Bike choking on rainy ride home

[Luca]

Hi everyone.

The bike: 1982 R65LS

The Problem:  When riding home from work yesterday my bike started choking.  I thought maybe I was running out of fuel, or that my new tank bag was smothering the cap vents, but neither were the case.  It felt like it was running on one cylinder.  Keeping the revs up kept the bike going, for the most part...  it also got me the hairy eyeball at the couple stoplights I take after the highway

Here are my considerations:
Water plugged up the vent on my tank?  The cap is still a little wobbly because I haven't drilled a hole and put a nail in it yet.  Doesn't screw fully home into the tank.  However, perhaps more likely...

Water in the gas?  I need to check the carb bowls... but I decided last night to just park it and keep a cool head.  Still, doesn't explain the one cylinder thing.

Crud in a carburetor?  I did just rebuild the petcock (or tried to... Beemershop sent me 1 part out of 4 that fit) and the tank liner is removing itself pretty quickly.  I do have an in line paper filter installed, and it stays clean because my tank screen is good.

Something electrical...  I have waterproof plug caps, so I don't think it would be them.  My electronic ignition has new thermal paste on it, so I doubt I've fried that.

I'm guessing something behind the front engine cover... Only problem is I don't know what I'm looking at down there.  Any ideas on what to look for are appreciated.  I've got a digital multimeter, and with some direction, can stick my probes in the right place    Seriously, I'll try anything shy of dielectric grease in a super soaker

My current plan is to make sure I have no water in the gas and see if drying the bike out gets her going right again, indicating an electrical problem (that I hope won't plague me on my ride to upstate NY this Friday)

Thanks in advance,
Luca

[Bob_Roller]

Do you still have the OEM black and gray ignition coil .

It develops cracks in the plastic case and give problems in damp/ wet conditions .

Remove the tank and see what you have, if you still have the original, repalce it now .

A popular aftermarket replacement coil, is the DYNA 'brown' coil .

Probably the least costly place to get them from, it comes with an adapter bracket, 30 minute installation .

http://www.motoelekt.com/ignition.htm

Also, how old are the ignition wires ?

[montmil]

Luca, Do you still have the OEM ignition coil on your bike?

It's a gray and black evil thing affectionately known as the "Crack-O-Matic."  

These Bosch coils have a propensity to develop tiny, hairline cracks that create massive headaches and often cause large amounts of cash to disappear from the owner's pocket. Many of us have been there...

My '81 R65 did the same thing on wet or even simple dewy mornings. As a newbie to the forum, I was encouraged to check the Crack-O-Matic. It looked OK at first glance but a wipe down and closer inspection revealed... tiny cracks on the end. That's all it takes to create operational problems.

A Dyna "brown" coil from Rick Jones at Motorrad Elektrik cured all.

http://www.motoelekt.com/index.html

[Bob_Roller]

If it looks like you may ride in wet weather this weekend, you could probably coat the coil with a rubber sealant (RTV type material) to help keep water out of the coil .

[Luca]

Montmil and Bob, I am still running on the factory crack-o-matic.  And here I am thinking you had to pay extra for that.  I still haven't checked the coil for cracks--it's been a busy week--but it sounds like I should just replace the thing anyways since it's a question of when, not if.

I did think of putting some dielectric grease or silicone over cracks if I find them as a temporary measure, although it seems a bit risky.  Whole weekend looks like rain, which puts a sure damper on my plans to drive around on the tractor and do some plinking with the .22  ...breaking down on the turnpike sure wouldnt help.

Also Bob, the ignition wires are only a couple months old.

Looks like I'll head over to Motorrad Elektrik then.  Might even pick me up a copy of the famed Classic Boxer Charging V.2  

Thanks for the help,
Luca

Edit:  Update.  The coil was indeed cracked just like in the photo (on the water scooping side).  It dried out and the bike runs properly again, so Ive slathered some rtv over it.

Looking at Rick Jones' site, I might go with the heavy duty ignition module and coil, eventually working up to a digital bean can.  My advance seems to be a little sticky already (high idle sometimes, and revs that dont always like to drop).  Part of getting a  bike that spend most its life sitting I suppose.  Any opinions on going with the Dyna BLUE?

[montmil]

You really can't go wrong with the Dyna brown coil... although it sure looks orange to me. Easy install and has excellent instructions and mounting hardware with the coil.

I have since replaced the OEM voltage regulator with the solid state unit and now get a much healthier charge into the battery.

The Ignition Control Unit (ICU) is between the coil and regulator components. Note the slight amount of heat sink paste squeezed out from between the ICU and the aluminum heat sink. This is something else you may want to check. Small tubes of the paste are available at Radio Shack.

Catch Rick Jones soon if you plan on ordering parts as he will be at the AHRMA / Barber Motorsports Park event 11-14 October. I'll usually find him hangin' out at Airhead Central.

[Luca]

Monte,

I did end up getting the brown coil after talking to Rick.  Got an LED tail/brake light, and his book too.  Maybe one day I can beat both you and Ausherman to the punch on electrical questions  

And yes, my ICU has got a nice thin layer of the fanciest thermal compound Radio Shack carries--Arctic Silver 5--Keeps my computer processeor down to a cool 21C to boot

[montmil]

Good choices, Luca. You da man.