Piston-cylinder clearance: So uh..yea, anyone see anything wrong here ***Pics***

K

Kennay

Squarenose for the _____
Location
Myrtle Beach, SC
DrewNJ said:
Bross is right about the compression on the 760. I've done compression tests on about 4-5 760's with stock heads and all of them were 10-15lbs lighter on the back jug. These were all on bone stock 760's in sitdowns....
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Sounds good.

This thing is getting an ADA on there, so no worries.
 
crammit442

crammit442

makin' legs
Location
here
Mouthfulloflake said:
why though?

are the cranks indexed with the PTo cylinder having slightly retarted timing to prevent DETO under load on them?

I still dont see how that would effect compression?
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The head is cut with slightly different combustion chamber sizes to account for timing change due to possible crank twist. Jetting is usually staggered as well. That should make more sense.:smile:
 
BROSS

BROSS

The future right here
Location
Lake Norman, NC
The crank is the same from 650 to 760, and mass produced is my guess, back to the start I was next to my buddy while I taught him how to build the motor and my father did the bore job, so I will back the motor personally, if there is a problem with the clearance I will fix it, no worries. The motor sat for 1-2 years on the self at my shop and assembled with klotz assembly lube so there should be no problems. Please don't get the wrong opinion I just want to clear the air way.
 
BROSS

BROSS

The future right here
Location
Lake Norman, NC
Like I said, I don't want anyone to have the wrong opinion on me on my shop, not trying to sound eregant, just make shure there is no rust on the rings or the cylinder walls and check compression again with the ADA head and I don't see any problems. Oh yea, would deff leak the motor down before install and make shure jetting is right, let me know if you have any questions, thanks
 
K

Kennay

Squarenose for the _____
Location
Myrtle Beach, SC
Nobody would think that Bross. I didn't want anyone to look down on anyone else, or myself (For not knowing for sure what I was asking) so I didn't mention names. I just posted this to double check, and was in no way implying that anyone in particular was to blame if something was wrong.
 
BROSS

BROSS

The future right here
Location
Lake Norman, NC
Thanks man, good luck with the build, let me know if you need anything. When U comming west to LKN? and we need to come down there, my boss has a condo in garden city and I have a great place to ride.
 
K

Kennay

Squarenose for the _____
Location
Myrtle Beach, SC
That there is truff'!

I just went out and checked... the squish is a little larger on the rear cylinder. It's obvious enough to see with the eye, and you can feel the difference with your fingernail.

cool deal
 
D

DrewNJ

X
Location
Marlton, NJ
Sounds like your good already but anyway...
I've never heard a real GOOD explenation on why yami did the staggered compression on that motor.
I've heard things like others have mentioned with crank twist causing deto from the timing advance as well.
From what I understand it's more of a problem with the 760's they used in sitdowns due to the weight of the ski vs. the standups.... and like I said, every stock 760 I've done a compression test on has been that way..

I've also been hearing about some staggered 1300 efi gpr motors too on the #3 cyl... never seen it though...

Anyway, sounds like your good to go. Good Luck with the build!
Doug:veryhappy:
 
K

Kennay

Squarenose for the _____
Location
Myrtle Beach, SC
BROSS said:
Thanks man, good luck with the build, let me know if you need anything. When U comming west to LKN? and we need to come down there, my boss has a condo in garden city and I have a great place to ride.
Click to expand...


Whenever this ski is up and going, I'm going to want to do alot of road trips. I could definitely use some flat water instruction too! :cool: I've never ridden down in Garden City, but up my way we have very easy access to the inlet and the waterway, so we have a good mix here on the north end of SC (Little River)

My goal is to have it done sometime in April. I plan on starting some glass work tomorrow, today is was 31, so there wasn't much I could do outside.

I still need:

footholds
front foothold (24/7 Pancake Petey edition haha)
carbs- going with dual 46's as suggested by team scream
FA's for carbs
exhaust, B pipe I guess when they are available again
waterbox
get the ski wrapped, or flat black it myself

I think those are all the major things, but also need other small misc. items, here and there. I'm not too far off I don't guess. :Banane01:

Basically I have alot of labor to do.
 
BROSS

BROSS

The future right here
Location
Lake Norman, NC
Kennay said:
Whenever this ski is up and going, I'm going to want to do alot of road trips. I could definitely use some flat water instruction too! :cool: I've never ridden down in Garden City, but up my way we have very easy access to the inlet and the waterway, so we have a good mix here on the north end of SC (Little River)

My goal is to have it done sometime in April. I plan on starting some glass work tomorrow, today is was 31, so there wasn't much I could do outside.

I still need:

footholds
front foothold (24/7 Pancake Petey edition haha)
carbs- going with dual 46's as suggested by team scream
FA's for carbs
exhaust, B pipe I guess when they are available again
waterbox
get the ski wrapped, or flat black it myself

I think those are all the major things, but also need other small misc. items, here and there. I'm not too far off I don't guess. :Banane01:

Basically I have alot of labor to do.
Click to expand...

31 is way to cold to glass unless you have a shop. BTW is it Sn or RN were building? I wish I had something you need but all I have is a set of mint 38's for sale, maybe parts of a factory pipe if you want to piece it together. Anyways let me know.
 
K

Kennay

Squarenose for the _____
Location
Myrtle Beach, SC
BROSS said:
31 is way to cold to glass unless you have a shop. BTW is it Sn or RN were building? I wish I had something you need but all I have is a set of mint 38's for sale, maybe parts of a factory pipe if you want to piece it together. Anyways let me know.
Click to expand...


Oh yeah. It's supposed to get to about 60 today, and I'm going to try to find a way to heat the garage and still keep it somewhat ventilated.

It's a squarenose. I will def. let you know about that pipe stuff when the time comes. :439:
 
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