Knock Knock

[killerplumber]

Hey guys i just bought a 07 z400, and today in the first chance ive had to really ride it. After riding for a while i heard a knocking sound coming from the top of the engine, it dosent knock all the time, but it is worse when the motor is under a strain, like climbing a hill ect. any help would be greatly appreciated !!!

[711streetfighter]

Is the engine stock? I don't know how mechanically inclined you are but did you check the oil level? Sorry but you've go to cover the basics, I don't mean in any way to insult your intelligence. Sounds like detonation though, if it's a knock under load and you might try a higher octane gas. If the previous owner put a high compression piston or a drz base gasket you need to run 91 or higher. A sharp ticking is valve lash. A stretched cam chain can also make some noises.

[killerplumber]

ok here is what i know bout the bike, stock far as i know, just bought it as i said and of course the old owner said it was running great so here is all the minor stuff out of the way, the oil lvl is good, gas is 91, and also it dosent sound like detonation it is a harder knock than that, detonation i would say is more of a clatter then a knocking sound but anyways thats all i know so far bout it

[711streetfighter]

Knock from the top end is just weird. Check the timing chain for stretch and pull the valve cover to see how the clearances are and if there is anything obviously broke in there.

[CFM-Z440]

I would see how many clicks are left on the cam chain tensioner. The stock timing chains are known for not lasting long in these engines. What you do is first remove the spring from the tensioner, then remove the tensioner. Once out, pull out on the adjusting rod and count how many clicks it makes before its fully extended. 2 clicks or less, you need a new timing chain.

If you need a replacement chain, a couple of our site sponsors can hook you up with a DID cam chain that will last much longer.