engine removal

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Fossilrider
Posts: 36
Joined: Fri Oct 06, 2017 2:49 am
Location: Chattanooga, Tn.

Re: engine removal

Postby Fossilrider » Mon Feb 01, 2021 2:56 pm

Wow, is my face red! Yesterday I turned the engine over, again, to the point where is "stopped" and felt like it wouldn't go any farther. I then pulled the head back off and looked very closely to see any signs that anything at all had touched any other part, and could find nothing.? So, after a lot of head and butt scratching, and rechecking all the timing marks, I re-installed the head. I then turned it over again to the "stopping point" and started to gently nudge it farther.... and it went farther!!!! It made a complete revolution. I then turned it several more revolutions and realized that what I thought was some collision was actually the resistance of the valve springs. I had no idea it would be as strong as it is. HUGE relief! So I think I am now ready to forge ahead with the project. I guess if I had been turning it over faster I wouldn't have noticed the resistance so much, but since I was being very slow, to not damage anything it felt like something was holding it inside.? Other than the paint on the sheet metal, I am on the home stretch. Many thanks to all you guys for the info and help on this. Like I said it makes me feel a little foolish. Regards, Steve

Duccout
Posts: 1285
Joined: Wed Feb 05, 2020 1:20 pm
Location: Essex UK

Re: engine removal

Postby Duccout » Mon Feb 01, 2021 6:06 pm

They are very strong valve springs! Hence the use of desmo valve gear.

Fossilrider
Posts: 36
Joined: Fri Oct 06, 2017 2:49 am
Location: Chattanooga, Tn.

Re: engine removal

Postby Fossilrider » Fri Feb 05, 2021 2:43 pm

Since you guys have been so great to offer info and advice, let me lean on you once again. I am at the point that I need to set the valve clearance and ignition timing but the manual is a bit confusing on these, at least to me. First, what is up with all the process they go through about using a degree wheel to get the degree of advance? I have been working with ignitions for decades and have never had to do this to set the timing. Are there no timing marks to set it by? And second, If I am reading it correctly, they valve clearances are 0.002" intake and 0.003" exhaust. Seems a little tight to me. Anyway, thanks in advance for any enlightenment.

Bob_Matthews
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Joined: Fri Sep 18, 2020 11:32 pm
Location: Surrey
Contact:

Re: engine removal

Postby Bob_Matthews » Fri Feb 05, 2021 3:14 pm

Personally, I never use a degree wheel or use the manufacturer's settings for ignition timings (others may disagree) as a lot depends on the fuel used and other conditions.

To initially set the ignition timing I get the piston just before top dead centre on the compression stroke and then rotate the points backplate until the points are just opening, this should get you in the ball park and allow the engine to be started. I then advance the ignition until I'm getting an amount of kick back upon starting and then retard a tad. This will be close so long as your advance/retard unit is working as it should. I will then do a road test and advance the timing until pinking is heard when in top gear at about 30 - 40mph on full throttle, if pinking is heard I retard until the pinking disappears and then retard just a tad more to be on the safe side. This method has always worked for me on old bikes and touch wood, I've not had any problems, but you do need to know what to listen for and how pinking sounds.

Not sure about your valve clearances as they vary from engine to engine.

Jordan
Posts: 1380
Joined: Fri Dec 24, 2010 11:29 am

Re: engine removal

Postby Jordan » Fri Feb 05, 2021 11:43 pm

A degree wheel is the classic tool for checking engine timing.
They can be large for easy static viewing, or smaller and more robust for convenient strobe timing with the engine running.
A stick or dial gauge can also be used for static checking by piston movement in a straight line.

I have an old converted 12 inch LP record, marked on the outer edge with the degree scale.
It's by the Village People - Can't Stop the Music, but any old record would probably work.

Bevel bob
Posts: 1043
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: engine removal

Postby Bevel bob » Sat Feb 06, 2021 9:02 am

I set timing as Bob Matthews, set the static timing just before tdc and adjust with tiny movements of the points assembly to arrive at situation where its just possible to provoke a mild kickback if you are not positive enough with the kickstart.If you still have points you can fine tune the timing by opening or closing the gap by a thou or two. This only works if you have the advance retard unit as fitted to Monza ,Mach1 etc that has a mechanical 18 degree range that equates to 36 in use.

blethermaskite
Posts: 477
Joined: Thu Mar 01, 2018 1:06 am
Location: northern ireland

Re: engine removal

Postby blethermaskite » Sat Feb 06, 2021 10:00 am

Have to agree with both Bob's.....within a fine line of adjustment every engine has an ideal ignition timing and it is seldom exactly the same for two similar engines, there are so many variables...mechanical condition of the engine, compression ratio, carburettor condition, sparkplug type, chemical formulation of fuel, average air temperature and altitude, we are only talking variations in timing of maybe 1/2 to 1 degree between similar engines but this could be worth as much as 5% total power output of the smaller singles, so as described just set the static timing a "smitge" before tdc on the compression stroke then start adjusting in more advance by small increments and road testing each adjustment at relatively low speed (40mph) under load(up a gentle gradient) in top gear until the engine starts to pink ......... then start retarding by tiny increments until (under the same loading) the pinking is gone. And that's the ignition timing for "your" engine. :)
Cheers,
George

Fossilrider
Posts: 36
Joined: Fri Oct 06, 2017 2:49 am
Location: Chattanooga, Tn.

Re: engine removal

Postby Fossilrider » Sat Feb 06, 2021 6:49 pm

Great info. This is how I have always set the timing on cars, then, when you can, check with a strobe timing light. As to the second part of my question, is the valve clearance setting of 0.002" intake and 0.003" exhaust correct? Thanks so much for the help. Regards, Steve

Davescycles72
Posts: 27
Joined: Fri Jun 11, 2021 4:03 pm
Location: Johnson City, Tn

Re: engine removal

Postby Davescycles72 » Mon Jun 14, 2021 12:22 pm

Monza, and GT is .002 intake,.003 exhaust. Some just do .004 for both for safety


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