Help with carb Issues. | Page 2 | GTAMotorcycle.com

Help with carb Issues.

boyoboy said:
What make of carb kit? pods are good for a race bike - but make for poor drive ability on a street bike. imo.

1999? Would be reasonable to replace the float needles and seats while the carbs are apart... its req'd maintenance with carbs. A steel ruler can be used to set float height.
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The carbs have been serviced, not within the last 4 years however (I know because all of my brass screws and plugs were already removed and replaced with stainless)

The problem is the service manual does not specify a measurement without the Yamaha fuel level gauge, seems like a clear plastic tube with a gauge attached. It's supposed to be 4/5 mm above the line on the float chamber.

As for the make of the pods, not really a brand I guess. Some dude in the states puts them together, they are used by hundreds of people.

I'll order up the new parts and give her a go. Its the floats that concern me.

The other option is to pay someone else. The one shop in my area is down for a few weeks and I honestly don't now of any others that work on metric cruisers. Even finding him was tough. (I'm near Newmarket if anyone has a suggestion)

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boyoboy said:
ok. Im thinking that maybe you went pods and jetting because of "popping" issues on stock set up. ?
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Popping existed without the pods, with just a gutted exhaust. However not as bad and there was no hesitation.

I may have handled the floats to much while jetting the carbs.

My main reason for pods was knee issues. The stock air filter holder pushes my knee out. It never used to be an issue but has become one. Getting rid of the stock box made the ride perfectly comfortable for me.

There is many people on another forum with the exact same setup as me that do not have an issue. That leads me to believe it's not actually the pods causing the problem.

However I'm smart enough that if I need to stock out the bike I have everything to do so, including another full exhaust.
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peterm15 said:
The thing is that these pods are tried and tested by many members on another forum.

The kit itself is tailored to your exhaust type/modification so I didn't really see that being an issue. I'm not expert however.

I'll give a go to the floats before removing the jet, and pods otherwise I'll have no choice but to stock out the bike until I can figure out the issue.

Any suggestions on dealing with the floats? That how to is long gone from my memory. And I don't have the tool to measure the fuel level. I do however have access to high precision measuring devices (I'm a machinist, obviously not for bikes)

Thanks.
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are you saying the "jet kit" was a single jet changed? doesn't sound like a kit ? what make is jet kit?
 
You know the only time I ever had a problem with a float height setting it was because I put the float in upside-down
:/ they don't just suddenly fall out of adjustment and need bending back into shape.
If the floats haven't been man handled to date, I'd be looking more at the needle and seat that the float operates.

The float needle and seat is little more then a toilet tank valve, is basic plumbing.
 
Trials said:
You know the only time I ever had a problem with a float height setting it was because I put the float in upside-down
:/ they don't just suddenly fall out of adjustment and need bending back into shape.
If the floats haven't been man handled to date, I'd be looking more at the needle and seat that the float operates.

The float needle and seat is little more then a toilet tank valve, is basic plumbing.
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That's my problem. When I cleaned and jetted the carb, some decent pressure may have been put on it. I'm thinking human error may have messed it up.

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peterm15 said:
The service manual does not give a measurement for that. It wouldn't be the 4-5mm like with the gauge.

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I would think if the specs say 4-5mm, that would be the measurement from the float bowl/ carb body mating surface to the bottom of the float. Hold the carb at an angle that allows the measurement to be made w/o the float needle spring compressing at all.

sounds like your bike simply has a main jet change. On a hunch? - go up one size on the pilot jet. a jetting kit generally includes main, pilot and even a needle change if req'd.
 
boyoboy said:
I would think if the specs say 4-5mm, that would be the measurement from the float bowl/ carb body mating surface to the bottom of the float. Hold the carb at an angle that allows the measurement to be made w/o the float needle spring compressing at all.
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boyoboy said:
I would think if the specs say 4-5mm, that would be the measurement from the float bowl/ carb body mating surface to the bottom of the float. Hold the carb at an angle that allows the measurement to be made w/o the float needle spring compressing at all.

sounds like your bike simply has a main jet change. On a hunch? - go up one size on the pilot jet. a jetting kit generally includes main, pilot and even a needle change if req'd.
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A main jet only has an effect on mixture at ~ 1/2 to full throttle. At idle to near half throttle the pilot jet has the most effect. You didn't get a jetting kit.
 
peterm15 said:
The pod kit came with a single jet. Short brass one.

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Something sounds wrong with the jet kit. This might not be the problem, but it might and you might be setup for more problems down the road.

Main Jets: Most Yamaha XV bikes use different size main jets for the front and rear cylinders, you may want to double check these were not switched and that they are the right sizes. Size is 120-125 range. Re-jets include new needles, they should have 2 shims or set on clip 4 if the exhaust is gutted. THE MAIN JETS IN THESE CARBS ARE SUSCEPTIBLE TO CORROSION IF ETHANOL FUEL IS USED. It's quite common for the main jet and needle to have a slight blockage or buildup that needs to be cleaned up.

Use the standard pilot (idle) jets.

Mixture should be about 3.5 turns out

Check the needlevalve seats and spring. Remove the needle seats - there is an O ring that fails on these carbs - check and replace if necessary.
 
On some carbs it is as easy as using your finger to move the float up and down while the float bowl is removed ;)
... which I totally do not suggest any body else do for obvious flammable implications.

Start with an inspection of the spark plugs to see if one side is running different then the other, compression test is another good base line, if the problems reside in only one side it simplifies trouble-shooting and might give you the opportunity to switch parts from side to side which even further trouble-shoots the problem. If there is a problem with a float I would maybe try switching parts around, see if the idle change symptom follows the float.
 
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Trials said:
On some carbs it is as easy as using your finger to move the float up and down while the float bowl is removed ;)
... which I totally do not suggest any body else do for obvious flammable implications.

Start with an inspection of the spark plugs to see if one side is running different then the other, compression test is another good base line, if the problems reside in only one side it simplifies trouble-shooting and might give you the opportunity to switch parts from side to side which even further trouble-shoots the problem. If there is a problem with a float I would maybe try switching parts around, see if the idle change symptom follows the float.
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These carbs are not all that sensitive to a slight maladjustment in float height. With the bowl off, look for a seam line on the float. When hanging, the seam line should be on a 45degree angle that intersects with the corner of the carb base. Hard to explain, I'll look for a pic.

Based on the symptoms my guess is a worn O-ring or gummed main needle/jet.
 
I decided to do a little test with a rubber hose attached to the drain valve, it's how you're supposed to check level according to the service manual except with a special tool.
Both levels are the same but I can't tell if it's a good level or not. So may be off.

Well I had them apart, I decided to do another inspection of the Jets.

Main jet is new and looks that way. Pilot jet on the front carb was pretty gummed up, and the float valve didn't seem properly connected in the rear carb.

Another round of carb cleaner, and overnight soak I'll see what's up tomorrow.

If my issues aren't fixed I MAY just get someone else to do it. If it was winter, trial and error wouldn't be an issue. Prime riding season I'd rather be on the bike.

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What's with the over-night soak :/ it is sitting in solvent all the time, just clean the thing.
 
Trials said:
What's with the over-night soak :/ it is sitting in solvent all the time, just clean the thing.
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I did clean it. But I had to leave for work, (night shift) so I'm just letting them sit until tomorrow. There was a bit of gummyness around the gaskets (after removing them) that I didn't have time to scrub away.

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Bunch of years ago I had a carb that was acting up, I had to field clean it 7 times and it wasn't until the 7th. attempt that it started to work good. Stick with it, sometimes persistence pays off.

... field cleaning a carburetor is when you are out in the middle of a field and working with little more then a swiss army knife and a thorn bush :|
 
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