Reviving a battered 1200

E

Ernestee0

New member
Location
Netherlands
I recently purchased a 1200 from 1978.
Details:
  1. Wire wheels
  2. Zinc coated frame, or alike,not sure yet what it is :)
  3. Stainless exhaust with no baffle
  4. Open trumpets

  6. Owner indicated state
    1. Fully functional
    2. Running fine
    3. Needs some attention
  7. Owner indicated improvements
    1. Completely overhauled engine
    2. Overhauled carburettors
    3. New tyres
    4. Brakes revised
All that done between it's birth and present state
If make a list of everything wrong wit this bike you would be astonished, but I will tell the story for the fun and learnings of it
 
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Ernestee0 said:
I recently purchased a 1200 from 1978.
Details:
  1. Wire wheels
  2. Zinc coated frame, or alike,not sure yet what it is :)
  3. Stainless exhaust with no baffle
  4. Open trumpets

  6. Owner indicated state
    1. Fully functional
    2. Running fine
    3. Needs some attention
  7. Owner indicated improvements
    1. Completely overhauled engine
    2. Overhauled carburettors
    3. New tyres
    4. Brakes revised
All that done between it's birth and present state
If make a list of everything wrong wit this bike you would be astonished, but I will tell the story for the fun and learnings of it
Click to expand...
I doubt that we'll be astonished.
We've seen plenty, but go ahead.
Paul
 
I am an engineer, and think of machines in risks and requirements, so did I procure this bike.
Compression 8.0 Bar and running like shit, blue smoke and black smoke.
It had the original bosch ignition and pickups, ND clocks, bodgy wiring, but the reassurance that all was revised, overhauled and attended to.
Interesting project for me, as I had already owned an original SFC bought from Richard Slater and missed it, a whole different story.
So I set up a project file, assessed risks, costs and feasibility, but in fact really wanted the bike.
 

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Ernestee0 said:
So I set up a project file, assessed risks, costs and feasibility, but in fact really wanted the bike.
Click to expand...

Welcome to the club Ernestee0! I think I know what you're talking about and also did kind of comprehensive lists before deciding a purchase. But also I know the point when I stopped doing this approach because I wanted the bloody thing ...
:cool:
 
Ernestee0 said:
I am an engineer, and think of machines in risks and requirements, so did I procure this bike.
Compression 8.0 Bar and running like shit, blue smoke and black smoke.
It had the original bosch ignition and pickups, ND clocks, bodgy wiring, but the reassurance that all was revised, overhauled and attended to.
Interesting project for me, as I had already owned an original SFC bought from Richard Slater and missed it, a whole different story.
So I set up a project file, assessed risks, costs and feasibility, but in fact really wanted the bike.
Click to expand...

Orange... makes grown men wet their undies. Works every time. :ROFLMAO:

piet
 
Where do you start, I mean get it running and see what happens, that's what I did, many trials.
-Replacement of the ignition unit,coils
-Jumping back to the rolling chassis, acquiring Arashi shocks, great finish and working for that price!
-Still could not get to run right, suspect ignitor coils after some long researches on the forums.
After this, the ignition should be good and dependable. No such thing, the carbs needed desperate help too!
 
You have the shiny but doesn't work model. Start from scratch and work your way through it. It will come good in the end. The ignition is probably in need of replacement for starters, the insulation falls off at the drop of a hat.
 
100%, the insulation fell of and there was a short circuit in one of the coils. Progressing, going all the way, I found a broken inlet manifold.
I ordered an Ignitech DCCDIP4 unit and experimented with pickups and hall sensors, no avail.
I rechecked carbs, rebuild them, found damaged choke plungers, broken starter jets, leaking float valves, running, but not as it should.
Now took the liberty of completely stripping it and at whatever cost, start rebuilding it .
No end to the agony, I am still in the process of assessing the total damage.
Will keep you posted
 
Replace all the ignition parts including spark plugs to the run/stop 12V feed wire, everything in between. At least that will cut down the mystery chases... have fun. BTW 8 bar is a bit low on compression though could be the 1200 low comp ratio of the day pistons.

The mind here is not what it once was, thinking of what actually happens when you change low ratio piston for higher ratio, given the crank to gudgeon is fixed, raising the piston top will reduce maximum pre compression fuel load also?.... shout me down... as it may be deserved. j
 
iis_iis said:
Replace all the ignition parts including spark plugs to the run/stop 12V feed wire, everything in between. At least that will cut down the mystery chases... have fun. BTW 8 bar is a bit low on compression though could be the 1200 low comp ratio of the day pistons.

The mind here is not what it once was, thinking of what actually happens when you change low ratio piston for higher ratio, given the crank to gudgeon is fixed, raising the piston top will reduce maximum pre compression fuel load also?.... shout me down... as it may be deserved. j
Click to expand...
Compression check on an engine that hasn't run regularly in quite a while is of no value, unless there's a holed piston. Because the rings are gummed up and not sealing.
You need to run it a few hours and check again.
Paul
 
I'd have expected 10 to 12 bar compression. 8 bar and blowing blue smoke would seem to indicate that the engine is a bit worn out. But not in every case. There are other possibilities.

The blue smoke could indicate worn rings or valve guides. But as Paul said above, give it a bit of a run to get it up to normal operating temperature and check again when it's cooled down. It might come up OK. (you'll get a higher reading on a hot engine, so let it cool to compare with your first test).

This is all just basic engine maintenance so forgive me if I'm telling you stuff you already know.

If the compression is still low after it's been run for a while, squirt a small amount of oil into the cylinders and re-test. Don't over-do the oil. You don't want it to hydraulic lock the thing, or for the oil volume to increase the effective compression ratio. The oil will help seal the piston rings, so if the compression increases significantly then that indicates gas was leaking past worn or stuck rings. If there's little difference then the valves may need attention. Valve condition can have a huge effect on compression. I few years ago I resurrected a 3C that had low compression on one cylinder and almost zero on the other two. Taking the head off, re-lapping the valves and setting the correct valve clearances brought the compression up to an acceptable value.

Low compression could also be caused by incorrect valve clearances or valve timing. Set the valve clearances to factory spec and try again. If you have a degree wheel, it pays to check the valve timing. Some bikes (including my own) have been found to be a long way out of time. Dialling in the valve timing on my bike improved the compression from about 8 bar to 12 bar.

Black smoke is usually caused by a very rich fuel mixture or very bad ignition timing. Getting those right will make a big difference to the way it runs.

Good luck with the bike.
 
Thanks Dellorto man, I always listen and learn, although I have enough background to now a thing or two about engines. I appreciate any help or comment.
I took the engine out of the frame, just to make sure I was getting this right and found more gruesome evidence of a crash and more evidence of really dodgy repairs.
Engine covers welded, both primary drive side and of course the generator cover. A stripped sump plug, repaired with teflon tape and a helicoil which was protruding into the gears of the primary shaft.
Stripping the engine was a whole new level of pandora's box.Luckily the valve train was in good shape, except for the buckets which seem to have been hammered in at some time in the past. I really got into it now and suspected many more things wrong with this bike/engine.
I will post the pictures to show the "full engine rebuild" results from the previous owner.
 
Congrats on your purchase and well done for taking on a project even if it might have been unintended.
I also have a classic money pit and living on a small island in the Caribbean with next to no local resources the sides of my pit are particularly steep. Its handy to have an engineering background.And deep pockets !
 
Paul Marx said:
Compression check on an engine that hasn't run regularly in quite a while is of no value, unless there's a holed piston. Because the rings are gummed up and not sealing.
You need to run it a few hours and check again.
Paul
Click to expand...
Paraphrasing from Cams erudite posting and hands on skill....

Why i do a dry and wet comp test, as known, it is the comp test variation cylinder to cylinder that rates over actual comp value around here, actual overall comp test readings next on the pecking order.

Or the worst "gummed rings" precept i had on an ,import JDM ( Japanese Domestic Market, ie pulled from a working vehicle in Japan ) Mazda V6 motor, was actually giving a very low overall reading though did compress, reading of 110psi, factory manual 150 minimum. Treated the motor to several chemical soups to free the "gummed" rings, Acetone/ATF then straight diesel, both allowed 7 days to act. Almost imperceptible change in reading, located the real reason, crank gilmer belt pulley was fitted on backwards retarding the cams by 40degrees relative to the crank, inlets were not fully closed at TDC.

Even making a compression reading on a laid up motor has value, yields a workshop state for any improvements down the line, ie if it is rings you will see an improvement, before and after as it were, stand by my measure first precept, real time and recorded data indicates trends, a powerful tool in the right hands if not mind....j.
 
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...indeed, 'tis however a matter of well rounded informed assistance to the persons willing to learn, and all that goes with it. Each owner runs his workshop as he or she sees fit, processes and experience to be had from this forum is varied and many. Job lot as the time honoured phrase imposes, open technical forum as such, will be varied, will be broad in nature.

Never been aligned to the premise of assuming someone knows what is required, that is a damaging premise for new and evolving trades, taught 100's of apprentices and electrical engineering students over many decades. Allow them to be intuitive, provide instructive knowledge in that mix, a skill not oft found in teachers as such. Intent and outcomes, like life, never assured. j.
 
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