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Tiger Time => Steamers (1993-1998 Tigers) => Topic started by: Dr. Mordo on June 06, 2008, 10:51:55 PM

Title: Carb diagnosis question on my 96
Post by: Dr. Mordo on June 06, 2008, 10:51:55 PM
So I got my carbs back from the mechanic who has had them for a few months and did very little to them.  I had new floats, so I put them in and tested it to see if it was leaking, them put them back in.  

I looked at the float height and they were just a smidge over 14mm, not quite 14.5mm like the service manual recommends.  I figured my measuring stick might not be accurate down to 0.5mm so I just installed them.  

The bike fired right up but is running very rich and fouling the plugs.  Could 0.5mm of float height inaccuracy foul the plugs in 15-20 mins (maybe 30-40 mins including time at idle)?
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Post by: Mustang on June 07, 2008, 12:54:20 AM
I will pm you the page from the factory service manual and it shows how triumph sets the floats on a mikuni . and to answer your question YES float hieght will drown the plugs especially at idle where it is not burning off the excess gas fast enuff (too much incoming) also will run very rich !
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Post by: DesertDog on June 10, 2008, 08:19:05 PM
So I have not broke down and bought the Triumph parts to check float height yet.  They wanted $22 for the adapter and $22 for the marked sight cylinder.  Figured there had to be a way to check them with the bowls off.

Do I have to adjust as the service manual states (measure height against float bowl sealing surface) or is there a way to measure with the carb bowl off?  
thanks
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Post by: Mustang on June 10, 2008, 08:40:17 PM
While this is not the correct way to check them .......you can compare the hieght of all three and see if they are the same . the odds of all three being out the same amount from the factory are slim to none , if you know what I mean .
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Post by: Dr. Mordo on June 11, 2008, 04:05:39 AM
I have been working on mine, and as far as I can tell, my center carb is pissing gas (or perhaps not passing enough air?) from some place other than the needle/seat.  I've played with the float height a ton and it always does the same thing, which is foul out the center plug after about 15-20 mins of idling.

Any ideas about what could be happening?  I was thinking it might be the choke, so I pulled it and moved it to another carb, which had no effect.

BTW, thanks again Mustang for helping all us dudes who don't know much.
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Post by: Mustang on June 11, 2008, 05:51:25 PM
Quote from: "Dr. Mordo"I have been working on mine, and as far as I can tell, my center carb is pissing gas (or perhaps not passing enough air?) from some place other than the needle/seat.  I've played with the float height a ton and it always does the same thing, which is foul out the center plug after about 15-20 mins of idling.
with the carb bank off the bike hook up a fuel source to them and see if gas is pissing out the overflows , if it is you have a bad seat on the fuel needle .They should shut off all flow of gas once the floats come up .

Now if the carbs are working properly and you are still fouling plugs , are they totally gas soaked . cuz thats what a bad fuel needle will do , on the other hand when were the intake valve clearances checked last ?

Are you sure the center plug even sparks , check it with a new plug .
The triple will idle pretty damn good on two cyl. and you won't even realize one aint working !
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Post by: JetdocX on June 12, 2008, 04:17:19 AM
It even runs on one.  DAMHIK! :evil:
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Post by: Dr. Mordo on June 12, 2008, 04:57:49 AM
Man, I sure appreciate all the help, but this bike is beating me.  

I swapped the float assemblies between 2 and 3.
I checked for spark on 2.
I turned the pilot screw out a full turn.  
I pushed on the choke with a screwdriver to make sure it was seating.

Nothing.  It still fouls the plug very quickly.  I noticed tonight that if I open it up from idle it bogs down really bad, but I'm not sure what that means.

I'm almost ready to truck it 40 miles to the dealer.
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Post by: Mustang on June 12, 2008, 01:49:16 PM
so let me get this right no more pissing gas just fouled plugs ? This is almost starting to sound like a coil nightmare .  I have used an old style chevy coil to troubleshoot coils b4 on a steamer . just hook it up to # 1 cyl . then try it on #2 and so on .
Your problem seems to be #2 fouling plugs so start with the chevy coil hooked up to #2 and see if it fouls the plug or not .

You need an old style chevy coil you know the ones that have a + and - post on them for power and the center plug wire socket , something that would be on a 57 chevy LOL
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Post by: JetdocX on June 12, 2008, 03:54:51 PM
Or swap the coil to another cylinder and see if your problem moves with the coil.  May as well swap the sparkplug with it as well.
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Post by: aeronca on June 12, 2008, 04:10:31 PM
brother dr.mordo - i feel you'r pain :shock:   it does sound like a coil thang. listen to mustang, he's like a yogi or a swami with this stuff. i was going through the same crap as you, but so far(knock on wood), it seem's ok.
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Post by: Dr. Mordo on June 13, 2008, 05:14:10 AM
I swapped the coils a couple of days ago after reading about Aeronca's problems awhile back.  It didn't help.  I tested them with a multi meter, and they look to be in specs.  That is a great idea to use an old Chevy coil to test; I would never have though of that one.

I've also tried a brand new spark plug, and I've pulled the plug to be sure it was sparking.

I am freaking stumped.  I do think that it is still pissing gas - when you crank the throttle from idle the bike bogs really bad and starts spitting black smoke.  Also, of course, it's still fouling plugs.

Argghh!
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Post by: Mustang on June 13, 2008, 01:10:35 PM
If it is pissing gas that bad you will probably find that the float and or needle valve is screwed up or not seating right .
I like the Keihins carbs they are simple compared to the Mikunis and they get better gas mileage too .

If you are fouling the center plug that quick , I would check for gas contamination in the engine oil and would not run the bike too much more if there is . it will wash the oil off the cyl. walls and then you will be up shit creek so to speak ! :shock:

I had an old bonneville once that was pissing gas and it filled the engine oil with gas and would foul th eplugs when you tried to run it  LOL
If you have spark and compression , you have to have a buggered carb
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Post by: JetdocX on June 14, 2008, 04:16:16 AM
Are you sure you are making compression?  I don't think that has been established yet.
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Post by: Dr. Mordo on June 14, 2008, 04:41:34 AM
I have not tested it for compression yet.  I don't think that's the issue because it purrs like a kitten until the cylinder drops out.  I don't have a compression tester, so maybe it's time to buy one.

I dropped the needle  1 notch today and it was the first thing I have done that made any difference; now the bike seems starved for fuel.  It's late here, so I only played with it for a few minutes.  Tomorrow I'll figure out if the needle jet is the culprit.  My fingers are crossed; at this point I'm thrilled to get any reaction to my adjustments.

Thanks again for all the help, and I'll let you know tomorrow what I learn.
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Post by: JetdocX on June 14, 2008, 05:40:37 AM
Sorry, maybe have do the carb work yourself?  Seems like someone knackered the job the first time?  Maybe?
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Post by: Dr. Mordo on June 14, 2008, 06:49:37 AM
I read somewhere that the needle jets in the Mikunis will wear out, and that one of the symptoms is the bike running very rich (as in blowing smoke rich).    

But it's true that I don't know the history of the bike.  I've met two of the three owners, but the one in the middle when the bike broke is MIA.  So exactly why he gave up on it is a mystery.  I had assumed it was the sprag clutch that broke his will to fix it, but it may have been the sprag compounded by carb problems.
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Post by: pit0rz on June 14, 2008, 04:04:34 PM
:BangHead You know guys, they have a fix for all of your Steamer woes...
(http://www.hermys.com/images/triumph/03TIGER_08lrg.jpg)
 :pottytrain2  :eusa_dance   :icon_salut   :lol:   :hat10   :qgreenjumpers
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Post by: Mustang on June 14, 2008, 04:42:29 PM
(http://i231.photobucket.com/albums/ee47/2uoykcuf/emoticons/fuck.gif)
do you put mascara on those eyebrows  :ImaPoser
at least it wasn't a snot green one (http://i231.photobucket.com/albums/ee47/2uoykcuf/emoticons/pickingnose.gif)

(http://i231.photobucket.com/albums/ee47/2uoykcuf/emoticons/smilies0807.gif) :twisted:
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Post by: JetdocX on June 14, 2008, 05:49:01 PM
I've ridden the Girly (even that color).  The ergos are wrong for me.  I'd hate it after about an hour.

Then there's the whole "testicular shrinkage" thing that come with riding one of those "pretty bikes". :P
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Post by: pit0rz on June 14, 2008, 08:56:45 PM
Quote from: "JetdocX"...Then there's the whole "testicular shrinkage" thing that come with riding one of those "pretty bikes". :P

Not a problem for those of us secure in our manhood!  :thumbsup

You know I'm just funnin' yas!  :wink:
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Post by: Dr. Mordo on June 14, 2008, 10:12:30 PM
I love the Steamer, but I'd own a Girly in a second if the price and color were right.  Mine would have to be silver or black.

Whatever the new Tigers are called (Electrics?), Triumph can keep 'em.  They do nothing for me.

Ok, I'm off to work on my bike.
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Post by: Dr. Mordo on June 15, 2008, 01:40:39 AM
Well, I'm 90% certain the needle jet is the problem.  With rough tweaking of the float and pilot screw I have gotten the bike running fairly well with needle dropped a notch.  I ordered a skew-driver to really dial it in.  Early on Mustang said needle, but I, not knowing much about carbs, thought he meant the needle attached to the float.  So, Mustang was right all along, I just wasn't smart enough to know it.

You guys kick ass.  When I finally ride it around I'll up some pics.

Hopefully I won't have any more questions for a while.
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Post by: JetdocX on June 15, 2008, 06:02:31 AM
I like to see progress! :D

Keep at it and you may find your problem.  Please let us know what it is.
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Post by: Mudhen on June 15, 2008, 11:40:11 AM
Quote from: "Dr. Mordo"I read somewhere that the needle jets in the Mikunis will wear out, and that one of the symptoms is the bike running very rich (as in blowing smoke rich).    

I replaced mine...got me back about 5mpg - and that was just the emulsion tubes, I didn't go through them to dial them in after...still need to do that.

Supposedly they can wear out in only 5k miles...of course, this news is brought to you by the same people trying to sell them to you...

http://www.factorypro.com/ (http://www.factorypro.com/)
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Post by: Mudhen on June 15, 2008, 11:49:50 AM
One question for you carb tinkerers...how the heck do you know they're running rich/lean?  Just running it for awhile and looking at the plugs?  I can't imagine doing that on a Steamer...
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Post by: Dr. Mordo on June 15, 2008, 04:48:54 PM
Well, I am obviously no expert, but if you open the throttle from idle, and the bike bogs that is an indication of a problem.  If when it bogs you see black smoke, that means it's running rich.  If it bogs and you don't see any smoke but hear some light popping (which is actually a small backfire) that means it's lean.  

Also, if anytime you are riding you let off the throttle and it drops down to idle with some popping, that popping is indicative of a lean running bike.  Often abike (or car,too) runs lean because of leaks letting air into the system - i.e. cracks in the rubber intake manifolds or a vacuum line left off.

With my bike, I fired it up and it started to run like crap after 10-15 mins, and when I pulled the plugs one of them was no longer firing because it had so much black gunk on it from running extremely rich.  So, yes I have been pulling the plug every time I test it to see if I am making progress with my tinkering.  And yes it is a PITA, but not as much as pulling and draining the carbs to make an adjustment!
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Post by: nightrunner on June 16, 2008, 06:13:53 PM
On tuning, you can also start with a set up (pilot/main/needle position/mixture screw position/any airbox mods/exhaust) that someone else is using and has dialed in about right, and just copy that.  It still may need some minor tweeking from there but at least you'll be close.  Can also have a dyno shop do the fine tuning.  There are several threads here about carb tuning.   But yes, its tough to do without some sort of feedback like measuring exhaust carbon monoxide or O2.
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Post by: Mudhen on June 16, 2008, 06:26:24 PM
I had mine done at a dyno shop ($ouch.00)...and brought in a printout of someone else's settings.  Funny...after all the bitching and ranting the guy did about, 'you can't trust everything you read on the Interweb, every bike is different, blah, blah, blah...' the solution he arrived at was strangely similar to what I gave him...
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Post by: Mustang on June 16, 2008, 07:42:27 PM
Quote from: "Mudhen"Funny...after all the bitching and ranting the guy did about, 'you can't trust everything you read on the Interweb, every bike is different, blah, blah, blah...' the solution he arrived at was strangely similar to what I gave him...
Imagine that !  :shock:
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Post by: Dr. Mordo on June 17, 2008, 01:23:23 AM
Yeah, I got a similar thing recently from a Triumph Dealership mechanic who didn't know about all the sprag clutch issues the Steamers had.  He made some comment about, "well, you know sometimes that stuff on the internet..."
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Post by: nightrunner on June 17, 2008, 09:24:17 PM
+1  When I bought mine it had the DAR noise.  Local Triumph dealer told me they are just noisy engines and not to worry about it.   Joined a chat group and learned about DAR.  Years later I mention it to the head mechanic at another local Triumph dealer.  He hadn't heard of it either and of course warned me of BS on the net.  Oh yeah, this same guy told me that bikes run better with lean factory jetting.   :lol:
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Post by: Mudhen on June 17, 2008, 09:43:07 PM
I think we're the best buncha g'damn Steamer mechanics on the planet!

Well...Mustang is...but we'll all back him up. :wink:
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Post by: Stretch on June 18, 2008, 02:11:50 AM
Internet rumors...

That's what I thought about most of the whining from BMW owners until I met up with two guys in Alaska that were trying to get their final drives rebuilt before they ran out of vacation days.

A number of guys reporting the same thing (based on their own experience) isn't internet rumor, it's a consensus.
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