Total Motorcycle Community Forums

hello to everyone im a newcomer to this forum and am in desperate need of some help. and one of my friends rcommended this forum as a great source for help

i recently picked up a free 78 cb250t that had been sitting in a friends uncles garage for the better part of 10 years

upon gettin it home and having a proper look over it i came to the conclusion that absolutely nothin on this bike seamed to work in a nut shell the carbs were badly blocked all the gaskets where ruined and or missing and upon takin off the head i found that the piston rings where in peices.

so i pulled the bike into a million peices and set to work cleanin out all the little broken piston fragments and a few washers i stumbled upon (suprisingly nothin had seized up after all this time)

then i got all new gaskets, rebuilt the heads with new piston rings and set to work on cleaning out the carbs, after which i kicked it over and it fired up off the second kick.

now the problems im having are the exhaust pipes are over heating very quickly, in the space of 1 minute the pipes are hot enough to sizzle water, (if i was looking to cook eggs this would be perfect) now i cant for the life of me figure out this problem and it seams to mainly be the right exhaust that is heatin up much more the left, ive also had to set the idle pretty high on this bike or it just dies out rather quickly.

also while inspecting i found that one of the bolts that holds the clutch cover engine case has been broken off in the thread and a little bit of oil spits out above it, not an insane amount but enough for me to see it happening. so on it im faced with the problem of extracting the old bolt without damaging the engine casing and then gettin a new one to fit right as im not sure what damage has been done. i was under the premise that the guy had just lost it and i was goin to get a new one(but its never that easy)

if any one has any suggestions as to why its heating up so bad, what i can do to help the idle and how i can fix this bolt that is stuck in there it would be greatly appreciated. i personally ride a gsxr750 but my girlfriend wanted something that was nice and reliable while not being too bad on fuel consumption and since a 250t was the first road bike i ever owned when i saw it in my friends uncles shed i thought it was perfect as she doesnt want anything to powerful to learn on.

i also fitted a suzuki across (gsx250) rear wheel on it to see how it would go and it fits like a dream and has no tracking problems, the only issue i encountered was the wheel has a disk brake and the bikes set for a drum brake but if i was to find a wheel with the same dimensions but with a drum set up would there be any implications for having the wider yetr smaller wheel on the rear, because i remember on my old 250t the rear end use to be a bit on a concern in the rain.

thank you to anyone who reads this in advance and any assistance would be greatly appreciated

Welcome to TMW.

Your heating problem is most likely due to a lean condition in the carbs(either partially blocked jets or too small jets) and the fact one side is worse than the other pionts to crud blocking both carbs, one more than the other.

Try stripping and re-cleaning the carbs. Make sure all the passages and jets are totally clean.

Good luck.

thanks for the speedy reply buzz and thanks for the welcome to TMW
ill strip back the carbs after work tomorrow and give them a more in depth tinkering... do u have any suggestions about the broken bolt caught up in the female thread of the engine case

or if the wider rear wheel will provide and problems with the bike as i dont wanna splash out on the larger wheel if its only gonna fudge things up

I would not bother with the wheel change if it was my bike. Alot of work for no real return. You can sometimes mess up the handling of a bike by changing width, profile or diameter of a wheel, especially just one. I would just put good replacement rubber in standard sizes on it and go with it. But that's just me....

Broken bolts suck. If it is broken below the surface of the threaded hole, you really have no option but to drill and extract the old one. Try to find a lefthand drillbit in the correct size and a good quality EZ Out to finish the job it the drill bit doesn't twist the junk bolt out during drilling. You probably want a tap in the appropriate thread size and pitch to chase the hole out when your done, so the new bolt has a nice, clean place to live.

Make sure to put an inline fuel filter between the tank and the carbs. Worst thing to deal with is have some junk from the tank go into the carbs after cleaning them and instantly clog things up again.