Z650 - metal bits in the oil & filter & butchered engine!

[Buckle]

Made a start on the 650 project bike this week and started the list of things to do - drill and tap a couple of broken bolts / studs, weld foot pegs, remove gaffer tape from (entire ) wiring loom etc. None of this unexpected really.

however finding the engine oil full of tiny metal fragments was. They are so tiny they seem to be held in suspension in the oil, although I haven't got the sump off yet so there may be some bigger bits yet! The filter also has a liberal covering - so hoping they have not got all round the lubrication system.

The engine was running but exhibited a nasty rattling noise, (like a high speed chain running over something?) but only on over run and not when the rev's were rising. So before I go dismantling the entire engine looking for the something that's broken I'm hoping there's someone on here with experience of the Z650 engine who may be able to point me at some possible causes

The bike is a B model so has a proper chain for the cams with roller guides unlike the later GPz style engines. Compression is good on all cylinders, cam chain tensioner seems to be functioning okay & chain looks okay. I've heard starter clutches are a possible weak point, but could a failure there contaminate the oil like this? Any ideas?

[Thezedsintheshed]

First thing you need to check is to find out if the metal fragments are alloy or steel.
Seeing that they seem to be in suspension in the oil then they sounds as if they are mostly alloy.

If the bike seems to be running well with no other noise's or rattles other than the noise on the over run then if the metal fragments are in fact mostly alloy then this sounds like it may well be caused by a worn out primary chain which can be a common fault on high milage or thrashed Z650 motors.
The primary chain is a Hy-vo type chain and there is no tensioner mechanism to adjust the chain.
The basic set up is that the chain runs from the center of the crank to the primary shaft and when the chain reaches a certain degree of wear then on the over run the chain backlash allows the chain to slowly saw it's way into the lower crankcases .

The bottom end of the Z650 is basically a near direct copy of the H***a CB500/4, and they suffer from exactly the same problem.
The good news is that it is possible to check the amount of primary chain wear without first having to remove the engine from the frame or to totally strip the engine .
First , drain the oil ,then take the sump off, then its fingers in the engine time to feel for the amount of slack in the primary chain and any wear on the lower crankcase below the primary chain area.
Bad news is that if the chain is knackered then the engine will have to be totally stripped to fit a new one.

[Buckle]

Don't ya just hate it when you have to put right what some ham fisted pillock has f****d up?

Here's what I found in the bottom end of the 650 today....


a cam chain tensioner / guide sprocket rubber block....

and.......



Lots of instant gasket and paper ( ) stuck in oil filter pick up along with alloy / brass / bronze (?) paste in the sump.



Would appear that the rubber block is from the rear tensioner / guide. Pics not very clear but the sprocket / guide is out of line with the chain. How the engine didn't fail catastrophically I don't know.

Be careful out there boys, there are some cowboys around

Thanks for the advice though , looks as though the primary chain is fairly stretched. No sign of it rubbing the casings anywhere but I will be replacing it along with the starter clutch. I just hope the filter was doing it's job and kept all the swarf out of the lubrication system. Will check tommorow and report back!

[Buckle]

The bottom end of the Z650 is basically a near direct copy of the H***a CB500/4, and they suffer from exactly the same problem.

PS - I resent the inference that I have anything even remotely resembling a H***a in my garage

[Pigford]

Buckle, so now we know what bthe 'tinkling' was

Hopefully that'll be the end of that then coz, as you say, the bike ran OK even with the guide f**ked

Keep the photo's coming......... I'm regretting selling it now me RedZeds finished

[Buckle]

Hello Mr Pigford

I'll get the top end stripped down this week hopefully, so we can see the extent of the damage. Looking at the receipts that came with the bike (for a cam chain replacement ) that wasn't really what I was expecting to find.......

Maybe I should start another thread in the Projects section to keep you all up to speed?

Anyway 550 (:sf) is now officially on the road - see avatar - so hopefully see you guys around soon

[Dark Skies]

S'truth! Lookit the thick sludge in that pan! Looks like oil changes weren't a high priority for the previous owner.

[Pigford]

Must be 'vogue' coz me RedZed had same sort of sludge in the sump
But as it turned out OK, don't panic yet

[Buckle]

well, I don't know whether to or

The 650 engine has gone from bad to write off I think, unless any of you clever metal machinists out there can tell me other wise.

Carried on stripping the motor down and was presented with the greatest display of incompetence I've ever seen (well, to date anyway!)

removed the cam cover and cams so I could see down the cam chain tunnel....



Yes the cam chain tensioner has been fitted backwards So the chain is running on the steel backing that should face the tensioner pushrod. And the rubber pads are missing both sides so the guide roller shaft is loose, very loose

Better shot, now with head removed. This is exactly as found, just lifted the head and took the picture



Cam guide roller at the front of the block has rubber pads present and correct though.

At this point noticed the centre guide roller also had loads of play - you guessed it - rubber blocks missing! So removed barrels to have a look....



The steel shaft supporting the guide roller has chewed it's way into the upper crank case enlarging the slot it is supposed to be clamped in by the rubber blocks that were missing. It has also chewed up the block between the centre bores - I assume where the rubber blocks are supposed to have been clamped.



To make it even worse ALL THIS WORK WAS CARRIED OUT BY A BIKE SHOP in Bristol. I have the receipt for the work - almost £500 worth. The engine must have been rattling the instant it was started - why didn't they investigate?

So what I have here is an engine with plenty of life left in the internals, but no way I can re-assemble as the upper crankcase, barrels and cylinder head are damaged beyond repair(?).

Any ideas?

[Pasc]

Ouch.
Name and shame the shop that butchered it.

[Dark Skies]

S'truth! I wonder how many other perfectly good engines that shop has buggered up over the years.

A good machine shop ought to be able to weld up and machine the slot though.

[RALPHARAMA]

NAME and SHAME the ARSEHOLE and I'll personally broadcast it around Bristol!!! Personally I would take the engine to them and ensure that they pay for the damage to be repaired ... by someone competent !!!!

[Thezedsintheshed]

I said it as probably alloy swarf because it was in suspension in the oil but didn't expect a can of worms like this to appear .

I agree with the rest of the lads, name and shame the wankers who did the engine work .

As has already been mentioned it is technically possible for a good machine shop to weld up and re machine both the crank case and the cylinder block but at what cost ?

you may be better off getting hold of a good second hand engine and cutting your losses, at least that way you will get it back on the road

[Steve R]

I would have a word with SEP engineering, let them see the pics of the damage and see what they think.

As well as boring out my cylinders they are also repairing the Fin I Broke taking it apart and the big bit of alloy missing round one of the exhaust studs on the head. When I say repairing they are re making them!

I have not yet seen the results yet but they are highly thought ofon here. They were certainly not at all fazed by it, so maybe they will be able to do something with your engine, worth a phone call any way.

There number is on the links page.

Good luck

[Geoff Meager]

Come on ... NAME & SHAME ... put the culprits on the site .... so no one else can get shafted

This is what this site is all about ........... helping each other out