3 cylinder issue

[Ikarus]

I have an 05 RSTD and it seems to run on 3 cylinders unless I hold the gears to red line ( or at least close to it) before the other cylinder kicks in. The motor smooths out and get a little quieter.

 

My question is it a carb issue, throttle issue, could one of the carbs not be opening when the throttle is engaged, blocked main/pilot/jet, spark plug?

 

I'm almost certain it's the front left cylinder, only because it's the coldest of the four pipes after a ride.

[Marcarl]

First off remove the plug wires one at a time and find out which one is causing your concern. The check to see if you have spark at that plug by using a screwdriver. If you have spark from the screwdriver, then pull the plug and check it. If it looks good then replace with a known good one. Through all this exercise you will now have determined that spark may not be the issue, but more than likely fuel related. If so, post again.

[Ikarus]

First off remove the plug wires one at a time and find out which one is causing your concern. The check to see if you have spark at that plug by using a screwdriver. If you have spark from the screwdriver, then pull the plug and check it. If it looks good then replace with a known good one. Through all this exercise you will now have determined that spark may not be the issue, but more than likely fuel related. If so, post again.

 

This may sound dumb but how do I check for spark with a screwdriver?

[Marcarl]

Use a phillips screwdriver. Take off the plug wire, insert the screwdriver where it would attach to the plug, hold the shaft of the screwdriver close to the metal of the engine and push the starter button. If you see spark, well enough. If you don't see a spark hold the screwdriver closer. No spark? You might have an ignition issue. Got spark, then check the plug. BTW, make sure you hold onto the handle of the screwdriver, not the shaft.

[Ikarus]

That's what I was assuming bit want to make sure. Thank you

[BlueSky]

Or you can remove the plug and put back in the plug cap. then lay the side of the plug against the engine and turn the engine with the starter and see if there is a spark at the plug gap. If you have spark on all cylinders, determine if the carb diaphragms are doing their job. On a Gen 1 you just remove the fake gas tank cover and air cleaner and watch the carbs while you blip the throttle. I'm not sure how you run your bike while looking down the carbs. And i would immediately put a half can of Seafoam or my favorite Gumout with PEA to the gas to start cleaning the carbs.

 

On my Kawasaki when I first bought it one cylinder was dead. I confirmed spark to the plugs but didn't check the plugs. One of the plugs was dead. Only plug I've ever experienced being dead in my over half century of working on autos and some bikes.

[grubsie]

Only plug I've ever experienced being dead in my over half century of working on autos and some bikes.

 

It sounds like in the early part of your half century you didn't own any 2 stroke dirt bikes. To be able to trail ride for the day and be sure you got back home, you had to carry at least a half dozen new spark plugs, a wire brush along with some fine sandpaper and a bag of tools. Those early 2 strokes ate spark plugs like it was their job.

[BlueSky]

It sounds like in the early part of your half century you didn't own any 2 stroke dirt bikes. To be able to trail ride for the day and be sure you got back home, you had to carry at least a half dozen new spark plugs, a wire brush along with some fine sandpaper and a bag of tools. Those early 2 strokes ate spark plugs like it was their job.

 

I've had plugs bridge over with carbon that wouldn't fire (in a Chevy of course) but this plug was the original plug in my 85 ZN700 Kawasaki bought in 2009 and it only had 1,054 miles on it and was clean.

 

You are correct in that I've never owned a two stroke motorcycle.

[Du-Rron]

I thought you were always supposed to hold the shaft of the screwdriver in your teeth when checking for spark and then ground yourself to the cylinder head by grabbing it.

 

 

ahhhhh what do I know......

[CaseyJ955]

First off remove the plug wires one at a time and find out which one is causing your concern. The check to see if you have spark at that plug by using a screwdriver. If you have spark from the screwdriver, then pull the plug and check it. If it looks good then replace with a known good one. Through all this exercise you will now have determined that spark may not be the issue, but more than likely fuel related. If so, post again.

 

A common point of corrosion is where the HT lead plugs into the coil, really common to see that green gunk causing poor/no spark conditions. Not sure if this applies to gen2 but gen1 Venture and Vmax have the spark plug caps that can fail. Replacements can be had from NGK via auto parts stores for like $2.50 each, they can be disassembled and inspected. If replacing you must pay attention to the resistance value. If you get to that point I'll find something that I previously cut/paste regarding plug caps and resistances to use when finding replacements. If you have proper spark then disregard the above.

 

I bought a little gadget at NAPA (IIRC) that clips to a ground and you plug the plug wire into it as if it were a plug. It's a small glass cyl with an adjustable gap inside which makes the spark easier to spot. If you are likely only doing it this once than the screwdriver trick is great. The spark might be tough to see in direct sunlight.

 

I have to agree with Marcarl, this does sound more like fuel management. These CV carbs do not like sitting and also ethanol fuel has given me one headache after another. Since not using ethanol and running a few oz of Seafoam through a couple times a year and anytime before it sits for more than a week. I run it enough to make sure the Seafoam treated fuel gets through the carbs and into the bowls before shut down. Without fail it has always fired right up after sitting, even in the spring.

 

Let us know what you find after checking for proper spark. Youtube "spark tester" and "spark test screwdriver" and you can get a visual on what has been described on this thread. I got one because I knew I'd be using it over the years, and they are cheap. Good luck!

[Ikarus]

Well I have plenty of starting points for this weekend. Can the motor mount be removed without removing the gas tank

[BlueSky]

I thought you were always supposed to hold the shaft of the screwdriver in your teeth when checking for spark and then ground yourself to the cylinder head by grabbing it.

 

 

ahhhhh what do I know......

 

That must be the Texas way! When I was growing up in the 50's in a small NC town there was a mechanic called "Pluto" who had his own garage and worked by himself. He always wore one of those train engineer caps with the bib turned up. He only owned hand tools. He charged $4/hr. Anyway he was famous for holding a spark plug wire in one hand while holding his 3rd member close to the car so a spark would jump! Maybe he was from Texas originally! Maybe it was a substitute for Viagra? When I was 16 or so I took the family 55 chevy to him for swapping out the throwout bearing. I had bought the bearing. It took him one hour to remove the transmission and replace the bearing and reinstall the trans. Charged me $4.00.

[Du-Rron]

That must be the Texas way! When I was growing up in the 50's in a small NC town there was a mechanic called "Pluto" who had his own garage and worked by himself. He always wore one of those train engineer caps with the bib turned up. He only owned hand tools. He charged $4/hr. Anyway he was famous for holding a spark plug wire in one hand while holding his 3rd member close to the car so a spark would jump! Maybe he was from Texas originally! Maybe it was a substitute for Viagra? When I was 16 or so I took the family 55 chevy to him for swapping out the throwout bearing. I had bought the bearing. It took him one hour to remove the transmission and replace the bearing and reinstall the trans. Charged me $4.00.

 

 

.

[utadventure]

Having a similar issue with my '86 Venture. In addition, the tach doesn't work until the dropped cylinder kicks in around 4500 - 5000 plus.

 

Where it kicks in at higher rpm, I'm guessing that it's a potential carb issue, maybe plugged jets.

 

Can anyone tell me which cylinder the pick up is on? If I remember correctly, 1 is driver side rear, 2 driver side front etc.

 

Dave

[luvmy40]

I may be mistaken, but I think the tachometer reads from the number 2 cylinder and it is definitely is actuated by the ignition via the plug wire(or pick up?). Sounds like your issue is certainly in the ignition circuit, as was my '83's misfire issues. 2 bad coils, bad wires and old plugs, and as it turned out a faulty TCI.

 

If the misfire was carburetor/fuel related, the tach would be working A-OK.

Edited November 2, 2018 by luvmy40
added clarification(or rationalized a guess)

[cowpuc]

Start it up from cold, run it a couple minutes, put some spit on the end of your finger and touch each header pipe like your mom use to test a hot iron,, find the header pipe that dont sizzle when ya touch it (can also test with a lazer thermometer but the spit test is faster cause ya dont have to walk over to the tool box and fetch the spit). When ya find the cold pipe, take that jugs plug out and see if its wet,, if its wet it is probably ignition related - stick a new plug in it (check gap before install - dont trust NGK factory - by the way,, use a good old standard plug - nothing fancy - dont waste your money on a big dollar platinum fancy smancy yet,, if your into that - wait till you know that it was the plug, then swap em all out with the 10 bucks a piece stuff = IMHO of course). Unscrew the plug terminal and clip 1/4 inch from plug wire, check internal of cap for crud (you can ohm test it too if ya want - occassionally the plug cags go high resistance) and screw the cap back on. Reinstall new plug. Drain the bowl on the carb into a glass jar - let it set for few minutes to check for moisture - moisture gathered from alcholed fuel can act just like bad ignition. If you see moisture, drin all carb bowls (I like using a syringe for this on the drain tubes = really fast!!). Close the drains and refill the bowls by cycling the fuel pump - recheck for moisture after refilling bowls to make sure your not pulling water from fuel tank.

If the plug is dry when you pull it from the jug with the cold header inject a half a teaspoon of raw fuel into that plug hole/jug. I have done enough of this thru the years that I can effectively take a piece of clear fuel line attached to the squirt nozzle of rear end grease bottle filled with gas and not over do it but I would suggest that the first few times you try this to just suck about 2 inches of fuel up into a piece of clear 3/8th inch fuel line with your mouth, hold it there with vacuum from your tonge sealing off the end of the fuel line and then drapping the fuel line into the plug hole before you release the fuel into the cylinder = that way you want over fill and have a chance of hydrolocking er.. After you "prime" the jug, screw the plug back in and start it and see if it comes to life. If it does,, yeppersss,, carb related.. On a 1st Gen, all of this can be easily averted by just pulling the air filter and squirting a little raw fuel into what ever jug your working on,, much easier BUT what I just explained is TOTALLY workable..

Any of this make any sense?? Hard to follow aint I

[Ikarus]

Update:

 

I'm reviving my own dead thread.

After doing the touch test, I found the front right cylinder was the problem. With a can of carb cleaner and a printout from cowpuc's "how to clean carbs" I was ready to start the job.

 

After taking off the tank, I decided to change the plugs while I was there and lo and behold the front right plug was wet. So a quick plug swap and a short ride it seems like a dead plug was the issue.