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'93 VN 750
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23 Posts
Discussion Starter #1
I purchased a '93 a couple of weeks ago and it ran good when I test drove it. Liked it. Bought it. As soon as I got it home it was running rough and sputtering around 3k - 4k rpm. Read lots of threads on here = I added SEAFOAM because...well that was the answer (no matter what the quesion was...well almost anyway.)

After SEAFOAM. Bike started smoking but running better. Mostly smoking from the front cylinder exhaust...and I mean at times A LOT of white/grey smoke. Inside exhaust from front was wet; inside the exhaust from the rear was nice and dry. Smoke/Exhaust does not smell sweet like coolant but more like fuel. Idled okay at first but then I drove it and more sputtering and popping....then it wouldn't idle. Would only start with throttle opened about half way. I've read about this kind of problem on here and figured the SEAFOAM loosened something up and carbs needed a good cleaning. (IN PROCESS NOW = carbs are off the bike, tank drained in case of bad gas, petcock removed for cleaning)

Skip to here for the real question...
My question, for now, is that since the carbs are off the bike, should I change from the stock jets that are in there to larger size? The bike has the stock air box w/ears setup but it has Cobra pipes.

There will be more to come as I put the newly cleaned carbs back on the bike...
 

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On His Lady Vulcan
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1,647 Posts
On these bikes you do not need to rejet for after market pipes, rejet only if you change the air intake. Just make sure your pilot screws are turned out 2.5 - 2.75 out. It sounds to me like your front float got stuck is all, so a really good cleaning aught to do you wonders. Good luck.
 

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'93 VN 750
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23 Posts
Discussion Starter #3
Ok, thanks for the advice on jetting. I'll stick with the stock jets.
BTW, the pilot screws were at 4 turns out prior to the cleaning. I was planning on trying 2.5, so thanks for the tip on that too!
 

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Registered
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1,750 Posts
Skip to here for the real question...
My question, for now, is that since the carbs are off the bike, should I change from the stock jets that are in there to larger size? The bike has the stock air box w/ears setup but it has Cobra pipes.
Here's a suggestion: The tuning of the carbs can be easily determined by inspecting the spark plugs. They should be a light tan color if your jets correct.

I had Cobra's on for a few years (until I got tired of the noise - switched to HD Sportster XL mufflers) and should have changed the jetting but was too lazy to pull the carbs. The result was a loss of midrange and high end power and purple exhaust headers due to heat. I did get some great mpg running that lean! If you want maximum value from your Cobra's I'd go up one jet size on both the idle and mains - if your plugs tell you too...

BTW - If you are going to leave the ears on, invest in better air filters. Plan ahead - if you go with free flowing air filters, you will need to increase the jet size even more. Cobra's and K&N's really open up the power band on our little twins.

Have fun,

DT
 

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'93 VN 750
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23 Posts
Discussion Starter #5
The spark plugs from the rear cyl were more black than tan. The fronts were black and wet. I've cleaned them and will check them again after I put the carbs back on.

Any suggestions were I can get jets without buying a $$$ jet kit?

Also suggestions (including part no.) for better air filters (cheaper than K&N)?

Thanks again for the helpful suggestions!!
 

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On His Lady Vulcan
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1,647 Posts
Again, you DO NOT need to rejet for after market pipes on these bikes. If you still desire to go that route then so be it, you can get them at any local Kawasaki dealer for 6-7 bucks each, or google "motorcycle jets" and you can find them for cheaper but you'll pay shipping which will be more expensive in the end.
 

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'93 VN 750
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23 Posts
Discussion Starter #8
Thought I would share this picture of the petcock since there are some questions about the missing filter for the reserve. Yes, when I pulled mine the reserve was just an empty hole, but I heard something loose inside the tank. I found it to be the missing reserve filter. I was able to retrieve it with a piece of rubber hose and chewing gum on the end. Yes, I actually thought that might work...and so it did. On the FIRST try!!! Here's the pic after I put it back in the petcock.

 

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'93 VN 750
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23 Posts
Discussion Starter #9
At this point, I've decided to stick with the stock air filters and leave the stock jets alone. I got the carbs back in tonight (with quite a bit of sweat and twisting and pushing, I might add). I was about to install the gas tank and try to figure out where all of those vacuum lines went... when it started raining.


more to come....
 

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'93 VN 750
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23 Posts
Discussion Starter #10
Also, I wanted to say thank you to dirtrack650, wkrizan and slimvulcanrider for the suggestions about the jets, etc... I'll definitely look into those options when I decide to change the jets and go with better air filters. For now, I want to see how it runs with the stock ones after all of the cleaning.
 
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