www.zxrworld.co.uk

Hello everyone,im writing to you all the way from Bulgaria and this is my first post here. I recently bought a 1999 ZXR 400 L5 and it was running perfectly until yesterday when the engine died.My mechanic says the engine doesn't have any compression and needs an expensive cylinder head repair, replacing of all of the valves ect. I found a new cylinder head from a 1989 ZX-4 Formula 3, and my question is, will it fit on my engine? The ZX-4 has the same bore and stroke as mine (57x39) but the compression ration is different (11.5.1) I tried using the search option but didnt find any results.

I don't think that has ever been tried before. They look physically similar, but the part numbers are different, but that doesn't mean that it won't fit. I would be surprised, very surprised if you need an entire complete cylinder head. The most common compression failure points on these bikes is the head gasket, or the piston rings. I would be asking your mechanic a lot of questions first before making such a drastic alteration. You might be better off to buy a full replacement engine and keep yours for spare parts.

Also, a 1999 bike will be an L9, a L5 bike will be 1995 or 1996, there are differences to the engine between an L5 and an L9 so you need to know what you have first.