Deck height

[gearhead13]

I am installing a wiseco piston kit in my '82 750.
I have the cylinder block on and I noticed that the pistons were a fair amount above the deck. Measured with my calipers to be 26 thou above the deck. And with a 45 thou head gasket gives me 20 thou at best before gasket compression.
I compared the stock and wiseco pistons and they didnt seem to have much more height. More than I thought it seems.
Anyone know the compressed thickness of a stock suzuki base gasket? Can I run two or three of them to give me more clearance?
Wiseco sells an optional base gasket, maybe it is thicker?
What can i do?

 

[rapidray]

Order a .030 base gasket or a .010 & a .020 & stack them. PM me if you need to get the gaskets as I can get them for you. Ray.

 

[gearhead13]

So a 30 thou base gasket would be enough Ray? That would give me 30 thou uncompressed clearance.
I measured the stock gasket and it was 20 thou uncompressed, so if I add two more i guess?
I'm kinda bummed because i was hoping to get the bike running again this weekend after three months

 

[Frankenzuki]

hmmm

hmmm

So it's .026 out of the hole with a stock base gasket in place? That seems a bit much unless the cylinder block has been cut down a good bit. Ray s right, you can get a thicker base gasket, I'm just surprised that you actually need one. If I remember correctly the Wiseco kit for the 750 4valve motor is a flat top piston. I would double check the compression heights of the stock and wiseco pistons, something doesn't seem right there.

 

[gearhead13]

Ya I was surprised too. It hasn't been decked. The new pistons were a bit higher than the old ones, but i really didn't measure. I threw another .020 base gasket on it and the pistons are about even with the top of the block.

 

[Guest]

You don't have to stack the gaskets. You can get any thickness multy steel head gaskets from Cometic. .020, .030, .040, and so on.

 

[rapidray]

Rob, he's talking BASE gaskets. Only available in .005, .010,.020,.030, etc... They CAN be custom ordered in different thicknesses but not worth the extra cost over just stacking to get the correct height needed with off the shelf parts. If you order a head gasket, do NOT go thinner than .043! Ray.

 

[rosco15]

I would just call Cometic and ask. It's the only gaskets I'll run after blowing out a stock base gasket. I'm using their aluminum core robber coated gasket now.

 

[Frankenzuki]

Cometic

Cometic

Yes Cometic makes a sandwich style base gasket for the 2-valve motors I run. I'm sure they could do the same for the 750 4-valve

 

[rapidray]

Cometic & STOCK Suzuki are the ONLY gaskets I buy or use. Ray.

 

[mike-s]

I managed to mangle the base gasket on my 250 when i used the loctite #4 sealant and needed to take the top end apart a second time after fully assembling the engine. I went out and bought a roll of 2.5mm gasket paper and custom cut my own gasket. Once the topend was fully assembled the gasket ended up compressing to 1-1.25mm (1/64 - 3/128") or so.

Other gaskets that were available were 1mm & 4mm (1 & 3 64th " or so) thick, so i imagine you could quite easily use a thicker base gasket plus a custom head gasket to bump the compression down a bit. Also remember there's a compromise that is made with altering the timing when you raise or lower the head level so don't get too carrier away with lowering the compression.

 

[gearhead13]

The pistons were about level with the block with two .020 stock Suzuki base gaskets.
I noticed that Wiseco offered an optional base gasket so I emailed them about the thickness and they referred me to Cometic. So I assume most, some or all Wiseco gaskets are made be Cometic.

 

[rapidray]

Yes, Wiseco's gaskets are made by Cometic. Ray.