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1170 big bore kit......

7299 Views 14 Replies 6 Participants Last post by  Catahoulabulldog
Just got the last of the parts for my mates 1170 big bore kit, JE pistons, big bore gasket and a set of crankcases with bored out and Nikasil plated pots............... :'( :'( :'( :'( I wish it was for a Triumph!!!

Suzuki GSXR 1000, he already has 174 rwbhp with all the trick Yoshi cams and ECU, Akra SBK 4 into 1 titanium race system that it a work of art and weighs nothing.......

The one thing that did catch my eye was just how close the pistons are to each other now, I know that the pistons are smaller in bore and stroke and are a one piece unit but they are really thin.........

Just how hard would it be to make a billet three pot wet liner 1 mm bigger in the bore? I want an 1170 strokabora now!!!!!!!
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I have heard someone in the UK had/has a big bore kit for the 955i engines.

I would think that stock sleeves just might handle a 1mm over-bore and replate. If not, LA Sleeve might be able to produce something.
I could machine blanks myself easy enough, been making two stroke liners for years. It’s a one piece unit that would be stronger. You would have a lot more strength for the same thickness in the inside walls between the pistons because they are not machined flat and thin in the area were the liners sit next to each other.

If the three liners are a one piece unit you would be able to bore the liner out considerably more than a three liner system because there is much more strength. 1mm hmmmm maybe 2mm..... now I like that idea. I just don’t have the time to spend all weekend making a one piece unit to prove that it's doable!!! It's on the list...... Plus I like the strokabora idea
I completely agree that a one piece unit will be stronger, but will it fit on the block without major machine work? Looking at photos, the block looks like a lot of its design strength might be lost by machining it to fit a one piece liner - ala Honda race blocks.
The one piece unit will be almost the same as the three piece looks but without the slots in the middle, only 1 or 2 mm bigger in wall thickness. There would be a slight radius between bores externally but it's still a wet liner.

The receiver groves at the bottom is easy enough to do as a one piece unit, you would need some hell long milling tools though.

The other option and easier to do, is make three blanks from billet a bit thicker than STD, tig the three together and a few spud holes to stich the bores internally. Heat cure, then machine deck hight, line bore and plate the inside bore, not as strong as plan A but still a lot stronger than OEM and would easily be up to the task.
Any distortion from welding will be fixed by machining after heat treating. This is why you can’t use OEM ones, shrinkage and distortion would make them useless.
OK, you build a couple of them and I will buy one. ;D

I assume you want a closed deck to support the liners at the top? I have a friend that builds 6061-T651 liners for 3.5-3.625 inch bores using an outside thread (and green Loktite) to hold and seal them near the bottom of the block. It might be worth talking to him.
Hopefully you wouldn’t need to machine out the cases at the bottom; the OEM sleave has a fair bit of land on the bottom so that should accommodate the bigger bore size without making it to thin.

I would leave the liner as it is now push fit into the crank case, you can’t screw a one piece triple bore liner into the crank case....

I knew you would flick it back to me...LOL..LOL.... You make it and I'll buy one from you.......... I'm to busy at the moment mate........

I normally build a few parts when I’m making something new. So you never know.......... Not yet though.... in time.

I have pulled the pin on a lot of my bike stuff for a while, got to much on my plate with my real work., bikes are to become my hobby again and that’s how I want it to stay...... I will still make the carbon 1050 kit though; it’s something that I must do. It will be very excusive though, at best a hand full of parts will be made.
Like you, I'm trying to keep this as a hobby. Count me in on a carbon 1050 tank - minimum.

I have a new GT500 Shelby Mustang that is on order, and need to clear up a few projects before it shows up and gets broken in. I have an aluminum 5.4L block sitting here waiting on a crank and rods - next summer's project.

Not to mention a new supercharger design project.
I would love a blast in that Shelby…….. Not to mention a new supercharger design project. Err now that you have mentioned it…… Tell me more…..

Just measured the bore at 79mm with 9.5mm wall between bores, making a custom liner set-up as discussed before you could easily take the new bore out by 3.5mm, this would give you a new gap of 6mm between bores that’s plenty for a solid and stronger liner than the individual OEM set-up. The only part that’s of concern is the crankcase receiver for the liner it may need boring out 1 or 2 mm to take the new size liners. The more I think about it the easier the welded liner option sounds, if you blanket stich weld the sleaves in the middle you would have an extremely strong sleave, by custom making thicker liners the thrust side of the liner will be the same. A good jig ensure that the sleaves are relatively true during the tig welding process and some precise machine work and boring will make everything fit like it should. I’ll have a hunt around for a donor piston off the shelf, if I can’t find one JE or Wiseco will do short runs of pistons easy………..

So the new strokabora is as follows:

Bore: 79mm
Stroke: 71.4mm
X 3 = 1050cc

New bore size: 81.5mm
Stroke: 71.4mm
X 3= 1117.6cc = 67.6cc more………..

If I can push it to 82mm pistons…….

New bore size: 82.0mm
Stroke: 71.4mm
X 3= 1131.21cc = 81.21cc more………..

New bore size: 82.5mm
Stroke: 71.4mm
X 3= 1145.04cc = 95.04cc more………..

So I guess it’s just a mater of time before it’s a done thing……. Time…. I need more time…………..
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:eek: 8) ;D :eek: 8) ;D :eek: 8) ;D

You two make me want to have a machine shop and plenty of time. Although I can wrench around on bikes enough to get into trouble, this thread only makes me want to tear my motor apart this winter and figure stuff out (I've never been inside a gas 4-stroke before.) I understand everything you guys are talking about, but I need to see it for myself.
Go for it mate, if your not sure take pictures and ask questions.

A factory workshop manuel is a must. It's not rocket science; anything you try would have been done by someone else before, they just haven’t told us about it.

The tec guy's a Triumph would have had some good results when they were doing destruction tests on the engines.

What's that!!!! We are the destruction testers………
I can host photos if you take your motor apart. I'd love to see the guts of the 1050.
I have a question about the Nikasil liners.What year did Triumph start with these? Was it the same time for the Daytona and the S3?
No promises.........

If someone can provide drawings, material requirements, etc. I can see about making the liners.....but it won't be very swift. Until summer, students take precedence on the equipment.....and I may not have everything needed. We have 2 VMC's and a nice cnc turning center as well as a beautiful welding machine (GTAW, SMAW, etc), but I'd have to enlist the help of a better welder than myself (shouldn't be a problem though) to perform that end of things.

edit: I can't do the nikasil plating....just the other stuff if equipment requirements can be met in our shop.
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