Got some 79mm pistons with a bored cylinder today. Just need some rings, easy to get as Wiseco stocks them. I will need to put a motor together since all the parts are in boxes....go figure. Of course this will happen after I finish my current 92 project.

I still have the 4-valve GR650 project to dig into. Still have not decided what bike to put it into. Kinda want to put on the street. If that is the case then the 541 will need to find another home, maybe another track bike. Gotta have spare. The 555 will be slated for my track bike since it graciously donated the 541 for my 92. This works out well since I had to pull the MC cams from the 541 to be repaired along with removing the ported head. Looks like both of those will back in business with the 79s.

Too many parts and not enough time.

If I gave you a dollar, would you move to Seattle so we can be buddies?

Ooops... made a mistake.

They are not 79's......they 80's!! This would make it a 569. Cool.

Looks like the cylinder has been resleeved since it looks thicker than a stock bored for 79s.

I guess that means no...     dgyver doesn't want to move to Seattle and be my buddy.   

I'm going to spend time with dgyver this weekend..aren't you jealous!!!!!

Quote from: RVertigo on April 24, 2007, 04:35:09 PM
If I gave you a dollar, would you move to Seattle so we can be buddies?

I may be cheap and easy but not that cheap.

Quote from: heatherg11 on April 24, 2007, 05:18:01 PM
I'm going to spend time with dgyver this weekend..aren't you jealous!!!!!

quick, hide the salt

Did you get those out of the race bike that got parted out, as soon as I saw you where interested in them I knew something was up. Then I looked closer at teh pics and realized there not stock


Is there anyplace to buy 2mil or 1mil  oversize pistons anymore. The rules allow my race bike to be 2mil overbored but I cant find any pistons

Quote from: coll0412 on April 24, 2007, 08:31:51 PM
Did you get those out of the race bike that got parted out, as soon as I saw you where interested in them I knew something was up. Then I looked closer at teh pics and realized there not stock


Is there anyplace to buy 2mil or 1mil  oversize pistons anymore. The rules allow my race bike to be 2mil overbored but I cant find any pistons

Yep, from ducatiboy. I did not know the size, just guessing they were 78 or 79 by the smaller cylinder wall. One of the cylinders has a little scoring. Looks like the piston was replaced (which was a little larger) and the sleeve was not bored to fit. I will need to have the sleeve cleaned up a little. Not sure if I will do it or have someone with a little more experience. I will ask an ex-drag racer at work if he can or see if I can get hold of the guy who bored my last 555.

Not sure about the 1-2mm oversize. IIRC...Suzuki stopped selling the 1mm over but still sells the .5 over. The problem is the stock pistons use a ring size that is hard to find, if at all. They are not high compression.

I have not seen 76mm pistons, at least one with a 18mm wrist pin. The GR650 has a 77mm piston and 18mm wrist pin.

Wait a minute...the GPZ has 18 wrist pins, I have some 78mm pistons...so there may some smaller 76mm out there. Look for 83-84 GPZ1100, KZ1100, ZX1100.

Where can I buy oversized pistons?

Quote from: cosmiccharlie on April 25, 2007, 07:44:35 AM
Where can I buy oversized pistons?

What size do you want?

Here is the info on the 78mm pistons:
http://gstwins.com/gsboard/index.php?topic=14401.0

Not real sure.  I planned on replacing my pistons and rings while the motor is apart.  If I could go bigger and extract a few more ponies that I might as well do that.  Do you have any suggestions. 

Suzuki used to make 74.5 and 75mm pistons. Not sure if they are still available. To me not worth the cost. If I was spending the money I would get the 78's, higher compression too.

The other thread has good info!  Thanks!  So with the 78's I will have a streetable motor with few worries, right?

I would think so. I will be finding out once I get my 92 finished.

Awesome!  I think I am going to do this!

Picked up the cylinder Monday from being honed. $45 and well worth it....Ed does awesome work!

Whoever set up these pistons to run in this cylinder did not know what they were doing. They were way too tight for an air cooled motor. The piston to sleeve clearance needs to be .002"-.003". The left only had .001" clearance while the right had .004" interferance. There was some scoring in that sleeve but cleaned up nicely due to the amount of material that had to be removed. I questioned if that piston actual ran in this cylinder, but the cylinder scoring looked similar to the piston scoring...could have been from a different motor though.

Now all I need to do is order some rings and a wrist pin.....then assemble another motor......