Considering buying this CB750 and need advice

[Exodus5]

I have a local guy who has a 1981 with a little over 30K miles on it.  It appears to be in good condition but the seller states it needs the carbs synced and the valves adjusted.  he said it starts but won't idle.  My worry is that with over 30,000 on the clock there is something else wrong that he isn't telling me.  I want to go check it out.  Is there anything I can check to be sure it's just valves/carb syncing and not a dying engine?

[LukeM]

Most shops will be able to sync the carbs for you for about an hour's worth of labor. You can do this yourself, but you'll need a set of gauges and adaptors.  JC Whitney has them, and I'm sure people are selling them on EBay as well.  You'll need the proper adaptors. If the bike has been sitting a while, I'd recommend taking the carbs off and cleaning them very well.  It could just be that they're dirty or gummy or one of the other motorcycle dwarves.

Valve adjustment will take your shop a little longer, depending on how far off the valve adjustment is. I'd figure about an hour and a half, plus some shims.  You can do this yourself as well, and the process is very well documented in the Factory Service Manual (available on this site, under the main page). You'll need some good feeler gauges and some shims, and have to remove the valve cover gasket. Before adjusting the valves, it would be prudent to adjust the cam chains first.  Also a well documented procedure, and easily done.

As a reference, I got my 1979 model with 32000 on the clock, and put another 2500 on it before the cam chain broke.  Other riders have many more miles on their machines.  I'll be honest: these bikes are getting old, and you have to consider that they will need SOME repairs on them. However, there are a LOT of spare parts out there, and they are pretty easy to work on.

Let us know what you decide.  We're here to encourage and help if we can.
Luke M

[Exodus5]

Thanks for the info.  I looked at the bike but it was in near "barn-find" condition.  I turned another friend onto it who is interested in restoring it, but I want something to ride and that wasn't it.

[LukeM]

That may be fun, if you have LOTS of time to get it operational.  If it's your first time, that project may be a bit much.  I understand wanting to get some seat time in before the rainy season hits.  You may find you're curious about the inner workings of these bikes, setting timing, adjusting and cleaning carbs, valve trains, etc. I guess that's what winter is for.

Luke M