God, I don't really want to ask as I'm so p155ed off with the car. Got myself someone to retest on my behalf so I'm going to cancel next week and look for a new engine from a reliable source rather than some unknown Ebay gadgy. Anyhow, I will not let this engine beat me, no way!
I've disconnected the prop at the diff then grabbed hold of it and put it into 1st gear. I can feel a regular knocking coming down the prop. Has anyone got any ideas? Clutch or gearbox? I can't seperate the front of the prop from the engine, it seems seized so I don't think the adapter's come loose.

Check the UJ's on the prop before you go too far.
Is the Diff flange moving / tight.
Start with the easy and obvious bits.
Leave no stone unturned before pulling the engine.

Is the knocking, relative to the change in engine revs, or relative to the change in road speed?
Things like that can help point you in the right directions, and save you a lot of work and money.

I know how you feel. I had one Noisy tappet. (Really loud at tickover when hot).
It took me three weeks, three head gaskets, a set of shims, two Valley gaskets, and finally a new set of tappets.
It was a little bu**er.
Just couldnt find what was wrong. in then end, bit the bullet and put in new tappets.
Had to do the whole set as the others were Rhoads Bleed down. I recon one just bled down too much when the oil was hot. (oh and I had them all out, stripped and washed out - (only done 5k miles from new)

Still its fixed now.

Good luck

Bike boxes and clutches aren't my area of expertise but...

With the clutch out, in neutral, there should be no drive through the box. If the knock is there in neutral with clutch out I'd say gearbox. Does it go when you depress the clutch?

adrian

The knocking is only there on low revs or tickover (as in just leaving the engine in gear and the wheels turning - only works when on axle stands if all that makes sense) Once I press the accelerator the knocking usually goes. All except for the time when the SVA inspector had it on the rollers.
I thought it was the diff at first but like I said, I disconnected the prop from the diff and it was still there.

So its in gear, clutch out when you get it?

What happens with the clutch depressed?
What happens in neutral?

Just a thought - are you sure you are not just feeling the backlash in the gearbox - when up on stands with no load on the drive wheels but in gear and running they clatter and bang like a good un. Once driving under load they are fine.
Regards
Andy

Adi, when clutch is depressed and/or in neutral then it's all quiet.
That's interesting Andy, I wasn't aware that that may be the case. I've got to be extremely careful I don't get caught if I sneak the car onto the road but I never felt any banging. It was just during the SVA test when the tester was in 5th or 6th gear that a knocking started and I linked the two. Things don't seem too bad if you say that Andy.

My blade engined BEC clanked and knocked like a goodun when feathering the throttle trying to maintain a constant speed before I got the mixtures sorted out properly.

As above, when I tested my speedo on axles stands its makes an absolutely horrible noise, like two big hammers smashing into each other and the transmission tunnel, when you driven this noise does not exist.

This clucking has occured on 2 engines, especially bad when going slowly in 1st or second, even extremely small movements on the throttle pedal make the car lurch, your foot bounces on the throttle, everything gets worse..

On a bike your wrist control is far more delicate, feet are clumbsy !!

If you are running a non standard exhaust, airfilter on the engine then unless the carbs been corrected you will suffer similar problems, the urge is to change the engine!!!

Regards Mark

I definitely feel better now fellas. Think I'll get an early start tomorrow and have a long play with the mixture. Thought I had it right but I've just had to replace the plugs as they were fouled and stalling the engine.

Hi Not bike engine but
I had a Opel manta and if the timing was out the gear box sounded like a box of spanners

quote:

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Originally posted by mistergrumpy
Adi, when clutch is depressed and/or in neutral then it's all quiet.
That's interesting Andy, I wasn't aware that that may be the case. I've got to be extremely careful I don't get caught if I sneak the car onto the road but I never felt any banging. It was just during the SVA test when the tester was in 5th or 6th gear that a knocking started and I linked the two. Things don't seem too bad if you say that Andy.

---

Just to flog a dead horse. I disconnected the prop at the engine and put it into gear and running. The noise is still there, it sounds like a pea rattling round and it sounds to be in the clutch housing. If I pull the arm slightly out of the housing I can feel the tapping noise vibrating through.
I've just took the clutch off agin for the millionth time and I noticed that I can turn it 3/4 " before the output shaft will move. Is this normal too because the metallic clang noise it makes when what I'm guessing is the dog teeth hitting(?) is the same type of noise that the engine makes when it's running.

I thik your'e describing the backlash in the gear train, so that's probably normal.
Not familiar withthe specifics aof the engine, but it has been known for clutch centres to come loose in the clutcch body, just as another thought

drain the oil and see what comes out if it looks metalic remove sump for further inspection, mine rattles like a bag of shite but I know it's the cam chain so not really bothered clutch output bearing also rattles

tony

Removed the clutch cover and al the oils come out and there's nowt metallic in there.
I've heard the cam chain tensioner can be suspect and reading around the forums the description of the noise is exactly as mine sounds (like an aerosol can) but the fact that the noise goes when I press the clutch leads me to think it's something in the gearbox.

when you say it goes when you press the clutch pedal, do you mean fully depress the pedal or does it go when you just take up the slack in the cable and start to put pressure on the clutch operating mechanism,


tony

Hmm, not sure as there's no oil in it at the moment. Can I ask what you're thinking?

hard to explain, if it goes quiet when you fully depress the pedal you are disengaging the clutch therefore preventing anything after the clutch input shaft from spinning thereby pointing to something in the output side, if it goes when you just start to take up the pressure it points to a clutch thrust bearing, same principal as with a car with a noisy thrust bearing (not being funny but have you never experienced the same thing on a car where the bearing is noisy till you rest your foot on the pedal.)
I'm trying to think which pub the local bikers meet in in bolton, might be worth having a word with one of them with the same bike as your engine


tony

That's a good idea. I think they meet at Rivington Barn on Sunday mornings.
I see what you're saying though, that's about where I got up to this morning whilst sat in McDonalds car park drawing on napkins and old receipts.

If you only have 3 dogs on 1st gear (like many bike gear boxes) then the driven and splined gear wheels can rotate by up to 120 degrees. Under load, they will stay locked together, but when there is no load e.g. when on axle stands they will rotate relative to each other with the dogs bouncing back and forth and make that godawful clonking sound.

Also, note that with a wet multiplate clutch, you still get a small amount of drive to the transmission even with the clutch pulled. Its a tiny amount (you can stop it with your hand quite easily) but it actually helps you to engage gear when stationary. It also makes a big clonk when you engage 1st...

Bike gear boxes and clutches are a bit of a shock to the system if you are used to car boxes, but the payback is incredibly fast engagement.

Nick

Well I've just put the clutch back together for the umpteenth time. I gave the clutch plate a touch with a file where the springs had bitten in a bit and left marks and I packed the needle bearing thrust type washer out rather than just lightly coating as I did this time. Started it up and the noise has gone, for now. I just don't get it. I'm going to try and get it up to temperature tomorrow if the weather holds out and reassess it. I just don't know what's going on.
Have to sort the engine hunting out now and I'll be hopefully back where I started.