Problems with MZB ignition?

Well I reset the ignition to the factory specs of 2.3 mm btdc and went on an organised trail ride on last Sunday. The bike started on the 4th kick so I was happy. Boy has it got some get up and go now - I was afraid to really let it have it's head as well as I am still running it in. All was going well until 3/4 of the way around the 31km loop and she suddenly decided to boil furiously - a big clod of steam and green coolant dripping on the ground. I didn't have a chance to see where it was coming from as I was on a greasy hill and just wanted to finish the loop. (I am on medication which affected my riding a little).

I have just pulled the pump cover off and the impeller is fine and turns with the engine. I am wondering if at least one of the radiators is blocked up internally so coolant can't circulate - one has damaged and sealed-off tubes so maybe there is some sort of sealant which has blocked the other tubes.

Can anybody suggest a good supplier of a pair of new radiators or should I just go onto ebay? (I would like to go riding again on 30 October) Or should I reset the timing back to 2.0mm btdc and will that prevent future overheating?

Any advice in welcome
Rowan

Attach a hose pipe to each rad separately and see if you have flow.

As soon as I have radiator problems the first thing I do is buy a new radiator cap.

I have been really surprised with the difference in spring tension of a new cap to the old one.

Pressing it by hand, new cap spring really firm, old cap spring very soft.

I have seen Chinese radiators on E-bay and have heard good reports about them.

Cheers, Dave.

If any of the tubes have been crimped over replace the radiators.

http://www.ebay.com.au/itm/Aluminum...993545?hash=item210aac6f09:g:90YAAOSwWTRWzrwX

Cheers, Dave.