New project Introduction and questions

rv1890 said:
Next step. Piston ring gap. I'm using Hepolite pistons with their rings. PVD faced top compression ring, cast iron second compression ring, and two piece oil ring.

Can someone confirm my math? My bores are .060 over.

2.874 (standard) + .060 over = 2.934

If the rule of thumb is .004-.006 gap for every inch of bore then:

2.934*.004 = .0117
2.934*.006 = .0176

So I should be setting the gaps between .012-.018 on the first and second rings, correct?
Click to expand...
The ring gaps are in the workshop manual - no need for math. Generally, I have not needed to adjust them at all with Hepolite complete sets. I only would if the gap was too small, but it never has been.

BTW, yes, the oil rings are hard to get in the cylinder. DO NOT "adjust" the spring - they come correct!
 
Sounds good. I was thrown off since the workshop manual states it for standard bore and mine is .060 oversize...Unless I missed that part of the manual.

Guess I'll throw them in how they are out of the box and confirm at minimum a .012 gap??
 
rv1890 said:
Sounds good. I was thrown off since the workshop manual states it for standard bore and mine is .060 oversize...Unless I missed that part of the manual.

Guess I'll throw them in how they are out of the box and confirm at minimum a .012 gap??
Click to expand...
AFAIK, the "rule" is for standard bores. Once you go over, you still be the same gap so no math needed by the user, only the manufacturer.
 
oh, ok. That makes sense. I haven't checked yet as to what they are out of the box. I'll do that first and go from there
 
While I wait for some parts to arrive I plan to tackle the carbs next. Bike is a 750 and it has Amal 932 carbs.

I had the housings vapor blasted and they cleaned up nicely, but the jets and needle have seen better days.

I purchased the bike not running, so I dont know what was working or not. My research is showing that the 932's were for the 850 commandos, but can be used for the 750. It currently has a .106 needle and 220 mains. If I get a rebuild kit is it ok to go with .106 and 220 again?
 
It's not a bad idea to make the second ring gaps slightly bigger as it stops a build up of pressure between the rings and stops ring flutter .
 
rv1890 said:
Thanks Dennis, yes I plan on measuring the crank to verify con rod bearing size. I also will separate the crank for cleaning since there was lots of sludge.

Also, I didn’t notice the “restoration” section of the forum. Do I need to move it myself or does an admin need to?
Click to expand...
There is a set of crankshaft nuts, bolts and studs along with the metal strips that retain the nuts and the locating dowel. Sounds complicated but it isn't.
John in Texas
 


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