Gs1000 big bore....... What's best ?

[Spamwood]

I'm concidering a 1085 kit for my GS. 

Any opinions on best way to go ? 

Wiesco, MTC or other ? 

Cheers. 

[gs7_11]

Can't comment on the others, but I've had mixed experience with Wiseco 1085 kits.

On one hand, I've got a kit in my 7/11 which has been in for years and 25,000 miles (at a guess) and is still tight, pulls well, burns no oil.

Another kit I had, I found a circlip had receded into its groove, allowing the gudgeon pin to come out and damage the bore. After some toing and froing, Wiseco gave me a new kit at cost price for that.

Edited May 18, 2018 by gs7_11

[wraith]

+1 on that,

I had a 1100cc kit in one of my gs1000, had now problems with it, lots of happy riding, but had a 1148cc kit (using gpz 1170 kit) and the same thing circlip came out and fu#ked a bore.

Not tried a MTC kit.

[Reinhoud]

I had a 73mm Wiseco 10.5:1 in my GS1000, and that went quite alright.

 

The 78mm goes a lot better!!

[Reinhoud]

On 19-5-2018 at 4:08 AM, wraith said:

+1 on that,

I had a 1100cc kit in one of my gs1000, had now problems with it, lots of happy riding, but had a 1148cc kit (using gpz 1170 kit) and the same thing circlip came out and fu#ked a bore.

Not tried a MTC kit.

I had the same problem! 

 

Apparently you need to renew the clips every time you take them out..

[wraith]

2 hours ago, Reinhoud said:

 

 

Apparently you need to renew the clips every time you take them out..

Yes, you MUST replace with new the clips after you have removed them  the Wiseco kits come with there owen new clips, but I think they are/where a bit week  ended up putting OEM clips in.

[gs7_11]

3 hours ago, Reinhoud said:

I had the same problem! 

 

Apparently you need to renew the clips every time you take them out..

Of course you do, but in my case the clips stayed fitted fine, but the groove was too big, or became worn bigger with time, and the pin passed through the middle 

[Reinhoud]

I've been working since I was 14 y.o. (30 years now) on mopeds, bikes and cars, and till about 4 years ago I never experienced that problem.

Must have been lucky I guess.

[Cheeky4648]

Got 76mm MTC pistons in my gs1000. I use Teflon buttons rather than circlips.  No problems. When racing we found the Mtc pistons were better than the rest. Could use a tighter tolerance on bore as they don’t expand as much as wiseco wossner or je. 

Edited May 27, 2018 by Cheeky4648

[R1guy]

On 5/18/2018 at 7:08 PM, wraith said:

+1 on that,

I had a 1100cc kit in one of my gs1000, had now problems with it, lots of happy riding, but had a 1148cc kit (using gpz 1170 kit) and the same thing circlip came out and fu#ked a bore.

Not tried a MTC kit.

So a gpz1170 kit gives a gs1000 motor 1148cc on standard , bored out liners? Or is there more to this?

Edited November 10, 2020 by R1guy

[wraith]

53 minutes ago, R1guy said:

So a gpz1170 kit gives a gs1000 motor 1148cc on standard , bored out liners? Or is there more to this?

Much more, you need bigger liners and it's only one of the gpz models (can't remember which) but one of them has the same small end ( gudgeon pin) as the GS. 

I used them as at the time you couldn't get anything bigger than a 1100cc kit but now MTC do bigger kits for the GS 

[gshub]

Got Wiseco 1085cc fitted to mine!

Edited November 10, 2020 by gshub

[R1guy]

On 11/10/2020 at 6:30 PM, wraith said:

Much more, you need bigger liners and it's only one of the gpz models (can't remember which) but one of them has the same small end ( gudgeon pin) as the GS. 

I used them as at the time you couldn't get anything bigger than a 1100cc kit but now MTC do bigger kits for the GS 

Ah,

Is there a documented Frankenstein big bore option for gs1000 for , let’s say, 1150cc +?

The point is, you can use ‘Busa pistons to make a cheap 1216 on an oil cooled so is there a production bike piston that has 18mm wrist pins and will give 1150cc+ (N/A) on a gs1000, (I know it’ll need new liners )

Edited November 11, 2020 by R1guy

[wraith]

?

[R1guy]

14 minutes ago, wraith said:

?

Instead of buying a set of pistons for £500

[CockneyRick]

Wiseco in mine & no issues for over 10 years.

Mind you, it was done by Roger Upperton  

[clivegto]

On 11/11/2020 at 6:51 PM, R1guy said:

Ah,

Is there a documented Frankenstein big bore option for gs1000 for , let’s say, 1150cc +?

The point is, you can use ‘Busa pistons to make a cheap 1216 on an oil cooled so is there a production bike piston that has 18mm wrist pins and will give 1150cc+ (N/A) on a gs1000, (I know it’ll need new liners )

Mk2 busa pistons have 18mm pins as do gsx14. You could use b12 liners in the block, crank cases would need opening up & I belive the sleeves show through the barrel fins which need to sealed. 

Not done this but it might be possible. 

[Gixer1460]

1 hour ago, clivegto said:

Mk2 busa pistons have 18mm pins as do gsx14. You could use b12 liners in the block, crank cases would need opening up & I belive the sleeves show through the barrel fins which need to sealed. 

Not done this but it might be possible. 

That occurred to me but a calc would put finished capacity up over 1300cc ( I didn't know what the 1000 stroke was so used a 1100 stroke and took a bit off LOL!)

[Askamaskinservice]

1335cc if using 81mm pistons. (Is this even possible)

GSX1400 Bore x stroke 81 x 68

GSXR1300 Bore x stroke 81 x 65

GS1000E Bore X stroke 70 x 64.8

[Duckndive]

GS1000 is a 2V engine not 4V 

[Askamaskinservice]

Yes wasn't the question about a 2 Valve GS1000 bigbore or am i wrong again.......

[Gixer1460]

3 hours ago, Duckndive said:

GS1000 is a 2V engine not 4V 

We can't help that it's got the wrong head, can we! 

[wraith]

11 minutes ago, Gixer1460 said:

We can't help that it's got the wrong head, can we! 

Just put a 4v head on the GS 2v barrels/bottom end, I'm sure you could get some of the cylinder studs to go in the holes  or grind the 4v pistions down where the valves cut outs are so the 2v valves don't meat the pistons 

[clivegto]

Fairly flat is a gsx1400 piston like busa ones. 

[Duckndive]

Even stock comp slugs have a raised crown

 

 

so any flat tops will seriously affect CR  but ideal for a turbo job.....