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Discussion Starter · #1 ·
Just rebuilt complete ZX6R J model engine . started it up today 4 the 1st time the engine is sweet no rattles etc.But this is were i could do with some advice ,(please only reply if you are clued up with engines:shock: ) The bike wont run WITHOUT full choke also i can only rev it upto 4000rpm before it trys to cut out, I know its a fuel problem but as severe as needing full choke all time is more than a tweeking of the carbs,could a bad plug not firing correct (weak)under compression cause this,There is nothing ,nothing wrong in the line of vacuum every thing is piped right. Its not the timing not cylinder head valve leakage all hardware is new and within tolerance of service limit
 

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I know its a fuel problem but as severe as needing full choke all time is more than a tweeking of the carbs
Really? Doesn't full choke give you a rich mixture, so a very lean condition would seem to be the diagnosis to us simpler mechanics. A wet plug would indicate not firing, again to us less informed. A newbie might do a water mist spray to check for vacuum leaks, all of the way back and including the air box. And you know what? The crazy's might even tear down the carbs and give them a once over.

Sounds a lot like what was happening when I was trying to run pods w/o jetting the carbs, in which case I put the air box back on.

Some less initiated might look into the other ignition parts, like the ignition advance that might come on around 3500 RPMs. This is usually worked out on them there newer bikes, matter of fact, I think all of them Ninja motorcycles had that Electronic ignition stuff. People in the know told me that the cutoff switches ( side stand/clutch) acting up can cause some erratic behavior, but I don't know if they were on the same level as you need.

Hope somebody will be able to help!
 

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Really? Doesn't full choke give you a rich mixture, so a very lean condition would seem to be the diagnosis to us simpler mechanics. A wet plug would indicate not firing, again to us less informed. A newbie might do a water mist spray to check for vacuum leaks, all of the way back and including the air box. And you know what? The crazy's might even tear down the carbs and give them a once over.

Sounds a lot like what was happening when I was trying to run pods w/o jetting the carbs, in which case I put the air box back on.

Some less initiated might look into the other ignition parts, like the ignition advance that might come on around 3500 RPMs. This is usually worked out on them there newer bikes, matter of fact, I think all of them Ninja motorcycles had that Electronic ignition stuff. People in the know told me that the cutoff switches ( side stand/clutch) acting up can cause some erratic behavior, but I don't know if they were on the same level as you need.

Hope somebody will be able to help!
 

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First, start at the beginning. Was the bike running properly before the rebuild? Between 3500-4000 rpm's the carbs should be switching over to the main jet. Are all 4 exhaust pipes hot? Airbox needs to be connected or CV carbs will cause problems unless a jet kit has been installed. If the carbs weren't cleaned prior to the rebuild there could be a skin film over the pilot orifices from sitting around. Floats properly set? You didn't state the year of the bike but if one cylinder is cool check the plug boots for arcing to the cylinder head.
 

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Going to have to back up a little more with some questions:
1. What was the initial problem that required the bike to be "rebuilt"?
2. What did you do during the rebuild - pistons, rings, bearings, valves, etc?
3. What all did you have apart? Split cases?

Post back.
 

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Discussion Starter · #8 ·
:(( the problem was i snapped a con rod misgeared half of the piston went through head and bottom half through side of crankcasing.I bought a second hand engine stripped it and replaced:
Big ends ,mains,rings,honed bores ,oil pump,clutch,clutch bearings etc,.cylinder head :-valve seat inserts,lapped,valve springs,seals,pressure tested,skimmed .Ive had it running its quiet as a mouse i really dont think its anything to do with rebuild even when it warmed up it had trouble starting without choke (warm)This was happening before rebuild i thought engine was on its way out till it went bang but its obvious its something else.Ive stripped down carbs today they are back together but i checked timing wasnt out at 4pm so havnt had time to finish it will post bk tom and let you know outcome pal.Cheers Mik
 

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Discussion Starter · #12 ·
I want to thank everyone who took intrest and willing to help me solve this problem.The problem was .......................CARBS i put the wrong ones on bike haha ZX6R 'G' MODEL instead of 'J' Model ,there jetted different anyway its fine now
 
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