73 Commando 850 help!

kommando · Jun 20, 2017

PB Blaster works well, not as good as ATF and acetone but good enough to leave in there and let it do its job before trying something else. I freed an engine up with WD40 and did not further work on it and 5 years later its running fine, caught it just in time.

jzmax22 · Jun 20, 2017

Ok, I'm letting it soak. Patience is a virtue.
I've tried all the tips this great community has offered me.

I removed the primary case cover, put the bike 4th gear and and tried moving the back wheel, it moves about and inch , no movement in the chain in the primary case.
I put a ratchet on the end of the alternator bolt , couldn't budge it.
With the bike in neutral the Kickstart doesn't not even budge.

Is there anything else I should check while I wait for the penetrating oil to do it's magic, besides polishing all the metal on the bike

Also, anyone know what color black paint I should get to touch up the frame??

Thanks again.

Rohan · Jun 20, 2017

jzmax22 said:
Ok, I'm letting it soak. Patience is a virtue.
<snip>
I removed the primary case cover, put the bike 4th gear and and tried moving the back wheel, it moves about and inch , no movement in the chain in the primary case.

Did you see any sign of movement in the gearbox ?
With the bike in neutral, the back wheel should be easily able to be spun by hand,
and the gearbox will be turning over - without trying to turn the engine over.
That way you can also see that the chain is good, and not rusty or frozen somewhere.

Its probably important that you know that the back wheel can easily spin by hand,
and that the gearbox is also free to rotate.
Its not unknown for multiple components to stiffen up over the years, if unattended.
tlc and all that....

jzmax22 · Jun 20, 2017

Rohan said:
jzmax22 said:

Ok, I'm letting it soak. Patience is a virtue.
<snip>
I removed the primary case cover, put the bike 4th gear and and tried moving the back wheel, it moves about and inch , no movement in the chain in the primary case.

Click to expand...

Did you see any sign of movement in the gearbox ?
With the bike in neutral, the back wheel should be easily able to be spun by hand,
and the gearbox will be turning over - without trying to turn the engine over.
That way you can also see that the chain is good, and not rusty or frozen somewhere.

Its probably important that you know that the back wheel can easily spin by hand,
and that the gearbox is also free to rotate.
Its not unknown for multiple components to stiffen up over the years, if unattended.
tlc and all that....

When in neutral the back wheel does spin freely. how should i observe the gearbox? open the filler cap?

Dances with Shrapnel · Jun 20, 2017

What I suggest you do regarding Rohan's suggestion is:

Place the bike in a gear and pull in the clutch and try turning the rear wheel. It will budge and should turn (through the gear box) but reluctantly as there's considerable drag in the clutch. You won't see the clutch basket turn.

Try it in every gear to confirm you can turn the wheel in each gear with the clutch pulled in. If the wheel turns very freely as if it were in neutral, there's probably something wrong with the gear box.

Somebody correct me if I am wrong here as it has been a long time since I kick started a Norton Commando but you could achieve the same thing by putting the bike in a gear while on the center stand, pulling in the clutch and then gently kicking it through - the rear wheel should turn in each gear while you are kicking with the clutch pulled in.

concours · Jun 20, 2017

Primary kick starting lads, Norton does NOT have it.

https://www.jsae.or.jp/autotech/data_e/4-11e.html

Dances with Shrapnel · Jun 20, 2017

concours said:
Primary kick starting lads, Norton does NOT have it.

https://www.jsae.or.jp/autotech/data_e/4-11e.html

What this means, for the benefit of jzmax22 and others is that on your Norton you can pull in the clutch lever and while in gear and kicking the kick starter, the rear wheel should turn as I suggested above.

I really don't think you have a gearbox problem.

Rohan · Jun 20, 2017

Dances with Shrapnel said:
I really don't think you have a gearbox problem.

Already confirmed that there is no gearbox problem - "When in neutral the back wheel does spin freely."
So all that part is good.

When I got an 850 that had sat in someones back yard for several years, the pistons (rings) had well and truly stuck to the bores. Took a lot of soaking with WD40, oil, diesel, etc until jarred them loose with a large block of wood - with the head off. Left rust marks in the bores that might have "polished off with use", but I had it rebored with new pistons/rings. Good luck !

jzmax22 · Jun 21, 2017

Quick update,

Checked this morning, wasn't expecting much, still froze.

I did notice the chain in primary wants to move, but the alternator cog won't budge

With the bike on the center stand and in 4th gear, I'm just gently rocking the rear wheel back and forth. I can see the chain trying to move the clutch assembly, the chain in the primary slackens ever so slightly. Just keep waiting.

If I decide to try a different penetrating oil, is there a way to drain what's in the engine now?
Right now it's a mix of 50w oil and pb blaster (a whole can). It wasn't an intentional mix, there just happened to be oil in there when I filled it with PB blaster.
I'd like to try acetone and ATF , seems a lot of people have had good luck with it.

Thanks again!
What a great community.

kommando · Jun 21, 2017

Only way is to suck it out with syringe and plastic flexible pipe or a sump pump through the plug hole, you don't need to get it all out just enough so the new stuff you put in is most of the resulting mix. An 850 has flat piston tops so as soon as you can see piston most of the fluid is out. Its the alternator rotor you want to see moving, once it starts to show the slightest movement then it will not take much more, rocking back and forth will achieve a lot more than brute force in one direction.

jzmax22 · Jun 21, 2017

Thanks for the quick reply. Think I'll try that later. How are you guys seeing down the plug holes. Any type of light that's better than others, I use a super bright light, just can't see anything when looking in there, maybe a glimpse here and there!

jzmax22 · Jun 22, 2017

Update:
24 hours of soaking with ATF and acetone, still no movement yet.
I know , I still have alot of waiting. I filled the plug holes to the top, maybe a little too much, had fluids come out of the exhaust.
I'll just keep coming back and rocking the back wheel every few hours.

concours · Jun 22, 2017

jzmax22 said:
Update:
24 hours of soaking with ATF and acetone, still no movement yet.
I know , I still have alot of waiting. I filled the plug holes to the top, maybe a little too much, had fluids come out of the exhaust.
I'll just keep coming back and rocking the back wheel every few hours.

The penetrating oil fable is a romantic old tale, based on ancient stories of tractor (5:1 compression) engines. Iron oxide is harder than all adjacent parts. IF you could possibly get it to start, it will quickly consume itself.
At this point, diassembly is in order.

Also, as a service to any doubters, I invite any poster that is currently RIDING a bike that was stuck solid and the engine rescued with snake oil, to chime in.

jzmax22 · Jun 22, 2017

concours said:
jzmax22 said:

Update:
24 hours of soaking with ATF and acetone, still no movement yet.
I know , I still have alot of waiting. I filled the plug holes to the top, maybe a little too much, had fluids come out of the exhaust.
I'll just keep coming back and rocking the back wheel every few hours.

Click to expand...

The penetrating oil fable is a romantic old tale, based on ancient stories of tractor (5:1 compression) engines. Iron oxide is harder than all adjacent parts. IF you could possibly get it to start, it will quickly consume itself.
At this point, diassembly is in order.

Also, as a service to any doubters, I invite any poster that is currently RIDING a bike that was stuck solid and the engine rescued with snake oil, to chime in.

I take it the penatrating oil has never worked for you. Thank you for the input, I'm in no rush, so I'll give it a week or two and then on to disassembly.

kommando · Jun 22, 2017

I invite any poster that is currently RIDING a bike that was stuck solid and the engine rescued with snake oil, to chime in.

Chime, worked for me twice including on a Briggs alloy bore.

jzmax22 · Jun 22, 2017

kommando said:
I invite any poster that is currently RIDING a bike that was stuck solid and the engine rescued with snake oil, to chime in.

Click to expand...

Chime, worked for me twice including on a Briggs alloy bore.

Good to hear, did you also use atf /acetone mix?

kommando · Jun 22, 2017

First one was diesel, second one was WD40. The diesel took a week of daily rocking back and forwards before the first movement, but then within 15 mins it was free. Second with WD40 (had run out of my PB Blaster which is miles better but unavailable in UK, I bought 2 cans back in hold luggage and it should have been more

) , took 2 days but the engine had been free 18 months before.

jzmax22 · Jun 22, 2017

kommando said:
First one was diesel, second one was WD40. The diesel took a week of daily rocking back and forwards before the first movement, but then within 15 mins it was free. Second with WD40 (had run out of my PB Blaster which is miles better but unavailable in UK, I bought 2 cans back in hold luggage and it should have been more ) , took 2 days but the engine had been free 18 months before.

Thank you for the story, I think that's the road I'll take, its soaking in the ATF/acetone . I go to the garage a few times a day and just Rock the rear wheel, kinda relaxing.
Also gives me time to polish and clean all the little bits on the bike.
Thanks again . Great community here.

Tin Man · Jun 23, 2017

Also, as a service to any doubters, I invite any poster that is currently RIDING a bike that was stuck solid and the engine rescued with snake oil, to chime in.[/quote]

Not me! I worked at freeing the engine for about six weeks before finally giving up. After it was torn down I discovered that the right cylinder had water in it and was frozen solid. It would have never run, or if it did, it wouldn't have run long.

My advice is to tear it down.

(And at a minimum, for your piece of mind, you'll want to make sure that it has superblend bearings on the crank, that you've properly installed a reed-valve breather system, and that it has new gaskets and rod bearings.)

Congratulations.Photos please.

grandpaul · Jun 23, 2017

concours said:
The penetrating oil fable is a romantic old tale, based on ancient stories of tractor (5:1 compression) engines. Iron oxide is harder than all adjacent parts. IF you could possibly get it to start, it will quickly consume itself. At this point, diassembly is in order.

I bought a '67 Honda CL77 / 305 scrambler that was stuck, seller claimed it was a jammed kicker gear, right.

I still had a gallon can of WD40 that was about 1/3 full, that my Dad left in his boat shed; I poured the cylinders full and let them sit a few day - no joy. I also had some ice maker cleaner from my A/C repair days, poured THAT in and let is sit a week - no joy.

Then I tried brake fluid for a few days, after removing the head. One pop with a hunk of 2x4 trimmed to fit in the bore, and the pistons slid to BDC.

I replaced the rings, gave the bores a quick pass with a ball hone, and rode that bike hard for a couple of years, mostly off-road. You can believe me or not, but it didn't smoke more than a whisp at start-up, and ran great. Sold it a few years ago, buyer reports much fun, zero smoke.

73 Commando 850 help!

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