Topic: Advice on Buying a Honda CB500 4

[hummbug]

Hi All,

I am a new member from Australia and am planning to by my first classic CB. It's a '71 CB500 4 in pretty good nick with about 28k miles on it.

There aren't many of these in Australia and subsequently the best one I have found is a few thousand kms from my city. I have been sent a lot of detailed photos and now this video which makes me wonder a little about the engine. The bike is in great condition otherwise.

http://www.youtube.com/watch?v=IoGvWBaM5w4&feature=channel_page

There is a very pronounced rattle in the engine and from what I have read in the forums it could be a number of things. I thought I could get the best answer from someone on SOHC as to what this particular noise is and whether it may be a BIG or small problem. I understand it is 40 years old and prone to a few quirks but before I make an offer to the owner, I'd like to be prepared.

Any ideas would be greatly appreciated.

Cheers

[TwoTired]

Does the rattle change with the clutch lever in/out?

Has the bike had the tune up check list completed?
Have the carbs been vacuum synchronized?

Is it running on all four at idle?  Any head pipes cooler than others?

Can you localize the rattle source area?

[hummbug]

All very good questions -

All I have to go on is the video at this point. The current owner has not done a lot of work/tuning of this bike and I can only assume the answers which is no good to you.

I would say that neither has it had a good tune up recently (past few years) or had the carb synced. He has ridden it only a few times and is no Honda expert (more into Indians) I will ask more questions of him tonight. thanks for the questions.

from the video, it sounds as if the rattle is more pronounced on the clutch side of the bike...

[ChrisR]

Nice bike - originally it should have had a 4 into 4 exhaust system I think. David Silver sells them in England but they would cost £390 for exhausts and brackets and the postage is likely to be pretty high, so that might be something to bargain with when making an offer.
Sorry can't help much with the clattering noise but my 550 clutch rattles a lot at neutral as the carbs aren't that well balanced and it hasn't had a tune up in a while which causes it to snatch a bit. I think it is fairly common.
Having a 4 into 1 exhaust might be causing uneven running too as they weren't set up for it. Mine certainly improved when I put 4 into 4s on after getting rid of the 4 into 1 which it came with.
Good luck.
Chris

[ludo410]

well from the vid it sounds like both cam chain rattle and tappet noise, but without heaving the bike present it's just a guessing game

[hummbug]

Thanks Chris,  I am fine with the megaphone exhaust although I know what you mean about bargaining power.

Ludo - Tappet noise doesn't sound like a very positive thing...care to elaborate on the implication of that? ...I understand it's a guessing game but the more guesses there are the closer I get to knowing.

[Retro Rocket]

To be honest, if you listen carefully you can hear the camera mike changing pitch as he moves around and i think it is mainly picking up the cylinders firing through the pipes and magnifying the higher frequencies, making the whole thing sound "tinny". Videos are not the best way to "hear" how an engine sounds. Looking at the responsiveness of the throttle and lack of any smoke coming from the exhaust it looks ok to me. If the tappets and chains were "really" that noisy it wouldn't run as smooth...IMHO...


Mick

[hummbug]

Good answer Mick.

Yeah the sound is very tinny and it makes it hard to decipher the real sound of the engine. I guess I was just looking for some indication from people who know these engines if it sounds like it's running OK and it's not a death rattle. Sounds like a service, tune and cam chain adjustment might get it back to it's old self.

[Cvillechopper]

Like a couple have said, just sounds like cam chain and tappets which are all part of routine maintenance.  Sounds like it would be your first time with this type of bike so I'd guess you'd spend about 2 hours getting the cam chain, tappets and timing done.  It gets better the more you do it.

Looks like the bike is in great shape.  Good luck.

[bryanj]

Tick over too slow
cam chain rattling
primary chain noise due to carb imbalance.

There are 2 known faults with the 500

(1) the rocker spindles can rotate and wear the holes in the rocker cover oval:-  not all of them but enough to be known about

(2) As there is no primary chain tensioner if the bike is used hard and/or with unbalanced carbs for some time the chain wears and can eat into the oil galleries inside the cases:- Not a difficult fix but it is a complete engine stripdown.

Both of these faults are not super common but do exist and need to be considered. Most parts are available but some are not, like rear chrome fender, small speedo,new crankcase,etc

Bike looks reasonable and would be worth buying but not at top dollar as the 4 into 1 lets it down from that

[750goes]

Bike looks good, and sounds ok - as others have said, maybe  a tappet adjustment, cam chain adjustment and sync - all simple and easy..

If it's not rude - how much is the seller asking - I would think it may cost you $2500-3500 ?? plus transport from WA - big dollars, are you going to use it as a daily rider or weekender ??

I'm also not interested in it - live in Penrith NSW..

cheers
 

[hummbug]

I bought it.