Frame / engine numbers don't match!

[helvetica]

Hi all, this is my first post so this round is on me!

I'm just starting to rstore my dad's CB750K as he doesn't have the time or the inclination! I can't think of anything I'd rather do on a weekday evening than spend a few hours in the garage.

 I'm having trouble determining if the bike is original as the engine and frame numbers don't match. The engine is definitely a cb750kz from 1980, but the frame could to be from a 900fa. I wonder could someone clarify this for me? Can you check your frame number off your engine number? should they be an exact match? mine are like this:
Frame: JHM SC01 (older CB900F frame?)
Engine: RC01E  (CB750KZ)

the numbers (I have omitted) are quite similar, but the letters different. SC01 appears to  stand for a 900FA. RC01E is 750K. does anyone know what JHM stands for? In my haynes manual though it tells me my bike should have dual front brake calipers and comstar wheels, but it has spokes and a single caliper. Is it possible it is just a US model?

thanks a bunch, from ireland
Paul

[gonebiking-2]

Hi Paul from Ireland. I`m in Perth  Western Australia and yes there is something amiss allright. My frame is an RC01 1001328 and the engine number is RCO1E 1001348. I think the frame should also be RCO1. The RCO1 models are different to the USA whihc dont even have the prefix RCO1 . Seeing as you are where you are, why not give davidsilverspares.co.uk a call and see if they know which belongs to which. For all we know that frame number might be the correct number for the UK, Ireland , Scotland and Wales although I have my doubts as I havent heard of a frame number like the one you have. Is the bike all in one piece, and does it run - can you ride it on the open road ??????????????????? Any chance you can put a photo of the bike on the forum or email the photo of the bike to me. Mine has Comstar Wheels and a single disc up front with a drum brake on the rear - if thats any help. I bought mine in South Africa in 1980 before moving to Perth in 1983 and both Australian and South African bikes are the same

[Rick V]

It sounds to me like you do have a 750k. The engine and frame numbers dont usually match on a Honda.The 900f  also has a rubber mounted engine so if yours is solid mount it is not a 900. The 750 k had spoke wheels and one disc brake up front and a drum in the back.

[helvetica]

thanks for the replies lads. Here's the thing, it has all the features of a US 750K (spoked wheels, single front disk), and according the the haynes manual the engine number matches a 1980 K from the US. But the frame number matches a uk 1980 900F-A, and this is according to dave silver too. if this is the case, why would someone change ONLY a frame? If the engine lunched itself on a 900F-A you would pop another engine in, but the wheels, brakes etc would be from the 900. If it was a crashed 750 that needed a new frame, then surely there would be other damage to the front end, or anywhere for that matter!

I can't see any rubber mounts for the engine but maybe you could tell me where to look? The frame seems to be bolted together on the right side front I hadn't noticed this before.

The good news is the bike works ok - I can ride it, brakes are fine (just changed fluid), the steering head is a bit wayward, but I've ordered the conical bearings (the numbers match between 900 & 750 so hopefully they fit) and I'll tighten it all up. the engine is a bit soft and is hunting sometimes, there are new sparks and battery so I reckon the carbs are manky. was gonna try carb cleaner before I go and take them apart (in case I never get them back together!) and I'll get them balanced then.

If this is somehow an original bike (except for the awful motad 4 into 1 exhaust) I would be delighted, and I would be tempted to get the frame powder coated and give the body a respray, but i'm hesitant to spend money on a bitsa bike. I have popped afew pics below my garage is small I'll take a few decent ones when the rain stops! sorry for the giant post thanks if you're still reading!!! Paul

[ferroussphinx]

not sure i know this post is old but did he ever notice the front tire was on backwards meaining the tread was going wrong way ................................................................