76 Commando 850 Cam install

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JcJamez

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Hi guys,

After getting a quote on a cam install from a few local mechanics I've decided I'm going to have to do this myself. I've got the head and cylinders off and now I'm not sure whats next. I have the service manual but it basically walks you through disassembling everything but I don't want to tear into anything that isn't necessary. Is it possible to pull the entire engine and primary out in one piece and split the case or does the primary have to be taken apart? If I do have to remove the primary are there any special tools I'll have to acquire?

I was pretty confident I could accomplish this until I pulled the primary casing off. It looks complicated. Any help would be greatly appreciated.

Jesse - Fort Worth, Texas
 
Not too many shortcuts on that one. Primary needs to be removed. You will need a puller for the crank gear. A steering wheel puller and a couple long 5/16 fine thread bolts will do along with a torch to heat the sprocket. After it's hot and the puller has pressure on it smack the sprocket with a hammer and punch to help jar it loose. You will need a clutch spring compressor to remove the clutch snap ring. Make a note of the position of the chain tensioner blocks. You will want them back exactly the way they came out.
You will need to pull the lower end of the motor and disassemble the timing chest parts [you will need a pinion gear puller- a special Norton item] and then split the cases. It's a lot of work but it's just nuts and bolts. Jim
 
comnoz said:
Not too many shortcuts on that one. Primary needs to be removed. You will need a puller for the crank gear. A steering wheel puller and a couple long 5/16 fine thread bolts will do along with a torch to heat the sprocket. After it's hot and the puller has pressure on it smack the sprocket with a hammer and punch to help jar it loose. You will need a clutch spring compressor to remove the clutch snap ring. Make a note of the position of the chain tensioner blocks. You will want them back exactly the way they came out.
You will need to pull the lower end of the motor and disassemble the timing chest parts [you will need a pinion gear puller- a special Norton item] and then split the cases. It's a lot of work but it's just nuts and bolts. Jim
Click to expand...


Thanks Jim
 
You can get the camshaft out without pulling the crank pinion. Just putting my combat engine together after changing to a Norris RX cam. Pull the left side crankcase off the crankshaft leaving timing side case connected to the crank. you will need to remove the cam chain and camshaft sprocket off the end to be able to remove the camshaft. I don't envy your electric start at this point. Kickstart primary has many fewer parts.
 
illf8ed said:
You can get the camshaft out without pulling the crank pinion. Just putting my combat engine together after changing to a Norris RX cam. Pull the left side crankcase off the crankshaft leaving timing side case connected to the crank. you will need to remove the cam chain and camshaft sprocket off the end to be able to remove the camshaft. I don't envy your electric start at this point. Kickstart primary has many fewer parts.
Click to expand...

That is true, just be careful so you don't damage the sealing disk on the RH end of the crank. With superblends it is easy to bend that disk when the crank moves out of the bearing but the disk doesn't clear the rollers. jim
 
BEWARE BEWARE BEWARE, this is exactly how I got sucked into mechanics over my head - by the knowing experts tricking me how easy and straight forward such a simple machine is, even a caveman can do it. ugh.

Do not believe JIm that your gearbox mounts/adjusters are in the right place. Will have to verify and adjust on the way back out so primary chain lines up with correct tension. Might want to buy a spare sprag gear thingy going by its reported failure rate.

D/t clutch and primary and tranny up keep...
You should own a clutch spring compressor anyway, make your own or buy it.
Aslo need crank sprocket puller, but best get the Norton item or one as robust of the steering wheel type. I send out my extra pinion puller as they are only needed once or twice a regular owners life time. Oh yeah call a vendor and get the curved 1/4" Whitworth spanner, it will be most used wrench and saves straining on hard to reach nuts. Don't be afraid of a little frying pan hot oil smoke to get stubborn fasteners removed.

Hardly anyone gets that far in w/o renewing the rings too and all the seals, Get some extra oil pump nipples. TS cover gaskets thickness must be a matched to the oil nipple thickness, so order in pairs or poor sealing results. There are 2 combos of these, either works fine.


Of course you must mess with getting electrics out the way, so expect some connection failures to fix back up. Good time to renew isolastics or grind a bevel on the front ones for extra smooth sooner signature isolation.
 
hobot said:
BEWARE BEWARE BEWARE, this is exactly how I got sucked into mechanics over my head - by the knowing experts tricking me how easy and straight forward such a simple machine is, even a caveman can do it. ugh.

Do not believe JIm that your gearbox mounts/adjusters are in the right place. Will have to verify and adjust on the way back out so primary chain lines up with correct tension. Might want to buy a spare sprag gear thingy going by its reported failure rate.


It's a Mk3. No gearbox adjusters. Just tensioner shoes that need to go back like they came out or they will wear badly. Jim
Click to expand...
 
Replacing a Cam - Ouch!
Man, it's a lot of work.
I wouldn't even want to do it now without a lift and a dedicated workbench (I must be getting soft in my old age :oops: )

Seriously,
if you don't have the tools, a dedicated place to work on it, and some mechanical skill, You should consider finding someone
with experience rebuilding Nortons and pay him to do it.
It will end up being cheaper in the long run.
 
Mark said:
Replacing a Cam - Ouch!
Man, it's a lot of work.
I wouldn't even want to do it now without a lift and a dedicated workbench (I must be getting soft in my old age :oops: )

Seriously,
if you don't have the tools, a dedicated place to work on it, and some mechanical skill, You should consider finding someone
with experience rebuilding Nortons and pay him to do it.
It will end up being cheaper in the long run.
Click to expand...

Ah but the satisfaction of knowing you did it yourself- priceless. :D Jim
 
face it this is a real man's machine and not everyone, including me is always fit or competent to own one. Expensive parts that break and tools to acquire then all the time to steal away from everything else. Glad I don't have to know the whole scope of Cdo's and parts they wear out, just Combats. If I'd only known half the mechanic involvement they've forced me into at time of purchase decision...might not of, and missed out on extremes of emotion and self doubt and proof I'm not really cut out for this but fumbled on till they ran ok again. Gave some adventure and rides that are never really out of mind-heart-bones 24/7.

Cheap old man way to hold a Cdo frame up to work on is a sky hook come-a-long and proper hieght box under to stabilze. Btw I finally got a pure Noton only took kit together, fits in one capentry like open top box type carrier. Everything needed form tires to clock lens but a bench mounted vise and 3 lb sledge.
 
Life is an adventure.
I wouldn't know what it looks like inside of a commando engine if I'd never took the chance and tore into one.
If personal experience is the goal, then I say "have at it" , Damn the Torpedoes!
The worse that's going to happen is that there will be a pile of parts where a motorcycle once stood.

When I think of the amount of money that I have tied up in tools (not just wrenches and sockets either) needed to work
on my bikes, If I had to buy it all again, it would be cheaper to send the engine out for rebuild.

I am sure that the quality of work would be better too if someone like comnoz was to do it in his shop compared to
someone doing it themselves on the kitchen floor with a hammer and pair of vice grips.
 
Mght be a good idea to look up http://www.norvilmotorcycle.co.uk/ and read TechTalk number 10. I have no experience with Commando cams but reading this indicates it is a job requiring a lot of skill and judgement; that is if Mr Emery is to be believed and that he is not over-hyping it meet his own ends!
Good luck!
 
Ahh, I will never have those days on my custom. I installed a quick change bearing holder. I can have the cam out in 15 minutes. Only removing the timing and intake and exhaust covers.
Hopefully I don't need to do it on my combat, but If I do i'll install another quick change.

Good luck with yours, I haven't pulled an e-start down, but from what I have seen there are a lot of parts in that primary.

It would have been nice if the factory did this in the first place. Also should have added a quick change horn holder too :D

76 Commando 850 Cam install
 
Thanks everyone for the response.

There's more to this story. It's not even my bike. It's belonged to my mother since she was in high school. My grandfather went through it and tried to restore it. Unfortunately I don't think he's quite the mechanic he used to be and the bike didn't run very well. I talked her into letting me look at it. We were messing with the points and some how my buddy twisted the breaker cam bolt off. :shock: We tried to use an easy out but it didn't work and I'm sure we ruined the cam. I bought another cam thinking we could do it but now I'm not so sure.

Can anyone give me an estimate of what the job aught to cost? Assuming I took them the engine and primary in one piece? I had a guy quote me $1800 just to install the cam. :?
 
You might make inquiries of a machine shop with EDM or Electronic Discharge Machining equipment. Ask them if they have the ability to zap the remains of that broken bolt out of there.
 
Worth a call to a good machine shop with the EDM capability. There was a guy in Orange County who did great work--in Santa Anna I think. Lot cheaper than a complete tear down unless more work is required--then just depends of how well you want the bike to run when finished---and how reliable---well--to some degree anyway.
 
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