was oval pistons - now oval bores gs1000e

[Anonymous]

Dear gs'ers,
Over the w/end,I borrowed a dial gauge and measured the bores.Two of the cylinders were oversize at 2.7592" and the next best reading was 2.7588".These readings validated the poor compression readings I obtained and therefore I guess I'm in for a rebore!?.
The question I would like to ask therefore is thus;
If I rebore allowing for the Wiseco 1085 kit is there anything else that I need to consider, in respect of larger valves, bigger carb's etc ?.
I would rather keep it as stock as possible, but at the same time allowing the modification, to be utilised to it's best performance.
Regards Bilbo. 8O

[Hap Call]

Re: was oval pistons - now oval bores gs1000e

Dear gs'ers,
Over the w/end,I borrowed a dial gauge and measured the bores.Two of the cylinders were oversize at 2.7592" and the next best reading was 2.7588".These readings validated the poor compression readings I obtained and therefore I guess I'm in for a rebore!?.
The question I would like to ask therefore is thus;
If I rebore allowing for the Wiseco 1085 kit is there anything else that I need to consider, in respect of larger valves, bigger carb's etc ?.
I would rather keep it as stock as possible, but at the same time allowing the modification, to be utilised to it's best performance.
Regards Bilbo. 8O

Just over boring it will require little else...only a possible re-jet of the carbs. Of course, adding larger carbs, exhaust header, higher lift and/or duration cams will make the bike perform better if it is done correctly. Installing bigger valves requires major head work, but while the head is off it would be advisable to look into a valve job so you will have a fresh engine.

Hap

[saaz]

I agree with Hap. The oversize pistons will give you good everyday performance with little else required. A head tidy up would be a good idea, getting the valves reseated and replacing valve stem seals. This will keeps things going for a very long time.

Any money you would spend on more gets relatively less performance per dollar.

[focus frenzy]

You dont have to go all the way up to a wiseco 1085 kit, you can use the suzuki 1mm oversized pistons and rings. that is what I did, and with no other changes, I noticed a good increase in power, if my numbers are correct, 1mm over sized takes displacement up to about 1025cc
the only draw backs I have discovered are that the bike does not like lower octaine gas (petrol to our British friends) it pings pretty bad when pulling above 1/4 throttle below 3000rpm on regular, but does pretty good on premium.

remember, that wich ever way you go, (wiseco 1085, or stock 1mm over) to have the cylinders matched bored to the new pistons.

[Anonymous]

was oval pistons now oval bores - reply

Dear gs'ers,
Thank you for the responses.Mr frenzy your idea about oversize pistons looks a good idea, however the cost of stock pistons, rings and all, is about the same as the Wiseco set-up and therefore I think the extra cc's and resulting power is a bonus for approx the same cost?.
I reckon having the head sorted is good practice and shall contact a company called 'the cylinder-head shop'. A couple of years ago they sorted the head for me on my yam xs-2(they use Serdi equipment)and have much experience in various head set-ups.
My xmas wish list, now looks like it is under revision!!!!! so I'll have to behave, work hard and hope Santa delivers the goods?
thanks for the replies
Regards Bilbo. 8O

[KGB]

I agree with Hap also.....

I had a a similar problem with my 80-GS-S.
What started out as a valve job, turned into a major rebuild.
It lacked compression and power, and the smoke gave it away.......
My # 2 and 3 cylinders were out of round.
This is typical for big air cooled motors.
I ended up about 20/ths over stock. I couldn't find pistons to fit.
I ended up using Oriental Express pistons and valves. Nothing major, just a pain in the butt getting parts. I had a 3 angle valve job done on the seats, new valve springs and left the cam stock.
The stock crank and cam is still in there, everything else was new.
$2500 later, I had a fresh motor. After a calm 500 mile break-in, this motor rips. I also had the carbs re-built and re-jetted.
That was 4 years and about 15,000 miles and it still idles and runs sweet.
I also put in a Barnett clutch, both sets of plates, fiber and steel.
My only advice is find the best machinist you can. I've heard of too many re-bores going bad due to an over vealous machinist.

This was one of those projects..."well its apart, lets do this and this and this and...." well you get the idea

Keith

[Anonymous]

Whoops-dropped something into transmission!

Dear gs'ers,
Firstly thankyou for the replies to my earlier post and as soon as Xmas has passed I shall start the upgrades.
For the present however I've realised that as I was removing the barrels an amount of abrasive cleaning medium has deposited it self into the transmission.(I was shot blasting prior to dismantling and wasn't thorough enough with the cleaning)
I've now, to split the tranmission cases apart and was wondering whilst I was in there, if there was anything that I need to look out for(apart from the grit).
Regards
A rather red faced Bilbo

[KGB]

Check the teeth on 1/st and 2/nd gears.
Under HARD use these have a tendency to chip or wear.
Also they sometimes slip on the splines.
Welding 2/nd gear was common back in the day..
I did mine about 13 years ago, no problems since or before.
I still find neutral without a problem.

How's the clutch? any slippage at high rev's?
I put in a Barnett and new plates a couple of years ago, and its still
hooking up fine.

One thing leads to another.......
Ask for money for Christmas
Keith