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General Category >> Technical Documents/Reference >> Clutch Cover "form-a-gasket" technique
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Message started by Oldfeller on 11/02/09 at 07:16:36

Title: Clutch Cover "form-a-gasket" technique
Post by Oldfeller on 11/02/09 at 07:16:36

A compression gasket requires an even application of a known torque value range to work correctly. Over torque crushes and ruins the gasket and warps the cover. Undertorque is just less clamping force but it does not damage the gasket nor warp the cover.

Long time ago I bought me a little quarter inch drive "inch pound" torque wrench for compression gasket use.

Default values for me if there are no known torque values for the involved gasket screws/bolts is 80-100 inch pounds with stress being put on a multi-level cross pattern pull up and consistency on final torque. This I got from oil pans on car engines -- the touchiest compression gaskets in the world for leaking over time.

I think our side cover gaskets DO have a spec at 6.5 - 9.5 foot pounds (given for 6mm crankcase fasteners) which translates to 78 to 114 inch pounds. Them, I'd shoot for 100 inch pounds on the nose with a good 3 level repeat cross pattern with first level at 50, second at 80 and last round at 100 inch pounds. This ought to do her jest fine.

Gasket torque wrenches cost $30 to $50 most places as they are somewhat "specialty tools" and are not big volume items by anybody's guesstimation. Shame that, every bike mechanic really needs one.

========== Ta Da !!! ========== Jedi science comes up with an answer !!

Now, for the budget minded amongst us Harbor Freight has the no-brainer 6 newton/meter (or 72 inch pound) install a gasket tool for your Savage engine for a whopping $3.97 price tag. Can't get more reasonable than this.

Yoda approved as it hits right close at the bottom end of the Suzuki/Clymer recommended gasket installation torque values.

(less a half a newton/meter off and the other torque wrenches don't even graduate that fine)

That's six inch pounds shy to you English speakers.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=66269

http://www.harborfreight.com/cpi/photos/66200-66299/66269.gif

Title: Re: Clutch Sidecover gasket (make your own)
Post by Oldfeller on 12/29/10 at 16:54:03

I mentioned earlier that the black gasket stuff keeps getting better and better.

It is now good enough not to require a paper gasket of any kind. Just coat both surfaces then assemble the cover and finger tighten the screws very lightly until the squeezing oozing action just barely starts. Stop there on purpose and wait 24 hours .....

You are permitting a good boundary layer to form and to remain in place between the two housings to become "the gasket".

Then after you wait 24 hours then you apply the required torque and wait an hour or two then retorque only once.

;)

Well, hells bells boys -- it is even cheaper and easier than a paper gasket and the stuff is good enough now for it to work reliably by itself.

Title: Re: Clutch Sidecover gasket (make your own)
Post by youzguyz on 01/03/11 at 07:28:09

OF. What kind of "black gasket stuff" are you speaking of?
Permatex Ultra Black?

http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_makers/auto_Permatex_Ultra_Black_Maximum_Oil_Resistance_RTV_Silicone_Gasket_Maker.htm

Something else?

Title: Re: Clutch Sidecover gasket (make your own)
Post by Oldfeller on 01/03/11 at 07:36:53

http://www.permatex.com/images/DisplayImage.asp?210|/images/ProductPhotos/82180.jpg

Yup, that's the black stuff -- they make the same stuff in a silver stuff too for those with older unpainted motors.

The stuff is now "safe for sensors" too, which is another improvement.

Title: Re: Clutch Sidecover gasket (make your own)
Post by Gyrobob on 05/07/11 at 10:19:18

motobuddha said "I know people who coat at least one side of their gaskets with ChapStick so it will release cleanly when they need to remove the cover. They swear they've had no problems, but I don't do it myself. "

I've used a trick sorta like this for decades to replace gaskets with RTV.

-- Clean both surfaces well.

-- Coat one surface with a very thin layer of grease.

-- I learned the hard way about using a a silicone-based grease -- don't do it. I use wheel bearing grease or some such.

-- Put a thin layer of RTV on one surface, coating only the outer 2/3 of the surface (you don't want a gob of sealant squeezed inside the joint).

-- Let it skin over -- takes maybe 10-15 minutes.

-- Gently join the surfaces, and tighten the fasteners evenly about 90% of the way.

-- Wait another 30 minutes, then tighten the rest of the way.

I love this technique because it never leaks, and if done correctly, you can pop the joint apart over and over again, and never have to reseal it. Cheap, too. In effect, it creates a permanent RTV gasket glued to one side of the joint.

Title: Re: Clutch Sidecover gasket (make your own)
Post by Gyrobob on 05/07/11 at 10:21:34

Do any of the clutch cover bolts need any washers? (metal or otherwise?)

Title: Re: Clutch Sidecover gasket (make your own)
Post by verslagen1 on 05/07/11 at 11:09:55

6C5259444944492B0 wrote:

Do any of the clutch cover bolts need any washers? (metal or otherwise?)

Yes 3 do, see cam chain adjuster check procedure.

Title: Re: Clutch Sidecover gasket (make your own)
Post by Oldfeller on 05/07/11 at 14:34:45

Specifically, these 3 need a rubber backed washer.

http://www.hunt101.com/data/500/medium/3screws.JPG

Title: Re: Clutch Sidecover gasket (make your own)
Post by Gyrobob on 05/07/11 at 19:45:18

Excellent. Now, I am wondering why these three need a rubber-backed washer.

Title: Re: Clutch Sidecover gasket (make your own)
Post by verslagen1 on 05/07/11 at 20:29:15

oil passage running behind them.

Title: Re: Clutch Sidecover gasket (make your own)
Post by Oldfeller on 05/09/11 at 04:34:29

Speaking of oil passages, there is the biggie, the 50-60 psi at full rpm main oil channel that rides along the top edge of the cover that has to be clamped and sealed against full rpm oil pressure.

Be sure not to block off any of the two outlets with excess RTV ooze ....

...... and I'd forgo any chapstick tricks in this area (you need an absolute maximum adhesion seal on both sides of that 1/8" wide top rib)