Smithy1216

Yes mate. Fresh coolant. Ran with cap off, can see coolant circulating and all hoses hot. 👍

The o rings have been changed this week and the head didn't appear warped when we checked it at the same time. The jetting has now been corrected but it is still getting ridiculously hot and steaming. After testing the fan this morning I'm fairly confident it is actually the culprit. New one should be here in the morning so watch this space! 🤞

That's great info thanks 👍

O rings now changed and still steaming through breather hose 🙉 Checked jetting and its actually running a 30 pilot. I've ordered a 36 which I believe is standard? My question is would it running so lean cause it to overheat?

Thanks for that. So presumably the further out the screw is the richer it will run?

I agree that changing the o rings first is probably the way to go before delving into anything else. Picking up on your comment about reading the plug, it's almost white which I always understood meant the bike was running lean? I'm thinking that when the barrel and head were changed the jetting and carb settings perhaps weren't touched causing it to run lean? Is the jetting any different on a 280 compared to a 300? Would the bike running lean contribute to it running hot? Thanks. Paul

Hi. Have ridden off road for years but never had trials bikes before. Bought an old 05 GG 300 txt pro which needed a bit of tlc to have a play about on. Only been out once on it and it popped the thermostat out along with all its coolant. Gear oil was milky too so replaced waterpump and put fresh fluids in. Need advice as it still seems to be overheating. Fan appears to come on and run as it should, then after pottering about for 5-10 mins it starts to steam and spit coolant out of the breather pipe. All hoses are hot so pretty sure circulation is OK. Don't know if it's relevant but I'm pretty sure the bike has a 280 top end not a 300. And having checked the plug it's definitely running lean. Thinking maybe radiator cap or leaking o rings on cylinder head?? Any advice would be appreciated as these things are totally new to me! TIA.