5th gear spitting and sputtering after deceleration

[Dasam]

My 01Vulcan 1500 nomad has starting to spit and sputter and does not want to accelerate after deceleration in 5th gear and some times in fourth gear. Runs fine in all other gears. It started this a while back after I had to use reserves to get to the gas station. I have run two cans of seafoam and one bottle of Lucas carburetor cleaner. I've come to the decision I'm going to have to remove the carb and take it apart and clean it to fix this I just wanted other people's input on this problem.

[plumber63]

Try MARVEL MYSTERY OIL. I've had better luck with it than the 2 that you have tried. Have you changed your fuel filter.

[Dasam]

Not yet. I ordered a carb rebuild kit for it. While i have it apart i plan to replace the fuel lines,filter and possibly the fuel pump rebuild or replace.

[mick56]

Originally Posted by Dasam

Not yet. I ordered a carb rebuild kit for it. While i have it apart i plan to replace the fuel lines,filter and possibly the fuel pump rebuild or replace.

I got a new pump on ebay for about $25, it worked fine, for next 5yrs that i had the bike.

[andyvh1959]

Wait a minute, you say your bike has a carb AND a fuel pump? Doesn't make sense. According to Ronayers.com parts fiche there is no carb for a 2001 1500 Nomad unless your bike was converted from fuel injection to carb. If it was converted to a carb there is no need for a fuel pump. Before you dig into it, when on closed throttle decel in 5th gear try pulling in the clutch to see if the engine continues the spit/sputter. If it settles down to normal idle with the clutch pulled in, but spits/sputters when the clutch is engaged, to me it means the engine is being forced by momentum to try and breathe in more air than it can take in. It spits/sputters because the throttle plate is sealing off all intake air to the engine.

Assuming your bike really does have fuel injection, it could simply be a very dirty/gummy/oily throttle plate in the intake. The engine crankcase breathing system directs crankcase mist into the airbox. Over time the oil mist builds up on the throttle body butterfly plate, creating a gummy edge goo that can seal off the intake and limit engine breathing at closed throttle.

Sometimes this can casue a fuel injected twin to suddenly stall at steady idle. Take the intake off the throttle body, turn the throttle wide open and hold it there. Use a long cotton swab soaked in denatured alcohol, Seafoam, WD40, some form of solvent and clean both sides of the butterfly valve. Also wipe around the bore of the throttle body where the butterfly contacts it. That may solve the issue before doing anything else.

[mick56]

Originally Posted by andyvh1959

Wait a minute, you say your bike has a carb AND a fuel pump? Doesn't make sense. According to Ronayers.com parts fiche there is no carb for a 2001 1500 Nomad unless your bike was converted from fuel injection to carb. If it was converted to a carb there is no need for a fuel pump. Before you dig into it, when on closed throttle decel in 5th gear try pulling in the clutch to see if the engine continues the spit/sputter. If it settles down to normal idle with the clutch pulled in, but spits/sputters when the clutch is engaged, to me it means the engine is being forced by momentum to try and breathe in more air than it can take in. It spits/sputters because the throttle plate is sealing off all intake air to the engine.

Assuming your bike really does have fuel injection, it could simply be a very dirty/gummy/oily throttle plate in the intake. The engine crankcase breathing system directs crankcase mist into the airbox. Over time the oil mist builds up on the throttle body butterfly plate, creating a gummy edge goo that can seal off the intake and limit engine breathing at closed throttle.

Sometimes this can casue a fuel injected twin to suddenly stall at steady idle. Take the intake off the throttle body, turn the throttle wide open and hold it there. Use a long cotton swab soaked in denatured alcohol, Seafoam, WD40, some form of solvent and clean both sides of the butterfly valve. Also wipe around the bore of the throttle body where the butterfly contacts it. That may solve the issue before doing anything else.

My 1999 carbed bike, had a fuel pump. And so does every other bike, and car. None of them worked on gravity. https://kawasakioriginalparts.com/pa...316568&type=MC

[VulcanJeff]

Originally Posted by mick56

My 1999 carbed bike, had a fuel pump. And so does every other bike, and car. None of them worked on gravity.

Excuse me?

[mick56]

Originally Posted by VulcanJeff

Excuse me?

Something you dont understand about my comment ? https://kawasakioriginalparts.com/pa...316568&type=MC

[andyvh1959]

Originally Posted by mick56

My 1999 carbed bike, had a fuel pump. And so does every other bike, and car. None of them worked on gravity. https://kawasakioriginalparts.com/pa...316568&type=MC

I stand corrected, corrected that on some models the carbbed VN1500 has a fuel pump, interesting. However, MOST motorcyices with carbs, with the fuel tank above the carb float bowls are gravity fed systems with no fuel pump. Until I bought my 94 BMW R1100RS with fuel injection, I never owned a bike with carbs and fuel tank above the carbs. Of the 12 bikes in my shed right now, three have fuel pumps fuel injection. The other nine, a BMW, five Hondas, three Suzukis all are carbbed, all have the fuel tank above the carbs and not has a fuel pump, all gravity fed, just like my riding mower, and snowblower. Snowmobile, has carbs and a fuel tank, because the fuel tank is lower then the carb bowls and uses pre-mix, 2-stroke.

[mick56]

Originally Posted by andyvh1959

I stand corrected, corrected that on some models the carbbed VN1500 has a fuel pump, interesting. However, MOST motorcyices with carbs, with the fuel tank above the carb float bowls are gravity fed systems with no fuel pump. Until I bought my 94 BMW R1100RS with fuel injection, I never owned a bike with carbs and fuel tank above the carbs. Of the 12 bikes in my shed right now, three have fuel pumps fuel injection. The other nine, a BMW, five Hondas, three Suzukis all are carbbed, all have the fuel tank above the carbs and not has a fuel pump, all gravity fed, just like my riding mower, and snowblower. Snowmobile, has carbs and a fuel tank, because the fuel tank is lower then the carb bowls and uses pre-mix, 2-stroke.

All, of the classics and nomads, have fuel pumps. Carbed are under the tank. FI are inside it.

[andyvh1959]

I bet the only reason those Kawwys have a fuel pump on a carbbed bike is because of the fuel tank design. Perhaps the tank shape and low position over the carbs in the V didn't allow space for a fuel valve and consistent gravity fed fuel to the carbs.

Back to the OP and the issues on his carbbed bike. I still recommend riding the bike in 5th gear, let it decel with the clutch engaged, then pull in the clutch to check if the stutter/spit stops. On a carbbed bike it can indicate gummy residue in the carb, on the slides, so a good thorough manual cleaning should clear the issue. Also check the crankcase vent system, hoses, connections to check for any leaks. The easiest way to check for intake and venting leaks is get the bike warmed up and idling steady. Then spray a mist of WD40 around the engine carbs, hoses, air box connections, avoid the exhaust as much as you can. If the idle picks up when you spray WD40 on it, there is a leak sucking air into the system. Closed throttle decel creates the highest vacuum, and any leaks suck in additional air which leans out the air/fuel mix. On closed throttle decel that alone can cause stuttering/popping wiht the clutch out.

When you take the carbs apart also check the rubber diaphragms for stiffness, cracks/tears, and insure the diaphragm sits properly in the top of the carb and seals completely. Good luck and let us know the results.

[mick56]

Originally Posted by andyvh1959

I bet the only reason those Kawwys have a fuel pump on a carbbed bike is because of the fuel tank design. Perhaps the tank shape and low position over the carbs in the V didn't allow space for a fuel valve and consistent gravity fed fuel to the carbs.

Back to the OP and the issues on his carbbed bike. I still recommend riding the bike in 5th gear, let it decel with the clutch engaged, then pull in the clutch to check if the stutter/spit stops. On a carbbed bike it can indicate gummy residue in the carb, on the slides, so a good thorough manual cleaning should clear the issue. Also check the crankcase vent system, hoses, connections to check for any leaks. The easiest way to check for intake and venting leaks is get the bike warmed up and idling steady. Then spray a mist of WD40 around the engine carbs, hoses, air box connections, avoid the exhaust as much as you can. If the idle picks up when you spray WD40 on it, there is a leak sucking air into the system. Closed throttle decel creates the highest vacuum, and any leaks suck in additional air which leans out the air/fuel mix. On closed throttle decel that alone can cause stuttering/popping wiht the clutch out.
.
When you take the carbs apart also check the rubber diaphragms for stiffness, cracks/tears, and insure the diaphragm sits properly in the top of the carb and seals completely. Good luck and let us know the results.

Almost total bullshit.What difference can the gear you are in, possibly make ? I struggled to read any further

[mick56]

[QUOTE=andyvh1959;729587]I bet the only reason those Kawwys have a fuel pump on a carbbed bike is because of the fuel tank design. Perhaps the tank shape and low position over the carbs in the V didn't allow space for a fuel valve and consistent gravity fed fuel to the carbs.

Back to the OP and the issues on his carbbed bike. I still recommend riding the bike in 5th gear, let it decel with the clutch engaged, then pull in the clutch to check if the stutter/spit stops. On a carbbed bike it can indicate gummy residue in the carb, on the slides, so a good thorough manual cleaning should clear the issue. Also check the crankcase vent system, hoses, connections to check for any leaks. The easiest way to check for intake and venting leaks is get the bike warmed up and idling steady. Then spray a mist of WD40 around the engine carbs, hoses, air box connections, avoid the exhaust as much as you can. If the idle picks up when you spray WD40 on it, there is a leak sucking air into the system. Closed throttle decel creates the highest vacuum, and any leaks suck in additional air which leans out the air/fuel mix. On closed throttle decel that alone can cause stuttering/popping wiht the clutch out.

When you take the carbs apart also check the rubber diaphragms for stiffness, cracks/tears, and insure the diaphragm sits properly in the top of the carb and seals completely. Good luck and let us know the results.[/QUO Have you ever owned a nomad ?

[andyvh1959]

What's "total bullshit?" You ever changed the exhaust, opened up the exhaust, on a bike and notice the excessive popping on decel (it is not backfiring as many call it). On closed throttle decel the bike cant breathe enough as the momentum of the slowing bike wants to push the engine. Try it next time you decel in gear and hear popping, Two things will stop it, slightly open the throttle or pull in the clutch. Same here, if he pulls in the clutch and the stutter stops, then its a lean closed throttle condition, and likely a dirty gummed up carb.

For the gear, its not the gear its in that causes the reaction. The gear has little to do with it but usually at 45mph and more is when we're 5th or 4th. SO the bike has a lot more momentum to slow over time. On closed throttle decel the momentum of the bike is trying to push the engine. It'll do it in 3rd or 2nd too, just have to find the right road speed to make it happen.

What is "total bullshit" is saying "My 1999 carbed bike, had a fuel pump. And so does every other bike, and car. None of them worked on gravity." Yes, the Kawwy V-twins have fuel pumps. But absolutley no way dies every bike have a fuel pump. A very high percentage of carbbed bikes from 1900 to present day do NOT have fuel pumps and rely on gravity to cause fuel to flow from the tank into the carb bowl. That's why the carbs have tiny fuel shut off valves actuated by the floats to allow fuel to flow into the carb and also to stop fuel flooding when the carb bowl is full. The in carb shut off valve is operating against gravity.

[VulcanJeff]

Originally Posted by mick56

Something you dont understand about my comment ? https://kawasakioriginalparts.com/pa...316568&type=MC

I was not aware the carbed Vulcans had a fuel pump. Thanks for clarifying. I have dealt only with EFI Vulcan 15/1600 engines/bikes.

I hope that you are now aware countless numbers of carbed bikes throughout history relied on a gravity feed fuel system.