Topic: NOT a SOHC but...

[kach_me]

Someone local to me has a CB 900F 1981 for sale for $600.  I am wondering if any of you have had any experience with this particular model.  I am looking for either a daily rider or my next project bike.  At $600, it looks as if it'll be the project.  Anyway,  tell me what you know...  (related to the CB 900F that is...)

[6adan]

I have just got a 81 750K running(same type engine) and the main problem I had was getting the carbs clean.If you thing our old 750 carbs are bad wait till you try too work on thees.One other thing do not try to run pods on this bike,use only stock air box and filter.

[CBJoe]

5 high ... 5 low ...

what more could you want

But seriously, great bike if the upkeep has been good....

good luck.... joe

[Geeto67]

the Fs do not have the 10 speed tranny that the customs had (cb900c). they are also not shaft drive but good old chain drive.

I am a 1982 cb900F owner and let me tell you the bike flat out rocks. The chassis is much more refined than the SOHC bikes ever would be and the motor pulls for days. these are very european bikes never intended to be imported here and when they were finally imported they were only brought in for 2 years (1981-1982). They are bigger bikes and really they make awsome sport tourers and daily commuters. my 79 750F was really good for back and forth kind of work - I have the 900F apart right now so it doesn't do anything but collect dust.

The problem areas are:

timing chain - the chain has a tendency to eat the motor alive if not maintained. Thrown chains were a problem back in the day. If the chain was maintained then the bike will run forever. I have a set of barrels in my garage from a buddy who didn't maintain his chain and the thing sawed the cylinder block in half.

starter clutch - these had a tendency to work loose and they make an awful noise. Tighten them down with some blue locktite and you should be good to go. If the clutch goes bad it can wreck the starter and then you are left push starting your bike (these don't have a kicker).

Electrics - 1980s honda electrics are just bad all around. However the weak points on these bikes are the pulse controller (electronic ignition) and the starter solenoid. Regulators/rectifiers also have been known to go bad from time to time. If it is running like it has a coil out and all the wiring seems fine - then the pulse controller has crapped the bed.

cb1100f.net is an awsome resource for these bikes (much the the sohc4.net is a cool place for sohc4 bikes). Download your service manual there.

cb900Fs normally trade for around $1500-$2000 so @ $600 it sounds like a project. however some small stupid fixes can really make these bikes seem like they will never run again. I bought my 900F for $350 because it had a dead battery and a flat tire (because of the e-iggy if the batt is totally flat you don't get spark), my '79 750F I got for $350 because the fuel line was too long (way way way too long).  I was offered an 1100F recently for $700 because it was thought the electrics were junk (actually it had a bad pulse controller - $120 new part) and carb running issues (actually the reg/rect was going and throwing incosistent spark). So deals are out there to be had.

[Geeto67]

I forgot to add - these bikes use the large round top CV carbs hated by most honda riders. they are ok for round town work and even spirited riding but they are not performance carbs. They are very finiky and all the settings must be exact so if you can try to keep the float settings and such the same when you rebuild them. the biggest problem with the 900 carbs is lag. You open twist the throttle wfo and wait and then the bike kicks you in the pants. A common upgrade back in the day was to put 750F carbs on it. the smaller passages combined with the increased engine vaccum of the 900cc mill means those carbs snap open when you whack it. you loose a couple of ponies up top but the increased throttle response makes it worth it.

you can also upgrade to CRs and FCR carbs if you really want some power out of the bike. Personally I like mine stock for fast running around town work so it does the job well.

BTW these motors are 16 valve and the valve adjustments are bucket and shim at every 20K. On personal preference alone I would do a valve adjustment when I get a new DOHC and that way I never have to worry about it again.

not that I need to say this but wiseco still sells big bore pistons for these bikes....