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Tiger Time => Steamers (1993-1998 Tigers) => Topic started by: harre on June 16, 2009, 08:13:44 PM

Title: Strange fuel or ignition problem
Post by: harre on June 16, 2009, 08:13:44 PM
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.
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Post by: aeronca on June 16, 2009, 08:45:21 PM
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?
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Post by: Mustang on June 16, 2009, 09:42:08 PM
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
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Post by: harre on June 17, 2009, 02:00:23 AM
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?
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Post by: Mustang on June 17, 2009, 02:55:53 AM
#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 .
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Post by: JetdocX on June 17, 2009, 03:24:18 AM
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.
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Post by: Dr. Mordo on June 17, 2009, 04:15:28 AM
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?
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Post by: harre on June 17, 2009, 11:53:09 AM
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.
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Post by: Mustang on June 18, 2009, 01:29:00 AM
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/
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Post by: nightrunner on June 18, 2009, 06:19:56 PM
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.
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Post by: harre on June 18, 2009, 07:32:02 PM
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.
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Post by: harre on June 19, 2009, 02:07:54 AM
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.
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Post by: nightrunner on June 19, 2009, 07:48:22 AM
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
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Post by: harre on June 19, 2009, 11:23:01 AM
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.
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Post by: harre on June 21, 2009, 09:23:34 PM
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.
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Post by: JetdocX on June 22, 2009, 05:11:25 AM
Glad you got that figured.  I guess a Steamer will run on one.  Live and learn.  Now go ride the piss out of it before winter returns to your homeland!
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Post by: Mustang on June 22, 2009, 01:17:02 PM
Harre

if you want to shim the needles on Keihin carbs , it's cheap and easy
go mto the hardware store and get some flat washers that are about 8mm in diameter with a 3 mm hole in them and start with one washer under each needle to raise them up .

Tiggers with Keihin carbs run really well in colder climates with
105 main jets and the stock pilots
shim the needles so they are about .75 mm (.030 inch)higher than stock
and the pilot screws set at 2 to 2 1/4 turns out .
And one side of the airbox has the cap on the snorkel .

Starting is much easier (especially when below 15 or so degrees C)
and you will only need to be on choke for a few minutes .

It will be crisper and that god awful bog in the power at 4k will be gone
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Post by: harre on June 23, 2009, 01:01:47 AM
Interesting. Your recommended setup has bigger main jets and thicker washers than Nightrunners setup, but he also changed the pilot jets. What about fuel consumption?
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Post by: nightrunner on June 23, 2009, 02:27:07 AM
I recall my gas mileage went up a few MPG, and the mid-range 'stumble' went away.   And starting is easy.  After 3 turns out the screws are at the end of their range so the stock setting is getting close to that.  Also, the pilot has a big impact on low RPM roll-on power.   You may have already seen this but this is a really good write-up on how M/C carbs work and how to re-jet.  Note the chart showing that the pilot jet is "active" over the entire trottle range.  The main jet plays no role until just under 1/2 throttle opening!

Edit. corrected link: http://hondanighthawks.net/carb14.htm (http://hondanighthawks.net/carb14.htm)

In my opinions, most of the M/C jetting wisdom comes from racing and they don't care much about the low end of the range.  If I were only allowed one change in a carb I would change the pilot before the main.   Just my 0.02
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Post by: nightrunner on June 23, 2009, 02:40:39 AM
And I set it up so I can run with the right side air cap on normally, and take it off for more air at hgh altitude.

Edit:  The jetting I did was for stock exhaust and air filter.  Mustang may(?) be running a K&N and/or aftermarket cans.  Just a thought.   Optimal jetting is very sensitive to intake and exhaust mods.
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Post by: jsingraham on June 23, 2009, 03:28:45 AM
Ummm, Nightrunner, is that really the link you meant to post? :5huh
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Post by: nightrunner on June 23, 2009, 04:21:40 AM
Quote from: "jsingraham"Ummm, Nightrunner, is that really the link you meant to post? :5huh

D'OH!  Fixed.  Thanks.  I have no idea how I managed to screw that up.
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Post by: Mustang on June 23, 2009, 12:56:14 PM
Quote from: "nightrunner"And I set it up so I can run with the right side air cap on normally, and take it off for more air at hgh altitude.

Edit:  The jetting I did was for stock exhaust and air filter.  Mustang may(?) be running a K&N and/or aftermarket cans.  Just a thought.   Optimal jetting is very sensitive to intake and exhaust mods.

Every bike is an individual , you have to find what works for that bike ..........and where you live has a big impact on what works for carb tuning . ie at sea level you can run giant mains and get away with it . I live and ride most of the time at sea level to 1000 ft . and the ambient temperature hardly ever gets to the mid 80's F

my other 98 jetted the same as my favorite doesn't want the choke at all while cranking but as soon as it blubbers it wants all the choke you can give it .

My favorite steamer starts with choke on and just a stab at the button , no cranking req'd .

Harre said his bike ran better when he went back to two turns on the pilot so he is right on the money with the pilot jets . The 105 mains will get rid of that awful bog in the power at 4000 to 5000 rpm when you have a healthy handful of throttle .

While I agree that the mains are mostly noticeable to change on the upper rpms , it will also affect the transition from the pilot circuit to the mid range to a lesser extent .
If you whack the throttle to the stop when you are rolling at 3000 rpm in 3rd or 4th gear and the engine stumbles and won't pick up rpm until you shut the throttle a bit ....You need bigger main jets .
on the other hand if you are trying to cruise at a steady rpm and the engine wants to "hunt" all the time rpm fluctuating without throttle movement your mains are too big .

There is no "recipe" that can be applied to all bikes as they are all unique individuals . and to truly benefit from carb tuning you need a dyno and lots of wrench time to make changes and see what gives the best results on the dyno .
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Post by: harre on June 24, 2009, 12:29:01 AM
I have a new K&N air filter installed and I will ride the bike mostly at sea level, or at the most, 1000 m above sea level. Original cans. I want a quicker throttle response on low revs as well as getting rid of the 4000 rpm bog. The Mustang #105 route requires fewer changes , so I'm leaning towards that option, however that may not give me the desired effect on low revs, so maybe I'll have to change the pilot jets and needle washers as well. I'm dazed an confused right now. Maybe I'm better off just riding. :?
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Post by: nightrunner on June 24, 2009, 08:06:00 AM
Riding will definitely bring you peace and tanquility so that's the way to go.

I agree with most of Mustang's comments; expecially that each bike needs to be custom tuned.   If all carbs of the same model were exactly identical, then there would be no need for the sync adjustment because they would all be the same all the time.  

There's more than one way to get most things done so whatever works for you.  When I was learning about jetting I searched the web and that Carb Theory 101 is one of the things I found.  It made a lot of sense.   Since the pilot is the only controlling factor for starting and low throttle position, it made sense to sort that first and work my way up.  Look at that figure in the link.  At 1/2 to full WOT, there are four factors affecting performance.  I'd rather tweak one adjustment at a time than deal with four overlapping ones.  Of course its not likely that street riders are ever going to mess with the shape of the slide so its really only three.   However if you are changing a main jet to affect starting, then what are you going to change for optimum performance at 3/4 throttle?   And don't forget that for acceleration, you can also drill the hole in the slide a bit larger.  Many of the jet kits tell you to do this.  It is the vacuum of the air flowing through the carb that lifts the slide and draws the needle up and out of the main jet.  A larger hole in the slide lets the slide rise a bit faster (but it does not rise any higher).    So if there is hesitation when you whack the throttle, you may need a larger air hole in the slide as opposed to a larger main jet.    

I do think we can all agree that Tigers are damn lean out of the box.  With a K&N its going to be even harder to start, and you'll have more air flowing at high RPM too.   But if she starts easy now, then leave the pilots and go with Mustang's jets.  Use his advice for whether the jets are too big or small.  As for the shims I used brass so they wont rust.  Bought a little box of them from McMaster Carr.  I would mail you a few but I'm out of town for a while and there's no point in waiting that long.  Steel or aluminum washers should work fine too.  I would doubt you could tell a difference between 0.025 and 0.030 shims so just get the right ID and OD.  Keep us posted on how it works.
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Post by: harre on June 24, 2009, 10:53:39 AM
Thanks for the advice Nightrunner. Bike is easy to start cold, needs just a little choke the first minute or so. I'll start with Mustangs settings and see how it works. I also appreciate your offer about shims. Feels good to know that I can solve that issue if I cant' find them here. I would prefer brass shims for longevity. Today is the big day. Going to do a vehicle safety inspection. In Sweden we have to do this every second year (cars yearly). They check if there is something wrong the vehicle, like steering, brakes, tyres, horns, wheel bearings, lights, emissions and so on. Of course you should check this yourself, but it does not cost much, so I try see it as a service provided by the government.
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