Carb or Valve Problem...PLEASE HELP?

[Blurrman]

Update:

Ok, so i managed to take the carbs apart one more time and frigged with the floats till i could get the pins out.  Managed to clean it all out and the gunk in there was unbelievable.  So i reassembled and managed to get my hand on a DynoJet Stage kit.  Now i have a different problem that i am sure you can help me with.....

So i made sure i put an inline fuel filter on the bike to make sure i didnt have to clean the carbs again.  Having said that i inspected the jets that i had...and jets from a parts bike and decided that since the parts bike had a DynoJet kit in it....i would install that.  Heres what i did:

1) Used the DynoJet Needles and springs (clip position#2)
2) used the 114 Main jet instead of my 112.5 jet
3) stayed with the stock pilot jet (37.5) and the main air jet (155)
4) turned the mixture screws 3 turns from seated position

After all this i took the bike for a run and it went really fast and worked really well.  The next day i went to take the bike to work and at about 1/4 throttle...the bike would bog out and almost want to stall.  I then thought that maybe there was a kink in the fuel line and sure enough...it was kinked a little.  I then looked at the plugs and the plugs look white....I then thought that maybe that was because of the kinked line.

I managed to shortin the fuel line and make it so it wouldnt kink but no fix.  It still bogs at 1/4 throttle.  It idles really nice other than that.  Could this be a jet problem or what?  I took the needles back out and set the DynoJet needles on the 3rd position instead of the 2nd thinking it would give it more fuel but still no fix.

Am i missing something?  I tried adjusting the mixture screws but anything more than 3 turns and the bike runs like crap.

If you could help me with this i would greatly appreciate it!!!  Thanks

Darren

[andyb]

That 114 jet is a DynoJet size, so while it seems like it's slightly bigger than a 112.5, they're not directly comparable.

On the 86, I'm not certain that a inline fuel filter is a good idea, they're exceptionally sensitive to fuel line routing.  Ridiculously so.

I'm sorry, but I didn't see if you had pods or an airbox on that bike.  With the exhaust if you have pods I can take a clear guess to say that you don't have big enough pilot jets.  40's will be closer, but even a 42.5 might be necessary.

If the bog occurs during high demand at low speed (example:  third gear, 2500rpm at steady throttle, then snap open to half throttle or more) I would suggest looking at float height as the culprit.  If it's surging at a steady state condition (say 4th gear at 2000rpm on reasonably flat), then I'd look at pilot jets and mix screws (and possibly a worn chain, which feels damned similar sometimes).

From what you describe and assuming a little bit (like everything synch'd well, transitions between needle and mains is good, needles are right side up, etc etc), I'd bet that your float height needs tweaked.  Adjust in 1mm (0.040ish) increments until you're happy with it.

[Blurrman]

I have the stock air box.  I guess i was just kinda baffled cause it was working great the night after i put it together but the next morning it was bogging out. it idles fine and revs fine when its stopped...its just when there is a load on it.  When i start out it goes ok but when i start to open it up...it bogs right out. 

[andyb]

Fuel height (float height) or line routing would be my first guesses.

[SlowOldGuy]

At 1/4 throttle, you're stil in the idle circuit.  Something may still be clogged.  Or, it might be fuel level like Andy says. 

Is there any rust in the tank?  I've never seen a filter that was capable of keeping rust out of the carbs.  Keep working on the line routing.

WIll it pull throughthe bog, or does it just bog and not do anything else when accelerating?

DavidR.

[Pat Conlon]

Try running the bike without the fuel filter.
Gravity flow FJ's are very fussy about fuel flow, and fuel filters impede this flow.
Which is perhaps why your FJ did not come with a fuel filter.

Also, while you're down there..... check your 2 fuel bowl vent hoses.

Hope this helps....Pat

[andyb]

Because the FJ lacks an accellerator pump, getting that initial burst of fuel in response to a sudden throttle opening at fairly low revs is directly related to fuel height.  With the stock airbox, it shouldn't be too far out on the needle, though.

[Blurrman]

Okay< so i took the inline fuel filter off and tried it and its still doing the same thing>  I tried pulling the choke a little bit but it made no difference.  I also checked to see if it would come out of the bog and the only way it would is if you pull in the clutch and let off the gas completely...then it will come back.

[Blurrman]

Im gonna LOSE MY MIND !!!

Today i took the carbs all apart and cleaned everything out.  I checked the float levels and swapped the 37.5 pilot jets with the 40's.  I put it all back together and its still doing the same thing.  It just bogs right out.  My battery needs to be charged all the time before i start it as i think thats worn out.  ARRGGHHHH!!!!

What could be the problem???  Next i guess i could tear apart the petcock but something tells me that maybe something else is wrong.  Could it be electrical? or something crazy like that?  I set the float levels at 22mm.  Geesh...im ready to give...its driving me mad !!!!!!

Please please please help me

[Alf]

Hola
I´ve reading carefully the complete post and thinking about it
Understandably I´ve seen that you´re lost and desperate. What would I do if it was my bike?
1.- stay resigned and start form the begining
2.- check the fuel petcock. Is it working ok?. FJ1100 & 1200 fade with the time and the membrane lost the elasticity, blocking the fuel flow.
3.- I´ve understand that you continues with the FJ 1100 carbs with FJ1200 dynojet needles and settings, don´t you?. Have you changed the needle jet?. 1100 & 1200 are different
4.- I understand that you continue with 4/1 race exhaust & OE airbox, is it ok?
5.- Something obvious; is it your airfilter clean?, is it a KN one?
6.- Now, if everything above is correct, I think you must run Dynojet recommended settings for a race can with OE airbox
7.- In my last post I suggested the problem was with the float valves. You didn´t say anything about. If all above is correct, I´m SURE that the problem is or microscopic gunk in the float valve seats or valve seat orings leaking fuel or incorrect valve clip positions or anything around

If you want I could send you a set of 2nd hand float valves & seats working perfectly until extracted last week, when changing the emulsion tubes I rebuilt my carbs with new elements

[Blurrman]

Silly question but could a dead battery cause this?  It just seems to be electrical or something like that.  I mean...the bike runs fine at idle and when i rev it up it works great too.  It idles perfect.  When i start out in gear it starts to go but then completely shuts down when i give it the gas....if i pull in the clutch and rev it up its fine.  Its just when its under load.  I am really goin crazy.

I checked the routing, cleaned the carbs a million times....swapped pilot jets....the only other thing i havent done is take apart the petcock and tried a new battery.

PLEASE help someone...im running out of things to try.

[Alf]

It could be a part of, but the wet plugs show a carb problem. And the problem resides at the low down circuit: floats, fuel level, pilot jets, float bowls valves or valve seat o rings
Well, there is no more... or the petcock. Have you tried with a suplementary deposit?. If the membrane have lost its elasticity itcould be is not responsive at low rpm

[Blurrman]

Alf, the plugs arent wet anymore.  I guess there has been alot taken place since i have had the problem.  I have cleaned it a million times really good and somehow i get the feeling that there is a central problem here.  maybe electrical or something like that.  Its definitely wierd. The carbs are immaculate and the fuel line routing is good.  All the vacuum lines are good as well.  i'm just reachin for straws by thinking it could be the petcock or battery but thought i would ask. 

[Alf]

Ahhhhh. Ok. Mmmmmmmmm. Really it is bewitch!
Try with an auxiliary gas deposit. It could be the petcock
sorry, no more things come to my mind
Keep us informed
Good luck

[Mark Olson]

see if one of your slides is stuck open or you may have a big ass vacuum leak.

I tried to read the whole post but didn't find this.

can you ride thru the flat spot ?
is the only thing it does is idle?
will the motor rev up past 6,000 rpm while not in motion?
are your mix screws at 2.5-3 turns out?
have you used the float bowel drains with a clear plastic tube pointed up to see what is really in the bowels when running?
run it at night and see if you are sparking along the wires under load?

start with that.