TOPIC:

I looked on website but couldn't find it.

Was wondering what the piston to cylinder clearance is for a 1980 A4 KZ 1000 - 1075 Wiseco piston.

Looks like factory piston clearance is 0.039 mm to 0.070 mm

Thanks.

Wiseco quote a 0.0020" (0.051mm) std clearance on all their piston kits and you will be ok with that.
You can go from 0.0015" to 0.003" depending application.
Lower end for street . Higher end for racing and turbo.

The Wiseco pistons are FORGED so run tighter clearances than the OEM CAST pistons as they don't expand as much.

zed1015 wrote: Wiseco quote a 0.0020" (0.051mm) std clearance on all their piston kits and you will be ok with that.
You can go from 0.0015" to 0.003" depending application.
Lower end for street . Higher end for racing and turbo.

The Wiseco pistons are FORGED so run tighter clearances than the OEM CAST pistons as they don't expand as much.

Surprised by this comment. Forged pistons typically expand more than cast, but I'm not sure about the specific pistons being discussed here.

Nessism wrote:

zed1015 wrote: Wiseco quote a 0.0020" (0.051mm) std clearance on all their piston kits and you will be ok with that.
You can go from 0.0015" to 0.003" depending application.
Lower end for street . Higher end for racing and turbo.

The Wiseco pistons are FORGED so run tighter clearances than the OEM CAST pistons as they don't expand as much.

Surprised by this comment. Forged pistons typically expand more than cast, but I'm not sure about the specific pistons being discussed here.

From what I've read, Wiseco is a bit vague on this point. Notice in the Wiseco link below, in the "Piston Engineering / ArmorGlide™ Coating" section, they state "Some forging alloys expand more than casting alloys, but each Wiseco piston is designed with the proper installed clearance to produce the most power, least wear, and best seal at running temperature, for each application." They aren't specific as to whether or not their pistons do this. Maybe it depends on the specific Wiseco piston selected? Ed

www.wiseco.com/Powersports/Pistons.aspx

ya, I couldn't find anything Ed?

Nessism wrote:

zed1015 wrote: Wiseco quote a 0.0020" (0.051mm) std clearance on all their piston kits and you will be ok with that.
You can go from 0.0015" to 0.003" depending application.
Lower end for street . Higher end for racing and turbo.

The Wiseco pistons are FORGED so run tighter clearances than the OEM CAST pistons as they don't expand as much.

Surprised by this comment. Forged pistons typically expand more than cast, but I'm not sure about the specific pistons being discussed here.

Yes! Generally that is correct but it all depends on piston design and silicon content etc.
Wiseco used to state that their pistons ran smaller clearances due to their silicone /alloy mix and typically there kits ran tighter than the OEM cast items they replaced.
Whether that is due to the factorys clearances being on the safe side for mass production I don't know.
I notice that the info on Wiseco's site has changed with no mention of this.

I guess the Kaws have a taper bore that gets wider as the piston descends. The piston at top dead center is tight with no discernible gap in the bore, as I rotate the piston down the bore I can see the piston gap increase.

4TheKZ1000 wrote: I guess the Kaws have a taper bore that gets wider as the piston descends. The piston at top dead center is tight with no discernible gap in the bore, as I rotate the piston down the bore I can see the piston gap increase.

?

Dr. Gamma wrote:

4TheKZ1000 wrote: I guess the Kaws have a taper bore that gets wider as the piston descends. The piston at top dead center is tight with no discernible gap in the bore, as I rotate the piston down the bore I can see the piston gap increase.

?

I guess that a no

I am no big time motor builder but I have bored a few cylinders in my day. I only used a Kwik Way boring bar, and Sunnen hones on the cylinders I did over the years. I always tried to keep no more 1 or 2 tenths of taper from top to bottom in my finished cylinders..

Something just don't sound right to me. Thats all!!!

Dr. Gamma wrote: I am no big time motor builder but I have bored a few cylinders in my day. I only used a Kwik Way boring bar, and Sunnen hones on the cylinders I did over the years. I always tried to keep no more 1 or 2 tenths of taper in my cylinders from top to bottom.

Something just don't sound right to me. Thats all!!!

Yep, I agree.

Bore should be parallel all the way down.
Any tapered wear should be invisible to the naked eye.