Carb tuning questions...

[h2olawyer]

The adjusters you have found are the only ones I've dealt with.  Beyond those adjustments is the jetting that I'm experimenting with now.  Lucky and Rick_G may know of additional adjustments but I can't think of any at the moment.

Mine seems very sensitive to mixture balance between front & rear carbs for smooth off idle performance.  That's where I tend to spend most of my time messing with them.

[Lucky]

Kevin, you pretty much got it covered, just to note, there is a pilot (mixture) screw on both carbs (your description was singular..) they were origanally covered with an aluminum plug, and if you only saw it on one, then the plug may still be intact on the other. if so, when you remove it, (and you will) please count the # of turns in to lightly seat it.  we have very little info on what was the factory settings.

--Lucky

[Rick G]

The low speed adjuster screw on the rear carb is hard to see and a little hard to get at . Take a look with a flash light to find it.

[Henri]

h2o,  I see exactly what you mean.  I am now experiencing the same flat spot that you are describing.  Maybe I just wasnt wanting to find it there before but it definately is there albeit subtle.  So I think you are on the right track going back to your original setup.  I may try that as well.  I've not been able to lift the tire in 1&2 yet sot I'll try your setup to see how it goes.  I hope my suggestion didn't cause you too much headache.  Seems like my problems are very inconsistent though.  They come and go.  How do you feel about using the same jets in both main air jets?  I have the updated carbs w/ vacume airbox and understand that part of the update was a change in one of the main air jets.  Have you tried other combinations for those? Any thoughts?
_H

[h2olawyer]

My carbs and airbox are updated as well. ?The dealer in Steamboat - where I bought the bike - told me they had spent a lot of time on the carbs and had put the 135s in both main air jets. ?It sure seemed to be working well last summer. ?Still want to try that 125 in the rear carb (keeping both main air jets @ 135).

I think the fuel / air ratio needs to be different from front to rear because of the way the exhaust is set up. ?I don't know if you were considering going larger with the rear main air jet but that would just be using a larger volume of a similar fuel / air mix as the front carb. ?(make sense?)

No headache in your suggestions, just raised curiosity. ?Learning more about how to get the most out of these bikes is always a good thing - even when experiments don't quite work as intended.

H2o

[Jon]

Well I've got both carbs completely dissasembled and sitting in Barryman's ChemDip at the moment... perhaps tommorrow I'll have her running again. ?
Just to make sure H20, when you said 4.5 turns out for the mixture screws, you meant 4.5 complete (360) rotations?? ? I figure you did, but at the cost of taking the carbs off again to adjust that rear screw...
Thanks again yall.
By the way, for anyone who's used the Barryman's, is it supposed to be half separated and settled??  Mine needed a serious stirring and I'm not sure it did the trick.  I went back to the store and opened a different can to check its condidtion and it looked the same.   I still think somethings fishy.

[Lucky]

Berrymans is normally half seperated & that's fine & normal. a few tips:
don't keep the throttle bodies in for more than an hour or you'll weaken the throttle seals, & we can't get replacements.

gently agitate the basket every 5-minuets

rinse the carbs well with a hose and blow dry with compressed air.

lightly seal the can while the carbs are in there, humidity & moisture shorten the working life of the dip.  also don't store it on a concrete floor (don't remember exactly why, but I never have...advice from an old wrench I knew) put a piece of wood under it

I have 2 cans of it, one is a few years old. it seems the older this stuff gets the better it works...

--Lucky

[h2olawyer]

Yes - I use 4.5 complete turns on both screws.  But that is just to get it to fire up.  You'll still need to adjust them further when they are on your bike and it's running.  Find a long, skinny screwdriver to get to that screw on the rear carb.  It is reachable.  I get to mine by going in right above the black bolt that mounts the engine to the upper steel plate brace (right where the bottom of the bolt head and the plate meet) If you need to, you can grind down the edges of a wider screwdriver to make one suitable for getting to the little #$@&%^! screws.  There are also flexible drivers made just for this purpose but I find them more of a hassle in this instance.

That B-9 is amazing stuff.  I agree with Lucky, it gets better with age & use.  It does eventually wear out but I don't know how many carbs or years it would take to do that.  My can is at least 6 years old.  Should last a good long time for those of us who rebuild an average of 3 or 4 carbs a year.  I keep mine in my chem storage cupboard in the garage.  Wood w/ vented door.  Neighbors have learned that I know how to do carbs and I get the occasional request to see if theirs needs a dip & rebuild.  Too bad I can't charge them my lawyer rates!

[gbranche]

I have 2 cans of it, one is a few years old. it seems the older this stuff gets the better it works...

Hmmmm...Sounds a lot like motorcycle mechanics...

:-)

Greg

[Lucky]

ok, so this conversation has gone from carb tuning to the age of my cans... your a weird bunch (probably why I hang out here)

[Jon]

Success. ?Fired her up today and she runs better than ever! ?1500-10,000 rpms free and clear. ?(except for the stumble... ::)
I suppose I should sync the carbs before fine tuning the mixture screws?
Also, should I wait to tune untill I get a real gas tank on there and ditch the Gatorade bottle rig I've got set up now? ?
I've been shaking bb's in that gas tank but have yet to figure out how to get the rust out that's now loose inside.

[Lucky]

use one of those round magnets with a hole in the middle on a string, or other magnet set up.  I left a magnet stuck to the inside of my tank just in case...
--Lucky

[Rick G]

There are at least two kinds of Berrymans one is labeled" Not for sale in the state of California", thats the good stuff , I bought it in Wa. the OR.stuff is like the CA stuff.

[h2olawyer]

Good going, Jon!

Just got back from my Yamaha dealer with the 125 jet for rear carb so I'll give that a try to see if my new flat spot goes away.  Let y'all know what I discover later today.

[h2olawyer]

Changed rear carb main jet from 122.5 to 125.  122.5 was just too small.  Went for my reservoir test loop.  Still some minor flat spots in hard acceleration but got rid of the major 4,500 - 5,000 RPM spot.  What flat spots there are are all under 5K and the most noticeable is now down to 3,500 - 4,000, but it isn't very bad, just kind of a hiccup - less than 1 second.  Enough to notice but over before I can think about it.

Think I'll leave it like it is for now and see if it smooths out over the next few days.  Pulled very strong to redline in second gear.  I only took it to 9K in 3rd (intentionally) and 8K in 4th.  The meat of the powerband is very strong.

Additional info -  Ambient air temp about 90 degrees F.  Did not get much above 1/2 on temp gauge.  Even at stoplights and signs in town, it didn't get above 3/4 - still well below the red zone. (Yes, I did come to a full stop with feet down at all red lights & stop signs ;D).  Last year, it constantly ran from 3/4 to fan on.  Differences are foam air filter, now leaner main jets (I'd think that might tend to heat things up a bit) and the big difference - synthetic oil.  The Rick's stator is still doing great.  Must have sealed my case right - no leaks @ 100 miles.

[kd47828]

I used 1/2" heater hose hooked up to my shop-vac to remove the mouse poop and rice that the now dead mice had dropped in my tank over the winter.  Good thing I brought it in the house instead of leaving it in the garage.