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Discussion Starter · #1 ·
Hi,

Apologies for the length of this one but I need to explain the full picture in order to seek correct advice. I have a kawasaki zx9r B1 which was running fine for yonks. I started it up in the garage one day just to keep things rolling as it had sat for a fortnight - all running fine the engine had been idling ok for around 3 minutes or so then started making this terrible tin can noise. I stopped the bike immediately, re-started then the same noise again. I knew something was badly wrong so as it happened I opened the whole top of the engine up..., it turns out one of the pistons had exploded and also ruined the valves and top part of the engine. So.... having checked not too much damage except to piston and valves at top (barrels were ok)I have replaced the broken piston, bought a second hand head as well. Seeing as I had the head off I removed, cleaned and lapped all the valves, refit everything with new gaskets etc. checked the cams and timing chain were on right as per manual(counted the links in timing chain correctly and cams aligned etc.), put engine back, new oil and oil filter. I have been really careful throughout and followed the haynes manual to the letter. Having reassembled the bike it just wont start... the engine turns, if I remove the plugs I can see the piston heads moving fluidly. I replaced the battery as it seemed a bit ropey. New fuel. First, I thought fuel might not be getting to engine as it took about three months to do all this so thought carbs might be gummed up, so removed main and pilot jets making sure they were clear/blew through with carb cleaner and compressed air. I know fuel is getting to carb as float bowls will drain if I unscrew drain screws. I can see spark on all four spark plugs. After trying to start her the plugs are wet if I take them out. I just don't get it as was running first start every time before the blown piston and I have only changed the parts mentioned. I'm not sure what else to check or where to go from here, any suggestions would be really helpful! Thanks!
 

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I would check plug leads as suggested by davidr1963 and if that's not the issue I think I would do a compression check next.
 

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Discussion Starter · #4 ·
Thanks for the replies, I'm pretty sure they are in correct order but I will double check. Update shortly!
 

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Discussion Starter · #6 ·
Hi, I have checked the coil leads - left hand coil is to cylinders 1 and 4 right hand coil is to 2 and 3 - I took photos of all the wires before I removed the engine in case there might be any confusion so they are all wired the same as before when it worked... I've never done a compression test - surely if that was the issue the engine would still fire at least for a second or two or run roughly - since the re-build I have had nothing at all - not even a splutter... I did get one massive backfire at one point then it just went back to turning over same as before but nothing else...still stumped...?
 

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Discussion Starter · #7 ·
Could it be the pick up sensor? I checked the resistance according to the manual and was within right limits but dunno if other stuff can go wrong that's not detectable like that?
 

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I know you are sure you got the cam timing correct, but a compression test can reveal bad timing. It is also a really good health checkup of the entire top end.
 

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I would check plug leads as suggested by davidr1963 and if that's not the issue I think I would do a compression check next.
Sounds like the time I managed to time an engine 180 degrees out, so I agree with above,
but would take it one step further: swap the 1,4 coil wires with the 2,3 coil wires; see result?
 
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