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I never heard anyone ask if the main jet diaphram spring seat has been positioned properly. If the spring seat covers the hole in the base of the piston assembly, the piston vacuum will not operate properly. Simple check.
Edit: Also, how many turns are on your primary jet pilot air screws each side ?
When it's idling, do both exhaust pipes get hot ?
 

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Discussion Starter #142
Spring seat is spot on. That was my first check. Pilot air screws are 2.5 turns each. I have been goin through the electrics again today, checking and double checking everything. So far what i have found is 2 of my plug caps have no resistance when checked with the multimeter. The big cap on the front cylinder and the short cap on the rear cylinder. The other to are working fine. So here is my thinking. If the caps are dead it means they were probably arching off the jugs, in turn causing a limited spark under load. I have ordered new caps and leads and i am cleaning every electrical connection on the bike along with checking every single wire in the harness ( godamn hate electrics). Anyone ever had a problem with the spark plug caps cause something similar?
 

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The pickup coils are basically Hall Effect switches, they open and close by the magnetic field of the rotor passing over them. This the the same as a set of points opening and closing. Breaking the circuit to the ignition coil is what triggers the spark. Then ignition coil saturation begins all over again.
This is not exactly right. There are no hall effect switches in this circuit. The pickups are just coils. When the magnets on the rotor pass the coils, a small current is induced providing a pulse to the IC ignitor module. I would imagine that the pulse would get stronger as the rpm increased. This signal gates transistors in the IC ignitor module that provide a pulse of current in the primary coils of the ignition coils. Just a technicality, but the reliability of a (low voltage) coil that passes an ohm check is much better than a switch of any kind.
As for the on-going issue, I'm left with high voltage breakdown somewhere, or fuel delivery. I don't think a carb sync issue would do this, but have you checked sync ?
Edit#1: Have you tried setting you floats to slightly overfill the fuel bowls? I'm just wondering if your pickups are too shallow in the fuel.
Edit#2: You can check the IC ignitor module, but you will need to have an older style analog meter. The older style meters provide enough test voltage to "turn on" all the diodes in the circuit. I think that's all the Kawi tester is.
 
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This is not exactly right. There are no hall effect switches in this circuit. The pickups are just coils. When the magnets on the rotor pass the coils, a small current is induced providing a pulse to the IC ignitor module. I would imagine that the pulse would get stronger as the rpm increased. .....
Close enough. I said basically, maybe I should've said essentially. The magnetic field acts upon the coils, which triggers the spark at the correct time.
 

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Spring seat is spot on. That was my first check. Pilot air screws are 2.5 turns each. I have been goin through the electrics again today, checking and double checking everything. So far what i have found is 2 of my plug caps have no resistance when checked with the multimeter. The big cap on the front cylinder and the short cap on the rear cylinder. The other to are working fine. So here is my thinking. If the caps are dead it means they were probably arching off the jugs, in turn causing a limited spark under load. I have ordered new caps and leads and i am cleaning every electrical connection on the bike along with checking every single wire in the harness ( godamn hate electrics). Anyone ever had a problem with the spark plug caps cause something similar?
I've had caps that were open,. No spark getting through, is this what's happening?

These are resistor plug boots, so it should give some reading. Did you test the other two boots?
 

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Discussion Starter #146
Yes i tested all 4 of them. I am getting a reading off the other 2 but nothing from the ones mentioned. If i test the caps with the wires attached i get a reading but no reading with the caps on there own. Its Very strange. I am goin to replace the caps and wires just to rule them out anyway.
 

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Discussion Starter #147
This is not exactly right. There are no hall effect switches in this circuit. The pickups are just coils. When the magnets on the rotor pass the coils, a small current is induced providing a pulse to the IC ignitor module. I would imagine that the pulse would get stronger as the rpm increased. This signal gates transistors in the IC ignitor module that provide a pulse of current in the primary coils of the ignition coils. Just a technicality, but the reliability of a (low voltage) coil that passes an ohm check is much better than a switch of any kind.
As for the on-going issue, I'm left with high voltage breakdown somewhere, or fuel delivery. I don't think a carb sync issue would do this, but have you checked sync ?
Edit#1: Have you tried setting you floats to slightly overfill the fuel bowls? I'm just wondering if your pickups are too shallow in the fuel.
Edit#2: You can check the IC ignitor module, but you will need to have an older style analog meter. The older style meters provide enough test voltage to "turn on" all the diodes in the circuit. I think that's all the Kawi tester is.
I havs not tried setting the fuel bowl to overfill but it is something i can try deffo try. The ic igniter might be outta my depth to test. I will try it if all else fails tho
 

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This is not exactly right. There are no hall effect switches in this circuit. The pickups are just coils. When the magnets on the rotor pass the coils, a small current is induced providing a pulse to the IC ignitor module. I would imagine that the pulse would get stronger as the rpm increased. This signal gates transistors in the IC ignitor module that provide a pulse of current in the primary coils of the ignition coils. Just a technicality, but the reliability of a (low voltage) coil that passes an ohm check is much better than a switch of any kind.
As for the on-going issue, I'm left with high voltage breakdown somewhere, or fuel delivery. I don't think a carb sync issue would do this, but have you checked sync ?
Edit#1: Have you tried setting you floats to slightly overfill the fuel bowls? I'm just wondering if your pickups are too shallow in the fuel.
Edit#2: You can check the IC ignitor module, but you will need to have an older style analog meter. The older style meters provide enough test voltage to "turn on" all the diodes in the circuit. I think that's all the Kawi tester is.
I’d have to dig up the article I posted previously but we found that the spark output actually decreases as the RPMs increase.
 

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I’d have to dig up the article I posted previously but we found that the spark output actually decreases as the RPMs increase.
Yes, I agree with the article you posted. That is referring to the secondary of the ignition coils. My statement concerned the signal from the pickups to the IC ignitor module.
 

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Discussion Starter #150 (Edited)
Ok been doing a lot of testing on the wiring and decided to check the spark plug caps again. So get this, i tested them on the 20k setting on the multimeter. One long cap and one short cap are 4.6. The other short one is 5.0. The other long one had nothing so i checked it on the 200k setting. Bingo. Got a reading of 171.8 😮. Just waiting on replacements. Im going to replace all 4 caps and wires.
 

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Discussion Starter #151
Update number 7000 i think. Lol. Plug caps and wires changed. Spark verified while giving full throttle by using spare spark plug. Same problem exsists. Checked compression again myself with my own tester as apose to the garage.
Front cylinder is 150 psi.
Rear cylinder is 165 psi.
Also lots of smoke from front exhaust. Deffo burning oil. Would the commpression difference be causing the problem. Im out of ideas. Everything i could check i checked. So to be honest i dunno what to check or do anymore. This bike has been a nightmare.
 

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Also lots of smoke from front exhaust. Deffo burning oil. Would the commpression difference be causing the problem.
These compression numbers seem within tolerance. The Clymer manual states compression test should range 129-199 psi. Looks like the rear is spot on, and the front is showing a slight bit of wear.
So, from what you have said previously, you put the new carb bodies on. Did that correct the fuel entering the throat of the carb through the main jet while idling ?
The bike idles fine, both pipes get hot ?
When you roll the throttle up, the bike won't rev past 4K, and you get black smoke from the front jug. Is that about right ? Is there more ?
 

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Discussion Starter #153 (Edited)
These compression numbers seem within tolerance. The Clymer manual states compression test should range 129-199 psi. Looks like the rear is spot on, and the front is showing a slight bit of wear.
So, from what you have said previously, you put the new carb bodies on. Did that correct the fuel entering the throat of the carb through the main jet while idling ?
The bike idles fine, both pipes get hot ?
When you roll the throttle up, the bike won't rev past 4K, and you get black smoke from the front jug. Is that about right ? Is there more ?
Yes the bike idles perfect. Fuel flow seems to be good. Both pipes get hot pretty evenly. It wont rev passed 3k revs. Just goes bwaaaaa. It will not die however. Just goes back to idle when i let the throttle go. If i give it choke while it idles the bike will die. The smoke is grey like from a 2 stroke on startup. Very heavy until the bike warms up.
 

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You said the slides were bouncing. Here's a video of normal slide action on the highway. You'll notice the slides only lift during acceleration, particularly around the 3 and 5 minute mark. No bounce, no fluttering, just controlled lifting.

Gray smoke is rich, flooding. Most likely because the slide is bouncing up with no throttle, letting too much fuel flow in.

 

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Discussion Starter #156
Riped the carbs apart again today. Diaphragms are perfect. Seated correctly. Dont matter what i seem to do its just same story. Checked timing just there now and its still spot on. I think its time to hand it to a mechanic and let him sort it. Iv had enough at this stage.
 

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Can you still see the slides bouncing when the engine is idling ?
If so, I figure the only way you could see that, is with the air intake ducts removed from the carbs. There's no way vacuum should be pulling the slides up with the intake boots removed. If they're bouncing, I'm starting to think the diaphram springs are too weak. Maybe someone on here with more carb expertise can chime in on this one. If the springs are weak, it would make the mixture very rich I would think. Other than that, it would also be nice to see what an ignitor swap would show.
Edit: I wouldn't take it to a mechanic until I looked at those two things at least.
 
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Discussion Starter #158 (Edited)
Can you still see the slides bouncing when the engine is idling ?
If so, I figure the only way you could see that, is with the air intake ducts removed from the carbs. There's no way vacuum should be pulling the slides up with the intake boots removed. If they're bouncing, I'm starting to think the diaphram springs are too weak. Maybe someone on here with more carb expertise can chime in on this one. If the springs are weak, it would make the mixture very rich I would think. Other than that, it would also be nice to see what an ignitor swap would show.
Edit: I wouldn't take it to a mechanic until I looked at those two things at least.
Thank you for the input. Yes i have the air intake off so i can see the slides. Only vibrating since i replaced the carb bodys. I have had the same problem with it on, put it all back to stock and still made no difference. What i did notice today when i started it up to try again was if i leave the throttle as is ( not twist it ) and manually push the 2 slides up the bike seems to idle much smoother. Not sure if that means anything or not. It was that last thing to try tbh. No leaks around the carb boots or the diaphagram caps. All tested by spraying wd40. No fuel leaks anywhere.
 

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What i did notice today when i started it up to try again was if i leave the throttle as is ( not twist it ) and manually push the 2 slides up the bike seems to idle much smoother. Not sure if that means anything or not. It was that last thing to try tbh. No leaks around the carb boots or the diaphagram caps. All tested by spraying wd40. No fuel leaks anywhere.
If you didn't block any air flow, that would seem to indicate that it's lean at idle. But that smoothness could be from an rpm increase, if that happened.

Did you stretch and flex the diaphragms in front of bright light to check for cracks?
 

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Discussion Starter #160
If you didn't block any air flow, that would seem to indicate that it's lean at idle. But that smoothness could be from an rpm increase, if that happened.

Did you stretch and flex the diaphragms in front of bright light to check for cracks?
Yes checked diaphrahms under a very bright light. Both make the woosh sound when lifting them up and also when coming down. Both drop evenly and slowley. My last and final option and i mean final option is to reposition the floats to allow more fuel in the bowl. Looking at the plugs yesterday, rear seems to be lean and front a tad rich. Although it was only idleing so not sure how viable the results are on the plugs. But its my last thing to try. I can conform it has compression, withing 15 psi of each other, it has spark both idleing and when throttle is twisted. It is getting fuel, weather its enough or not im not sure, there are no leaks of any kind and timing is spot on. I will try the floats again even though they were set right on the marks but i will try it anyway.
 
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