Tell me I am nuts or not.

[dardoonk]

Block & piston. Thoughts on C.R.? That's a stock 70mm piston beside it.

 

[BadBillyB]

Block & piston. Thoughts on C.R.? That's a stock 70mm piston beside it.
View attachment 38182

Hey Kurt, how about a pic with the 78mm piston and a stock piston side by side on one wrist pin (aligning the wrist pin bores). Do a profile shot instead of a top view......Billy

 

[BadBillyB]

The valves
View attachment 38181

The exhaust valve looks like it might be titanium. Compare the weight to a stocker.....Billy

 

[BadBillyB]

Here's a couple pics of the head.
View attachment 38180

Appears to be a large port head, which is good, as you can use the OEM inlet boots with "O" ring seal. Carb size options will be huge......No VHR tag attached to head????......Billy

 

[dardoonk]

I'll get a side by side shot of the piston & check the EX valve weight. The head does have a V&H tag. The carb boots that were on the head had been shaped to fit each intake port and the diameter at the carb mounts was about 41mm.
They are dried and cracked though.

 

[dardoonk]

Here's the side by side of the pistons. Billy, you are correct that the ex valve is noticeably lighter than a stock valve. Actually, the intake valve is lighter as well & 1-2mm larger

 

[BadBillyB]

Yikes, that is way more dome. Increasing bore size alone raises compression ratio. A rough calculation would be 1 point for each millimeter in bore size. Add to that the higher dome of the piston and well, If I had to guess, you are going to end up with at least 13:1 compression ratio. This would require race fuel only, limiting the distance you can ride not to mention overheating issues in traffic......Maybe you should seriously consider running the 1100 jugs and pistons you already have and your VHR cylinder head. The valve pockets in the pistons may need some minor machining to accommodate the larger valves. A simple mock up of the parts can determine if this is needed......With the mild cams you have I think this would be the way to go.....Those pistons look very heavy to me also which puts the small end of the connecting rods in danger. They are not very "beefy" on the stock 1000 rods......Billy

 

[dardoonk]

The valves sit easily into the pocket in the piston. Could I add a spacer or a thick base gasket to drop the CR?

I've got an RC Engineering block that is either 75mm & six pistons - Unfortunately, I have two sets of three and they aren't the same weight. One on the right is a JE & I have no idea of the other.

 

[BadBillyB]

The valves sit easily into the pocket in the piston. Could I add a spacer or a thick base gasket to drop the CR?

I've got an RC Engineering block that is either 75mm & six pistons - Unfortunately, I have two sets of three and they aren't the same weight. One on the right is a JE & I have no idea of the other.

View attachment 38192

Hey Kurt. Every piston you have shown has too much dome for a street application. You don't want to shim the block to lower compression as the combustion efficiency will go out the window. In order to run pump gas, your going to have to go with street pistons....Maybe contact Jay at APE about the new pistons he has that are 10.5:1 C.R. , 1146cc (75mm) kit is a bore in for your 1100 2V block. Kind of pricey though at $680 without a head gasket. I am assuming he can supply the proper head gasket, but I don't see it on his website. Another option would be the K1085 Wiseco kit. Your 1100 block is 72mm and the Wiseco 1085 is 73mm......He gets on here once in a while, maybe he will comment.....Billy

 

[first timer]

SGR 82 kat crank rebuild, pull apart, inspect, reassemble, new bearings (about 30 each), weld & balance cost me about 800ish 4 months ago. I told him I wanted a trouble free crank I never need to worry about for street use.