bent valve stem, since both valves are out of spec almost exactly the same amount.

My only remaining theory is this: could the first owner have installed a different cam than stock, one that uses different clearances? I know Husky sells power-up kits that include cams. And since the bike has the Arrow exhaust, lambda probe removed--and accelerates like crazy--I know the previous owner did something "power-up-ish" to it.

Any ideas? Install the fat shims, ignore the ticking, and assume the clearances will slowly decrease as the valves wear?

Are you sure about your specs? My 08 TE 450 clearance spec is .08 exhaust and .06 intake....

Edited by Jason S

It needs to be fixed !!!

First measure would be the length of the valves. Presumably, they are a bit short?

Didn't i talk to you on the phone? I think you said something about it being a TC head on a TE? Just trying to get all the info out to sort this. Maybe the TC has a different valve / cam / head setup?

Are you sure about your specs? My 08 TE 450 clearance spec is .08 exhaust and .06 intake....

No you mean .008 ex, .006 in. Thousanths. His specs are basically the same.

As for the excessive clearance, if you are sure about that, it can't be explained by a failure/problem as far as I'm concerned. Check the valves, seats, keepers, cams, finger followers and shafts, etc. With no issues found, shim it properly and check them after the first hour of use, then after two more hours. No change?? No problem, ride on!:thumbsup:

Thanks for the replies, guys. One more bit of info I should add is that the bike ran strong right until the piston went--and it seems like the valves were likely set with this wide clearance all the time.

Jason - sorry for the metric: as MotoMarc says, my measurements are equivalent to what you're suggesting. So, yes, the clearance should be .006 inches intake and .008 exhaust.

Ride - we didn't talk on the phone about this, but I suppose it could be a possibility that it's a different head (TC or TXC?). Any idea how I could determine if that has been done?

MotoMarc - I could just shim it and ride...but Husky doesn't have shims as thick as I need (they only go to 2.60; I would need 2.86). Think I could find thicker shims from some other bike that would fit?

No thoughts on whether the Husky power-up kit with a replacement cam might be the cause of the mystery?

Thanks again -- I need the input here: I'm at the end of my wit. And yes: I only have one wit.

Maybe the valve seats were replaced and not cut deep enough?

Ride - we didn't talk on the phone about this, but I suppose it could be a possibility that it's a different head (TC or TXC?). Any idea how I could determine if that has been done?

MotoMarc - I could just shim it and ride...but Husky doesn't have shims as thick as I need (they only go to 2.60; I would need 2.86). Think I could find thicker shims from some other bike that would fit?

No thoughts on whether the Husky power-up kit with a replacement cam might be the cause of the mystery?

Thanks again -- I need the input here: I'm at the end of my wit. And yes: I only have one wit.

According to the parts catalog all TE,TC,TXC and SMR 450 and 510 in 2008 have the same part number for the head assy. 8000 B0407.

For your shim just go to any Yamaha or Honda dealer CRF450 have the same diameter of shim.

Yep Honda shims (or other japoem) or Hotcams shims can be had up into the 3.45 range. I would have no second thoughts of running the 2.85 shims if nothing seems wrong during component inspection.

As for the cause, who knows? The shallow valveseat seems the most plausible, but could be any of a number of causes. Inspect the valveseat contact patch. Could be very telling. Cam could cause it if the base circle circuference is smaller than stock. Replacment cams are hard to come by for Huskies, I wouldn't think it to be the cause. Nothing "power-up" related should affect that.

Oops, sorry about the conversion thing.

It really couldent be the cam changeout because either cams would be machined the exact same other than the lobe. The lobe is what differs in different cams and your checking spec on the non lobe part.

Trying to summon up some of my old auto knowledge, a few things that could affect valve clearance more or less are possibly bad/ worn valve seat, streached valve stem, weak valve spring and flattened cam- that's when a bad cam looses metal thickness but its usually associated with the lobe. Check cam bearings too. If it's in their looser than supposed to be, could contribute to larger clearance.

If your heads still off, pour gasoline down the intake tract to see if it leaks out between the valve and seat. If it does that may point to a issue in the seat area.

Thanks for all the diagnosis, guys. We haven't solved the mystery, but at least I'm confident now that I haven't missed or done something stupid to explain these clearance measurements. My local parts guy/previous TXC owner concurs with your thoughts, too, and added, "You can get some quirky stuff with those Huskies."

I picked up a pair of 2.85 shims. I'll put them in, run it a bit, and re-check the clearances.

I'll let you know what happens.

Thanks again!

Maybe the valve seats were replaced and not cut deep enough?

My thoughts also.

Valves don't shrink, they stretch so if you have too big a clearance something has been wrong ever since the last head work was done. Try reseating the valves with a quick seat grind & as mentioned, check for correct valve length & correct fitment of all valve components. I now it means pulling the head back off but it could save you heaps in $$ & headaches. If you haven't yet started the engine since fitting the head you should be able to reuse the head gasket providing you don't damage it when pulling the head off.

Don't just leave it & put up with it coz you will do damage, most likely at high rpm &/or when the motor is under strain.

Not as drastic as your machine but my 08 TXC 250 shim sizes went from 2.30 to 2.45(320 hrs) on a specific valve and stopped moving after that ..

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