Topic: Buying a CB750 K1 - advice please

[neilbron]

Hi guys,

I'm looking fairly seriously at a 1970 CB750 K1 for sale by a Meloburne dealer whoo has imported it from the States (and has been doing this for over 17 years).

The chassis no is CB750-1056956, 9/70 build, Engine No. CB750E-1055228, 15374 miles.

The bike seems to be in very good original condition, I've checked the pipes for rust - none - and only one small dent. There is quite abit of rust in the rear guard (how much would one be on eBay?) and a small dent in the front guard - not much to worry about. The seat looks original and is in good nick. The Candy Gold was repainted by the dealer and the paint looks really good. Apparently a retired tradesman does his work. The dealer has fitted new Dunlop TT100's, an ew battery, tuned it and changed the plugs, and changed the oil (but not the filter).

I test rode it and it seems to run fine. Started instantly with the electric start from cold. Idels well.

Main questions:

1. The clocks (see photo). According the John Wyatts book the 8000 rpom redline was introduced on the K2 model, but this one has it. Is this correct, or does it indicate the clocks have bene replaced?

2. Looking at the phots - is there anything that doesn't look right? He is selling it as a very original bike, with a price to match.

3. Should I ask for a compression test? And what else?

4. Any general advice?

I really like the bike, but don't want to get caught out. Will have to buy a set of dining chairs to bribe my wife if I buy it.

Cheers, and thanks in anticipation.

Neil.

[techy5025]

See what number is stamped in the pipes near the midpoint.  HM300 are probably
original...HM341's are probably replacements, which may be better as they are newer.
the pipes rust from the inside out so its hard to tell if they are on the verge of  having
holes.  4 replacements are about 1000 bucks US. 

If the bike is running well, and the appearance is OK...I would probably go for it.  A lot
has to do with what you are going to do with it. If you are happy with riding it the way
it is then judge the price accordingly. If you want to fix the appearance items then figure
in their cost. You didn't say if you are able (or want to) work on the bike yourself or have
to include labor in fixes.

Jim

[neilbron]

Thanks Jim,

I can do most work myself. I'm after an original bike without much serious work to do. This seems like it.

The clocks have me concerned though.

I just realised that I went over the KB limit for the phots - will post a few more separately.

Cheers,

neil.

[neilbron]

Sorry guys & Jim,

Yes the pipes are HM300 - checked that.

Cheers,

Neil.

[Kevin D]

Neil, this bike looks nice and clean, but not necessarily all original.
 s/n's are good for a K1. Mine is 1067xxx, 11/70 build, E1068xxx - so these two bikes are fairly close.

I have 8000 rpm redline, which is correct for K1 - the book is a little bit wrong.

K1's had cut front fender, front edge - the later models had a rolled front edge. I wrecked my cut fender and replaced it with a rolled edge fender (K2?). Your photo looks like the bike has a rolled edge fender. I'm all wet on that one K1 rolled fender

Your seat looks identical to mine, I replaced my original after the vinyl piping cracked. I think I have a K2 seat now- can't remember what I did 34 years ago. The later seat has the piping that curves down to follow the back of the riders leg. Messed up here too   Seat looks good: DEFECTIVE MEMORY

The original pipes would be stamped with HM300, or not at all, and would not be stamped HM341. They would have a matte finish on the heat shield, and not chrome. 3 strikes and I'm out, chrome heat shields are correct My original pipes rusted out in about 3 years, and I replaced them with 341 pipes - looks are identical, but internals are not identical.

If you are paying big bucks for this bike you can ask for anything. I haven't ever done a compression test on my bike and it runs great. Look in the gas tank for rust. Open a float bowl and see how clean the carbs are. Has the front brake been rebuilt? Has the engine been apart? Has it thrown a drive chain through the engine case?

Is this to be your rider? Sunday rider? a show bike? added to your collection? an investment? If the dealer is reputable he knows the fair market price, and so should you before bribe your bride.

[GroovieGhoulie]

The 8000 RPM redline was introduced on the K1, so you're safe on that.  Only the K0 had the 8500 redline.

The HM300 exhausts, IMO, are better since they are glasspacks and after a while (about 10,000 miles), the glass burns out, giving you a quite unrestricted exhaust (nearly straight-through).  They also have less backpressure and sound throatier and louder (but still quiet compared to straight pipes or megas).  The HM341s on the other hand, are a 5-chamber (later 7-chamber) design that are quite restrictive and much quieter and "serene".

The factory jetting on the early bikes was fairly rich, so even as the 300s burn through, you shouldn't have to worry about running lean.

[neilbron]

Thanks Kevin and GG,

Nice to know the clocks are correct. And you are right about the pipes - they sound good - and loud!
The front guard does have arolled edge - good pickup! So it must have been replaced. I would be happy to replace that one day.

I've checked the price with the secretary of the local CB750 club and he said it sounded good, and it is to be a weekly runner.
I have an '83 VF750F Interceptor (yeah - everyone says they are trouble, but mine has 80,000 km on it, original cams (good for another 20,000 km according to the dealer) and purrs like a kitten). Needs alot of tidy up work though (especially paint). And I have an '83 XR350 for the dirt, in good restored condition.

But back to the K1. I checked inside the tank - looked clean. Couldn't see any obvious signs of case damage, and as the dealer bought it through a wholesaler in the States he says he hasn't any service history. This seems logical. It still has the plastic chain guard, which I thought were prone to breaking.

i think I will discuss it with my wife (man - hope I can catch her in a good mood!), and ask for a compression test.

Will let you know how I go.

Thanks again guys,

Cheers,

Neil.

[Magpie]

I have a K1 with a rolled edge on the front fender. That's the fender it came with, I bought the bike new in September of 1971 and have never crashed it.
That's a good looking bike in my opinion. Ask for any checks you want. Unless there's a cash buyer waiting that doesn't care about checking it out the seller should accommadate you.
if you're concerned about case damage take the primary sprocket cover off the engine and look for any signs of welding. If a chain did break in it's past it may have damaged the cases there. I have two sets of cases welded there so it does happen. That's the "usual" place for damage I've found.
Nice bike!
Good luck!
Cliff.

[neilbron]

Hi Kevin,

Looks like someone could write a book on what is not included in the books! It would be an interesting project to document the changes using original bikes such as yours as a the source of the data.

Thanks for your encouragement. First step - be very nice to my wife!

Cheers,

Neil.

[Raul CB750K1]

You probably have read in many books all those things you have to check when buying a used bike: tyre condition, wheel sideplay, compression test etc.

In my experience, all of this goes out of the window when you are buying a classic bike. If they are scarce and desirable, it takes a long time for them to appear in the classifieds. When they do, it's difficult to be the first one to have the chance to see it. And if you don't want it, the seller have a list of another 10 waiting for their turn. So many times you have to pay what the seller is asking for and get ready to replace or repair all those things yourself.

When I see a classic bike in the classifieds whose owner ask a high price, I don't even take the annoyance to arrange a meeting, as I know whether I can afford it or not.

What I mean is: you will probably be able to tell which parts are wrong or not. With that in mind, you can calculate how much will it take you to put the bike in original condition -selling price + parts price-. Then, you will compare with similar prices of the same bike and you will be able to tell the seller to make you a discount. And he will probably tell you: "this is the final price. Take it or leave it". I've seen rusted old mopeds in the spanish classifieds selling for 1.000 euro. I don't even take the annoyance to call them and haggle the price. They just deserve not receiving any single call so they can realize what a piece of crap they have.


Raul

[Clyde]

Neil,
Is this the bike from Central Motorcycles? I just bought a GT750 from them and the guy I spoke to was Greg Lawn who was fairly reasonable.
If so I have seen it and it looked fairly correct.
The cut front fender was only used on a K0. in fact the later K0 (of which mine is- CB750-1036712) has a rolled top edge and a cut edge on the bottom, which is correct for my serial number.
The gauges are correct-the 8000 redline was introduced on the K1 and should have the indicator lights in the gauges. With steel case gauges and the lights in the gauges, they were only used for Honda 750 K1 model . The K0 had the same lights but they were plastic cases.They changed with the K2, when Honda introduced the little panel that clamps the handle bars on.
A good point to check is the frame and see if it has the lug for the rear brake lever height adjustment. K1 did not have this and it is the only feature that differs the early frames.
I would ask them to remove the sprocket cover and check the crankcase for a chain failure. It is easy to do but you will need to get a rag and clean it up very well with some petrol or cdegreaser. I have been caught once by not doing that
If it is Central motorcycles they were a bit negotiable, so try to get a bit of.
You could ask to have the carbs balanced and I would make sure the hydraulic fluid has been changed.

Regds
Clyde (Sydney)

[Kevin D]

Neil, I'm more than a little bit jealous. That bike looks terrific, as nice as I wish mine did.

a little bit wrong

Of course I could be all wet about the seat and fender - I know I have replaced them along with the pipes and I have some vague recollection about the new parts being slightly different. This was 30+ years ago. And I'm no expert on authenticity - or anything else for that matter.

 I think you will love this bike as much as I do mine - It has NEVER let me down. And I hope your bride will love her new chairs equally.

[bryanj]

One point of worry to me that you 750 bobs haven't picked up on is that the engine number is LOWER than the frame number which whilst it is not unheard of is VERY unusual and would normally mean a replacement used engine

[neilbron]

Thanks guys,

I really appreciate your comments. Yes Clyde, it is at Central Motorcycles, and he seems a reasonable guy. He just sold a K3 to the Secretary of the QLD 750/4 club, and has a lot of interesting old bikes there.

Provided I am not divorced by the end of the week I will follow up as you suggest: compression test, check cases, perhaps change of fork oil, carb balance. The frame/engine no. question is a concern, but difficult to check. Thanks Bryan.

I'm keeping my fingers crossed!

Cheers,

Neil.

[elisent]

Neil, Don't discuss with wife !!! Forgiveness is much easier than permission. I now only buy red bikes. My wife thinks it's the same bike I already have. Great info from group about front fender and instruments. Cut front is only very early 750s, 8000 redline is K1. The 300s are great sounding pipes and originals are hard to come by. Goodluck. Eli

geocities.com/indian440

[Bob Wessner]

I now only buy red bikes. My wife thinks it's the same bike I already have.

  Eli, I just stole your idea.

[elisent]

Hi Bob, I'm happy to have something to steal. After all, I stole your Master Cylinder rebuilding techniques. I'll Email you off list with the current personal crap. Good to see you keeping us idiots inline. Eli

geocities.com/indian440