www.zxrworld.co.uk

From the US but living in Germany now and looking for another project since the ZXR was officially imported here. Wrench for 600 rider and I hear a lot of 400 riders being dominated by the SV. So yes I am going to build an SV killer. Not just a 1mm or 2mm motor, I am talking about a real beast!!!!!!!! 95hp min!!! Yep.........keep reading.

I use to build 1WG FZR400's since it was the only 400 imported to the US and had great success. Fortunate for me Yamaha is very parts bin oriented company. I could use the FZR600 or YZF600 crank in the FZR400 cases and bolt cylinders and head in varies combinations. With stock parts I could put together of 489cc (FZR400 crank + YZF600 pistons), 542cc YZF600 crank + FZR600 pistons bush small end) or 660cc (FZR600 crank +YZF600 pistons) without having to bore a single cylinder. I had to deck a cylinder and head for my squish and valve to piston clearance but as you can imagine, these things were cheap for the HP results. 90hp all day with a 489cc with good head and cams.

Why not build another FZR400 monster you ask? Been there, done that!
Why an SV killer? Because it is fun!

My question is the following: Like the FZR, can I bolt any of the Kawi 600 cylinders to the ZXR400 cases? Are the cranks interchangeable? Anyone know racers had have done this?

Thanks in advance for the information.

Hey whats up? Just read your post and like you I am in the U.S. I currently have a FZR 400, the last year with the deltabox combination, and it has a 632 wiesco motor in it. 104 rear HP, a real bumble bee. I just read somewhere in the last few days about the ZXR 400 motor interchangeability with the ZZR600 heads. I also have a ZXR 400 here in Florida but it has a fried head from the oil tube fracturing and not bringing oil to the right side of the head and melted the cams into the head. In my search for someone to provide me with info on sticking a 600R motor into this little rocket I read that the 600R motor will bolt right into the bottom frame rails but the head and carbs will not fit up into the frame itself. This pro motor builder over in the UK was taking the 400 head and cylinders and using them on the 600 botom end ( he was boring the 400 cylinders to fit the pistons of the 600 due to the motor looked better because the fins on the cylinders matched the rest of the engine profile) and then using the exhaust cam of the 400 due to duration. He said he was making 92bhp with this combo. Hope this helps. If you know where I can get a 1989 H1 head in good shape or a running motor for a decent price shipped over to me that would be of great help as I have had this bike since 1997 and it is still sitting in my garage with no motor. Chad

OP is in Germany now

You been reading about a ZRX400 conversion using ZZR600 parts and 92BHP is fookin optimistic somewhere around 75~82 at very best !

ZXR400 engine is unique in the Kawasaki range - the new breed of ZX engines were developed from it but share nothing in common except name. The SP pulsar is now used right across the range with different crank firing positions.

If your going to go, bolt an engine in - none will drop right on in so dont bother with a 600 lump look for lightweight litre lumps like the FZR exup or fireblade motors - there is plenty room for them.

PS. That pro motor builder in the UK has blown up every motor he has ever made