Glowing bright red

[Captain Black]

Doing a charity run tmrw so i thought i had better waken the old 89 PD out of it's slumber today. When i fired it up in the garage (with the door open) I noticed In the semi darkness the near side header pipe was glowing bright red after just a few minutes running, certainly no more than 5 Minutes. The otherside seemed fine. Now I am thinking Ignition, but surely both pipes would suffer the same effects ?
Anyone had this or know if it's an issue ?

 

[Rob Farmer]

yep!! With a knackered valve seat letting the flame past. Check your valve clearance and do a compression test PDQ

Had this on a mates bike as well

http://www.ukgser.com/forums/showthread.php?t=265529&highlight=valve+seat

 

[Captain Black]

Thanks Rob. I supose i better take the head off and have a look. Can't do it until tonight as I'm off to the football now. Just hope i can sought it for Tmrw!

 

[Captain Black]

Just as an aside, I set the tappets last summer only done a few miles on it. Could a tight tappet cause this ??

 

[CJM180]

Just as an aside, I set the tappets last summer only done a few miles on it. Could a tight tappet cause this ??

Possibly!, if when warm it is holding the valve slightly open. However it wont take very long to damage the valve and seat if this is the case, and if you have run it like that in the garage you may of already damaged it.

I would sheck the clearance, if tight adjust it correctly. start the bike up again and if it starts to glow again stop it, and look towards repairing it.

Kr
Craig

 

[Captain Black]

Possibly!, if when warm it is holding the valve slightly open. However it wont take very long to damage the valve and seat if this is the case, and if you have run it like that in the garage you may of already damaged it.

I would sheck the clearance, if tight adjust it correctly. start the bike up again and if it starts to glow again stop it, and look towards repairing it.

Kr
Craig

Ok thank's I'll take a look at the clearances first. It did'nt make any horrid sounds, but even so I guess that means very little. Even If the valves are tight and I let them back a little, I reckon I need to take the head off just to be sure It's ok, then I may as well do the otherside laa la la and on It goes. I did wonder If the carb on that side could be running really really lean and cause the red hot glow on the header ? Any thoughts anyone If that could be a cause ?

 

[Kenny]

Mixture screw for the pilot jet only covers first quarter throttle or so......so may be worth removing that to see if 'O' ring is OK (doubtful)?
Ensure carb to cylinder head rubber is 100% sound as they crack usually from the inside out ( hope this makes sense, been on the all evening ) and spray WD40 around the rubber when running and look/hear is change of engine etc. Be quick, don't knacker the engine !!!

 

[Smug]

Happens a lot and is not necessarily a problem. Sometimes a siamese exhaust causes one side to appear hotter than the other.

 

[Captain Black]

Just done a compression check all be It with an old Gunson cheapo gauge.
I left plug in the o/s cylinder and the n/s which is the one where the exhaust got cherry red hot read upto 200 psi with a few flicks, also the spark plug looked a very light tan colour, as though it maybe lean ? I replaced the plug and tested the otherside and that showed 185 to 190 psi with a much darker sooty plug, so that maybe is very rich ?
Not sure what to do really, either reset all the tappets and see what happens, but risk engine damage perhaps ? or just take the heads off and have them looked at ? I can MOT my other bike next week so It's not like i will be without two wheels.