Firing on two of four!

Hello Folks,

I have what seems to be the never ending saga of my Royal Star not running properly (see my other post).

Just reassembled the bike (1997 Royal Star Tour Deluxe) after a long winter trouble shooting quest. I had # 4 cylinder popping and cold to the touch at idle speed.

Turns out that # 1 is in the same condition as well, #2 & 3 are carrying the load at idle. I did some test and they are as follows:

Swapped plugs, no difference.

Measure primary and secondary voltage to all plugs and coils (all read about the same).

Swapped coil on one cylinder, made no difference.

Checked connections, coils, plug caps, compression, all good.

I can pull coil a wire while the bike is running for # 1 & 4, makes no difference.

Pull #3 and bike quits, #1, run rough,

Checked all electrical connections, good to go.

Started out 3.5 turns out on idle, #1 & 4 have wet plugs, #2 and #3 burning fine

If I pull ignition wire to #1 & 4, no difference, pull #2 and bike almost quits, pull #3 and bike quits. Can grab pipe for #1 & 4 no mater how long the bike runs.

I did test on pick up coil, good, primary & secondary voltage for coils all read about the same.

If I close idle mixture on #1 & 4, no difference, wet plugs on both.

Fuel is wet on #1 & 4

Checked all electrical connection on ignition system, all good

I hear the spark popping on # 1 & 4 when I remove the plug boot.

I am at a loss here, any help would be appreciated, I used all trouble shooting recommended by the manual, it recommends igniter replacement if all checks well. I don't care to purchase one but want to make sure it is going to fix the problem before I do.

I like this bike! Would like it twice as much if the other two cylinders worked!

#2 & 4 plugs have half rpm as # 1 & 3 with my digital tachometer/strobe gun, why is this??

I hate to comment with something simple, but mine ran like this when I crossed ignition wires. 1 plug to 3 cyl. My mistake. Again. You went in great detail so I doubt this could be your problem.

Also, was this a new occurrence. Did the bike run well before, when did the problem start?

Bike always had the problem since I bought it, it might be that simple. I will check that both the primary and secondary IGN wires are where they belong. I'm somewhat embarrassed that I did not check this before, on the other hand I will take an easy fix any time I can get it. I get back with you & thanks.

This was your pass problem.. I was wondering did you ever adjust the floats?

Hello folks, I'm new to the site and have enjoyed the various threads. I have read up on exhaust popping but I think I have an other than "lean" condition. I will try not to be long winded but want to give those out there all the info I have on the symptoms/condition.

 

Bought the bike with 21K miles.

I get about 25 miles to the gal

Popping from both sides but mostly from the right at idle and deceleration.

Compression check, bike at normal temp/then added a little oil, #1-185/190, #2-180/180, #3-180/185, #4-160/165

Bike fowled out #3 & 4 plugs after putting a few hundred miles on it and I had to limp back to the house, new plugs and ran great.

Bike has K & N air intake, drilled exhaust pipes

Inspected carbs and floats/jets. Found idle mixture screws out collectively 3.5 on the left and 12.75 on the right!

I turned all to 1.5 from seated and synced the carbs, got rid of a lot of the popping but still fowling out right side #3 & 4. Turned in right side to .75 open and after two tanks of gas the plugs look like they are burning correctly and I further reduced the popping but I still have it on the right side only @ idle.

If I am cursing in 4th without loading the bike I hear a ping in the right front cylinder every so often like improper ignition timing (I checked timing @ idle and it was with in the little window) Seems like a valve sticking open or maybe burnt?

My compression is low in accordance with the manual, is this due to burnt or sticky exhaust valves?

I would think that this bike should not be worn out (ring/cylinder) @ 21K miles

Can I get away with operating it until a winter dismantle?

Could a K & N filter and drilled pipes caused a lean condition?

Looking forward to your input.

The problem sounds similar to mine this past 2 weeks. the bike was new to me but I thought it felt like a hog. Power but nothing blazing fast. I just hated the 29mpg I was getting. I decided to go and change the plugs but was stopped in my tracks when I saw right front cyl plug wire wasn't even connected. I haven't take her out on the road dyet but I will tell you that I pissed my neighbors off riding like a lunatic up and down the street. ay more power.

Just wondering if may the wire is cracked as you said some plugs were fouled. Maybe the wires crossed or maybe the wrong plug .

Have tried a new ignition module?

Is your ignition module stock or DYNA 3K?

I know you say you have checked the primary and secondary voltages, but maybe could be something goofy going on in the ignition module.

There maybe someone on he forum that has swapped their stock one out for a DYNA and would be willing to loan you a stock one just for grins to check it out.

All wires are going to the right plug and primary wires are as follows: #1, orange, #2 grey, #3 yellow & #4 white. My manual does not tell me what # cylinder is what but I bought a set of coils from eBay and #1&3 came with the bracket and harness, my wire are in the same order.

My troubleshooting guide states that if I cannot find nothing wrong with all of the above step...."replace ignition module".

I used a peak volt adapter on my fluke (I used it in the 90s to test outboard ignition voltages), I show both primary and secondary voltage to be about the same for all 4 cylinders 5.1/117 to 142. This tells me that I do not have a bad connection in the harness (voltage drop due to high resistance).

Pick up coil test good @ 120 ohms.

The next step is IGN module replacement, It would be nice if someone had a loaner to see if it corrects the problem. What do you folks suggest, starting a new post soliciting for a loaner?

This was your pass problem.. I was wondering did you ever adjust the floats?

I did not use the liquid level tool to check float adjustment, didn't have one. I think I got a measurement from this site or another listing the measurement in mm (for those that did not have the tool), all floats were the same height and at the listed height.

Are you thinking I'm getting a "wash out" on #1 & 4? I thought about this early in the troubleshooting process (a long process its been) but my floats were the same heights.

If ran the bike at high revs for a few minutes, I would be able to "burn" the excess fuel pouring into the cylinder and my cylinder temp would rise from the combustion. I know during yesterdays idle running for about an hour combined time while I was checking things out, it seemed to me it was using a lot of fuel. I had one of those test tanks and I could see the fuel going down, I had my idle needles open to 3.5 turns as per Goose's recommendations to start the tune up process. I never went down that road because I had two cold to the touch cylinders with wet plugs.

My factory float levels were all over the place when I checked mine a few years ago,

The other problem I had that coils 1 and 3 (both rears) stopped working and I ordered a few more sets off pinwall for about $29 each set of 4, so I have spares now, not sure why Yamaha

Made the rears so exposed the the elements under the bike like that.

So anyways when I changed them out all was good for me.

Same symptoms as yours.

Good lunch with what you find.

Note:: both rears are cyl 1 and 3

And over the years goose figured out that it's really not the coil itself

It's the wire that you can not change out, bench testing doesn't really seem

To work that we'll from what I have noticed on these forums .

Jeff

Jeff,

Are you saying you had a similar problem and bought new coils and that solved the problem? Did you have no spark on #1&3 ? Or just a cold cylinder like mine?

Also, if I understand you correctly, when you test the resistance in these coils (in accordance with the tech manual) your saying they could test ok but not give enough hot spark to run the cylinder? I swapped out the coil (with a used one purchased on eBay) and made no difference.

I guess what I could do is swap the two hot cylinder coils with the cold ones and see if my problem follows the swap. If so buy some new coils, if not, get a new igniter module.

Also I was thinking of getting a colortune so I can se what's going on in each cylinder.

Correct, both 1 and 3 where dead.

If I remember correctly I think I had a small spark.

My plugs were wet and the pipes didn't get hot.

Been about 4 years since this happened. I was just

throwing this out to you just in case.

I am almost sure you can not swap them out do the length of the coil wires,

both sets a different.

Like you say you swapped out the coil (with a used one purchased on eBay) and made no difference. so then I guess that is not the problem in your case.

colortune is expensive and I never could get to see what was going on down

there in the hole, its very hard to view the colortune in the chamber.

Let me know how you did it if you get one.

There maybe some members on this site that might loan you one.

I can not remember who loaned me there's

Swapped #1 & 3 coils, #3 was firing and #1 was cold as it has been, its not the coils. Has to be the wiring or the IGN module.

I don't thing there is any thing wrong with the wiring, connectors pass a visual. I will do a resistance test tomorrow.

Just confirming that you know your carbs are in good shape - that the diaphragms are not pinholed, that the jets are clear as are all channels within the carb body.

If you are over-gassing your mixture no amount of spark will overcome that.

Before condemning the igniter....have you tested all ignition interlocks in case one is trying to shutdown igniter? ie Sidestand relay, tipover switch.

Not sure on the 97 TD, but on the RSV the interlock circuit goes through a set of contacts in the ignition switch too.

Gents,

Had the carbs apart twice, all passages clear and no pinholes or miss aligned floats. Floats shut of fuel.

As far as the interlocks, I had the main ignition switch out and it checks out good, have not checked the side stand or handlebar stop switch. If I understand you correctly Neal, your saying that if I had a high resistance condition across one of these switches...lower voltage will make part of the ignition malfunction and not all of them?

I'll check them out and also see if I have a tip-over as well.

The spark is very weak when I pull the wire and place a plug in the boot and hold it to the block.

Appreciate the input and will get back with the results.

I think this is true and maybe some one with a bit more knowledge can chime in and agree or correct my bad.

I am pretty sure these bike have what they call a waste spark, that is the coils fire twice during a complete 360 degree cycle, the first spark being for the combustion stroke to drive the piston down the second on the exhaust stroke to help burn any left over hydrocarbons before they exit the tail pipe. I would suspect that the second spark may intentionally be weaker that the primary spark, maybe what you are seeing is the secondary spark and you are not getting any primary spark.

Again I may be totally wrong, I am working on memory here, so hopefully someone can chime in here and help.

Yes I'm saying check over that the interlocks are doing what they should.

You'll need the manual to go through the checks....since the

Royal Stars were different than the 1st & 2nd Gen Ventures.

Stuff like the sidestand relay (not just the sidestand switch), the

tip over switch (if they even have one...) looking at the wiring diagram should

show you exactly what affects the Igniter operation.

I'm guessing that a lot of your troubleshooting was done with the bike running on the sidestand so even stuff like whether you have a good neutral switch path might have an effect.

Side stand, clutch switch are good. Seems as though the main switch does not pass the stink test. The heaver red to brn/blu wire has 1.5 ohms, the smaller wires in the interlock circuit have k & mega ohms some times and the best I can get it is at about 265 ohms moving the key around. Both circuits "beep" but the interlock circuit is too high resistance. iwould think. I will look at the neutral switch tomorrow along with making up some jumpers bypass the main ign switch and see if this corrects the problem.

As far as the waste spark, I find that interesting, that sounds like that might be a way for dealing with emissions. I have been thinking that I have an explosion in the pipe every so often (pop, like a late timing thing) on #4 cylinder, that would be all that gas I'm not burning first time around.

you can check the timing. if it's off it's likely the Igniter unit. if the pickup coil and Ignition coil is good. No adjustments on the timing but can help finding a problem.

I think once you get the interlock circuit "cleaned up" it will sort out the igniter and discrepancy in the tachometer test readings you found.

I suspect your problem is in the carbs - no real reason I can explain - I just do.

Here is a very simple test to verify if you actually have a usable spark on each cylinder:

First, go get some spray starting fluid (ether). Turn off the gas and drain the carbs. Now pull the two vacuum lines and two vacuum caps from the intake manifolds (like you were going to sync the carbs).

While hitting the starter, spray a shot of starting fluid in each vacuum port, one at a time. If there is good spark at the right time, you will hear the cylinder fire a couple of times. No need to crank long, this is an instant test as long as you get the spray into the vacuum port.

You can do the same test by taking the air plenum boots off the top of the carbs and giving each carb throat a quick shot of the fluid while cranking. But you have to do each carb individually or you will not know if each cylinder starts to fire.

One other point I do not remember seeing covered in this thread - have you checked the spark plug caps for high resistance? If you do not have an ohmmeter, just swap the caps and see if the problem stays with the same cylinders.

Goose

This is probably a dumb question or otherwise a dumb suggestion.

For my two cents worth , have you tried replacing the fouled , dirty spark plugs with new and properly gaped ones?

Cheers .

Winston66,

Northampton , Western Australia

Goose,

Thinking about the test you wanted me to preform I decided to modify it a bit. I have spark...I was thinking it wasn't a good spark looking at it while the bike is running. What I did was pull the high end lead from the plug and put another plug with the proper gap in the plug cap and held it next to the block for observation while the engine was at idle. Spark looked weak to me. I did check the resistance of the plug caps last fall and they were within spec. Would a weak spark not ignite ether because it is so volatile?

I swapped out and swapped over coils and leads only to have the same two cylinders cold, coils & plugs are good (plugs have been replaced three times).

However, as another member pointed out, matters not how much spark is there if I have a wash out condition. So thinking about how the carbs work and that if I'm not mistaken, you get fuel to the cylinders in three ways: Idle circuit (adjustable), mid range jet & high range jet, the latter two being fixed.

What I thought I would do is turn in on fuel idle screw to close it off, start bike and run it at idle speed. Shut it down after a few minutes and pull the plug and see if it was wet. If so, this would mean I was getting fuel in the cylinder through other than the "idle circuit" (wash out). I had to use some choke but tried to use it as little as possible. I did this test with both affected cylinders: both wet

I can still do your test with the ether, but the rate at which I am using fuel in my test tank, I think I'm flooding.

If this is the case, what am I looking for on the carbs when I pull them? I have had these things out twice and went through the and found nothing wrong. Flipping carbs upside down and measuring float height, they're all the same, needles and seats look good, diaphragms & choke pistons. I know that there is a liquid level gage to set the floats, but can it not be done the old way of measuring from the bowl mounting surface?

Saturday morning I will pull the carbs for another look.

Did you resolve the high resistance across the ignition switch?