Hi Guys, I'm new to the forums but have read through a few threads on this site before just through google searches. I was having a read over at edwardo's thread here http://2fiftycc.com/index.php?threads/zxr250-cam-chain-tensioner.1245/ and I'm having some similar problems. I'm in the middle of trying to hunt down the infamous ZXR250 cam chain rattle on my 1999 C model. I replaced the tensioner with a brand new one last service but the rattle remained and I just gave up and rode it. Now its time for another service and I'm having another go at fixing it. I've spent most of the day pulling bits of the bike with the idea that I would probably have to replace the cam chain. Got the valve cover off and had a look at the cam chain only to find it didn't even seem that loose. How much slack is normal? Just looking at it between the two camshaft sprockets there appears to be no slack. If I apply some force I can move it up and down a total of maybe 10mm. I have basically no experience with this stuff, but to me that doesn't really seem like enough to be causing such a rattle? On the other hand, I assume if it can move 10mm between the sprockets that it can probably move a bunch more down the sides of the tunnel? Another thought I had is that if the cam chain isn't loose, maybe the two plastic guides that go down either side are worn/broken. Which leads to the question how the hell to I get them out lol? There's really not much information in the manual, but from what I can tell there's a bolt on the side of the engine that holds the one towards the back of the bike in place, but the one towards the front of the bike I have no idea. Do you need to take the head off to get to them? From what I can tell you guys have a wealth of experience with these bikes. Any help would be greatly appreciated Thanks
Heres another thread with info about installing the tensioner ..... check to see that it was correctly done last time http://2fiftycc.com/index.php?threads/shauns-zxr250-a-model-build-thread.1310/ cheers
Hi Grey, thanks for the reply. Had a look at that thread and I'm fairly sure I did it right. Definitely clicked into place and was applying pressure to the little mechanism, although probably no more than the 'old' one.
Hey Peli You are 100% correct, the plastic guides for the cam chain are as you said, one is bolted and the other slips in and is not secured from memory, it's been awhile since I last worked on one. Kawasaki's do rattle a little, unless it is very pronounced probably wouldnt worry to much.
I have thought about this, maybe its a completely normal sound for these bikes, especially as after all the youtube videos I've watched I think I'm yet to hear one without it. But then again it is a pretty harsh sound, I'm just worried its chewing a hole in the engine somewhere. I've seen numerous people post on this topic claiming a new chain/tensioner fixed it, so I must be able to get rid of it somehow. Here's a link that shows the same noise So can someone tell me how much slack a new cam chain normally has, on a zxr or any other 250cc bike? Had another look for the guides with the clutch cover off, and yea the back one has one bolt on the side of the engine and also the bolt that goes through the little tensioner mechanism, so would have to take that off and I think it might come out the bottom. The front one has no bolts, but from the way it is held in at the bottom looks like it might have to come out the top? Could be difficult.
Thumbs up from the A-Team These inline 4s are made to rev high not to piddle along at low revs....... I wish my Fizzer sounded that good .... oh wait , it makes no sound at all ATM !
That sounded pretty spot on to me, if yours is like that, don't think you have to much to worry about.
Really that's normal? Guess they just have noisy cam chains. To me it sounds pretty unhealthy, but I guess the way it sounds on idle is a small price to pay for the way it sounds at 18k I looked under the valve cover and there's no chew marks, so unless its chewing somewhere in the tunnel I think I'm good. I might try measuring the valve clearance and having a quick look inside the carbs seeing as its all apart.
Yea valves are important and definately do the carb shuffle ..... as can be seen in some of our threads the carbs can be a real mess inside
Bit of an update, I've been really busy and haven't had much time for the bike so progress has been very slow. On the home stretch now though. Checked valve clearances, was mostly good, there were a couple on the exhaust side that were just out but I didn't think it was worth the hassle fixing seeing as there were only two of them, they were very close and the bike was running good. Put new spark plugs in, the old ones looked pretty healthy and were still the right gap, but changed them anyway. New clutch fibres and springs are in, new clutch gasket on and the the clutch cover is on as well. Radiator also back on but yet to be filled. Decided I'd leave the carbies until next time seeing as they are working well now and I'm strapped for time. Was just putting the carbies back on and noticed the decelerator cable had a heap of slack in it. As in a good 2 inches of slack. Throttle cable and throttle free-play seems good. Throttle snaps back nicely, which leads the question, what exactly does the other cable do??? There is a spring on the throttle that ensures the throttle snaps back, so what's the point of the other cable? When the throttle is opened is it meant to be pulled back by this cable as well as the spring? Not really sure what the point of it is? I didn't take a lot of notice, but I think there was a fair bit of slack when I took it apart, although I don't think this much.
if the valve clearances were a bit tight i would give them a little more clearance as they wil tighten up with heat and the bike will be hard to start when hot. and /or the valves could burn out.with the radiator red anti- corrosion is the way to go. buy the concentrate and mix your own brew. should last 5 years.
