Z1OwnersClub GB

In negotiations to buy a 1973 Z1. Bike has a specific and possibly identifiable noise which I'm hoping someone might be able to identify I appreciate it's difficult without hearing the noise). I'm convinced its not the cam chain setup. I've had a stethoscope on it and the noise in the valve train is normal Bottom end appears sound and nothing in that vicinity to indicate the problems in that area
When I probed the area to the rear of the front sprocket the noise was more evident there. Difficult with transmitted noise I know.
The bike rides well. The noise doesn't disappear once it's underway. Nor when gears are changed and the bike varies in speed.. The noise seems to stay at the same frequency-perhaps increasing slightly. It doesn't noticeably increase in frequency or volume as the bike accelerates or increases in speed. Noticeable on tick over as at a speed.

Appreciate that it's difficult to describe a noise. Flame me for stupidity if you want- I know with other marques there are common recurring issues that are well known.

Hi,Does sound go when clutch pulled in? if so its the clutch basket...Paul J

Is it a knocking or a rumble?

Hi

Thanks for your response. The noise remains even after the clutch is pulled in

Hi . The noise is not a knocking but more of a cyclic rumble. A vague description of the sound would be similar to a dishwasher or washing machine pumping water out at the end of the wash cycle but softer in intensity.

Got to start thinking it's one of the gearbox bearings.

I'm inclined to agree, look at what's in the left hand side, the crank drives directly the first layshaft through to the clutch, also though, there is the starter clutch and alternator all on the left hand side, we've only one bloody chain to worry about, and you say its not that area, I went to look at a 73 with my mate, it looked great, really pretty, but, evidence of the motor out, and top end LHS normal but RHS very metallic suggesting wear, £12,500. I told my mate to leave it, the seller later sold it, for that amount needing work, if your prepared to do it and you get it for a decent price you must knock off at least a couple of grand to get it OK, rose tinted glasses an all that, its not buyer beware, some of those at the shows may have shite motors but look good, yes the brakes will work, for getting them in and out of vans, we all need a reference with all the correct bits on, BUT IF YOU WANT TO RIDE. Things that spin

Hi Agree with all that'd thanks for your sage advice. Through a process of elimination it does suggest gearbox to me too. Like all diagnostic work, human or otherwise a certain degree of clairvoyance is needed unless the patients arm is in a bag or the cylinder head is now poking through the fuel tank. I do like things to break! That way the uncertainty of what's wrong is reduced drastically! Slowly wearing items create confusion.

I'm pretty certain that the cam chain assembly isn't the culprit. The noise is not in accord with what the chain does and I would expect the referred noise to be amplified particularly on the tensioner post at the rear of the cylinder when I put the stethoscope/screwdriver on it - I had these bikes 30 years ago and distinctly recall the cam chain noise (when a Z! a went for £600- I know we were only on £60 a week then!)

Yes I want to ride any machine that I buy. That takes me down a certain path. I'm happy I'm competent to strip the motor and replace any components that are shot. Then... 'the curse of the obsessive' kicks in' - whilst its down why not do everything! It's interesting to add up the cost of all the parts which cumulatively add up to a good deal of money. An amount that has to be considered in respect of the purchase price.

So -my search for an 'apprentice goes on" I've left negotiations open with the owner of the bike who maybe lucky and get his asking price from someone who has the 'rose specs ' on. Nice chap though.

P

HI,

Well - Not a club person in any way. Have joined this one. Seems a bunch of helpful folk.

Rotor or starter gear maybe?

Hi,
If it was my bike I'd strip the starter out and run the motor up and eliminate items i could remove easily. Just not my bike as I'm still n negotiations to buy it. A difficult situation. I suspect the current owner has done some preliminary checks and hasn't revealed the source of the problem-m or has it!!!

That would suggest that it's not going to be an easy fix.....

Hi,

I'd agree. However; it may pan out that the seller appreciates that and reduces the price to take that into account. I'd probably be stripping it anyway. Was hoping just the head off and cylinders for check

That would be great. be sure to let us know how you get on ...

Barnsley? my mate went to look, its the crank he thinks,