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Carb tuning help

Started by balky1, September 08, 2015, 12:52:24 PM

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balky1

Quote from: JohnnyW on November 03, 2015, 02:23:29 PM
Quote from: balky1 on October 27, 2015, 11:36:24 AM
I actually gave up on this and found a good mechanic. I lost a ton of nerves and it's better to give it to someone with far more experience than I have.

So did you let someone have a look at it Balky1? I am starting to think I will need to, but I wonder what thy're going to do differently?

Hi JohnnyW!

Yes, I drove my bock to a repair shop, hopefully they can find out what happened. Sorry for a late reply, for some reason I wasn't informed by e-mail about new posts in this topic.
Best of luck!

Ivan


FJ 1100, 1985, sold
FJR 1300, 2009

Alf

Johny

You have checked every possible issue regarding to carbs, I see. So I think its time to look to other places. You say you have spark and your coils are perfect and the connection between wires and spark plug caps are fine. I supposse the fuel petcock is working properly and that you have tried to sync the carbs when refitted

Well, I am going to speak with another 2 competent mechanics (FJ owners both) and I hope to have any suggestion

JohnnyW

Thanks Alf.

The issue is that the bike was working fine before I had the sticky float/fuel overflow. That prompted the strip/new gaskets/new needles & seats/clean. Only then, when I put the carbs back on has the high revving/rough running happened. I have done the usual checks on the coils/plugs/HT leads, but really had no reason to suspect them anyway.

I suppose the symptoms suggest the inlet manifold is leaking, but they all look sound to me, no cracks obvious.

Alf

Stupid question: after reassembly the carbs on the bike, have you sync them?

JohnnyW

I have bench-synched them, yes, using a sewing needle as the guide on the butterflies, but cannot vacuum synch them as it won't run on idle without the choke, and therefore there is no vacuum.

The only questions that are stupid Alf, are the ones we don't ask ;)

Alf

I asked it because after much discussions my friends and me think that your problem is simpley due to incorrect sync. My friend Mingo and myself, both have had this problem years ago, Mingo in his bike and myself in another 86 1TX.

In my case, only after a lot of tries and screwing the idle to 3.000 rpm. I could have the bike running enough time to start to sync the bike. When stabilized, it was then a doddle to finish the correct sync procedure and having the bike running without problems

Dont rely on the stactic idle measure. You need a vacuum

mr blackstock

After re-reading the posts, and imagining the enormous frustration at not being able to think of what was done wrong, try from the start again, but keep it really simple.  I have messed up quite a few attempts to get a bike running properly, only to discover I installed something incorrectly.
Here is a sampling of some easy mistakes to make: (some I have done)
-installed diaphragms reversed -doing this really messes up things
installing something upside down -it happens...
not taking care when putting stuff back together, and bending something -this is a real bastard!
crimping choke or accelerator cable -this does interesting stuff
blocked hoses -blow up 'em, should be clear.
electrical -did you bump wiring, dislodge something, wiring to the coils? very important...
coil leads -check the resistance, a bad lead will wreck things for tuning.

in other words, try to re-check on how you assembled the carbs, it is hopefully something really simple.  I always dis-assemble carbs one by one, that way I have a good reference if I am unsure of something.  Maybe bench synch with a bigger object, a drill bit for instance.

Anyway, just some thoughts, good luck
Gareth
Squeaky wheels always get the grease...

Yamaha FJ1100 1985

homerfj1100

Hello there.
I had exactly the same symptoms after leaving my FJ11 for 9 months, in the corner on it's own.
Terrible.
Carb cleaner. Two cans. Fuel additive (Wurth) two cans. Eventually I took the advice of a Brit FJ bloke and took the carbs off. It's horrible, I know...the daft airbox etc. But I took my time and the carbs came off. I cleaned all I could see on the outside.
Then I unscrewed the float bowl screws and the top screws. All slow and careful.
Diaphragms looked OK ( but who am I?). Then I got to the emulsion tubes. 4 of them.
Two were full of crap. One contained an insect. I am amazed that the bike ran. I have the pictures.
I left the emulsion tubes in carb cleaner (after removing the fly) and made sure they were completely clean....all the little holes. I even used a Jewellers loupe to see if they were clean.
Carefully reversed the dismantling and slowly put them back together.
Remember I only cleaned the emulsion tubes.
She started and runs as well as she did before. That's good enough for me. And now I ride her every day, to buy er...milk, beer, cigs, pizzas or wine.
Best wishes
Tony
Homerfj1100

FJools

The other option I would try, if you haven't already done this, is to put the original needles and seats back in and try it.

I have heard some iffy stories about keyster stuff and Yambits supplied parts. Nothing to lose.
Still thinking of something..................

JohnnyW

Aye, not a daft idea.

I am scunnered* with it at the moment, and just keep squeezing by it in the garage, all forlorn. It is going to have to wait until we get the odd day of blue skies and my thoughts turn to the road, rather than wind, rain, ice and snow which is the Scottish situation right now.

I will not be beaten, though I am 2-1 down in extra time right now...... ;)




* Scots for absolutely pissed off!

balky1

Haha!

My bike is finally returning from the shop. There was a problem with the rubbers that hold the carbs and with carb tunning and my lack of experience.
But, another problem! I never had it before! Guy says he can't open the fuel cap! One of the pinions works fine, but the other one won't loosen up! Any ideas?

Ivan


FJ 1100, 1985, sold
FJR 1300, 2009