New project Introduction and questions

[rv1890]

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??

 

[htown16]

Slightly too big is better than slightly too small.

 

[marshg246]

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??

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.

 

[rv1890]

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

 

[rv1890]

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?

 

[htown16]

yes

 

[L.A.B.]

My research is showing that the 932's were for the 850 commandos, but can be used for the 750.

932s were fitted to the Combat 750 models in 1972 and most later 750s.

 

[Shelby-Right]

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 .

 

[N0rt0nelectr@]

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?

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

 

[rv1890]

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?

 

[marshg246]

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?

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

 

[rv1890]

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?

 

[marshg246]

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?

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.

 

[marinatlas]

Three pre MK3 are 2.64 long , the pair of MK3 bushes are 2.4 long , so you need to adjust the lenght .