GS1150E big bore kit question...

[Matt W.]

I am considering a GS1100E street fighter project. Big bore, GSX-R running gear, banana swingarm, etc.

Trying to find out how far I can go in displacment before it becomes impractical for street use. I've heard 1261cc's on here...but the APE catalog has a 1395 kit that they market as a "street" kit. Please shed some light on this issue. Pretty much I am trying to find out how far I can go before I loose the adequate cooling properties. Also I am assuming that the "Gorilla" blocks are made to provide proper cooling. The description of their role seems very vauge and I am not sure if they are desinged to withstand "street riding conditions".

Am I right, or am I off???

Please let me know what I would be up against when it comes to trying to keep that kind of size motor, cool.

Thank you,
Matt W.

p.s. This board is freaking great. It took me two days to find it, but it is well worth it.

[Dink]

Matt get the biggest oil cooler you can fit, 750 oil pump gears and a topend oiling kit, add these up with a good quality oil and frequent oil and filter changes and you can run as big as you like.
I am in Australia and know of several bikes running on the street with 1430cc kits and even one that is a daily driver (rider?) that is 1770cc.
It is all in the planning and preparation, you need to be sure that what you are doing will work together.
You will of cause find that going bigbore will also create clutch and gearbox issues, as well as crank twist issues, and of cause it will lead to ignition and then fuelling issues. so if you want to go huge you are gonna need a pile of money to throw at it, and fairly large pile of determination as well.
I would not recommend going larger than 1260cc as it is after this point that the big issues start to arrise.
Dink

[Anonymous]

yeah Dink is right on the money here.. (well almost )
just let me add some extra comments if you will..

without resleeving or big block 1260cc is as big as you can go on a GS1150.. the older 1100 will stretch to max 1170 or 1200cc..

any bigger will require resleeving or fitting a big block which will allow anything up to about 1500.. (Dink, I think the 1770 has a stroked crank?)
reasons for a big block are: 1)more meat for the big sleeves.. 2)crank support due to rigid block of metal..
the main disadvantage is HEAT.. standard blocks have the airpassages between the cylinders which the big block must do without.. also of course larger capacity means more power means more heat!
so when choosing a big block look for one with a lot of and big cooling fins..
as to deciding on the size of an oilcooler.. don't fit anything bigger than you actually need.. because big coolers lengthen the warmup time which is a bad thing.. fitting a thermostat would solve this point of course..

because of the extra power the load on the engine increases.. just like Dink suggested the crank is prone to twisting even after fitting just a 1170 kit.. (I believe as of '84 suzuki started welding these 1100 cranks)
second main issue is the clutch (backing plate and to lesser extent the basket)
the gearbox is able to cope with a lot of stress though (it's about the strongest OE box out there!)
ignition will be fine too.. maybe just new coils and leads..

oh btw.. the "street" indication of some piston kits depends solely on their compression ratio! ..the CR of a street kit will be low enough for the bike to be able to run on pump gas..

[Matt W.]

Thanks guys. Really.

That's allot better news than I was expecting to hear.

Now onto saving a BUNCH of $$$.

[Richie]

pistons

to be honest i would not go above a 1197 10.5-1 comp. for the street, with a little porting and bigger carbs weve had motors running 9.20's @around 145 all day long, without an air shifter.

Richie

[Anonymous]

Re: pistons

to be honest i would not go above a 1197 10.5-1 comp. for the street, with a little porting and bigger carbs weve had motors running 9.20's @around 145 all day long, without an air shifter.

Richie

Now you are talking of my fantisy bike. :P :P :P

[skip]

Re: pistons

to be honest i would not go above a 1197 10.5-1 comp. for the street, with a little porting and bigger carbs weve had motors running 9.20's @around 145 all day long, without an air shifter.

Richie

Ive ben running 1229 cc for about ten years now. the bike weighs a ton and with me on it its 750 lbs. I have gone 10.30's at 135+mph with a stock chassies (no wheeliebars) and small 130 street tire. at 1229 cc you can get away without sleeving in the 1150 motor and at 10.5 to 1 comp ratio it runs great on pump gas. If i ever put the bike on a diet and did a drag chassie im sure it would be in the 9,s with pump gas.

[Anonymous]

Hi all!
I?ve read in many forums about this topic and it is the same as you guys say. But here in Sweden, one of the biggest companys that build engines and sell all the goodies(MotoSpeed) do resleeve the 1150 block and bore it to 1327cc. Many has done it and it seems to work too. I just handen them my crank for welding and my upper case for machining it to fit bigger sleeves if I would want too(1327cc). And the enginebuilder did confirm to me that 1327cc is no problem with a 1150 block. I also know a few with the 1100 block that are resleeved and bored to 1295cc. I think it is the 1100 block that www.biker66.com uses on his bike but I?m not 100% sure. And we have been out on the roads many times together last summer. And his engine is great. Like an electrical motors torquerange, totally even. And at 7000rpm in 2:nd gear the front wheel leaves the ground slowly and sophisticated like a starting airplane, so nice....