Ignition, coils, carbs or what?

[Tripodtiger]

G'day

Occasional visitor, but I've now registered.  I usually inhabit AdvRider and just lurk here, TriumphRat plus various Yamaha forums to see what's going on in the world.

I posted this question of TriumphRat, but didn't get much reply.
So, here it is here.   I've done a bit since the original question, which I've added at the end.  Any suggestions?


I've been trying to locate specifications for the coils and plug leads for a '94 Tiger. Can't seem to find a specs sheet and my service manual for my other Tiger is 1000km away, with my other Tiger.

I've not long had this bike and have encountered a problem with No 3 cylinder. The bike is very thirsty (in comparison with my '96), barely getting 300km to a tank of 95RON unleaded.
Both snorkels are opened and the mufflers have been gutted and re-welded. Sounds fabulous but looks a bit crap. It also wont run with pre-filters on the snorkels nor with one snorkel closed off (as OEM).

It's a spare bike so I don't ride it often but still have need for it to be available whenever I want it.
Both times I've ridden it outside town, and started cruising with the engine above 4000rpm No 3 spark plug has fouled. The plug comes out black & sooty, not oily.
First time I thought it was just the plug, so I replaced it.
500km, and one day ride, later, No 3 has fouled again.

On both occasions the bike has run fine for a period then had an increasing miss. Progressively the miss increases but, as the revs reduce under around 4000, the engine smooths out.
Eventually, as the plug gets fouled, the engine wont run properly at all. It pops & backfires (unburnt fuel igniting, I expect), running on 2 cylinders.

I ripped out No 3 plug. There was a visible spark at idle. The gap was a bit big, so I closed that down to 0.88mm & cleaned the plug with a brass brush & fine emery cloth (a bit hit & miss, but it's only one plug)
The plug continued to fire okay. But I have noticed that the spark is not 'between' the electrodes, it is more 'around' the electrodes.
What can I use to properly clean the plug - would contact cleaner do the job (I've got some of that)?

I pulled the carbs out, thinking that there may be something obvious making No 3 cylinder rich. Nothing of significant difference identified.
135 mains
40 pilots
5E65 needles set with the circlip in the 2nd lowest position
Diaphrams look almost new and sit tight inside the caps.

I didn't measure the float heights. I don't have the specs. The floats pivoted freely and the needle & seat set up on each cylinder was free.

I did notice a wear mark around the No 3 needle, visible about 1mm below the bottom of the slide body, ie in the airstream with the carbs closed.
I also noticed that the spacer under the needle clip in No 1 was a slightly different sectional shape than the other two.

The butterflies appear to open simultaneously and equally. The slides move smoothly.

To the limit of my electrical knowledge, I put the ohmmeter across the coils and plug leads.

For the plug leads -
No 1 = 4.68
No 2 = 5.09
No 3 = 4.67

Across the coils (one probe on the connector to the wiring loom, the other where the plug lead connects)
No 1 = 10.03
No 2 = 10.43
No 3 = 9.96

My next test is to swap No1 & No 3 coils and see what happens.

Anyway, lot of information to ask the question

Can anyone point me in the direction for on-line specifications for the '94 Tiger?

Otherwise, someone may be able to look at the above and say, "Wow, that's pretty crap. How about you start with....."

My '96 Tiger has had it's ups & downs, but usually associated with the airbox filling with dust and providing a 'failure to proceed'



Okay.

I've been able to locate the specs via a factory workshop manual I procured.  So you can ignore that bit (or the whole post, if you choose).

Since I've done that I did swap the coils & leads around without success.

I've also swapped all three coil/lead sets with those from my '96 Tiger.  No success.

I checked the air gap between the rotor & the ignition pick up.  0.63mm

Obviously, because it was cold I had to start it with choke on.
When it eventually fired the saliva on the exhaust test revealed that No 1 was firing, No 2 was thinking about it and no 3 was essentially dead.

I swapped No 1 & 3 plugs over, fired it up with the exactly the same result.

So, it would appear that the problem isn't coils, leads or plugs.

Maybe the ignitor box has a problem?

This is the girl I'm trying to fix.


This is my other English Cat, at least as it was.  It's getting a new sidecar at the moment.

[JetdocX]

Other than your sidecar appears to be mounted to the wrong side.... :lol:

I'd go with three new coils and plugs.  Nology has the coils you need.  And go from there.  Swapping bad coils for bad ones won't get you home.  The coils tend to fail under load and at operating temps.  It's a known shortcomming, start with a clean ignition system and the rest of the troubleshooting will go smoothly if required.

Good luck. 8)

[Tripodtiger]

Other than your sidecar appears to be mounted to the wrong side.... :lol:

I'd go with three new coils and plugs.  Nology has the coils you need.  And go from there.  Swapping bad coils for bad ones won't get you home.  The coils tend to fail under load and at operating temps.  It's a known shortcomming, start with a clean ignition system and the rest of the troubleshooting will go smoothly if required.

Good luck. 8)

Only issue I have with that is that the coils from the '96 (black) Tiger are fine, AFAIK.
(and my outfit is on the correct side.  It's you lot that put things arse about
:lol: )
Looking at Nology and Ignitech if I need replacements.

[JetdocX]

OK, Really just trying to help.  No further reference to your sidecar rig on the wrong side.  cheers!

Really, start fresh with a clean ignition, then go from there.  This swapping business just muddies the waters.

[Mustang]

mikuni carbs have an issue with wear over time on the needle tubes #13 and the oring drying out #15
http://www.bikebandit.com/showschematic/m17534sch560785

If the hack is running well .and there is no change in the problem with coil swap to the 94 I would rule out coils as problem .
The key here is you said it's a gas hog and the plug confirms that with the fouling . I would seriously look at the needle tubes and orings on all three carbs as this is a known issue with the Mikunis.
I would also put the needle clip back to the middle position which should lean out the midrange some . Me thinks you have bad o rings that is letting excess fuel into the mix .

[Tripodtiger]

Jet.
Thanks for the advice and I don't mind you firing one across my bow and hope you don't mind me having a bit of shot back.  I reckon this is supposed to be fun as well as helpful.:)

I think the ignitor from my '96 might be helpful.

Mustang,
I did the carbs on my '96 around 18 months ago.  Emulsion tubes were out of round through wear over the years, so all the brass wear was replaced.  Biggest hassle was getting the spare parts bloke to understand that I have a steamer and order the correct bits.  Geez, was that frustrating or what!!! Especially since the shop is 130km away.

The O rings you mention - are they those that seal the float assembly into the bowl?  There was a nice sealed feeling when I pulled them out and again when I returned them.

Good thing is that, when it is fixed, the thing will run properly and it goes like a cut snake!  The engine is super strong!
 :lol:
Lucky I've got a few other things in the garage to get me about.

[Mustang]

from the parts schematic it looks to be the o ring that seals the needle tube #15 on bike bandits drawing

try the carbs from the 96 on the 94 that will tell you instantly if it is a carb issue

[nightrunner]

I think the others have got you fixed up.  I would only add that there is a much cheaper way to upgrade the coils.  The TT600 and some others use a coil that sits on top of the plug like a plug boot.  This also eliminates the need for the plug wires.   You can get a set of four on ebay for like $30.   Good luck with it.

PS. Nice hack!

[Tripodtiger]

Regarding the carb wear - the bike has only 34000km on the odometer and I think that that is genuine.  It's not been really closely cared for, buyt I don't think it's done a heap of kays.  It's partially pulled down, so I may pull the carbs again and have a look at the emulsion tubes.

Maybe a good idea to drop the needles down a clip and see if that helps, too.

Is there a thread that deals with the change over to the TT600 coils?  I'm not a mechanic /auto electrician and very few around here have any knowledge of Triumph triples, let alone the TT600 (I do assume you mean the Triumph TT600).  There were very very few of the 600s sold here, even fewer than the Tigers I'd reckon.

Another problem we have is that most bike shops wont touch anything more than 10 years old and we've also just lost one of our shops.

Anyway, it'll workout eventually.

[nightrunner]

I would search on TT600.  Its been covered in a number of threads but I don't think anyone ever did an official mod report.   Supposedly the 660 (?) coils work too.   And I don't know what other models they were used on.  Triumph has basically two versions of on-the-plug coils.  One is quite skinny, and the other is thicker with a flat top and mounting tabs to attach to the valve cover.  The later ones are too thick to fit into the deep recess on the Tiger,   The skinny ones are the ones you want.  Just look for "Triumph coils" on ebay and see what comes up.  The TT600 happens to be a 4-cylinder so you get a spare coil.  But they do not have to come from a TT600.

To mount them, you have to run extension wires from the stock location over to the coils.   You could cut and splice or make a true extension wire.  The other thing you need is the small female spade connectors to attach to the little terminals in the coils.   They are not the standard 1/4" automotive terminals, they are smaller than that.  I just mail-ordered a bag of 50 from an on-line electronics store.  If you make an extension wire, then on the non-coil end you would use the standard 1/4" male spade connectors.   Otherwise just cut the stock connector and splice the longer wire in.   Very easy.  Mo easier than fixing carbs.  You don't need a mechanic.

[Tomas03]

G'day Ray
I haven't mucked around much with Tiger carbs, but I recently spent a whole heap of time mucking around with 91 GSXR1100 carbies (which I put on a GSX1100), and a very similar problem occurred.
Turns out that model Mikuni had a major problem with the emulsion tubes (needle jets) going out of round and it caused 2 carbs to do what your no. 3 is doing.  So I would have to agree with Mustang (who by the way has the best footpegs in the world   )
It sounds like from what you have described you have that issue.  It made a massive difference to my GSX carbs.