yzf 250 glowing red exaust after 20 seconds running

[steptoe1111]

hey guys i got a yzf 250 here an "04"modlle that i dont think is quite right and im looking for any advice or info anybody could possibly shed on this problem, like i said above it has a problem with the exaust glowing red after a cold start and 20 seconds of idle , now its not my bike but its a freinds he only bought it a few days ago and we where planning a ride this weekend and i was going to drag the old "77"dt175e out and give a run for his money ..... but id thought it would be safer to try and see if this is normal or not...? a few people i have read about said that it is normal for the exaust to glow bright red but i would of expected that after a 5-10 minits of thrashing it is a high performance motor cross bike but not bright orange at startup within 20seconds at idle ....!! to me it seems like it has maybe burnt out an exaust valve or starting to maybe im not sure due to the design of these bikes ive only ever worken on old school stuff and have never wanted to work on and overhead cam but what els could cause this ?? i am able to take the rocker cover off and mesure the valve clearences and the carby should be due for clean as its been sitting for about a year so thats definatly on the cards but the only other things i can possibly think of woud be lean mixture ,exaust/intake restriction,bad water pump or lack off lubrication do they run plastic gears as oil pumps? ,,,i read you can check the presure by undoing a nut two turns and waiting for a bit oil to droop out so that will be done with the carby but any help or advice froom anyone is greatly apreciated as im not to up to date with these later modlle bikes thanks steptoe1111

[drewpy]

did a quick google and they seem to have titanium pipes which absorb heat quickly.

Apart from checking the carb mix and valves, its seem quite normal. need to ride rather than sit idling

http://www.dirtrider.net/forums3/text/topic/157945-1.html

[steptoe1111]

cheers mate, i read every wher that these thin titanium header to heat up quite a bit due to the ultrathin light wight metal, and also because these things are so tweaked up from factory they like only to riden at 35 pluss kmh, to keep the wind goin through the radiator and motor to cool it down , but it was already chery red in 20 seconds just at idle but after more reading and reserch i have come to a conclushion that it my be what i thought in the beging(possibly)just a lean condition i am yet to clean the carb the cause ive been busy but i have read that the pilot jet likes to crap out on after a while clogs very easyly (the has been sitting a while) caus when you blip the throttle to get some more unburnt fuel trough the exaust it doesent cool it.... dosent turn to a glowing orange like it shoudl but just gets hoter and the red glow just spreads and im realy paranoid caus i dont want to burn a valve out,, they seem at the moment no poping or back fireing just red hot i havent mesured the clearences for tightness but im shure they are sealing

[Ryan09]

Carbon build up can cause excessive heat, when was the top end last checked?