Hey all Im a motorcycle mechanic here in Australia I have a 2004 yamaha 660 Grizzly that is giving me grief. Its gettign hot and boiling. I have replaced the fan sensor on the radiator as the fan wasnt kicking in originally. I tested it and it didnt get hot and the fan kicked in I thought ok all fixed. My mate took it for a weekend and tryed it and it is ok at speed doesnt get hot but when you slow down through the tight woods or in a mud hole its gettign hot again.
I have checked voltage to the fan which is all good and checked the thermostat which is ok.

I now have the front gaurds off it and checked the wiering for chafing or pulled out wires their all ok. What has me stumped is it has to be a yamaha warning signal as its idoling the reverse light on the dash flashes sometimes as though the fan should be cutting in and isnt. Does anyone out there know what this is for?

i have exhausted my thoughts of what i can be I just dont know cheers for any help

Mark

 

I don't have a Grizzly but on the Raptor the flashing reverse light indicates it's overheating. Which you already know. Have you checked the water pump for proper flow, blockage?

Not much help I know, tell you buddy just to ride fast all the time, problem solved.

 

Make sure the radiator is clean I mean you can see through the fins , all of them, also if you over rev the quad in neutral the reverse light will also flash. good luck.If it over heats you should get a temp. light like a thermom picture indicating overheating. good luck.

 

This is important, I was having frequent issues of overheating with my '02 once and I thought the radiator was clean by looking at it through the nooks and crannies without taking anything apart. I normally hose it off through the front grill and from behind via the fender wells. Then I finally ended up taking the front rack and the plastic cover that is underneith the front rack off so you can get a really good view of the radiator. That's when I found that both sides of the radiator had a strip about 1 1/2 " in width that was clogged with mud. My problem went away after I cleaned that out...

 

Oggy is correct, the reverse light does not flash when you overheat, thats what the temp light is for. Sorry about that, I did not think before I wrote. Please ignore my previous post.

 

have you checked the coolant

 

i am not sure about yall in austraila but we use aintifreeze which works so much better than straight water! 50 50 aintfreeze to water but if you do does the atv have allot of hours on it??? If so mabey it is time to change it?

 

yes anti freeze i believe is better

 

cheers for the tips

as stated I am a motorcycle mechanic have worked full time for 8 years yes there is coolant in the engine yes i have flushed the system and replaced with a 50 50 glycol mix which works a treat here in the hot part of oz. there is two tpes of coolant one is designed as anti freeze which as the name suggests it better for colder parts of the world and resists freezing in low temperatures, the other coolant which i run here is designed for climates which do not get cold only hot it is designed to reduce the surface tension of the water and allow it to blend in and absorb the heat from the alloy parts of the engine better. Redline water wetter is the product I use.

when you hit the starter button or turn the ignition on does the temp light com on on your bikes? the part of the manual i have states it should but when you start the bike or turn the ignition on it doesnt come on. When the bike boils it does come on. I thought it might be an over rev situation for the reverse light to come onlike a limit switch inthe kawasaki's when they substain belt dammage.


Thank you for all your ideas its given me new things to look for i appreciate all your ideas.
Mark