Dodgy running

[matt2301]

Hiya guys, this is my first post on this particular forum, so please bear with me!

My friend's ZXR400-L basically runs and sounds like a bag of spanners. I could out-accelerate him on my RS125, never mind my Fazer! LOL It has poor power output, and very bad acceleration. Whereas my Fazer and my mates Z750 sound revvy like inline 4s should, his sounds too deep, y and too throaty. All noise and no go, I hope this rings a bell with someone.

It sounds to me like the valve timing is all messed up, and as a result my first thoughts are that the cam chain tension is all tits up, or that the chain itself needs replacing. A typical ZXR problem as I have read.

From what I have learned from browing this site, the chain tensioner is automatic, as it is spring loaded. If your cam chain is gone, then you just replace the tensioner?

The thing is I'm not too sure as to how to do it. There are a few things I really need to know, and would be grateful for some advice!

Firstly, is my diagnosis of dodgy valve clearances or timing correct in your eyes?

If I need to replace the tensioner, how much are they and are they easily available?

And lastly, are the tensioners easy to fit? I'm pretty handy with a spanner. If someone were to briefly describe it to me I'm sure I can do it no problem.



Many thanks for any and all replies, ride safe!

[masterofinsanity]

firstly the manuals are available on the main site if you need them, if the cam chain has gone just replacing the tensioner isn't going to solve the problem, are you sure the plugs coils and cdi are all ok, checked for good sparks?

[matt2301]

I'm very sure about the sparkies, it's getting a good solid blue jolt on all four cylinders. Plus the fact that there's a tell tale loud rattle where the cam chain is, which is concerning:(

[RedexRobB]

Well cam chain at least sounds like it needs sorting, if it goes quiet when you rev it its defo the cam tensioner.

As for its go, you sure your mate is giving it some proper revs off of the lights when you race him? If its deeper and throatier, is he running a standard exhaust or not? If hes put a race can on, it might be the exhaust has messed up the fueling and playing havoc with the running, although as severe as that might not be that at all.

Whats it like once its going tho? does it just completely bog down or is it just slow off the lights?

[matt2301]

He has a stock exhaust system. I'm very sure he's giving it some, as being embarrassed by an RS125 is something he wouldn't undergo lightly:)

So from what you've read, is my thinking the cam tensioner is on the way out correct? Ideally I'd like to replace the cam chain and tensioner at the same time, both have had a very rough life in my opinion, and I'd prefer if I knew fresh metal was in there.

Would someone just outline the basic costs and procedure to replacing the tensioner? I can't find it in the manual. If I've overlooked it (which is entirely possible:D) please just say so.

Thanks a bunch,

Matt

[masterofinsanity]

your cam tensioner should be ok it is self adjusting to the chain, if the chain is renewed just reset the tensioner, its a matter of unbolting it at the bottom and pushing the rod back down , you will need a bit of wire to reset it but its all in the manual. as for the chain, depends if you get a cheap split chain or a genuine kwak full chain which means you will need to split the engine in half.

you may have missed it if you were looking in the L model manual as it is just a supplement to the H model manual, look at the H model "engine top end" from page 9 onwards.

[matt2301]

Is there any chance of getting a proper rivetted chain to do the job?

[masterofinsanity]

i have heard of them on the market but personally i'd stick with what kawasaki intended.Obviously its down to budget and experience.

[matt2301]

Hmmm. I'm well experienced in rivetting chains. I have the proper tools to do a good job on it. (not just a hammer:D)

But if you guys truly reccomend the endless chain I'll tell my mate to go with that.