Coinasseur advice for CB 750 '79

[lucadortenzi]

Hi there everyone.
I am after this CB 750 but I would like to have some piece of advice from you guys. It is a non running model, still sounding good from what he says on the advert on ebay. I will go saturday morning to check it out.

I would really appreciate any feedback about the advert and/or any advice about what to look for on the viewing and what to be warn about.

Does not make much sense to me that he drained the oil and never refilled it (so basically the bike now can't be seen running).

Here is the link, many thanks in advacend for your time lads.

http://www.ebay.co.uk/itm/161263471792?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[LukeM]

4 months of no oil in the crankcase might be a problem. 4 months of non-treated fuel in the tank may lead to clogged jets or passages in the carbs. I'd have him put oil in the engine, and fresh fuel in the tank, and show you that it runs well before dropping some money on this bike.  I think the price is good, but typically EBay auctions go up dramatically in the last hour.

Cosmetically, I can't comment on that. Me personally, I care how it runs and works, more than how it looks.

Good luck, and let us know how it turns out.
Luke M

[sgtslag]

Pod filters are nigh impossible to make work properly on the OEM constant velocity carbs of the DOHC engines -- those are the stock carbs, and you will want an OEM air box to make it run properly, throughout the RPM range, running down the road (running with load, as opposed to running without strain on the engine).

The oil cooler is nice, even if you only ride it leisurely, as the 79's ran at 250 F, the thermal limit of conventional oil, back in that day.  I would only run synthetic in it, as it is better quality in so many ways.  An oil thermostat would improve the warm-up time, tremendously, as it would bypass the oil radiator until the oil reached 180 F (I installed an oil cooler, with thermostat, on my '79, several years ago, ran it two flawless years, then sold the bike).  Do NOT add extra oil for the cooler -- it doesn't hold very much, and you could overfill the crankcase, damaging seals...

The 'new' battery, if it has been activated (acid and water added), but it has not been maintained (smart trickle charger is the safest, and the best), is now somewhat damaged, due to discharge (4 months of never being charged, will drain it through internal discharge, leading to sulfation, if it is a flooded acid battery; if it is a Gel, or an AGM, disregard my comments, as they won't apply).  If it is a flooded, conventional battery, plan to replace it sooner, rather than later, due to sulfation seriously shortening its life (normally 2 years, probably around 1 year, now).

There is a lot of customization done to this bike.  That could be really wonderful (if done properly), or it could be really dangerous (if they did not know what they were doing -- not likely, considering what has been done to it, as converting it to a mono-shock swing arm is no simple modification!).

Ask him to show you that it runs, first.  Ask if he has the OEM air box, "In case I want to go back to factory?"  The OEM air boxes are hard to find -- you have been warned.  Best of luck!  Cheers!

[icerigger]

Always be very suspicious of somebody's project bike that is "nearly finished". Chances are really good that he's run into a problem and can't resolve it or isn't willing to put in the effort. An engine that may or may not run is a BIG runaway sign.