Strange fuel or ignition problem

[harre]

Steamer (1998) with Keihin carbs only runs on cylinder #2. I have sparks on all plugs both with original and daytona coils. Plug # 1 is clean and #3 is black. Both plugs are dry after running, (runs only on cyl 2). This looks as fuel starvation problem to me.

Valves have been adjusted (at a shop) and carbs cleaned (not with ultra sound though). The voltage regulator is new and charging is approx 13, 5 volts. New battery, new spark plugs and new air filter (K&N).
Original small in-line fuel filter is replaced with new in-line filter below the petcock and fuel line is re-routed under the carbs. Tank vent seems to work just fine.

Can my problem be related to the pick up coil? Is the igniter (CDI) box failing even though I have sparks?
I suspect a fuel starvation problem. I will drain the float bowls to see if the have fuel in them. I have the Haynes manual, so I may be able to clean the carbs myself. Do I have to replace seemingly fine gaskets? Any suggestions? I'm running out of ideas.

[aeronca]

brother harr, its not the pick up coil - if it was failing, it would not run at all, and i dont think the cdi is bad either if your getting spark. i would be in line with the fuel thinking. whats the compresion reading on 1&2?

[Mustang]

What's it do on full choke , should be running on all 3 at about 4ooo rpm if the choke /enrichener is right

sounds almost like a carb sync problem to me , if you tighten the throttle cable with the adjuster at the twist grip do the missing cylinders suddenly appear after increasing the rpm with the adjuster

[harre]

Firstly, cannot say how much I appreciate you guys taking your time with this. Thanks brothers. At least I'm not alone.
Engine is difficult to start when cold. Needs choke to start at all. Runs without choke when warm. I haven't tested running on choke when warm. When engine is warm I can rev it to 6000-7000 rpm without stalling.
Mustang, carb sync idea is interesting. I will try to tighten the throttle cable and see what happens. Could a small difference in sync give these large problems? Occasionally I get BANGS from the exhaust as well. The throttles appear to open simultaniously when I have the carbs loose, but maybe the story is different when I have the carbs in place.
Aeronca, good news about the pickup coil and CDI, that's a relief. Don't feel to spend more money right now.
I have checked the carbs now and I found no debris in the float chambers or in the jets, everything seems fine. Didn't use any solvents to clean, just compressed air.
Since I only have problems with cylinder 1 and 3, maybe the coil wires got mixed up somewhere in this whole mess. What are the colors for the wire pairs leading to the spark coils?

[Mustang]

#1 should have a brown wire with yellow dash
and #3 should be a green wire and all three have a red wire
or it could be the other way round  #1 is the green wire .....don't have a tank off so can't say for sure looking at the schematic
if it's running good at 6-7000 rpm it aint the coil wires anyway

#2 is the master carb and it is set by the idle screw on the side of the carbs , #1 and #3 are set to coincide with #2 by turning the philips screw that is on the linkage for #1 and #3
ideally at 1200 rpm you want to see vaccuum of 5-6 hg on all three carbs and then you know that when you open the throttle all three carbs open precisely and exactly the same .

[JetdocX]

I doubt it would run at all on one cylinder, so the idea that the coils have been swapped is unlikely to me.

How about Aeronca's compression question?  If you have negative valve clearance on one and three, it will be very hard to start, but run normally when warm.

[Dr. Mordo]

What all has recently been done maintenance-wise to the bike?  It seems very unlikely that the bike would just start doing this out of nowhere.

Have you checked to see if there is any spark on the two bad cylinders?

[harre]

The bike has recently been tested for compression due to this problem, and it looked good. I have sparks on all plugs.
The problem arose last fall immidiately after the 4000 km service including valve adjustment at a local shop. I did not test the bike when they returned it (in winter), so it stood still for three months until I attempted to use it last August. See the thread http://tigertriple.com/forum/index.php/topic,4860 (http://tigertriple.com/forum/index.php/topic,4860)

The guys messed up the valve adjustment for #1 exhaust valve, this was evident when I let another local shop change the sprag this spring.
I have now mounted the engine to the frame and thought the problem was gone, but the bike runs just as bad as it did before the sprag failed.
Maybe something happened when I removed the carbs to change the air filter immediately after the 4000 km service, I also tested the TT600 coils at that time. However even prior to this the bike ran really bad. I had to run it on choke and it died at about 5000 rpm. This was somewhat remedied after a draining the carb bowls. The thing is that it was running really well prior to the service. Now I put my hopes in the sync issue proposed by master Mustang. Don't have the sync tools though... Hope someone sells them cheap around here. Probably not.

[Mustang]

When you have had the carbs out did you do anything to them

It sounds entirely like a carb problem to me so
#1  remove the bank of all three carbs from the bike  ( unhook the throttle cable at the twist grip )
2. go sit down at the work bench with your carbs
3. start with 1 carb pick one , any one
4. unscrew the 4 screws that hold the float bowl on . remove bowl
5. without bending the float adjustment tab remove the pin that holds the floats on
6. the needle valve will come off with the floats
7. unscrew the pilot jet   and place aside
8. remove the main jet and place aside
9. if your pilot screws have been uncovered  remove them and make sure you don't lose these little bitty pcs. that will come out also :
a. spring
b. flat washer
c. oring
d. the pilot needle
10. Now take off the top cover and diaphram and make sure you don't stretch tear or generally fuck up the rubber diaphram. ( The needle will come out with the slide and diaphram .)
11. get some carb cleaner in a spray can and shoot some into all the little holes in the carb body
12. spray the little holes and such with a good shot of compressed air
13. Now let's put em back together
14 Screw the main jet in after looking physically thru it by holding it up to the light
15. do the same with the pilot jet ( this will be the picky little bugger that's probably got your bike unhappy right now .)
take a pc of copper strand from a pc of wire and run it thru the pilot jet to make sure it is not blocked , when you are convinced it is open and free screw it back in the carb body
16 . put the floats back in and screw the float bowl back on
17 .put the slide and diaphram back in the top and make sure that the diaphram is seated properly in the groove before screwing the cover on
18 put the cover on already  hehehe
19. now put the spring washer , o ring on the pilot screw in the order listed , screw it in all the way until gently seated , then back it out 2 to 2 1/2 turns will have you right in the ball park (2 1/4 works really well , just sayin )  8)
now repeat on the other two carbs doing each one at a time

If it still doesn't run right it's not the carbs , but you will need to sync them
a morgan carbtune works really well , it's what I have
http://www.carbtune.com/

[nightrunner]

Interesting problem.  One thing is puzzling.  I don't think the bike would start or run at all with only one cylinder.  So something more to it here.

Anyway the others have posted good advice.  I would also check for vacuum leaks around the carb boots.  With bike parked and running, spray some starting fluid around the boots.  If there is a vacuum leak the RPM's will rise when the fluid gets sucked into the leak.  Those boots can crack or could have a leak around the gasket.   Do not smoke or BBQ or any open flames while doing this.  Starting fluid is extremely flammable.  Keep an extinguisher near by.

Also Mustang's detail carb cleaning.  Might first just check the vacuum diaphragms.  They can rip and creat problems.  

Still hard to imagine how you could rev to 6000 RPM on only one cyl.  Maybe some intermittant firing on the the others cyls.

Another quick test is to use the drain screws to drain each float bowl.  That will at least tell you that fuel is getting to each carb.

By the way, add a thin layer of wheel bearing grease or even petrolium jelly to all 6 rubber boots where they slip  over the carbs.  It will make install/removal a LOT easier and improve the seal as well.

[harre]

Thanks for the advice. I aready have cleaned the carbs, but not with carb cleaner, only air. I will do it again with carb cleaner and follow Mustang's instuctions. I will try several things now. First check comresssion and carb sync. I found a compression measuring device and a vacuum gauge in the garage that I will try.
The rubber boots already have grease on them. Will try with starting fluid when I get the motor running, will also try to measure the vacuum in the carbs then. I haven't got the carbtune (yet), so this first measurement will only be a rough guide. Anther thing to try is to run engine with only #2 coils attached, to see if it can run with #2 cylinder only.

Must have the good ol' steamer running, my brother just got himself a Girly, and is now constantly talking about planned trips. The Swedish summer is approaching awfully fast and I need my bike NOW.

[harre]

Hot update: She runs fine now! I almost had forgotten how she should sound, Purrs really nice and reponds quickly to throttle. However high idling, around 3000 rpm, maybe because I fiddled with the pilot screws. They're out 2,5 turns now. Does this have an effect on the idling? In that case, should I go up or down? The idling screw is out and isn't pushing on the arm, so it does not affect the idling. The throttle wire does not appear to be stretched, but I will loosen it at the grip to rule that out. I'm getting quite good at removing the carbs now, I suspect I will need to do it again. One good tool for the pilot screws would be a flexible screwdriver so I could adjust them with the carbs in place.

What did I do to get her running? I swapped the connections between #1 and #3 coils! Mustang, it's the green that goes to #1 and the brown/yellow to #3, #2 has a yellow/green wire. Thank you guys for helping me out with your suggestions, pointing me in the right direction. The strange thing is that the coil supply wires were marked wrongly (by me). How that happened is a mystery. One lesson learned is that the engine will be difficult to start, but still run with #1 and #3 coils swapped, I would have preferred that it hadn't. But that's water under the bridge now.

[nightrunner]

Well that is good news.  You did say this happened right after a tune up.  Maybe the shop mixed them up.

2.5 turns is typical for a stock setting.  Although still idling with the idle screw all  the way out does not sound right.  The butterflies should close all the way and cut off the air.  Are you sure they are all properly seated in the carb bore?  A little misalignment can bind and keep them from closing all the way.  

Anyway now that you're a carb expert, check my thread on rejetting.  It really improves cold starts and roll on power.  Also note that after 3 turns there is no more change in the pilot screw.  After 3, you go up one jet size and crank the screw in to about 1 turn.

Cheers

[harre]

One thing that has made my fault finding really slow, is the weak sprag. It died on me really fast, had no time to figure out what was wrong. Why on earth did the Triumph engineers remove the sprag cover on later engines? Hopefully my new sprag will be lasting the bike's lifetime.
Nightrunner, I have read your rejetting thread several times. Now I know that I can do this myself, not so difficult as I first believed. I have some difficulties in finding the needle shims. There is a Swedish internet store that has Kehin main and pilot jets, but apparently no shims. $45 for a set.
These thing are som small and tiny, so it would be possible to order them from any place in the world without having to deal with high shipping costs.
Any recommendations? The Factory pro kit is available in Sweden, but costs $185.
I agree that the butterflies must be held open somehow, because when I tried to start with pilots at 2,5 turns, it idled at 1000 rpm, but at that time the gas wire had jumped loose, when I attached the wire the idling increased.

[harre]

Lubricated the gas wire and set the pilot screws 2 turns out. Engine idles good now and is easy to start. I have been thinking about the swapping of the #1 and #3 coil wires. Is it necessary to remove the coils for a valve adjustment? If the workshop mechanic did so, he may have swapped the wires by mistake, I thoroughly marked the coil supply wires before I began the daytona coil installment, so a mistake on my behalf is unlikely, but of course possible. Next step is to add the extra headlights and the new handlebar and I am ready to go! I will post pics of my modifications on another tread.