KAWASAKI ZZR 1100 ENGINE PROBLEM

[davetbee]

Hi, i have an autograss car wich has a kawasaki zzr 1100 engine in it. Down low in the revs the engine bakfires, splutters nd dus evertin not rite and is totally un usable , as soon as the revs eventually build up to about 6000 it seems fine and drives really well, the engine has a different set of carbs and it has no alternator so the battery goes flat, and maybe it wont provide a good enough spark???????? there is also a loud knock wich i kno comes from a dodgy cam and follower, so cud it be that, but wont that get worse up the revs???????? does ny1 know exactly whats wrong i would really appreciate any help
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D alexander

[woodyfjr]

The only thing I know about ZZR 1100's were that the early one's had chocolate cams thats about it Dave!

I hope it helps a bit.
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If you don't pay your exorcist you can get repossessed.

If you have to rev it! Don't Buy it!

[Kickstart]

Hi

If the battery has a decent amount of charge then the lack of a charging system is probably not the problem. Also suspect that the CDI would might only have issues if the power supply is too lower but with no charging it would not get better with revs. A problem with the coils would likely get worse with revs (higher revs means less time for them to "charge up").

What carbs are you running? Have they been set up for the engine in its current state of tune?

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[davetbee]

the carbs are kiehin flatsides and i was told off the person i bought them off they had been set up, but it bakfires alot down low and it is a very early engine thats probably had a good hammering round the race track for a long time!!!

Dave
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D alexander

[sickpup]

So you have a set of FCR's probably in the 41mm size if I know racers with no airbox and you wonder why you have no bottom end?

Because the engine is set up for top end power alone and is expected to be kept above 6000rpm at all times.

[davetbee]

Hi

it has got a standard airbox on and i don't think there has been any other work done to it apart from a different exhaust can, and below the power range it is really jumpy and backfires alot and is generally undriveable until you get it above 6000 rpm
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D alexander

[sickpup]

So fit a set of smaller carbs to it then.

[Kickstart]

Hi

Also, how are you "driving" it? Flat slide carbs will not appreciate just being given full throttle at low revs. The original CV carbs are partly chosen for their ability to cope with this.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[davetbee]

Hi

I try not to use full throttle down low in the revs as it won't go as quick as if you only use a little throttle, however still using a little throttle will cause alot of backfiring and it is very jumpy, i think it may be something to do with the camshafts and valves.
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D alexander

[Kickstart]

Hi

Is it backfiring through the carbs? Can you stick some vacuum gauges on and see whether they are balanced (which will also give you some idea of how healthy the valves are).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[davetbee]

no, its bakfirin through the exhaust, but i will stick some vaccuum gauges on to see what state the valves are in
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D alexander

[Kickstart]

Hi

If it is backfiring in the exhaust then it suggests the exhaust valves are either not doing their job (ie, cam timing out, valves not sealing) or far more likely it is dumping large amounts of petrol down the exhaust.

Vacuum gauges are mainly for balancing the carbs but if they are a nightmare to balance then it suggests an issue with the cylinders.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[ZRX61]

First thing to do it pull the float bowls off & clean out the pilot jets....

[bish777]

is it BACKFIRING ie BANG out the pipe, or popping?

if its flames, try lowering the needles a clip, if popping raise it a clip and see how it goes.
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GSXR1100J