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Discussion Starter · #1 ·
I have a 1990~ish vulcan 500, and it was badly out of tune...The exhaust was put together out of hollowed out Korean motorcycle mufflers, and some bent steel pipe. The air box never had a filter and it was drilled out...open to the filth and dust that is prevelant in Seoul.

The bike had some mechanical issues, which has resulted in my spending a lot of money and even more time sorting the bike out. Months later and loads of new parts later, it just doesn't want to start.

I think the problem lies in the carbs, but in another thread we are trying to get that sorted.

I don't want to buy a jet kit. 1. I am not a fool. 2. I know its stupid to drill a carburetor. 3. It's ok to drill them when they are easily replaced, but I have to wait at least 3 weeks for all parts here, and pay 3 times the price for them....4. Jet kits are designed for lazy people. With some searching online, you can find www.carbjetkits.com.

They sell the Keihin factory spec main and pilot jets, along with the shims. For right around 25 dollars, you have a properly jetted carb, with the (hopefully) higher quality parts that are supposed to be in it. And you don't have to use a drill.

I know that much, from reading disclaimers and practicing on carbs when I was first getting into fixing bikes. I've always stayed away from any kind of modding, because I don't care about performance.

Now, that being said, how should I jet this bike? I really don't know what jets are currently in it. I looked at them when I cleaned the carbs, and there were no marks on any of them. The main jet (the one with the plug in it) was already drilled out. I am inclined to think somebody messed with it at some time. The screws were not turned the same amount. The right was about 2 1/2 turns, the Left side was around 3. (I counted half turns. I don't know where the ideal setting should be for my altitude.)

If anyone has any jetting advice or tips, please let me know.
And please this is not about increasing power, its about getting a bike to run straight.

Thanks!

Josh
 

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I have a 1990~ish vulcan 500, and it was badly out of tune...The exhaust was put together out of hollowed out Korean motorcycle mufflers, and some bent steel pipe. The air box never had a filter and it was drilled out...open to the filth and dust that is prevelant in Seoul.

The bike had some mechanical issues, which has resulted in my spending a lot of money and even more time sorting the bike out. Months later and loads of new parts later, it just doesn't want to start.

I think the problem lies in the carbs, but in another thread we are trying to get that sorted.

I don't want to buy a jet kit. 1. I am not a fool. 2. I know its stupid to drill a carburetor. 3. It's ok to drill them when they are easily replaced, but I have to wait at least 3 weeks for all parts here, and pay 3 times the price for them....4. Jet kits are designed for lazy people. With some searching online, you can find www.carbjetkits.com.

They sell the Keihin factory spec main and pilot jets, along with the shims. For right around 25 dollars, you have a properly jetted carb, with the (hopefully) higher quality parts that are supposed to be in it. And you don't have to use a drill.

I know that much, from reading disclaimers and practicing on carbs when I was first getting into fixing bikes. I've always stayed away from any kind of modding, because I don't care about performance.

Now, that being said, how should I jet this bike? I really don't know what jets are currently in it. I looked at them when I cleaned the carbs, and there were no marks on any of them. The main jet (the one with the plug in it) was already drilled out. I am inclined to think somebody messed with it at some time. The screws were not turned the same amount. The right was about 2 1/2 turns, the Left side was around 3. (I counted half turns. I don't know where the ideal setting should be for my altitude.)

If anyone has any jetting advice or tips, please let me know.
And please this is not about increasing power, its about getting a bike to run straight.

Thanks!

Josh
The screw that has the plug over it is the pilot jet.It is common for one side to have a different setting from the other.They need to be adjusted with the bike running.2 1/2 turns out is a good starting point.Than adjust for best idle.If you are using the original air box you should not need to change main jets.
:):cool:
 

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Discussion Starter · #3 ·
I'm not using the original air box, for two reasons...it had holes drilled in it and it had no air filter the entire time i've owned the bike. It was never there and the bike ran, so i left it alone.

I added the pod air filters, because they have to be better than what was essentially nothing. Unfortunately, the bike won't start now, so I can't adjust the carbs to run better...

When I changed the plugs, the right said was much darker than the left side. I attributed this to the carburetor never being seated in the boot properly. I'm hoping that with proper settings, a rebuild kit, and fresh jets, the bike will be a fun ride.

The jets that I cleaned looked ok, but for the price, I don't mind buying the new ones. The pilot jets are 8$ for the pair, and the Main jets are 4$ for the pair. You get 12 shims for 2.50$. To have the peace of mind of practically new carbs (minus the diaphram/piston/body) I dont mind that at all.

Which size should I shoot for? How would I go about figuring this out? I would like to order something, as it usually takes 2~3 weeks to get stuff.

Thanks!
 

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I'm not using the original air box, for two reasons...it had holes drilled in it and it had no air filter the entire time i've owned the bike. It was never there and the bike ran, so i left it alone.

I added the pod air filters, because they have to be better than what was essentially nothing. Unfortunately, the bike won't start now, so I can't adjust the carbs to run better...

When I changed the plugs, the right said was much darker than the left side. I attributed this to the carburetor never being seated in the boot properly. I'm hoping that with proper settings, a rebuild kit, and fresh jets, the bike will be a fun ride.

The jets that I cleaned looked ok, but for the price, I don't mind buying the new ones. The pilot jets are 8$ for the pair, and the Main jets are 4$ for the pair. You get 12 shims for 2.50$. To have the peace of mind of practically new carbs (minus the diaphram/piston/body) I dont mind that at all.

Which size should I shoot for? How would I go about figuring this out? I would like to order something, as it usually takes 2~3 weeks to get stuff.

Thanks!
I run pod filters and run#132 M.J.s.The needles have one shim under each one.You may need to block of part of the surface of the pod filter to keep vacuum high,so the needles open without a hesitation.That is one of the down falls of the CVK carb.Depending on altitude,you may not have this problem.
:):cool:
 

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Discussion Starter · #5 ·
Did you change the Pilot Jets? if so, what size?

Is there any way to measure the jets that I have, with a micrometer or something to know? If I have a bigger size, then I won't worry about replacing them.

Did you change the exhaust on your bike?

Mine isn't factory, and I don't know how to describe it other than it was a can on a 150cc bike, and some of the baffles were removed to accomodate the extra flow that the 500cc was making. (Since each cylinder is 250 cc, the mechanic said this would be fine. The pipe is the same size as the stock kawasaki pipe)

The performance was slightly better with the new pipes, probably owed to good back pressure, and the sound is nice.

Bike feels peppy, but averaging 30 miles to the gallon and eatting batteries led me to repair things and currently being in possession of a non-running EN500....

Hopefully I can get it started and figure out the carb situation. I hope it is a carb problem why it won't start....
 

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Did you change the Pilot Jets? if so, what size?

Is there any way to measure the jets that I have, with a micrometer or something to know? If I have a bigger size, then I won't worry about replacing them.

Did you change the exhaust on your bike?

Mine isn't factory, and I don't know how to describe it other than it was a can on a 150cc bike, and some of the baffles were removed to accomodate the extra flow that the 500cc was making. (Since each cylinder is 250 cc, the mechanic said this would be fine. The pipe is the same size as the stock kawasaki pipe)

The performance was slightly better with the new pipes, probably owed to good back pressure, and the sound is nice.

Bike feels peppy, but averaging 30 miles to the gallon and eatting batteries led me to repair things and currently being in possession of a non-running EN500....

Hopefully I can get it started and figure out the carb situation. I hope it is a carb problem why it won't start....
I'm not sure about measuring your jets.Mine had the number stamped on the bottom of the jet,it's small and hard to see.My originals were #125's.I never changed the pilot jets,had no reason to.I changed my mufflers to Harley mufflers.But they were changed at the first & needed no carb mods until I removed the air box.I average 50 MPG.
 

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Discussion Starter · #7 ·
When the rebuild kit gets here and I get the the carbs apart, and off the bike, I'll look at the jets again. Maybe I need a magnifing glass...if there's a number there I'll find it.

Is there a cleaning agent I can use besides carb cleaner or vinegar to clean these. I need like a home-remedy based on where I live.

I like to use coke a cola for cleaning most of my rusty corroded crap. The acid in it cleans things up quite nicely.

What other signs should i look for that my jets are bad? would I even be able to see something?

Thanks for the input!
 

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When the rebuild kit gets here and I get the the carbs apart, and off the bike, I'll look at the jets again. Maybe I need a magnifing glass...if there's a number there I'll find it.

Is there a cleaning agent I can use besides carb cleaner or vinegar to clean these. I need like a home-remedy based on where I live.

I like to use coke a cola for cleaning most of my rusty corroded crap. The acid in it cleans things up quite nicely.

What other signs should i look for that my jets are bad? would I even be able to see something?

Thanks for the input!
Take your carbs apart and soak them in them in Pine-Sol over night.You won't believe how they look in the morning.It's not so much that your jets are bad,as being the wrong ones for your condition's.As long as every thing is clean & assembled correctly the bike will start.Then you can check your plugs to determine if you need bigger jets or not.
;):cool:
 

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Discussion Starter · #9 ·
Take your carbs apart and soak them in them in Pine-Sol over night.You won't believe how they look in the morning.It's not so much that your jets are bad,as being the wrong ones for your condition's.As long as every thing is clean & assembled correctly the bike will start.Then you can check your plugs to determine if you need bigger jets or not.
;):cool:
I'll be doing that when I get back to the bike in a day or so.

I was only concerned about bad jets because I read somewhere online (probably dynojet or sigmajet website :mad: ) that jets can be destroyed pretty easily. bent or misshapen. They looked fine. Just dirty. They soaked in carb cleaner for a couple of hours, and looked better, but not the usuall improvement I go for.


this is trying to start the bike. about 35 seconds in it catches, very briefly then goes back to nothing. I hope I can get it sorted soon

thanks for the pine-sol tip!
 

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Keep in mind also that (from what I understand), with a more free-flowing exhaust and/or intake, you're going to make the power band peakier, losing low-end power and piling it onto the high-end. I'm not dissing on anyone's choices about intakes or anything, but unless you spend most of your time with the engine pegged out, I think you'll find the bike a more pleasurable ride with the more restrictive factory intake.

With the problems you've described in the other thread, I think your best course of action would probably be to restore the bike to as stock a condition as possible (perhaps you can cover the holes in the airbox with cardboard and get a filter or something) and go from there. :3 Fooling with carb tuning is really, really aggrivating (imo).
 

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Discussion Starter · #11 ·
Fooling with it is more than aggrivating to me. But, it was running so poorly before...rich on one side, lean on the other (the air intake on the left carb was all tore up....) I actually think that the pod filters are providing more filtering than what was on there. If it was easy enough to replace the air box I would, but I will only have the bike a couple more months, at most...and as cruddy as that is, i'd rather get it running and sell it.

I'm not sure how free flowing the exhaust is. It's not that loud. Not that much air comes out. I've been behind 125cc scooters that the exhaust hits me in the face. Mine comes out, but its not blowing up any skirts :(

If I can get it started, I'm gonna see what happens. If I have to resort to the old air box setup, I will try to repair what I have.

What I've read online about jets, and what I've talked with other mechanics about...mine are probably worn out enough, being more than 20 years old, that with the exhaust and intake changes, it probably doesn't need anything.
That's what I'm hoping for anyhow!
 

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I'll be doing that when I get back to the bike in a day or so.

I was only concerned about bad jets because I read somewhere online (probably dynojet or sigmajet website :mad: ) that jets can be destroyed pretty easily. bent or misshapen. They looked fine. Just dirty. They soaked in carb cleaner for a couple of hours, and looked better, but not the usuall improvement I go for.

http://www.youtube.com/watch?v=SNn5oPgbmnI

this is trying to start the bike. about 35 seconds in it catches, very briefly then goes back to nothing. I hope I can get it sorted soon

thanks for the pine-sol tip!
"oh, I've got some smoke on the engine now, and I don't know why!"

I'd say it's your starter burning up!
 

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Discussion Starter · #13 ·
I don't think it was the starter burning up...right after that, I stopped the video and got a massive backfire. I think it was what should have been exhaust gas, leaking out of the exhaust manifold instead of the muffler. (I didn't tighten the manifold bolts yet, because the exhaust may come off yet again to try and sort out my kickstand before I'm finished...

It only made one puff of smoke, and the strater when under no load (starter chain off) is spinning nicely with no strange noises.

The noise I couldn't identify I think was the starter clutch springs. The rest of the starter clutch assembly looked great. No marks, dings, cracks, anything. All three springs were different lengths and some wouldn't even hold on that end cap that pushes into the bearing.

I got new springs and will put them on soon and find out what happens with a flywheel all tightened (and torqued) this time.
 

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I'm having the same problem with my 93'. (I've converted to a cafe racerish style, don't hate) Although I did change out the jets to ex500 ones and added pod filters. Not sure if that will cause the no starting issue but that was the only thing I changed before trying to start it after the last 9 months. That and the new spark plug leads. I'm waiting on a new full carb rebuild kit specifically for my year.
Weird thing is on this setup it started the very first time I tried, ran for a minute or so then stalled, then refuses to start again. Now it only pops and occasionally will backfire. Before I changed the jets it ran fine (with pod filters). I rode it for 2 years . I'm hoping it's the new jets that are the wrong size... Or I'm completely lost...it's an amazing engine and had so much fun power that I couldn't enjoy in the cruiser position hence why I've converted it. It felt like riding a triumph before, just wanted that feeling again.
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Did you check to make sure you are still getting a good solid spark from each plug.
the fact that it started and ran then died and wont start leads me to believe wither you lost spark or your jets have become plugged.
Also check any vacuum lines for cracks or leaks
 

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Did you check to make sure you are still getting a good solid spark from each plug.
the fact that it started and ran then died and wont start leads me to believe wither you lost spark or your jets have become plugged.
Also check any vacuum lines for cracks or leaks
Yeah I checked each plug and got a nice blue spark. I've completely disassembled the carbs again and cleaned it out. To be safe I'll wait for the original repair kit for the en500 rather than the ex500 that I used. Also I wasn't using a fuel filter so I'll add one just in case as well. End of month I'll have everything and try again and update what happens. Fingers crossed.
 
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