137 replies to this topic

[Catteeclan]

Isn't that wear to far down to be caused by the washer? If you're sure then that suggested to needle is moving the slide, shouldn't do that should it?

[Studley Ramrod]

Yeah, I thought the coil reading was borderline FS.  Also, coil problems don't always show up on a resistance test anyhoos.

 

Could it be running a bit rich in that range for whatever reason and a slightly colder plug might just run hot enough to overcome it?

Good question.   I've noticed backfiring through the no1 carb when the spluttering starts, suggesting either a weak spark or a lean mixture.  I managed to reduce the amount of spluttering by turning out the pilot screw from the standard 3 turns to 4 turns.  Also, the problem seems to be worse when the engine is cold and reduces when the engine is up to temps.  But then, to throw a curveball, it ran ok at 2000rpm under load at constant throttle for a good 1/2 mile and then suddenly started spluttering.

 

Isn't that wear to far down to be caused by the washer? If you're sure then that suggested to needle is moving the slide, shouldn't do that should it?

 

Never thought of that tbh Dave, according to Factory Pro the wear is caused by the needle not rotating but they don't state if it's rubbed against the washer or the emulsion toob.  What I do know is that once it's worn the washer can tilt and snag the needle.  It makes sense that the needle shouldn't move up and down the slide as it's got a mahoosive spring pushing it down, BUT, I honestly don't know if that happens in practice or if there is some movement of the needle.  Also, the wear on the needle is cutting into the needle, whereas in theory, wear caused by the emulsion tube would only rub against the needle causing wear further down the needle, if ya get me drift.

[TinTin]

Just been consulting my Honda book of wisdom on carburettors & it says "the needle & needle jet controls the air-fuel mixture from 1/4 to 3/4 throttle openings" so if your problem is fuel related this is probably where the investigation should be conducted  M Poirot says  

However, I had an ignition coil that checked out with a multi meter but started breaking down under load with the coil tester.

If I was a betting man I would say give me a tenner on the dodgy coil running at Nottingham because there was no misfire when you laid the bike up last year and leccy gremlins pop up with no warning.

I went into a service station in Lincoln in a perfectly running Toyota, had my lunch & came out to a non runner. The condenser had packed in   

[Catteeclan]

Not that up to date with these carbs as my 3vd went about 12 years ago but I don't remember seeing wear like that, or on the many 2 strokes of yesteryear.

​Is it just the slider spring keeping the wieght on the C clip keeping them in position, like other carbs?

 

Coil would be an easy test as tintin sugests. 

[Studley Ramrod]

Yup, just the spring.  The washers are, imho, too big though, the diameter of the hole is way bigger than the diameter of the needle.

 

I'll take a paypal payment Sam.   Deffo not the coil, caps, leads or plug.  Refitted the coil and, as it's a wasted spark system, I swapped the leads over and still got no1 spluttering.  Soooooo, godda be the carbs.  Didn't get time yesterday to look into them so will brave the cold today and see if I can find anything.  Will also have a look at the vac pipe, it's got a T fitting in it for the scottoiler so just want to be sure it's not letting air in.

[Bjørge]

Fuel pump ? 

[TinTin]

Is the pipe the T piece is in the fuel tap vac.

I assume it also opens a diaphragm in the scottoiler & if so is that pierced or faulty.

Have you tried clamping the pipe to the oiler to rule that out all together.

 

 

[bfb1150gs]

i got similar symptoms with my 92 3vd  ...its like a missfire on one cylinder and really bad popping on the over run...make town riding very interesting so waiting with baited breath to see if you can find the problem

Edited by bfb1150gs, 28 December 2016 - 07:23 pm.

[Studley Ramrod]

Fuel pump is fine Bjorge.

 

Is the pipe the T piece is in the fuel tap vac.

I assume it also opens a diaphragm in the scottoiler & if so is that pierced or faulty.

Have you tried clamping the pipe to the oiler to rule that out all together.

 

 

 

It was doing this when I bought the bike, scottoiler had been removed but the vac pipe was left connected to the carb vac pipe, to which I duly bunged the end up.  I did notice the T piece was swivelling in the vac pipe so gonna visit that and make sure it's sealed up.

 

i got similar symptoms with my 92 3vd  ...its like a missfire on one cylinder and really bad popping on the over run...make town riding very interesting so waiting with baited breath to see if you can find the problem

 

Not sure if you have the same problem as I do but happy to share the info if it helps you with yours.

[Studley Ramrod]

Nope, despite checking every jet, blasting the passages with compressed air, swapping over the pilots, needles and inlet rubbers it still has a wee splutter just as the needle starts to lift on no1 carb.  If I try to hold it at 2000rpm it slowly drops.

The only things I haven't checked are the air cut-off valves, the butterfly throttle rod gaskets and the FP toobs.  Might try swapping the toobs over, or, put it back together, order a Viton kit and then split the carbs when the kit arrives.

[fixitsan]

Butterfly shaft seals sound a possibility too.

 

I have a viton kit I won't be using, and a spare pair of carbs the viton kit was for if you wanted to try them in order to eliminate everything else

[TinTin]

Oh my. Think you otta see if you can buy your niner back  

[dablik]

And i had a tinkling for a mk1 again 

[chrisbee]

I don't think buying back his old niner is an option...LOL
It is now part of the family😁

Oh my. Think you otta see if you can buy your niner back

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[Studley Ramrod]

Butterfly shaft seals sound a possibility too.

 

I have a viton kit I won't be using, and a spare pair of carbs the viton kit was for if you wanted to try them in order to eliminate everything else

 

Thanks for the offer, I'll see how I get on after I've been for a ride.  Just remembered I've got the viton seals for the butterfly shaft, part of the kit I didn't need for fixing Sideys mk2.  Just a bit apprehensive about removing and re-fitting the butterfly's without ham fisting it.  Also, not exactly sure what I need to remove in order to fit the seals.  One end of the shaft is sealed with a metal cap that looks like it's been crimped in place and I dunno if these need removing or not.

 

 

Oh my. Think you otta see if you can buy your niner back

 

  Or spend a lot less fixing the mk1.

 

And i had a tinkling for a mk1 again 

 

Along with a GS, an XT660, a ZZR600, a Versys and many many other bikes.

[fixitsan]

 

Thanks for the offer, I'll see how I get on after I've been for a ride.  Just remembered I've got the viton seals for the butterfly shaft, part of the kit I didn't need for fixing Sideys mk2.  Just a bit apprehensive about removing and re-fitting the butterfly's without ham fisting it.  Also, not exactly sure what I need to remove in order to fit the seals.  One end of the shaft is sealed with a metal cap that looks like it's been crimped in place and I dunno if these need removing or not.

 

 

Hmmm, wouldn't be something I would look forward to either.

 

Thinking about it, air leaks around throttle shafts like that tend to only be particularly relevant at very small throttle openings and become less important as the rpm's rise....if you aren't having a problem at 1200-2000 rpm I wonder if it might be something else.

 

I just saw you were in Notts. I was down that way (Eastwood , and worked just off M1/A608 junction) for a week just before Christmas... Small world !

[Studley Ramrod]

Yeah, I think I'd need to support the shaft when removing the butterfly screws as it can easily be bent.  I also know the screws are threadlocked AND they're JIS screws. 

Some useful info on the Litetek site.  http://www.litetek.c...ST_Rebuild.html

 

I'm actually in North Notts, closer to Sheffield than Nottingham.

[TinTin]

I had a 12 year old BT1100 Bulldog in the frame till you started this thread. Hence me asking how old the bike was.

If the carbs on that started playing up it would be a nightmare so i binned the idea. Anyway Dablik wouldnt go n have a look at it.

He is banned from Wigan  

Sooooooooo I have done something else and if SWMBO ever comes down from the ceiling I will tell you about it  

[dablik]

Oh fook, you've bought a Kubota have'nt you Sam...............was in Wigan yesterday fella 

[Studley Ramrod]

I had a 12 year old BT1100 Bulldog in the frame till you started this thread. Hence me asking how old the bike was.

If the carbs on that started playing up it would be a nightmare so i binned the idea. Anyway Dablik wouldnt go n have a look at it.

He is banned from Wigan

Sooooooooo I have done something else and if SWMBO ever comes down from the ceiling I will tell you about it

 

You shudda gone for it Sam, the later carbs are much better quality than these early wans.

 

What's a Kubota ?