78mm MTC pistons

[Wraith]

Thinking of putting some in my GS1000, (as I can get some with barrels) but what else will I need to do?
I've already got a welded crank,H/D clutch, ported head, cams, stn valves, H/D studs top and bottom.

If I'm thinking wright 78mm is 1230cc?
Also the lad dose not know what comp the kit is did MTC do just one comp or more?


Thanks

 

[TeamDar]

1238cc. You may need to bore the top of the crankcase for the oversize sleeves to fit. you will need something besides stock carbs. MTC normally made three compression ratios. Turbo 7.8:1, street 10:1, and race 13.5:1.

 

[Wraith]

Cheers for that, Carbs not a prob as I'm running GSXR1100 36mm CV.

 

[Wraith]

Had a bit more of a chat to the lad who is selling the 1238cc kit. He says the c/r is 12.75/1 and he was running a cv head later model and just took a "tiny bit off" the outside of pots 1+4 and it fitted. He says the outer liners are 81mm. He also says that he had someone in a machine shop check a set of (I presume standard) crankcase halfs and their "case holes" are also 81mm "plus and minus, as they are just not perfectly round". Apparently the machine shop could do something with the cases as they are only "roughly finished" and are "close to fitting".

So what's the normal outer diameter of standard liners if the normal standard crankcase opening is 81mm (if indeed it is), and how much would I need to take the crankcase openings out to in order to get the right fit and seal for 81mm od oversize liners?

And what do you all think? A good buy or not? A load of hassle and/or cost or a good idea?

 

[JTGS850GL]

12.75/1 C/R is going to be a pain on the street when using pump gas.

 

[Wraith]

Cheers for the reply, I thort that c/r would be to much for the road but it's nice to have it conformed.

 

[Guest]

hi, if you call me i can give you details/pics re case boring...i just had a set done here in the uk to accept Billy's 78mm barrells.. they do need a reasonable amount taking out. nick 07900 362809

 

[Wraith]

hi, if you call me i can give you details/pics re case boring...i just had a set done here in the uk to accept Billy's 78mm barrells.. they do need a reasonable amount taking out. nick 07900 362809

Cheers for that, but I think I will stick will using a 1100cc kit as this 1238cc is going to be to hi a comp for the road. Cheers for the offer.

 

[Guest]

Suzuki Spares Nick Pepper would be able to take care of all of it for you.

 

[Wraith]

Cheers. I think as it's a 12.75 comp and will be to hi comp for the road I'm going to stick with the 1100cc kit I have in the motor. Thanks all.

 

[turboprime17]

from what I've experienced the 78mm high compression piston kit puts out 13.5 to 1 compression ratioe I have a set of 78mmhigh compression pistons in my 1979 GSX1100 16valve and it handles pretty well on the road with 93 octanethe problem is is when you polish the parts you can port tune but you don't want to polish unless you're doing drag racing where you're doing wide open throttle down the trackbecause when you polish the cylinder head on the intakes gas does not atomize correctly at low rpmif the head is important and non polished you will be perfectly fine for street use it will idle properly and accelerate properly at low rpmsbut when doing the skit I recommend using the multi-layer stainless spring steel head gasket for my schoo the copper ones give out after a whilethe stainless spring steel head gasket will be able to take more heatthen the copper head gasket you will still need to use a head sealerbecause unlike ODM head gaskets they do not come with o-rings attached to themI hope the information that I have given you was helpful and if you have anymore questions please feel free to ask me

 

[rapidray]

Punctuation can be your friend! Also, we don't polish the intake ports any more. Rough finishing the intake ports has been the best method for over 30 years. Also, where did they make a 16 valve 1100 before 1980?
Ray.

 

[gs11ezrydr]

So as far as compression ratios, I have used copper gaskets unlimited for years in making me different base gaskets, I have had some motors that came in with the pistons sticking out of there bores where someone over decked the top of the block and I used CGU to them back to where they should be. Also had them make a little thinner and thicker at times instead of cutting the deck height so I could play with comp. ratios instead of doing any cutting which is permanent They do head gaskets, base gaskets, any gasket you want, just send them one if they don't already have it in there system and they will copy it and send them all back to you.http://www.coppergaskets.us/