Topic: 1971 CB750 pre-purchase questions

[Snakeoil]

I'm a newb here and new to the CB750. But I'm not new to bikes or engines. I looked at a 750 tonight that is a bit ugly, but all there and not what I'd call molested. Needs her share of TLC to bring her back, but she has potential.

She starts instantly when cold. Engine sounds solid with no abnormal noises. She puffs blue smoke when you rev her. Not a lot, but some. She also puff black so she's a bit rich. That's okay with me because that means no lean conditions and pistons about to crater. Cases look good on only the tin cover on the right it dented. Bike has been down and original tank is dented on top rear and where right fork leg hit. Otherwise, tank is decent inside. It definitely fixable. Tank on the bike is also original paint, but no decals and has one shallow dent that is easily pulled. Side covers are cracks, but badges are there as are tank badges on both tanks. Controls, master cylinder fenders, headlight, and all the various cycle bits are there and working. Only starter button does not work and bike has remote button now. Bars are drag bars, but that's a minor detail. Original exhaust is there, in excellent shape except for dent in one header pipe and a small dent on the inside of one muffler. Exhaust is solid as a rock and only rust is on one header near the mounting flange. Probably out of site unless you look. There are two slight bent fins on the right side and a dinged up fin edge on the left. I'm not confident that the bent fins could be straightened without cracking. Dinged fin can be dressed up.

Odometer says 85K miles. But I don't believe it. Speedo face is gray and cracked like a dry riverbed. Tach face is much darker and not cracked. I want to believe the speedo is a junk yard replacement with high miles on it. Bike is a daily rider for a guy who owned it for 2 years. I spent quite a bit of time talking to him about the bike and a vintage guitar I have (he's in the music business) and all my people reading senses tell me the guy is legit.

Here are my questions:

1. Do these engines tend to smoke more due to worn rings or due to worn valve guides? Is this something to be concerned about on these engines.

2. I remember someone telling me that the cams run in the aluminum of the head with no bearings. Is this true? If so, does it mean new head when worn?

3. The fork stops seem to place the upper tubes extremely close to the tank. Closer than I've ever seen on any other bike. Is this normal? I'm wondering if the wrong lower tree was used as a replacement.

I'm thinking of making an offer in the $1000 - $1200 range. I know what it costs to restore a bike, even if you do most of the work yourself. Not that any of us do it to make money. But the general rule is to pay more and buy the better bike.

I realize that probably many of the answers are available in threads here if I do some searches. And I do plan to do a lot of research on the bike if I buy her. But since I'm trying to decide if I should cut a deal or walk away, I thought I'd ask here and hopefully get a jump start.

Thanks very much for any guidance that can be provided.

regards,
Rob

[bollingball]

I don't know any thing about the NY market but I would start lower you can allways go up. Put $800 in one pocket and see what he says keep the rest in the other and work up in $100 steps. Down here I would start at $400-$500. That is just me.
Ken

[brewsky]

Rob,
Your offer is probably where I would end up max.

The old "rule of thumb" I've always used is $1 per cc if you can ride it home for avg condition, unless it is really collectable.

Check the exhaust for hm 300 stamp, if it says 341 they are from a later model

The cams have no bearings, but ride in separate cam towers which are replaceable.

At 45,000 miles I'm just beginning to get a little smoke only on decel, and original rings did not need to be replaced....

Got any pics?

Good luck

[MoMo]

I would check the front rim to see if it is bent, as well as the steering neck and triple trees.  When a tank is dented from forks usually something else is bent...Larry

[Xnavylfr]

+1 what MOMO said, check the frontend real good. Just a laydown and slide won't cause a tank slap. Check to see if the fork stop on the side of the tank dent is gone or bent, they can easily slide past each other if worn pretty bad. The smoking you describe is more than likely valve seals (not a big deal).
The price sounds decent if everthing is straight!!! But like mentioned before, 1$ a CC unless it's ready to do a cross country!! Point out all the bad and give an average of what it may cost to repair,, 1200$ minus 500$ for parts /labor=700$.
You can pick it up for less than 1K.

Xnavylfr(CHUCK)

[wrenchmuch]

My k1 had no seals on the exhaust valve guides. The guides are cone shaped on top to shear excess oil off the valve stem. This is normal for the early engines. Not sure when exhaust seals started. A certain amount of smoke from burning oil is normal in the early engines. As for smoke from unburied fuel. Make sure the engine is fully warmed up before worrying about it. If its still smoking a lot the carbs may need a cleaning or spark may be weak. K0's are getting hard to find. K1's seem to be getting more attention these days.

[Snakeoil]

Thanks very much guys. I've been conditioned to ebay prices and crazy asking prices at big meets. I know they are high because you seem to see the same bikes for sale.

This is helpful because it makes it much easier to walk away if I have to. This kid paid $1000 for the bike and put new shocks and tires on it. Not sure he's going to budge much. But winter is coming so you never know. I'm only a few steps away from closing a deal on a '39 Indian Four so my disappointment if the Honda deal does not go thru will probably be short lived.

Getting back to the bike he has a spare chrome bottom tree he got from the PO who bought it and never installed it. I can see the stops on both the chrome tree and the tree on the bike are the same. The stop on the frame is a crescent piece of thin metal so I can see it becoming worn or distorted. Don't think this kid is trying to hide anything or he would have never shown me the original tank. The bike had clubman bars on it at one time and it could be they are what nailed the side of the tank. He did say that those bars will hit the tank if not installed right.

Great tip on the exhaust number. Were all the SOHC 750 exhausts one piece (header pipe welded to muffler) or was there a year where that one piece style cut in? My CB160 has a 2 piece arrangement, yet the bike came with one side in the one-piece later arrangement. I guess I can check the parts books. I see you have a very good collection of on-line manuals here. I guess I can check the on-line parts manuals to see what is listed.

Numbers do not match, but none of my eary Hondas match. I'll check the FAQ section here as I imagine a lot of basic stuff like that is in there.

I thought that maybe there were no valve seals on these engines. My Triumphs have no seals and putting a taper/sharp edge is a mod to reduce oil usage. Did not realize they installed seals on later models. Regaring rich running, he had the engine rejetted by a local shop when he put straight pipes and pod filters on it. My guess is they erred on the side of rich.

Thanks very much for the quick and helpful responses. I really want one of these bikes. They still make my juices flow just like that first bike did in the showroom back in 1969.

regards,
Rob

[Stev-o]

Sounds like a pretty solid bike, the K1's (1971) are getting more collectable and valuable.
$1000 sounds like a fair deal if the front end is not damaged. A bike like you describe would easily sell for $2K in TX. Bike values in your area are lower for some reason.
Have you ridden it?

Yes, the stock 4 into 4 exhausts are one piece. And, no, the engine and frame numbers will not match, they were manufactured in different factories and then assembled.
Does it come with title?

[754]

 If you get the indian post pics. what was the original color on the 71?..one of the best years..

[Snakeoil]

I don't think the seller is going to let the bike go for $1000. Says he's got another buyer who is not going to restore it that will probably pay more. I told him to throw his best price at me and worst I can say is no.

I'm sure more will surface.

Thanks,
Rob

[wvshooter]

I'm sure more will surface.

More will surface but it's hard to be patient.

I was looking a couple months ago and found one 340 miles away on Craig's List in the Erie PA area. Ask price was $750 but I was able to get that down to $450 before leaving the house. It was a running bike but needed extensive work to be first class. Don't they all.

You might cast your net a little wider if you have the patience.