[JohnC]

Hi all

My RD07A developed a fault in May 2019 which I am now going to try and fix.

It ran for about 40 minutes 25 miles and died. Sudden loss of power and it coasted to a halt. Restarting showed there was no engine turnover. Slowly over about 4 hours (the time it took for the recovery truck to arrive) it came back to life and cranked over so I was able to ride it up onto the recovery truck.

A race mechanic I know has suggested thermal cycling where the engine overheats and the pistons stick in the bores. Hence why it got better as the engine cooled and was able to crank over, so not a charging/battery problem. It also starts fine on the drive with the bike on a CTEC charger but I don't want to ride it anywhere to try and replicate the problem or it will stop and I will be stuck again.

My question is how can I check the cooling system to diagnose what I need to fix?

Will be done at home on the drive prior to ordering the necessary parts.

Thanks for your knowledgeable help

John

 

[een705]

I think its your fuel pump loads of threads about it. I've not known many cooling problems with thee bikes

 

[JohnC]

I think its your fuel pump loads of threads about it. I've not known many cooling problems with thee bikes

Nah don't see that. I've put a Facet on it years ago and why would it start again after 4 hours? If it was the pump once it had gone it would be dead

But thanks for the suggestion

 

[Eddy_B]

it wont be the pistons sticking in the bores, that is only a problem on two strokes or race engines with much tighter tolerances. to test the cooling systems look at the temperature gauge, if the temperature gauge is not working it wont show any temperature. also if it were running that hot that the pistons seized then the coolant would be boiling over and going in to the overflow tank, see if that is full. if the engine isnt turning over it sounds like an electrical fault. possibly the connection to the rectifier is burned. now the bike is home, does it run if so run it and see if the fan comes on and see if the coolant boils over to the overflow.

 

[Lensman]

Hi JohnC, What happened to the electrical items (lights, instrument indicators and Trip Meter) when you pushed the starter button? What sounds came from the starter motor?
I presume all fluid levels are correct!! Do you have a non-contact temperature sensor?

 

[Abraxas]

I also don't see how it can be pistons sticking. The engine is tractor-grade and tolerances are huge. That's why it works pretty much on anything including weasel pee

Here's a stupid suggestion, but an easy one to check - is there a vacuum in your fuel tank after riding/idling for a period of time?

 

[grbeiz]

Hi all

My RD07A developed a fault in May 2019 which I am now going to try and fix.

It ran for about 40 minutes 25 miles and died. Sudden loss of power and it coasted to a halt. Restarting showed there was no engine turnover. Slowly over about 4 hours (the time it took for the recovery truck to arrive) it came back to life and cranked over so I was able to ride it up onto the recovery truck.

A race mechanic I know has suggested thermal cycling where the engine overheats and the pistons stick in the bores. Hence why it got better as the engine cooled and was able to crank over, so not a charging/battery problem. It also starts fine on the drive with the bike on a CTEC charger but I don't want to ride it anywhere to try and replicate the problem or it will stop and I will be stuck again.

My question is how can I check the cooling system to diagnose what I need to fix?

Will be done at home on the drive prior to ordering the necessary parts.

Thanks for your knowledgeable help

John

Check and double all electrical connections..I am positive this can be a rectifier issue.. Not an engine issue for sure.. Fuel pump is also an option to double check..

 

[JohnC]

Thanks for all your suggestions guys

I have a friend who is a very experienced bike mechanic who is going to help me via email to start diagnosing this problem. Hopefully we will get to the bottom of it and I can post a happy ending sometime in the future