Won this big bore kit on EBay, need info?

[terry]

G'Day Guys, I just won this Ebay auction for a GS1000 Wiseco big bore kit, part #P1175.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=290010483908&ih=019&sspagename=STRK%3AMEWN%3AIT

Wiseco apparently don't list it anymore, and the couple of references I found on Google have been removed, do any of the "old hands" here have any info on it perhaps?

The seller says it's an 1175CC kit, and the pics sure do look like big "2 valve" pistons, but if they are 1175 I'm guessing the're 76mm or thereabouts, so I guess I'll have to resleeve my cylinder block and maybe hog my cases out somewhat? Looking at the other "P" part numbers it appears that it stands for "pro-stock" so I'm guessing (again) that I might need some headwork too?

No biggie there, I've got a milling machine and my old Repco boring bar, but if I need new sleeves, what can I use, overbored 1150 sleeves perhaps? Anyone got some old scored sleeves? I've got some big cams and a set of 34mm Mikuni flat slide race carbs as well, so I'm hoping it'll be a little more "peppy" next time I take it out?

Ha ha, as always, any help will be greatly appreciated, I'd like to spruce up my GS1000S by summer, (still months away in Oz) as the poor old girl is getting a little tired after 25 years on the original engine? Thanks in advance, Cheers, Terry.

[quakeholio]

Where I am at there is a shop that dose engine building, also a machine shop or at least has some of the stuff. I think that they might be able to hunt down a sleve that would work for you, but I don't know.

On a tractor engine of the farms we scared up the engine bore getting the sleve out (dry sleve diesel engine, just like a air cooled motorcycle). The block had to be bored out, then a new sleve put in, and that sleve bored to fit the sleve that came with the rebuild kit. Machine shops sure can do some very cool stuff.

[BadBillyB]

You do know that these are 13.5/1 compression (drag race only) pistons ?? They will require race fuel. They will also require the block to be bored and bigger sleeves installed. The upper case half will need some work in order for the large sleeves to fit down in them. A copper head gasket will also be needed. The top of the sleeve will also need to be "O ringed". If your thinking of running these on the street, it's not feasible as you will have serious over heating problems.......11/1 C.R. is the max for these older air cooled motors.......BadBillyB

[don_gibb6512]

'82 1100L sleeves

I've got the sleeves (cylinders) from an '82 GS1100GLD. Make me an offer offline. Shipping not included.

gibb.1@osu.edu

[terry]

You do know that these are 13.5/1 compression (drag race only) pistons ?? They will require race fuel. They will also require the block to be bored and bigger sleeves installed. The upper case half will need some work in order for the large sleeves to fit down in them. A copper head gasket will also be needed. The top of the sleeve will also need to be "O ringed". If your thinking of running these on the street, it's not feasible as you will have serious over heating problems.......11/1 C.R. is the max for these older air cooled motors.......BadBillyB

No biggie mate, if necessary I'll drop the CR by using a spacer under my base gasket, a copper head gasket's pretty much a cinch too. As I said, I've got an extensive workshop at home, my own boring bar and milling machine (and lathe, too) so the only machining costs will be my own time, and whatever I'm drinking while I'm doing it, ha ha! Cheers, Terry.

[terry]

I've got the sleeves (cylinders) from an '82 GS1100GLD. Make me an offer offline. Shipping not included.

gibb.1@osu.edu

Thanks for the offer mate, but I'll drop by my local wrecking yard on Saturday and see what they have first, as much as I'd like to buy yours, the shipping to Oz might cruel the deal. I'll get back to you if I have no luck here. Cheers, Terry.

[quakeholio]

How much space do you think you need to drop the engine down into the 10.5 or 10.25 range? I'm just using those numbers as that's about what the wiseco street kits run.

[terry]

How much space do you think you need to drop the engine down into the 10.5 or 10.25 range? I'm just using those numbers as that's about what the wiseco street kits run.

Well I'll have to measure the distance from the centre of the wrist pin to the top of the dome and then compare it to a standard piston, and try to find a happy medium between the two, as I don't have the specs for a 10.25:1 piston.

Years ago I fitted a drag bike engine with 13.5:1 pistons, monster cams etc in a GS1000 road bike, and to drop the CR I installed a 2.5mm base gasket, which was probably more like 2 mm when compressed, and the engine ran sweet. Not very scientific I know, but it worked fine. Cheers, Terry.

[Nessism]

What about wacking the dome down with the mill to lower compression?

[luc8421]

you'll ruin your flame front by 'wacking' the top of the piston down/off. they're domed for a reason, performance.

check out some piston pictures online, you'll see there are many different shapes to the tops of pistons, often having to do with the way the flame swirls around the combustion chamber during the different cycles. diesel engine pistons can get pretty interesting looking.

huge picture, but check out this one, a fairly common shape in diesels.

http://www.kolbenschmidt.de/img/ks_dieselkolben_mit_formk_gr.jpg

[Nessism]

you'll ruin your flame front by 'wacking' the top of the piston down/off. they're domed for a reason, performance.http://www.kolbenschmidt.de/img/ks_d...t_formk_gr.jpg

The piston is domed to get the compression up. I don't think the flame front will be effected in the least (may actually improve it since more combustion area will be centered over the top of the piston).

[BadBillyB]

You cant cut the top of the dome down on these light weight drag race pistons. They are as thin as Wiseco dared make them. Dropping the pistons down in the block by shimming the base gasket is what will ruin the combustion process. It will practically eliminate the "squish area" of the piston. It will probably run OK, but far from ideal. This is why racers meticulously set their deck height. It's important for proper combustion..These pistons are not suited to run in a street motor. They will require at least 102-104 octane fuel, and you will still have issues with overheating. Dont do it....[-o<

[Large]

you'll ruin your flame front by 'wacking' the top of the piston down/off. they're domed for a reason, performance.

check out some piston pictures online, you'll see there are many different shapes to the tops of pistons, often having to do with the way the flame swirls around the combustion chamber during the different cycles. diesel engine pistons can get pretty interesting looking.

huge picture, but check out this one, a fairly common shape in diesels.

http://www.kolbenschmidt.de/img/ks_d...t_formk_gr.jpg

lol

I love how the actual dome shape is "fuzzed" out...must be porn or something.

As for milling the top off the piston, if there's enough meat there, go for it...after all, they've been doing that forever on Hemis.

[terry]

You cant cut the top of the dome down on these light weight drag race pistons. They are as thin as Wiseco dared make them. Dropping the pistons down in the block by shimming the base gasket is what will ruin the combustion process. It will practically eliminate the "squish area" of the piston. It will probably run OK, but far from ideal. This is why racers meticulously set their deck height. It's important for proper combustion..These pistons are not suited to run in a street motor. They will require at least 102-104 octane fuel, and you will still have issues with overheating. Dont do it....[-o<

I'm still gonna! The engine outta the drag bike was a pig before I shimmed the base gasket, after that it ran like a clock and was Dyno'd at 120 BHP at the rear wheel, which was good enough for me mate, I don't need perfect and I'm not racing it, so "good enough" is fine!

I can buy 100 octane gas at most gas stations here in Oz, so even if I left it at 13.5:1 it'd probably be ok, and of course I make oil coolers for Suzy's, so that's not an issue either. Cheers, Terry.