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2014 KLR 650!
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Discussion Starter #1
Got a gopro hero3+, great camera. At the beginning of the clip when i get to the stop light, you can kinda hear the thump I've been talking about on the front cylinder. Sorry about the rattling sound which is the fishing leeder I used to make sure my new camera doesn't become road kill if the mount fails.

The thump goes way when you're going and the bike runs smoothly. Idle jet on the rear?

http://youtu.be/DeDI-04RTGo
 

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Sparky!!!
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The thump goes way when you're going and the bike runs smoothly. Idle jet on the rear?
I can hear it even when you get up to speed, and it sounds down low in the engine... i really don't think it is a carb issue, unless no fuel is flowing in there and I am hearing a dead piston moving.
 

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2014 KLR 650!
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3,365 Posts
Discussion Starter #3
I can hear it even when you get up to speed, and it sounds down low in the engine... i really don't think it is a carb issue, unless no fuel is flowing in there and I am hearing a dead piston moving.
Definitely no dead piston. She flies. I wasn't even goos'n it in this video. Still, PEOPLE WILL NOT STAY OUT OF THE LEFT LANE!
 

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Sparky!!!
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I have had mine up to 110 on one piston, and she seamed to scoot along fine, then when I got both working she flew. I had the same noise you do as well.
 

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2014 KLR 650!
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3,365 Posts
Discussion Starter #5
I have had mine up to 110 on one piston, and she seamed to scoot along fine, then when I got both working she flew. I had the same noise you do as well.
Ok, so how do I test this theory? wouldn't this thing be backfiring and all kinda stuff goin' on?
 

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Goofy, I do not hear well. I watched it twice, sounds like a dead cylinder or small exhaust leak to me. Too much throttle to move away from a stop sign.

You the guy that had trouble with synching? If so I would look for one carb with a plugged pilot circuit.
 

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2014 KLR 650!
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3,365 Posts
Discussion Starter #7
Goofy, I do not hear well. I watched it twice, sounds like a dead cylinder or small exhaust leak to me. Too much throttle to move away from a stop sign.

You the guy that had trouble with synching? If so I would look for one carb with a plugged pilot circuit.
So how do I check for a dead cylinder and then can I back blow the pilot?
 

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Goofy, does the motor USUALLY require a little cranking and nearly always likes a little choke when cold?

Describe how it starts. Mine starts warm instantly, when cold, half choke fires instantly.
 

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So how do I check for a dead cylinder
Cylinder short test ... Remove/replace plug wire as it idles, listen for any change. No change, dead cylinder. Would have to remove two plug wires, then replace one for the test, in this case.

Not a fan of backblow. Seems it would create a mushroom cloud of loose crud inside a dirty carb. I now it works in some cases, but anyway .... It can't remove crud, just move it around.
 

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2014 KLR 650!
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3,365 Posts
Discussion Starter #10
Goofy, does the motor USUALLY require a little cranking and nearly always likes a little choke when cold?

Describe how it starts. Mine starts warm instantly, when cold, half choke fires instantly.
Mine starts ok cold, sucks starting warm.
 

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2014 KLR 650!
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3,365 Posts
Discussion Starter #11
Cylinder short test ... Remove/replace plug wire as it idles, listen for any change. No change, dead cylinder. Would have to remove two plug wires, then replace one for the test, in this case.

Not a fan of backblow. Seems it would create a mushroom cloud of loose crud inside a dirty carb. I now it works in some cases, but anyway .... It can't remove crud, just move it around.
I will try that when I get home since I don't want to get stuck at work today :) On my bike, going to be a beautiful ride home.

So just top clarify, going to remove one of the plug wires on the rear and fire it up. Then remove the other and hope it sounds like crap. I have to say, if it has a cylinder that isn't working, then I don't need a bigger bike.
 

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I find it helps to loosen the plug wire before the test, just let it touch the plug deep enough to arc.

Hope you don't get the crap shocked out of you, it does happen. Suppose maybe a coil could be disconnected for the test, but don't know if that could hurt the CDI.
 

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I will try that when I get home since I don't want to get stuck at work today :) On my bike, going to be a beautiful ride home.

So just top clarify, going to remove one of the plug wires on the rear and fire it up. Then remove the other and hope it sounds like crap. I have to say, if it has a cylinder that isn't working, then I don't need a bigger bike.
If my suspicions are correct, you should have both cylinders above 1/4 throttle. Hard to plug a main circuit.

Spocks test is legitimate, but is mostly used to test ignition. If the front pilot orifice is somewhat/little open the test will not work as well.
 

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The test will locate a cylinder that's dead for any reason, compression, fuel, spark. The trick may be in telling the difference in the amount of change. (if there's some change but not enough)

You might need to test both cylinders to see how much change you should be seeing.
 

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2014 KLR 650!
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Discussion Starter #15
If my suspicions are correct, you should have both cylinders above 1/4 throttle. Hard to plug a main circuit.

Spocks test is legitimate, but is mostly used to test ignition. If the front pilot orifice is somewhat/little open the test will not work as well.
If you what you're saying is true then prolly a clogged artery. Cause if it uses a different jet above idle then that would certainly explain things.
 

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The pilot circuit is completely responsible for idle and the first 25% of throttle opening. the vacuum port for the intermediate circuit is not exposed to vacuum until then. The vacuum port visible in the throttle bore roof at idle (throttle closed) is for the cut off valve.

A plugged pilot circuit in one carb would explain your various symptoms.
 

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..have a vulcan good day!
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Not sure how to do that without the engine running.
I've watched a You-Tube Video online on Bench Syncing CV Carbs...

It is a 6 or 8 mm hex-head screw between the carbs....adjusted to where each Throttle Plate closes completely and simultaneously....testing with a piece of thin paper or such, being dragged between the (closed) Throttle Plate & Throttle Body Throat (incorrect names ?) checking for drag resistance...to/must be equal drag resistance on both carbs.

Maybe someone could locate the video.....

EDIT: Located a different Video, but I believe just as good.

https://www.youtube.com/watch?v=Zc59BThqRa4

:smiley_th
 
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