PH BB Mechanics, help me!

[VidalBaboon]

Yazza54 said:

VidalBaboon said:

No I don't think so, I did a float bowl mod (equalised the pressure between float bowl vent and airbox) but it ran exactly the same. So I've decided to go from square one and put it all back to standard.

Reet, read this (if you havent already) http://homepage.ntlworld.com/webzxr/zxr750r/Featur...

With your mod it sounds like your jetting may now be too rich which would explain the plugs fouling.

If it was jetting, it should have been cured by fitting the Muzzy system with the stage 1 dynojetted carbs. I thought exactly the same hence buying the exhaust, but this hasn't worked

I did the mod in the link above too (did it on the last one too), but it's all back as Kawasaki intended at present. Fault finding with modded bits is a bd

[CQ8]

VidalBaboon said:

I thought exactly the same hence buying the exhaust, but this hasn't worked

I told you it wouldn't! But you had to have the bling..

[VidalBaboon]

CQ8 said:

VidalBaboon said:

I thought exactly the same hence buying the exhaust, but this hasn't worked

I told you it wouldn't! But you had to have the bling..

It was an educated guess

[Yazza54]

But what is the dynojet setup? What is it to be used in conjunction with? Are dynojet jets bigger or smaller than the keihin ones?

ETA:


Kehien Jets -------- DJ Jets

Num / Thou. ------- Num / Thou.
92.5 / 0.035 ------- 92 / 0.035
95 / 0.036 ------- 94 / 0.036
97.5 / 0.037 ------- 96 / 0.037
100 / 0.038 ------- 98 / 0.038
102.5 / 0.039 ------- 100 / 0.039
105 / 0.040 ------- 102 / 0.040
107.5 / 0.041 ------- 104 / 0.041
110 / 0.042 ------- 106 / 0.042
112.5 / 0.043 ------- 108 / 0.043
115 / 0.044 ------- 110 / 0.044
117.5 / 0.045 ------- 112 / 0.045
120 / 0.046 ------- 114 / 0.046
122.5 / 0.047 ------- 116 / 0.047
125 / 0.048 ------- 118 / 0.048
127.5 / 0.049 ------- 120 / 0.049
130 / 0.050 ------- 122 / 0.050
132.5 / 0.051 ------- 124 / 0.051
135 / 0.052 ------- 126 / 0.052
137.5 / 0.053 ------- 128 / 0.053
140 / 0.054 ------- 130 / 0.054
142.5 / 0.055 ------- 132 / 0.055
145 / 0.056 ------- 134 / 0.056
147.5 / 0.057 ------- 136 / 0.057
150 / 0.058 ------- 138 / 0.058
152.5 / 0.059 ------- 140 / 0.059

TAPER of the DJ needle is much thinner than stock needle

Edited by Yazza54 on Monday 14th May 22:54

[VidalBaboon]

Yazza54 said:

But what is the dynojet setup? What is it to be used in conjunction with? Are dynojet jets bigger or smaller than the keihin ones?

ETA:


Kehien Jets -------- DJ Jets

Num / Thou. ------- Num / Thou.
92.5 / 0.035 ------- 92 / 0.035
95 / 0.036 ------- 94 / 0.036
97.5 / 0.037 ------- 96 / 0.037
100 / 0.038 ------- 98 / 0.038
102.5 / 0.039 ------- 100 / 0.039
105 / 0.040 ------- 102 / 0.040
107.5 / 0.041 ------- 104 / 0.041
110 / 0.042 ------- 106 / 0.042
112.5 / 0.043 ------- 108 / 0.043
115 / 0.044 ------- 110 / 0.044
117.5 / 0.045 ------- 112 / 0.045
120 / 0.046 ------- 114 / 0.046
122.5 / 0.047 ------- 116 / 0.047
125 / 0.048 ------- 118 / 0.048
127.5 / 0.049 ------- 120 / 0.049
130 / 0.050 ------- 122 / 0.050
132.5 / 0.051 ------- 124 / 0.051
135 / 0.052 ------- 126 / 0.052
137.5 / 0.053 ------- 128 / 0.053
140 / 0.054 ------- 130 / 0.054
142.5 / 0.055 ------- 132 / 0.055
145 / 0.056 ------- 134 / 0.056
147.5 / 0.057 ------- 136 / 0.057
150 / 0.058 ------- 138 / 0.058
152.5 / 0.059 ------- 140 / 0.059

TAPER of the DJ needle is much thinner than stock needle

Edited by Yazza54 on Monday 14th May 22:54

In conjunction with K&N and open system. Both were fitted and it still had the same problems. It still has the same problem with a standard set of carbs on, which leads me to think it's not fuel related, apart from as suggested, an air leak.

[Yazza54]

VidalBaboon said:

Yazza54 said:

But what is the dynojet setup? What is it to be used in conjunction with? Are dynojet jets bigger or smaller than the keihin ones?

ETA:


Kehien Jets -------- DJ Jets

Num / Thou. ------- Num / Thou.
92.5 / 0.035 ------- 92 / 0.035
95 / 0.036 ------- 94 / 0.036
97.5 / 0.037 ------- 96 / 0.037
100 / 0.038 ------- 98 / 0.038
102.5 / 0.039 ------- 100 / 0.039
105 / 0.040 ------- 102 / 0.040
107.5 / 0.041 ------- 104 / 0.041
110 / 0.042 ------- 106 / 0.042
112.5 / 0.043 ------- 108 / 0.043
115 / 0.044 ------- 110 / 0.044
117.5 / 0.045 ------- 112 / 0.045
120 / 0.046 ------- 114 / 0.046
122.5 / 0.047 ------- 116 / 0.047
125 / 0.048 ------- 118 / 0.048
127.5 / 0.049 ------- 120 / 0.049
130 / 0.050 ------- 122 / 0.050
132.5 / 0.051 ------- 124 / 0.051
135 / 0.052 ------- 126 / 0.052
137.5 / 0.053 ------- 128 / 0.053
140 / 0.054 ------- 130 / 0.054
142.5 / 0.055 ------- 132 / 0.055
145 / 0.056 ------- 134 / 0.056
147.5 / 0.057 ------- 136 / 0.057
150 / 0.058 ------- 138 / 0.058
152.5 / 0.059 ------- 140 / 0.059

TAPER of the DJ needle is much thinner than stock needle

Edited by Yazza54 on Monday 14th May 22:54

In conjunction with K&N and open system. Both were fitted and it still had the same problems. It still has the same problem with a standard set of carbs on, which leads me to think it's not fuel related, apart from as suggested, an air leak.

Hmm I just don't think it sounds like an ignition problem. The fact you said it gets worse with more throttle suggests something is wrong with the mixture, to me it does anyway. I may be wrong. Id be looking for any dodgy gaskets or split rubbers for a definite though.

[VidalBaboon]

Yazza54 said:

Hmm I just don't think it sounds like an ignition problem. The fact you said it gets worse with more throttle suggests something is wrong with the mixture, to me it does anyway. I may be wrong. Id be looking for any dodgy gaskets or split rubbers for a definite though.

It does. It almost went away when it was baltic cold in February, which would also suggest that it was running really rich. However, a bog standard set of carbs hasn't cured it.

Tis a weird one.

[Yazza54]

VidalBaboon said:

Yazza54 said:

Hmm I just don't think it sounds like an ignition problem. The fact you said it gets worse with more throttle suggests something is wrong with the mixture, to me it does anyway. I may be wrong. Id be looking for any dodgy gaskets or split rubbers for a definite though.

It does. It almost went away when it was baltic cold in February, which would also suggest that it was running really rich. However, a bog standard set of carbs hasn't cured it.

Tis a weird one.

Standard exhaust make no difference?

[kev b]

I know the carbs have been swapped over to no effect but are you sure the choke is not sticking on? Have you tried finding an air/ vacuum leak with carb cleaner or WD40? Is the air filter element blocked, wet or oily?

[VidalBaboon]

kev b said:

I know the carbs have been swapped over to no effect but are you sure the choke is not sticking on? Have you tried finding an air/ vacuum leak with carb cleaner or WD40? Is the air filter element blocked, wet or oily?

swapped air filters over, cleaned and oiled the K&N, it's all made no difference.

I take it finding a leak with WD is just a case of it running like a dog when it ingests it?

Never tried it to be honest, it's all be visual.

[VidalBaboon]

I can't see the inlets with the carbs fitted, I'll have to take them off.

[kev b]

The wd40 trick is to spray it around the intake rubbers on the engine side of the carbs, if the engine note /speed changes then you have found a leak. When the wd40 gets drawn into the intake it richens the mixture, this is obviously more useful when a motor is running lean as it will rev up a little or run more smoothly. You can also do this with an unlit propane blowwtorch, if your work area is not too draughty. This is also a quick way to find out if you have a cylinder running lean due to a blocked jet, just direct the spray/gas into the carb intake and see if the engine picks up.

[bob1179]

From the sound of it VB it might be an idea to go back to square one.

Put everything back to factory settings - exhaust, carbs, inlet filter etc. and start working at each system in turn.

Ensure the carbs are set up right and are working as they should be, no leaks, fuelling, throttle and choke doing what they should and the mixture is set up right.

Look at the air intake, look at the ignition, HT leads, plugs to make sure you are getting a good spark etc.

From all the woes you have spoken about I think you are going to have to look at each system in turn and work through a process of elimination. It's a pain in the arse to be honest.

You could always just give up and buy that 675R...?

[podman]

Dyno's (and a good operator) are ideal for fault finding like this, thats where id be taking it, you'll know if its electrical/fuel related after a run away...any good outlet will hsve a box of jets to set it up if needs be .

[3doorPete]

podman said:

Dyno's (and a good operator) are ideal for fault finding like this, thats where id be taking it, you'll know if its electrical/fuel related after a run away...any good outlet will hsve a box of jets to set it up if needs be .

+1 as I was saying in the pm too. The fact that it can be run up properly and under load on a dyno with the airbox and tank off under various throttle openings will speed diagnosis.

Changing pipe and air filter etc will never cause as bad a problems as you have.

Perplexing that replacement carbs have the same issue.

Seperate from the carbs you have the 2 rectangular bits that bolt the Kleanair emmissions gubbins to the cam cover. If these aren't sealing properly and there is an air leak you would have proper st running. It might be worth squirting some heat proof sealant around that and checking there are no other air leaks there. The weird way it works may mean that the air leak might not necessarily cause lean running. Most on here won't know about this peculiarity as it's particular to a few 90's Kawasakis.

Alternatively, your valve clearances could be completely FUBAR'ed.

Faulty fuel pump perhaps? I'm not sure of the effect of if it was producing too much pressure but that would perhaps hit low end running rather than top end where a decent amount of fuel is flowing through anyway.

As others have said - perhaps electrical. Weak spark at low revs, spark healthies up at higher revs? Regulator, coil packs, resistance somewhere??

If you didn't live down in Carrot cruncher land, I'd come and take a look myself.

If you get really pissed off - I'll buy it off you for £900 as it's clearly fked and fit for the bin.

[zippo]

Just a thought.. When were the cam clearances last checked?

[VidalBaboon]

Last week

I did the float bowl vent mod but it made cock all difference, worth checking the reed valves though. Thanks for the offer Pete but ill pass

[3doorPete]

VidalBaboon said:

Thanks for the offer Pete but ill pass

It's ok - I'll just sit here and wait...

[VidalBaboon]

Its like redmonkey in here!! Ku-kaw

[Fleegle]

Have you tried a spare CDI yet?