HELP.. ZXR400 PROBLEM
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Re: HELP.. ZXR400 PROBLEM
bloody ell sounds like my zxr, i'm gonna change the pickup coil next.
Don't forget people there is more to the zxr400 than this forum... check out www.zxrworld.co.uk also.
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Re: HELP.. ZXR400 PROBLEM
jamkwak wrote:Yep.. cables all ok... needs the choke everytime to start though....!
really does sound like a pilot jet issue
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Re: HELP.. ZXR400 PROBLEM
How are you going, I dont think it is park related as probably wouldnt run on choke well either. However It is still worth investigating charging/ Battery voltage just to eliminate it. Next I would check is Vacumn leak, This would definately cause those symtoms ( use a hose put to your ear and search for leaks).
As for pilot circuit, There are two things to consider. First the pilot screw and second the pilot Jet. Check the Pilot Jet for obstruction etc. check the Pilot screw for damaged Oring and or broken tip. Also blast pasages of these to circuits with cleaner and compressed air. As for having your pilot screw out more than 2.5 turns ( ie 3) at that point it really calls for a pilot jet change in order to bring the screw back in to 1 - 2.5 turn range.
I also Agree totally with every one elses sugestions in relation to Float heights.........Cheers
.
Regrds TK400
As for pilot circuit, There are two things to consider. First the pilot screw and second the pilot Jet. Check the Pilot Jet for obstruction etc. check the Pilot screw for damaged Oring and or broken tip. Also blast pasages of these to circuits with cleaner and compressed air. As for having your pilot screw out more than 2.5 turns ( ie 3) at that point it really calls for a pilot jet change in order to bring the screw back in to 1 - 2.5 turn range.
I also Agree totally with every one elses sugestions in relation to Float heights.........Cheers

Regrds TK400
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Re: HELP.. ZXR400 PROBLEM
Hi,
Have you tried new plugs? How old are the plugs? When were they last changed?
What have you got the mixture set at?
Have you checked for air leaks at the inlet rubbers and airbox?
Regards
Rich
Have you tried new plugs? How old are the plugs? When were they last changed?
What have you got the mixture set at?
Have you checked for air leaks at the inlet rubbers and airbox?
Regards
Rich
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Re: HELP.. ZXR400 PROBLEM
Ta Everyone for all your help...
As I stated initially the engine was removed and top end stripped and rebuilt, including spark plugs (iridium)new cam chain, adjuster, good camshafts thanks to zimm, valve clearances now set to Inlet 0.15 and exhaust 0.2, stage 1 dynojet kit and carbs thoroughly cleaned, K&N filter cleaned and re-oiled...New fuel filter and tap repair kit...
After all your advice I lifted the carbs off again, set the needles on the top groove, kept the 97.5 main jet, re checked float heights, re oiled throttle cable, put it all back together and refitted carbs, set pilot screws to 2.5 turns.............
Bike fired up nicely with choke and ran on throttle when choke was closed.....
Still very lumpy but a lot better and now able to balance carbs...
Carb slightly off on No3 but 1 & 2... HOLY toad... WAY WAY OFF !
Balanced nicely, rechecked and now running beautifly on idle at 1000 rpm.
One last thing for advice please... It doesn't rev above 11,000 and still a minor splutter on first twist of throttle below 2000 rpm... would a 100 or 105 main jet sort this out ?
As I stated initially the engine was removed and top end stripped and rebuilt, including spark plugs (iridium)new cam chain, adjuster, good camshafts thanks to zimm, valve clearances now set to Inlet 0.15 and exhaust 0.2, stage 1 dynojet kit and carbs thoroughly cleaned, K&N filter cleaned and re-oiled...New fuel filter and tap repair kit...
After all your advice I lifted the carbs off again, set the needles on the top groove, kept the 97.5 main jet, re checked float heights, re oiled throttle cable, put it all back together and refitted carbs, set pilot screws to 2.5 turns.............
Bike fired up nicely with choke and ran on throttle when choke was closed.....
Still very lumpy but a lot better and now able to balance carbs...

Carb slightly off on No3 but 1 & 2... HOLY toad... WAY WAY OFF !
Balanced nicely, rechecked and now running beautifly on idle at 1000 rpm.
One last thing for advice please... It doesn't rev above 11,000 and still a minor splutter on first twist of throttle below 2000 rpm... would a 100 or 105 main jet sort this out ?
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Re: HELP.. ZXR400 PROBLEM
11000rpm is near where the limiter cuts in . check the pink wire.
else yes mains will be the main contribution to fueling at that rpm on full throttle.
else yes mains will be the main contribution to fueling at that rpm on full throttle.
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Re: HELP.. ZXR400 PROBLEM
also I would set idle to 1500ish as it will help your offidle transition. also reduces engine braking a little.
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Re: HELP.. ZXR400 PROBLEM
good work !
this is why i always set carb balance on the bench.
not revving could be a few things,
im guessing you are revving it in neutral at a standstill ? in which case, it may well be revving out but the delay on the tacho means it looks like the limiter is cutting in at 11ish .. it isnt .. this is normal
if its genuinely not revving out under load then ..
assuming no speedo is fitted (?)
what cdi is fitted ? should be a number starting 21119-13**
if it doesnt say 21119-1332, and there isnt an Mmax box or something, then it will be in "limp home" mode, which caps the revs at 10500-11000 rpm
the fix is a de-restrictor box, or a uk spec cdi (21119-1332) - this doesnt talk to the speedo to see if you are exceeding 180kph, and consequently wont cripple the bike if it doesnt find a speedo to talk to.
this is why i always set carb balance on the bench.
not revving could be a few things,
im guessing you are revving it in neutral at a standstill ? in which case, it may well be revving out but the delay on the tacho means it looks like the limiter is cutting in at 11ish .. it isnt .. this is normal
if its genuinely not revving out under load then ..
assuming no speedo is fitted (?)
what cdi is fitted ? should be a number starting 21119-13**
if it doesnt say 21119-1332, and there isnt an Mmax box or something, then it will be in "limp home" mode, which caps the revs at 10500-11000 rpm
the fix is a de-restrictor box, or a uk spec cdi (21119-1332) - this doesnt talk to the speedo to see if you are exceeding 180kph, and consequently wont cripple the bike if it doesnt find a speedo to talk to.
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Re: HELP.. ZXR400 PROBLEM
eh ? zxr's rev to 14,500rpm or 14,800, or 14,900rpm depending on the cdi fitted.tk400 wrote:11000rpm is near where the limiter cuts in . check the pink wire
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Re: HELP.. ZXR400 PROBLEM
splutter when cracking the throttle at low rpm is the mixture screws, basically lean them off untill the revs start hanging at 2k (after a blip) before dropping back to idle, then go a quarter turn richer. If you get it perfect with DJ needles you get automatic entry to an exclusive club, total membership 1.
its unnoticeable when riding as even on the road you're never under 4k really, and on track the revs are over 9k 90% of the time.
to get the mains right its dyno time really, they can feel almost spot on and be wildly off on the af at the topend. from 10k to the redline should be crisp with little drop off, thing is .. once you've got lowered track gearing on there they'll rev out in top even if they are quite sickly*, and on road (15/45) gearing you're looking at a topend of 145mph ! so need a longer straight that you are going to find in order to properly evaluate the topend or perform a proper plug chop (not that these really tell you toad on a zxr)
*mine was quite happy battering the rev limiter in top on 14/47, when i got it on the dyno it was WAY rich and only making 57bhp
its unnoticeable when riding as even on the road you're never under 4k really, and on track the revs are over 9k 90% of the time.
to get the mains right its dyno time really, they can feel almost spot on and be wildly off on the af at the topend. from 10k to the redline should be crisp with little drop off, thing is .. once you've got lowered track gearing on there they'll rev out in top even if they are quite sickly*, and on road (15/45) gearing you're looking at a topend of 145mph ! so need a longer straight that you are going to find in order to properly evaluate the topend or perform a proper plug chop (not that these really tell you toad on a zxr)
*mine was quite happy battering the rev limiter in top on 14/47, when i got it on the dyno it was WAY rich and only making 57bhp

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Re: HELP.. ZXR400 PROBLEM
11000rpm is near where the limiter cuts in . check the pink wire
zimm : eh ? zxr's rev to 14,500rpm or 14,800, or 14,900rpm depending on the cdi fitted.
As I said " check the pink wire" CDI limiter comes it at 11 if its not deristricted or hooked up to a speedo opto=coupler circuit.
As for Rpm limits its actually either 14,200rpm 14,800rpm 15,200rpm and (16,200rpm factory kit CDI) in case your interested. Dont mean to be a smart ass just had my head stuck in an oscilloscope all week modifying some SP CDI's to kit specs is all.......lol...
cheers TK400
zimm : eh ? zxr's rev to 14,500rpm or 14,800, or 14,900rpm depending on the cdi fitted.
As I said " check the pink wire" CDI limiter comes it at 11 if its not deristricted or hooked up to a speedo opto=coupler circuit.
As for Rpm limits its actually either 14,200rpm 14,800rpm 15,200rpm and (16,200rpm factory kit CDI) in case your interested. Dont mean to be a smart ass just had my head stuck in an oscilloscope all week modifying some SP CDI's to kit specs is all.......lol...
cheers TK400
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Re: HELP.. ZXR400 PROBLEM
fair enough ..
which is which then ? i dont have an oscilloscope so am just going by the published specs (which i know are always out a bit, as are the tacho's)
as i understand it,
H cdi 14,500
L cdi 14,500
uk spec L cdi 14,900
H sp cdi 14,800
L sp cdi ?
f3 kit 15,200
and i've been told about an L3 (?) that limited at around 13,500 ?
which is which then ? i dont have an oscilloscope so am just going by the published specs (which i know are always out a bit, as are the tacho's)
as i understand it,
H cdi 14,500
L cdi 14,500
uk spec L cdi 14,900
H sp cdi 14,800
L sp cdi ?
f3 kit 15,200
and i've been told about an L3 (?) that limited at around 13,500 ?
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Re: HELP.. ZXR400 PROBLEM
How ya goin Zimm,
Ive tested a few tacho's on the scope and they were spot on. They were L model tachs. I have heard the H's were worse. As for the CDI's
I mostly only waste my time on the SP/F3 stuff. These come in a few flavours but are all mitsubishi units. The H models were without TPS or fuel solenoid and The L models were with fuel solenoid and TPS. Due to this the H model SP/F3 Box was smaller and same size as a standard denso unit from an H or L. The L model SP/F3 was larger and one mounting web on each side of the box.
As for the RPM limits the L model SP is 15,200rpm outa the box and the F3 Kit box was 16,200rpm.
standard L model 14,800rpm
standard L model ( some countries) 14,500rpm (maybe im out here it may be as you say 14,400rpm)
As for the H model I think the SP/F3 was 14,800rpm standard and 15,200rpm in Kit form. ( The manual I got translated and posted on greybike forum a couple of years back confirms this. But is a bit faigue on the F3/SP difference.
I do Know the full fuel map for the Solenoid on the SP box now. with over 200 data points...LOL
Ive tested a few tacho's on the scope and they were spot on. They were L model tachs. I have heard the H's were worse. As for the CDI's
I mostly only waste my time on the SP/F3 stuff. These come in a few flavours but are all mitsubishi units. The H models were without TPS or fuel solenoid and The L models were with fuel solenoid and TPS. Due to this the H model SP/F3 Box was smaller and same size as a standard denso unit from an H or L. The L model SP/F3 was larger and one mounting web on each side of the box.
As for the RPM limits the L model SP is 15,200rpm outa the box and the F3 Kit box was 16,200rpm.
standard L model 14,800rpm
standard L model ( some countries) 14,500rpm (maybe im out here it may be as you say 14,400rpm)
As for the H model I think the SP/F3 was 14,800rpm standard and 15,200rpm in Kit form. ( The manual I got translated and posted on greybike forum a couple of years back confirms this. But is a bit faigue on the F3/SP difference.
I do Know the full fuel map for the Solenoid on the SP box now. with over 200 data points...LOL
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Re: HELP.. ZXR400 PROBLEM
hey TK400
i know we are dragging this OT .. but ... well ..
ok, well, my H tacho is miles out, revs to almost 16k on the clock, but the dyno revealed this to be 14,500 (stock H cdi *-1271) and when i had an L4 it would go to bang on 14,500 on the clock, but after switching for a uk spec cdi (cos de-restrictors are clumsy, and it was cheap) it would rev to a smidge under 15k on the same set of clocks. Original cdi was a *-1394, replaced by a *-1332
the advance seems different too, but i've nothing to back this up other than how the bike felt
I could never quite work out which cdi's the translated f3 manual was referring to, but what you say makes sense (i presume the one you had translated is the same one thats found its way on here ?)
im quite surprised that the L sp runs to 16,200 i think im right in saying that rmkd's full-bore missile runs to 16,100 and that seems to have issues holding the bottom end together
i know we are dragging this OT .. but ... well ..
ok, well, my H tacho is miles out, revs to almost 16k on the clock, but the dyno revealed this to be 14,500 (stock H cdi *-1271) and when i had an L4 it would go to bang on 14,500 on the clock, but after switching for a uk spec cdi (cos de-restrictors are clumsy, and it was cheap) it would rev to a smidge under 15k on the same set of clocks. Original cdi was a *-1394, replaced by a *-1332
the advance seems different too, but i've nothing to back this up other than how the bike felt
I could never quite work out which cdi's the translated f3 manual was referring to, but what you say makes sense (i presume the one you had translated is the same one thats found its way on here ?)
im quite surprised that the L sp runs to 16,200 i think im right in saying that rmkd's full-bore missile runs to 16,100 and that seems to have issues holding the bottom end together

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Re: HELP.. ZXR400 PROBLEM
Gday Zimm,
Yes the manual on here is the same one I speak of......Wish we could get a hold of The L model kit manual.....It must exist?
The L model SP is 15,200 rpm
it is the L model F3 Kit spek box that is 16,200rpm ( This would have been on very well prepared Japanese bikes).
At this Rpm valve springs and Cam ramp rates are what becomes the limitation. I am pretty shore the SP valve springs were a higher N/mm rating and had shiming to optimise spring rates. I am not sure what valve springs and valves RMKD runs but would guess they would be these springs. I am looking for flat faced valves at the moment and SP springs or other if you know any manufacturer (maybe APE).
I would say RMKD are running a KIT CDI with 16,200 rpm and may be a custom limiter that comes in at 16,100rpm for a less harsh limiter.
Do you run an SP box at all or do you have one in spares. They are needed for proper fuelling with flatslides if you want to get the fueling correct at lower RPM's and also have much better ignition maps.
I have an SP (possibly kit) CDI from J model that I have on the test bench at the moment running a simulation and once Ive finished with it may be selling it.....If your interested. As the J model SP did not have flatslides, It does not have TPS or solenoid. But it is a genuine mitsubishi igniter.
I am very interested in all this at the moment and dont mind at all continuing the conversation at length.
cheers,
kind regards TK400
Yes the manual on here is the same one I speak of......Wish we could get a hold of The L model kit manual.....It must exist?
The L model SP is 15,200 rpm
it is the L model F3 Kit spek box that is 16,200rpm ( This would have been on very well prepared Japanese bikes).
At this Rpm valve springs and Cam ramp rates are what becomes the limitation. I am pretty shore the SP valve springs were a higher N/mm rating and had shiming to optimise spring rates. I am not sure what valve springs and valves RMKD runs but would guess they would be these springs. I am looking for flat faced valves at the moment and SP springs or other if you know any manufacturer (maybe APE).
I would say RMKD are running a KIT CDI with 16,200 rpm and may be a custom limiter that comes in at 16,100rpm for a less harsh limiter.
Do you run an SP box at all or do you have one in spares. They are needed for proper fuelling with flatslides if you want to get the fueling correct at lower RPM's and also have much better ignition maps.
I have an SP (possibly kit) CDI from J model that I have on the test bench at the moment running a simulation and once Ive finished with it may be selling it.....If your interested. As the J model SP did not have flatslides, It does not have TPS or solenoid. But it is a genuine mitsubishi igniter.
I am very interested in all this at the moment and dont mind at all continuing the conversation at length.
cheers,
kind regards TK400