GS1000 1085cc Yoshi kit

[Anonymous]

I have obtained a set of 73mm bore Yoshimura pistons for a GS1000, giving 1085cc as per the Wiseco kit. They look about the same as the Wiseco pistons, but can anyone confirm what the Compression ratio is likely to be. They are 3 ring pistons, not the racing 2 ringers.
Has anyone used this kit who could give me some advice? Would the Wiseco rings, circlips and wrist pins fit?

Thanks in anticipation.

[Anonymous]

the figures i have are ;11.5:1 yosh
10.25:1 wiseco
wrist pin should fit
but rings are normally kept to same make as pistons
tk

[Anonymous]

Thanks TK.

Do you think the 11.5:1 pistons will run on regular pump gas(as you guys call it)?
Are any other mods needed or is it pretty much a plug'n'play deal like the Wiseco?

(I have a GS7/11 with a 1085 Wiseco kit which runs with no mods at all. I use "super" unleaded but have used regular with no pinking when unable to get super.)

This kit is for my second bike and I have a choice of Wiseco or Yosh pistons, anyone got any recommendations?

On the same subject, I have noticed that after fitting the 1085 kit there is an increase in piston noise from the engine. This noise is quite high pitched and sound a little like a loose small end bearing, and occurs at moderate to large throttle settings. It decreases when the engine is warmed. It isn't detonation and there is no appreciable wear in the engine. I have used the same pistons in 2 different engines, 2 different blocks etc. with the same noise
I think the noise is either some piston rock, or just a characteristic combustion noise due to the increase in c.r. and I just live with it, but can anyone else confirm that this is normal with a Wiseco kitted GS1000?

GS1000's!!! Exploding starter clutches and rattling clutches, lets rock!! :twisted:

[Anonymous]

90 to93 octane
as for the sound of your pistons
when you had them out you would
have noticed rubing marks on the piston skirts
this would indicate that piston rock (slapping)
if all was to speck when assembling
the second engine then it may be
the higher crank case pressure that you hear
when the pistons are on they're down stroke
if every thing is running well don't worry!
rattle and hum on starter and clutch?
tk

[Anonymous]

SAY I AM WONDERING WHAT WOULD CAUSE THE INCREASED CRANK CASE PRESSURE ON THE DOWN STROKE IS IT THE EXTRA BORE AND THE VENT NOT BEING LARGE ENOUGH TO ACCOMODATE THE RELEASE OF THE AIR???