no starter when the bike is hot.

[BoxerTwin]

OK, twice now I've had the bike not start after a ride.
I'll stop to get gas, or take in the view. Get back on, press the starter button and nothing.

It only happens when the bike is warm after riding.
It starts the first time once it is cool.

I put a meter on the battery, which I had recent problem with but seems to be fine, and pressed the starter. I'm not seeing any dip in the battery voltage. This is telling me that maybe the starter relay is acting up one hot...maybe?
I imagine it could be the starter solenoid too but I would think that if the electronics were connecting, that even it wasn't working, you would see a drop in the battery.

I'll probably pull the tank and hit things with a heat gun to see if it gets affected but maybe someone else has had this issue before.
Any ideas?

[Ken in Oklahoma]

OK, twice now I've had the bike not start after a ride.
I'll stop to get gas, or take in the view. Get back on, press the starter button and nothing.

It only happens when the bike is warm after riding.
It starts the first time once it is cool.

I put a meter on the battery, which I had recent problem with but seems to be fine, and pressed the starter. I'm not seeing any dip in the battery voltage. This is telling me that maybe the starter relay is acting up one hot...maybe?
I imagine it could be the starter solenoid too but I would think that if the electronics were connecting, that even it wasn't working, you would see a drop in the battery.

I'll probably pull the tank and hit things with a heat gun to see if it gets affected but maybe someone else has had this issue before.
Any ideas?

Your problem is likely to be a bad electrical connection--somewhere. I think that's more likely than a faulty component like a starter, solenoid, or starter relay since everything works fine cold.

One thing you didn't mention is whether your dash lights come on when the bike is warm but doesn't start. If the dash lights don't light when you turn the key on that is an all too common symptom of a bad connection of the starter relay with it's mating socket. What year and model is your bike? The above problem is common with the bikes with the under-the-tank master cylinder. The fix is to clean both the starter relay contacts but also, and especially, the contacts of the starter relay socket.

Ken

[BoxerTwin]

Hi Ken,

yes, all panel lights come on as normal. The horn, headlight, turn signals all work in this condition.
It's a 1977 R100/7

my master cylinder is a bar mount so it's not the issue.
I pulled both of the relays that are next to each other and cleaned up the contacts.
I found a marginal connection to one of the coils. It's the little lead that went to the coil on the right. Not the spark plug wire. I pulled it totally off and it still started. It might have been shorting against the tank but that's just a guess.

I'm going to test ride the bike tomorrow. I'll just make sure to stop on a hill so I can bump start it if needed.

thanks,

Glen

[SteveD]

This is an annoying problem isn't it.

I had a beautiful MG Le Mans about 25 years ago, an absolute cracker of a bike that I loved. However it had a 'orrible habit of doing just as you describe.

Luckily, with the Le Mans, the starter/solenoid is accessible by the left ankle, and starting was always a matter of shorting it.

The solenoid had been repaired, then replaced to no avail.

It had a Piranha Electronic ignition on it, which I never investigated.

[mattcfish]

OK, twice now I've had the bike not start after a ride.
I'll stop to get gas, or take in the view. Get back on, press the starter button and nothing.

Any ideas?

Nothing...not a click...or turn? No dip in voltage... Could be the relay..... But, make sure there is voltage coming from the starter switch itself. Also, check battery grounds. I run seperate grounds to frame, tranny and block.

[BoxerTwin]

yep, nothing, no click or turn, no dip in voltage.
I pulled the relay and cleaned the contacts. I haven't had time to take it for a ride since then.
The starter switch is clean and good.

I'll double check my grounds.

thanks

[BoxerTwin]

I was able to get it out for a couple hour ride.
I think that it was either the semi-loose wire that goes to the right coil shorting on the tank or dirty contacts on the relay. I stopped three times and it started up each time.

Now to figure out the gas mileage.