In a Jam with Wiseco Rings

[angus chapman]

hey all

i hope the wealth of knowledge out there can help me with this one.

the head has had to come off my '78 gs750e to fix an oil leak. once we openned her up, we found that the top ring on every piston was broken. the bike has a Wiseco 850 kit in it, but we have since discovered that they (wiseco) no longer make this kit, and thus the rings are no longer available. a new big bore kit is about AU$800 which is financially not an option for me.

can anyone suggest a course of action? what if i just put it all back together with new gaskets like planned? the bike was running before. i'd really appreciate the benefit of your collective experience.

cheers
gus

[madjack57754]

What is the bore in mm? May be able to find a ring set in another line or OEM of that size

[Tarbash 27]

How about gs850 rings. The gs750 big bore is 844cc, A gs850 is 844cc. So it might work.

[bwringer]

Sounds like you wouldn't want to put Wiseco rings back in there anyway. Unless they broke due to bad assembly technique, or the previous owner didn't check the end gap.

Once you have measured the bore precisely, you should be able to locate rings that will work.

I'll have to look up the stock bore for a GS850, or go out into the garage and measure...

[Tarbash 27]

The gs850 and gs750 big bore should be the exact same bore. The strokes are the same, so if its the same cc it must be the same bore. 69mm bore.

[first timer]

wiseco still makes the piston kit the 844 kit

look here

http://www.wiseco.com/PDFs/Catalogs/CB07/SuzukiCycleStreetOverbore.pdf

the part number for those rings are 2717xc

just measure the size of your piston, should be 69mm

[angus chapman]

thanks guys

you guys are legends! thanks for the responses, however i have a saddening development.

i now have the rings and pistons in my hot little hands and it appears they are NOT wiseco as first thought. on the underside of the piston seems to be written: 'ALCOA' and 'MTO' or 'MTC'. does this ring a bell with anyone?the bore has now been measured at 70mm, which is nowhere near the 69mm wiseco kit.

unless i can find the rings for the unknown brand pistons, then i will be looking for a secondhand engine i think, as re sleeving and new kit etc will cost too much.

cheers
gus

[bwringer]

Stock GS850 bores are 69mm.

But you can get Suzuki GS850 pistons (if you need them) and piston rings in +.5mm and +1mm oversizes.

The +1mm GS850 piston ring sets are part number 12140-49001
($23.15 each at Flat Out)

The +1mm GS850 pistons are part number 12111-45110-100
($33.68 each at Flat Out)

http://flatoutmotorcycles.com/fiche_select.asp

Punch the numbers into the part finder field at the bottom -- their fiche is pretty confusing.

Alpha-Sports.com has a better fiche, but their prices are just unholy.

[madjack57754]

MTC Still in business as MTC engineering. Google them

[first timer]

just looked don't have the kit listed but you should try contacting them. making rings shouldn't be to hard for them as long as you give them all the info they need

http://www.mtceng.com/pistonkits.htm

getting custom rings should be cheaper then replacing the motor

[Billy Ricks]

Give Total Seal a try. I have a set of NOS Cosworth pistons I could never find rings for. Total Seal recut the top two grooves to accept a set of their Gapless rings. Rings and machine work ran about $180. I believe they have a location in Oz. http://www.totalseal.com/

[angus chapman]

all sorted

hey all

thought i'd better let you know how i got on.
i found a guy here in brisbane - mick cashell - that can supply nearly every type of piston ring you can think of. the top ring groove on the pistons were worn, so we machined them to suit a thicker ring, and all is so far good. problem fixed. got all new rings, pistons machined and block honed for $340.

thanks heaps for yur help.

gus