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
 
What about the sleeve gear bronze bushings in the gearbox? I’ve moved onto the gearbox and when I pulled out the sleeve gear the bronze bushing had walked itself out and was chewed up on the end.

I have the sleeve gear without circlips on the ends, I’m guessing that’s the older style? I replaced it with two new ones from RGM motors. It leaves a gap in the middle. Upon research I have the following questions:

1. Do I install 2 or 3 bushings to fill up the space and what keeps it from walking out again?

2. The main shaft no longer slides in. I made sure the ends of the bushings weren’t mushroomed from installation and that the main shaft does not have any burred edges. I’m sure I can get it to fit if I slightly ream the bushings. Is this normal or do I have defective bushings?
 
rv1890 said:
What about the sleeve gear bronze bushings in the gearbox? I’ve moved onto the gearbox and when I pulled out the sleeve gear the bronze bushing had walked itself out and was chewed up on the end.

I have the sleeve gear without circlips on the ends, I’m guessing that’s the older style? I replaced it with two new ones from RGM motors. It leaves a gap in the middle. Upon research I have the following questions:

1. Do I install 2 or 3 bushings to fill up the space and what keeps it from walking out again?

2. The main shaft no longer slides in. I made sure the ends of the bushings weren’t mushroomed from installation and that the main shaft does not have any burred edges. I’m sure I can get it to fit if I slightly ream the bushings. Is this normal or do I have defective bushings?
Click to expand...
If the bushing fit the mainshaft before installing, then the bushing shrunk on the way in or it is mushroomed at the edge. If you didn't check the bushing before installing, then I don't know.

Oldest = no circlips
Newer = one circlip
Newest = two circlips
 
Yeah, I forgot to check before installing. It just needs ever so slightly of a ream, so I guess that what I'll be doing.

I went with the two 7/8" bushings per the manual. Currently I have them installed about an 1/8th inch from the edge with a gap in the middle. Is that correct or do I butt them up against each other?
 
rv1890 said:
Yeah, I forgot to check before installing. It just needs ever so slightly of a ream, so I guess that what I'll be doing.

I went with the two 7/8" bushings per the manual. Currently I have them installed about an 1/8th inch from the edge with a gap in the middle. Is that correct or do I butt them up against each other?
Click to expand...
They should be at the ends but what you have should be OK. The gap is normal, but many install 3 to get rid of it.

The current pre-MK3 AN bushes are .88" long. I don't remember if three of those fit. I know there's a write-up somewhere on installing three, but I haven't been able to find it and I don't have a no circlip sleeve gear right now to check.
 

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