What else can I do?

[sefer]

Ok, my continuing saga of doing the cam-chain in my zxr250.

You can check out my other threads

here : http://www.kiwibiker.co.nz/forums/showthread.php?t=22911

here:
http://www.kiwibiker.co.nz/forums/showthread.php?t=23635

and here:
http://www.kiwibiker.co.nz/forums/showthread.php?t=23155

Anyway, all parts sorted, got everything back together today with two additional hicups (oil shalf broke, but fixable :), water pump leaked everywhere due to the slight difference in clearance from fixing the oil shaft :doh: but both will be quickly repaired tomorrow :D ) BUT I'm still getting what I'd consider to be unusuall noise. This is the same noise the prompted me to remove my clutch and replace the transmission bearings, but now I listen to it again closer I find that it is centred around the top end/tank rather than the clutch, which I thought previously.

Now this is getting really frustrating as you can probably imagine :brick: so I'm wondering what else I can possibly do.

Just to review. I've:

Replaced the camchain
Replaced much of the clutch
Replaced the transmission bearings
Replace oil/filter

The bike starts fine
Blows a shit load of smoke currently, but this is to be expected really as it's engine has been upside down (now only really does it at high (10K +) revs)
Was having issues with reving over 8-10k at first (like hitting a flat spot), but poped over 10k (complete with HUGE black cloud :) ) and seems to be fine now
Idles fine

The sound it self is actually hard to explain, I call it a knocking sound for lack of a better way to explain it. If I had to guess I'd say it's coming from the camchain.

So, what are the suggestions as to what I do next? I keep thinking that it might very well be just me, that my bike might have always made this noise, but I'd still rather check it out first and make sure.

I'll get the pump back together asap tomorrow, and might record the noise and put it up here if I can. It's probably worth saying that from the riders position you actually can't really hear it, it comes from the right side mainly, but is still quite obvious from the left.

[Ixion]

Not saying you are, but is it possible you are being a bit over demanding? Double knocker engines , especially light alloy ones, are always going to be a bit noisy in the top end. That's why the OHC layout went out of fashion for many years. I've just done Ratty's cam chain, because it definately was rattling and clattering. All that noise is gone now but if I listen closely I can still hear little ticks and whirrs and whishes . Bear in mind you've got (I imagine) 16 bucket cam followers (non hydraulic) They're definately going to make some noise. And two morse type upper sprockets (morse chain never renowned for silence). Plus assorted bearings and such like. Can't expect it be as quiet as a side valve, or even a pushrod OHV (let alone a sensible two stroke engine, but that's another story !:bleh: ).

Hard to say of course without hearing it, but it's not going to be as quiet as a car engine. Prolly the only real way to tell is to line it up side by side with another bike of the same model and see if there's any difference ?

[sefer]

Yeah I've already considered that I'm just being fussy as hell :p

Totally agree with what your saying, half of me says " meh, it's seems to be running fine, so it's probably nothing, just engine noise," while the other half is "man that sounds like shit, got to be something not right there." Doesn't help that I'm actually looking for noise too.

It also doesn't help that I hadn't actually been on my bike in the two weeks before I took it apart, so what it sounded like to begin with isn't fresh in my mind.

I'll take it out tomorrow for a short run anyway, see if I can tell from actually riding it. I've just got to remember that the camchain was sounding really bad at speed and through my helmet, while ATM I'm listening with my head right next to the engine.

[limbimtimwim]

I'll take it out tomorrow for a short run anyway, see if I can tell from actually riding it. I've just got to remember that the camchain was sounding really bad at speed and through my helmet, while ATM I'm listening with my head right next to the engine.So you haven't even got it warm yet? Perhaps find someone else with zxr250 and compare.

[thealmightytaco]

You could try rubbing gravel on the windscreen.

You could.

[sefer]

So you haven't even got it warm yet? Perhaps find someone else with zxr250 and compare.

Well if you consider that the water pump pretty much blew out all the gasket after I had it running for 20min you could say it was probably a little too warm :D

(the story behind that is after repairing the oil shalf I had to estimate the length within a couple of mm, it was just too long which made the impeller rub slightly against the housing (which I couldn't see obviously). The cooling system obviously wasn't happy with the reduced flow. Couldn't be stuffed fixing it today thou, so I'll sort it tomorrow)



You could try rubbing gravel on the windscreen.


I could also put gravel into the oil, that might make the sound less obvious in comparison :P

[thealmightytaco]

I could also put gravel into the oil, that might make the sound less obvious in comparison :P

Bingo.

10 characters.

[FROSTY]

experience with mella yella here--Um I've been through 4 engines so Ive got to know a few noises.
1)did ya replace the tensioners when you replaced the camchain ?
2)valve clearances need to be checked.
3)cracked valve guide stem
4) con rod bolts slightly stretched so piston is clipping a valve
5)carb slides rattling around
6)worn cam bearings -dont usually cause that kind of sound.
7)One exhaust manifold slightly leaking --causes a cracking noise as the bike gets to exhaust cycle -ditto a cracked header pipe
8)previous overrevving has caused a very slightly bent valve so its sticking

I wont carry on cos itll depress ya -start by checking the simple stuff first

[sefer]

1)did ya replace the tensioners when you replaced the camchain ?


No, but if anything I'd say it's pushing too hard.



2)valve clearances need to be checked.


Ok, didn't do but is on my list if things don't improve.



3)cracked valve guide stem
4) con rod bolts slightly stretched so piston is clipping a valve
5)carb slides rattling around
6)worn cam bearings -dont usually cause that kind of sound.
7)One exhaust manifold slightly leaking --causes a cracking noise as the bike gets to exhaust cycle -ditto a cracked header pipe
8)previous overrevving has caused a very slightly bent valve so its sticking

I wont carry on cos itll depress ya -start by checking the simple stuff first


I don't want to even consider any of that :p

I'm about to get the pump back together, so I'll record the sound and see what everyone thinks of it :)

[sefer]

Well call me foolish but I think I've just figured it out, when I had the engine upside down (sans cam shafts) all the valve lifters and shims fell out...and of course having no idea where each came from, and they all looked the same of course, I just put them all back where they seemed to come from, most likely totally stuffing up the clearance :(

I'll post the noise it's making soon, but I think I've got the problem. Big question is how do I fix it?
(on that note, anyone in CHCH have some calipers I can borrow for a few days?)

[sefer]

Added drama, dropped my minidisc player when going to record and had to fix that first :doh: :D

Well here are my sounds, first is right next to the top end (RIGHT next), ten moves to the seat/tank area and includes revs up to 10 -14 then 16k, then back to right next to the top end.
(I took the bike for a spin, 30min before this, and let it warm 5-10 min right before recording)

File is not to big, just under a meg. (and why can I post a audio file via the forum! :D )

http://www.yourfilelink.com/get.php?fid=19593

New noise too on the road, it's a reasonbly steady knock, like a tapping on the fairing, but it gets faster at speed, slower as I slow (most noticible when slowing, but prob just because there is less noise in general), stops at very low speed (meaning I can't pinpoint it). Not discounting that it's actually something unrelated, or even a loose cable or similar, but it may be a tell-tale sign. Bike seems to run great however.