YPVS Getting Hot

[4ce]

I`ve recently rebuilt my YPVS 350R had the frame swinging arm all the black stuff and wheels powder coated, resprayed all the body work and had the cases barrels and head powder coated. I was told the crank was ok so were the barrels so just put new ring on.
Starts and rides great but in traffic or ticking over the tepreature guage heads for the red, it`s ok while moving. Had the rad off ond flushed it, had the thermostate in a pan and it opens just as the water starts to boil. The impeller turns when kicking so I think thats working ok.
Am I missing somthing here or has anyone had this problem or can tell me what is wrong.
Nigel.

[Shytalk]

It could be that the radiator is sludged up reducing cooling.

[guiri]

hi nigel,my f2 did the same when i had just bought it,the previous owner only used it to pop down the shop for fags an beer and when i started using it properly it would over heat going round town and then one day i went for a burn up my favorite mountain pass an the head gasket went pop because the thermostat wasnt opening fully.i replaced it and it obviously was better but it still over heats round town(tis 40 degrees in summer here)ive been told that with out the termostat they no longer overheat,haven tryed it yet though..john

[4ce]

Thanks for the advice, I had the radiator in the sink conneced to a tap for an hour it was flowing ok and the water looked clear.
John wouldn`t mind some of that outdoor temprature. Went out on the aircooled at Easter round Kielder and over the boarder to Hawick (Hoyk) and we were riding in snow. Went out again last week to Hartside and although dry and bright but cold to start with we ended up with rain.
I think I`ll replace the thromostat and the temp sensor see what it`s like.

[bare]

heating can occur from several causes:
Faulty cooling
Leaky head gasket
Faulty Timing
Jetting 'fuel / flow issues.
Thermo is pricey... IF.. it opens 1/4" by the time the water (in the pan) hits 80C then it's "fine"