Starting an 850 after 8 years

J

jh850es

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May 28, 2022
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My dad has a '75 Commando 850 electric start that has sat for at least 8 years. It's been garaged so is just a bit dusty. Should I do anything to prep it, besides draining the float bowls and tank, before cranking it? It was restored in the early 2000s and only ridden a few times after that before various events made my dad stop riding.
 
You might drain the engine sump then check the oil tank. If you need to put more oil in the tank, bring it up to just the very bottom of the dip stick for now. Normal oil weight is 20w50, but for this trial run anything will do.
Of course make sure there is a good charge on the battery.
 
You should definitely remove your valve covers and pour oil into them to drool down and lubricate your cam.
I would also go easy on your starter, kick it to loosen it up then use an assist kick when you are trying the electric.
Jaydee
 
Thanks for these ideas. They sound good. The battery is toast, and will need to be replaced; I've already verified that it loses voltage overnight after being fully charged on a 1A battery tender.
 
It would also be a good idea to check oil levels in the trans and primary. There are level plugs in both.

Glen
 
Everyone has good suggestions for start up. I am a strong advocate in making sure the oil system is primed before attempting to start. After changing oil and replacing oil filter, remove spark plugs and turn over with electric start or by kicking until there is oil returning to the oil tank. If you remove the oil tank cap there is a 5/16 return pipe toward the front of the tank about 3/4 inch down. When system is primed and pressurized oil will flow from this return pipe. It might take 15 or 20 kicks. Install spark plugs and good luck!
 
The clutch plates may have stuck. Kick the bike through gently with the clutch disengaged in gear.

Definitely change the oil and pour oil down the push rod tubes via the tappet covers.

I'd change all the oils and before riding replace the front and rear brake hydraulic fluid. Check the lines for leaks or perished pipes. Check tyres etc.

I'd give all cables chains etc a good lube. Wouldn't hurt to give the whole bike a good spray with WD40 and an oily rag wipe down. That will help you to notice anything loose. These bikes have a habit of corroding electrical connections while stored so if the kill button is still connected you may well find it does not have good continuity. Also the main switch or lever switches may be a bit unhappy. When I revived my 850 after 10 years stored I had to go through the whole wiring harness with a multimeter and found I think at least three dodgy connections I remember.

Don't let it idle. Once it's started keep the revs above 2000 until well warmed up and the oil is returning to the tank.

Your probably going to need to clean the carbs. As a minimum blow carb cleaner down any openning you can get at.

And maybe shout it some new plugs.
 
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All good tips. Change the oil in the front forks as well. One or both forks could be low or totally empty of oil. Check your private messages. You need to be signed in. Click on the envelope icon at the top/right of the screen to access them.
 
jh850es said:
My dad has a '75 Commando 850 electric start that has sat for at least 8 years. It's been garaged so is just a bit dusty. Should I do anything to prep it, besides draining the float bowls and tank, before cranking it? It was restored in the early 2000s and only ridden a few times after that before various events made my dad stop riding.
Click to expand...
Welcome!

How mechanical are you?

What @johnm and @chaztuna said are all good tips.

When you drain the float bowls definitely blow out the pilot jet. On the outside of the carbs there are two screws- the angled one is the idle screw, leave it be for now. The one mounted flat on the side is the idle air screw. Screw it in making note of how many revolutions, then screw it all the way out and blow carb cleaner and air thru it when the float bowl drain screw is out. Return it to its previous position.

Definitely use new plugs.

I would also pull the petcocks (fuel taps) out and check the filter screens for gunk and that they flow well. The rubber orings in some of them can degrade over that long, and if they are difficult to turn that may be the case.
 
gortnipper said:
Welcome!

How mechanical are you?
Click to expand...

Mechanical enough :)

I've rebuilt GL1100 Goldwing carbs, which I feel should give me a lifetime pass for... something. I got into the Amals on my dad's Triumph T100 Tiger back before I knew anything and managed to get it running, but this is the first time I've confronted Amals since then (30+ years later).

Basically I've done most things short of actual transmission and crankcase internals. But on BMWs and Japanese bikes.
 
I wouldn't drain the float bowls, I would completely pull the carbs down and clean every part in the carbs, as for all oil replace every oil, new battery, pull the clutch plates, lube all cable, go over the whole bike, drain the fuel tank make sure no crap is inside the tank, pour fresh oil under the valve covers and leave over night to run down the push rods, and before starting prime the oil pump, go over the whole bike and replace the brake fluids as well and give the bike a complete clean before even starting on anything.

Ashley
 
jh850es said:
Mechanical enough :)

I've rebuilt GL1100 Goldwing carbs, which I feel should give me a lifetime pass for... something. I got into the Amals on my dad's Triumph T100 Tiger back before I knew anything and managed to get it running, but this is the first time I've confronted Amals since then (30+ years later).

Basically I've done most things short of actual transmission and crankcase internals. But on BMWs and Japanese bikes.
Click to expand...
Then I agree with @ashman disassemble the carbs and give them an ultrasonic clean. Keep R/L parts separate. Note the screw and needle positions and measure the slide heights with a drill bit under the slides to measure the gap. Replace the gaskets and o rings. Don't over tighten the top and bowl screws, as the pot metal will distort.


Amal Concentric Tuning

The 5 stages of an Amal Concentric
www.accessnorton.com www.accessnorton.com

 
Last year I bought a Mk III that hadn't run in 11 years. I replaced some seized cables, changed the oils, gave the carb's float bowls quick clean up and with a new battery and fresh gas it fired up easily.
 
I once left my BSA A10 for 13 years
I drained the sump ,refilled the oil tank and it started right up as if I'd left it a couple of days no issues at all
It was in a bone dry shed though
 
So I've got enough to go on here. This will probably take several weeks at least, between work and kids and whatnot. I'll update the thread as I go.
 
I recently started my 750 after 31 years parked in my garage. I changed all the fluids, forks, crankcase, oil tank, gearbox, primary chaincase. Then stripped and cleaned the carbs, they were actually in great shape.

Biggest item of work was taking off the heads and checking the valve springs. Was concerned that any valve held open for that length of time would damage the valve springs, and that was the case, the springs were much shorter than they were when fitted, and were now well outside the allowed tolerance.

Got all that done, engine had wet-sumped by the time I got to kicking it over. Moved the oil back up into the oil tank, and the bike started second kick. Amazing!
 
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