Condensor insulation melted (twice )

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Dave Reina
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Joined: Sun Nov 21, 2010 11:23 am

Condensor insulation melted (twice )

Post by Dave Reina »

My 1980 R65 has twice melted the plastic insulating block causing the spade connector to short out to the metal points case (soup can style on my bike.) Is the motor getting too hot or is the plastic used for the insulating block an incorrect material? Is some electrical problem causing the condenser to overheat and melt the plastic?

Bike is very stock with emissions parts still present. I have been having trouble getting it to run well. So far have rebuilt carbs, adjusted valves, new points, condenser (twice), plugs, plug wires, and coils. Bike has power past idle but I have been having trouble getting a good idle. I may have had the carb jet needles in the wrong position and today had moved them from what I think was the 4th groove to the 3rd groove. I was a mile or so into my test ride in bumper to bumper city traffic. The bike quit because of this plastic meltdown which caused the condenser connection to short out to the engine metal and kill the ignition.

I had to push the bike about a half a mile to my work place.
In the photo the translucent grey stuff on the points can is the melted plastic. I chipped off the melted plastic and tomorrow may try to see how much heat it takes to melt. Has anyone seen this problem before? The condenser box said Made in Turkey.
Dave
Dave Reina
Brooklyn, NY

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srankin
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Location: Spencerport, NY USA

Re: Condensor insulation melted (twice )

Post by srankin »

Dave, yes there is a problem, LOL, sorry for the laugh.

You should not be melting condensers period. So, I would get yourself a wiring schematic and very carefully go over the ignition wiring circuit with a fine tooth comb and look for either a short, a wire out of place in the system.

Did you install a good set of points and not cheap ones?

I don't know what skills or tools you have but I would revisit and make sure the new coils and leads are the proper parts for the bike. I mean they have proper resistance as in spec. Snowbum or somewhere on the internet or a shop manual will have the specs for the coils and leads.

This is an electrical problem and not a carb or valve problem. Sorry there is not more I can do for you, good luck. St.
Owner of a 84, R80RT and 78, R100RS

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Dave Reina
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Re: Condensor insulation melted (twice )

Post by Dave Reina »

Hi St.
First new set of points and condenser were a cheap set sold as a pair. When the first plastic melted I said ah ha, cheap set and I ordered a $25 points and $25 condenser from MAX. (however I'm not positive I put the expensive condenser in. It may have been another less expensive one.).

I did wonder if it could have been caused by a bad coil. I removed both, one had very corroded terminals. Again, ah ha that's it. Cleaned the terminals well and tested and it seemed the resistance was in spec. Put the bike back together and it still ran badly. I wanted to order new coils but everyone was out of stock until recently when Euro Moto got them in. My mistake but I didn't test the new coils resistance before installing. Its possible they are wrong as 1980 was a transitional year for ignition. I will check today.

And I will go carefully over the wiring. This bike has been resisting getting a new life. First the tank which I spent so long cleaning only to find too many pinholes and now motor running issues.
Dave
Dave Reina
Brooklyn, NY

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schrader7032
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Re: Condensor insulation melted (twice )

Post by schrader7032 »

I thought 1981 was the transitional year when they moved towards the electronic ignition. Unless it was different for the R65.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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srankin
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Re: Condensor insulation melted (twice )

Post by srankin »

Hello Dave,
Double check and triple check your wiring to the coils and points. Also, at my friend's shop it was mentioned that yes the higher output coils could cause problems, sadly none of us have heard of melted condensers.

FYI, here is an interesting article about /5 system however the theory is the same for all the point bikes /5 to electronic ignition /7.

Good luck with the hunt and let us know what you find either as you go or if you find and correct the problem. St.
Owner of a 84, R80RT and 78, R100RS

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srankin
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Re: Condensor insulation melted (twice )

Post by srankin »

I do believe 81 was the first year for electronic ignition, I have never heard of 80 bikes being built one batch points and one electronic. However sadly my experience with the R65 bikes is limited and they can be a different animal in some cases.

A great bike, don't get me wrong but I wonder sometimes why BMW had to make things a bit different for them versus the bigger bikes. St.
Owner of a 84, R80RT and 78, R100RS

Caferacer
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Re: Condensor insulation melted (twice )

Post by Caferacer »

1980 was last year for points on the R65
1981 was first year for electronic ignition
the condenser body should NOT be insulated, it MUST have a good ground
is it possible that someone replaced the clamp that holds the capacitor (condenser) with a generic hardware store insulated clamp?
if so the capacitor/condenser body would not be grounded properly,
I imagine it could overheat and fail? not sure, never tried doing that

Caferacer
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Re: Condensor insulation melted (twice )

Post by Caferacer »

if however you are referring to the plastic piece that isolates the hot lead for the points, that is another issue
if that is melting it is doubtful that an electrical fault is the cause, as it would require a large power drain that would blow fuses and melt wires long before damage to the isolator block could occur.
if the points canister is heating up enough to melt stuff, it could be one of the the support bearings, inner or outer, in the canister has failed and is generating excess heat through friction,
I would suggest using a digital heat gun to determine exactly where the heat is coming from
and inexpensive and indispensable tool

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Dave Reina
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Re: Condensor insulation melted (twice )

Post by Dave Reina »

This bike has the can (soup can) which contains the points and the advance mechanism. I like this system as you remove the whole can and can go to a workbench to change the points. The condenser is mounted on the outside of the soup can. It has a square shaped plastic isolation piece which plugs into a square hole. On both the outside and inside of the isolation part is a spade connector, the inside connects to the points and the outside to power when the ignition is switched on. Then the actual condenser has a foot which when you screw down the condenser holds the isolation piece from coming out. So it is grounded.
Dave Reina
Brooklyn, NY

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srankin
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Re: Condensor insulation melted (twice )

Post by srankin »

Okay Dave, I have worked on that point system on my friend's 80 RT so I am vaguely aware of the set up. How about if you could post a picture of the failed parts, just to clarify the issue? I have to dig back into my teflon memory a bit and some of the knowledge may have slipped out.

Caferacer's reply to your post makes me wonder exactly what you mean by melting. Despite what he says, an electrical issue still could be the problem. But he makes a point, in why is there not other damage as well?

LOL, I am too lazy right now to dig out the schematics for your bike but I almost think there is no fuse in the ignition circuit to blow. Teflon memory serves me that the fuses are for lights and such. I could be wrong and if I am in the shop I will check to see if I can find the proper schematic to check to see I can perhaps spot a wiring area that may cause your problem.

St.
Owner of a 84, R80RT and 78, R100RS

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