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Big bore kits. What cc?


Ibbo

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This winter the gsx engine is coming apart for a spruce up. It's well known that it is illegal to strip a gsx without putting bigger slugs in there, and of course everyone wants more torque.

It is currently 1075cc, and as well as wanting more torque, i want to do miles. In the past i have bored bike engines out, only to have gasket hassle, so this time i have in mind to get 1135 barels, and give then a slight overbore. Increase compression, and use std gaskets to keep the reliability.

I am planning some european touring on the old girl next year, so reliabilty is paramount. 

I cant use std 1135 pistons due to the pin size. 

What advice do you all have? It currently runs fine, and doesnt use any oil, however leave it alone isn't in my dictionary.

Mike

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If you are going to use an 1135 ef  cylinder you can go 76mm (1198) which for reliable use is a good upgrade. Still leaves the liners with enough meat in them. MTC do a piston kit for this and it comes with a cometic mls head gasket, and use a Suzuki 1135 base gasket so keeping it all sealed up well. 

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6 hours ago, Ibbo said:

That sounds like a good option. Keeping some meat in the liners is something i'm very much in favour of.

Have you used one of these?

I havnt used one as I usually go stupid big lol. Used to work at MRE and we used to do a lot of upgrades cc wise. 

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 I usually go stupid big lol. Used to work at MRE and we used to do a lot of upgrades cc wise

 

i like your way of thinking, and id love to. Really want to go round europe next year though, so after reliable slightly more than fast.

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12 hours ago, Askamaskinservice said:

Be careful using a Prostock crank as they are usually / used to be fitted with a 750 gear to alter the clutch / primary gear ratio - good for racing out of the hole but not so much for 'normal' use. I thought GS1150 crank stroke dim was 66 odd mm as stock so those aren't stroked ? and also VERY cheap so are possibly s/hand and a  s/hand PS crank will have turned 13-14k rpm and are swopped out for good reason. Could still have good life turning lower rpm's but bearings may be suspect long term!

Edited by Gixer1460
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16 hours ago, Ibbo said:

Hi muddy,

I was thinking the finning is probably bigger on the 1135 for more cooling?

G'day Ibbo, yes my very limited understanding is that the 1135 block would be a better option, but I'm running out of money :o!  Sleeves, pistons, carbs all from the US (Aussie prices are expensive), plus cost of machining etc.  I'd love to get the 1135 block, but will try to make do with what I have at present.

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Steve Johnson's page looks quite old?

1135 barrels for me definately after this conflab.  No stroker cranks, though I've never seen any advertised.

All good fun. Thanks for the info.

Can't wait now. Even got permission to strip it in the living room. That will be interesting. 

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6 hours ago, Muddy said:

Righto, you've got me thinking now - bore and resleeve the stock block or bore a GSX1150 block (if I can find one - they seem to be rare in Aus)?

How about using GSXR sleeves in your 1100 block - they are 78mm std and so will be the biggest in that block = 1260cc and more likely to be plentiful in Aus. ? - looks like you'll be boring something but aluminium is easier than steel LOL!

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18 hours ago, Gixer1460 said:

How about using GSXR sleeves in your 1100 block - they are 78mm std and so will be the biggest in that block = 1260cc and more likely to be plentiful in Aus. ? - looks like you'll be boring something but aluminium is easier than steel LOL!

Yes, you're probably right, coupled with the observation that 1150 blocks are as rare as here.

5 hours ago, et1170 said:

Bore the standard block for a 1170 cc kit, a bit more power and totally reliable.  

So do the 1260 kits tend to make the set-up unreliable because of the oversized sleeves?

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2 hours ago, Muddy said:

Yes, you're probably right, coupled with the observation that 1150 blocks are as rare as here.

So do the 1260 kits tend to make the set-up unreliable because of the oversized sleeves?

No. It´s as reliable as original 1074 when done properly.

As a matter of fact 1074 block with 1135  sleeves  can have better cooling than original 1135 block, because the air gaps

between cylinders in 1074 block are wider.

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18 hours ago, Blower1 said:

No. It´s as reliable as original 1074 when done properly.

As a matter of fact 1074 block with 1135  sleeves  can have better cooling than original 1135 block, because the air gaps

between cylinders in 1074 block are wider.

Thanks, good to know.

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