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watson
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I am working on a 1966 R69S that has a strange starting problem. The engine is a fresh rebuild with about 5,000 miles. When I try to start the bike cold, I turn on the gas and ignition with no tickle. When I kick it over, sometimes it will start and run slowly as it warms up. On some tries, it will start for just a second and then die. When this happens, it is a problem to get it to start again. After many kicks it will finally start and run fine. I have been through both carbs and everything is clean and correct in both. I adjusted the valves and checked compression, both cylinders are fine. Once the bike is running, it is fine. I have a 69 R60/2 and I use the same starting procedure with that bike and it starts and runs like a dream every time. In trying to figure out the R69, I have started to suspect the magneto. Is it possible that the mag is weak and the first kick after the bike has been resting for hours results in a little hotter spark that subsequent kicks? Also, is there a way to check the mag output?

Thanks,

Doc

schrader7032
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I assume you've been through

I assume you've been through the basic settings for the ignition timing as well as the magneto timing...they're different, of course.

On the R60/2, sounds like you've figured it out. But there's no guarantee that starting procedure will work for the R69S. My R69S is pretty touchy to get started, but I do have a routine...it seems to easily flood. If it starts and I have trouble getting it started, usually I have to flush out the combustion chambers of any residual gas fumes. I open the throttle wide open and kick maybe 5-6 times. Usually then, it will start with little to no tickling. So, you might try that if it starts and then dies...assume it's flooded. If you're not sure it's flooded or not, you could pull a plug and see if it's wet or not.

Off hand, not sure to know if the mag is OK or not, other than to put a spark plug into the high tension lead and strap it so the plug's threads are grounded to the engine fins. With ignition on, kick the bike and look for a white/blue spark which is good; yellow spark means not good.

How are the safety gaps at the magneto coil? They should have a gap of around 10mm.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

808Airhead
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If you think your mag is

If you think your mag is weak,close up the spark plug gap a little.

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Thomas M.
R69s - R60/2 - R67/2 - R51/3

Twocams
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Right Kurt. But I turn the

Right Kurt. But I turn the gas off after the inline filters are full. That keeps it from flooding. 99% of the time it will start. Then turn the gas back on. And ride away into the sunset. I use the same tactic for a hot engine but have to open the throttle a little, Then kick her good.

twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

Daves79x
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You Can

You can check the magneto rotor by removing it and seeing if you can pick it up with a large open-end wrench. If it will lift off the bench, it's probably got enough magnetism, if not, it needs re-magnetized. Then, as Kurt said, very carefully time the magneto, then statically time the ignition, paying very close attention to differential timing. If that does not produce good results, and the bike has the original coil, I'd replace that.

All that said, I agree with Kurt also - the R69S can flood very easily.

Dave

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wa1nca
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the R69S can flood very easily

Yes
Before I shut my bike off I always turn off the gas and run it for at least 500 feet and then shut it down

Vech has told me that once the plugs have fouled then are junk
Says don't try cleaning just replace them B7HS for the r69
If my bike starts hard the 1st thing I do is replace the plugs even if they look ok and It starts right up

I also have my idle set a little higher for this bike as it wont take gas when cold because of the lack of a choke and wants to stall when giving it the slightest amount of throttle
For a faster warmup after it has been started I will put my hand over the inlet on the air filter to richen the mixture
( I am assuming you do not have a choke on your air filter box)

Try another set of plugs !!

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

schrader7032
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Quote: Vech has told me that

Quote:

Vech has told me that once the plugs have fouled then are junk

I've heard that from him and others. Define junk. Does that mean the plugs will never work again or that their life is limited??

To be honest, I'd have to fill my garage with boxes of spark plugs if this were true. I've had issues starting my bikes but I usually figure out that my technique was wrong. I regroup, try opening the throttle to dilute the mixture, and restart the process. I've never replaced plugs just because I had a bad day starting the engine. YMMV.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

wa1nca
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Plugs

It has worked for me
Doen't hurt to try

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

watson
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Thanks everyone, these are

Thanks everyone, these are great suggestions and they give me a direction to head next. I should have included that I went through the ignition set up as part of the work that has been done so far. I also appreciate the starting suggestions. On my 69 R60, I always turn off the gas and let the carbs drain a bit before shutdown. I had not thought of turning it off as part of the starting routine. I will try that on the R69. If it turns out to be a fuel issue that will be good news.

Doc

Danedg
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Properly grounded magneto

A properly grounded magneto is essential for the ignition system to fire reliably. Your plugs, caps, wires and coil all need to be zero resistance and thoroughly grounded. Often overlooked is the magneto assembly itself. It looks clean, but after 50 years, electrically it is not. Add heat and your magneto resistance to the block goes up, and your ground is compromised. This is why these bikes will start fine when cold but can be a bugger when hot. Remove the whole deal and carefully "clean" all mating surfaces from the points plate back to the timing case cover. 300 grit sandpaper works well. Your magneto assembly will then regain zero resistance (continuity) to ground, allowing the coil to "fire" properly. Try it, you'll like it!

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'54 R51/3, '65 R60/2, '69 R60/US, '95 Mystic, 74 MG Eldorado

watson
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OK, I tried all of the

OK, I tried all of the starting variations and the problem persists. I have been thinking of installing a Power Dynamo system, so this might be a good time to do that.

Doc

miller6997
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About the magneto...

I can confirm the previous poster's comment about the importance of magneto grounding. Some time ago, I spent weeks chasing hard-start gremlins and at some point Vech explained the importance of disassembling and thoroughly cleaning the mag surfaces. There are at least three different metals involved, and even though they may look clean, the grounding can be compromised by the accumulation of corrosion over the years. It's not a hard job to do, and in my case it made a very big difference.

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Jon Miller
'67 R69S
'13 F800GT

schrader7032
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IMO I'd determine exactly

IMO I'd determine exactly what the problem was. If it was electrical then maybe consider the new system. Sometimes throwing money at the problem just lessens your wallet. YMMV.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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