Pulled carbs of bike for cleaning and have a couple questions...can anybody tell me stock jets and needle and float settings so i can check.Would also like to know what idle/air screws should be turned from bottom.Last fall pulling away from a stop sign bike lost most of its power and was running horrible including backfiring.I changed fuel filter and drained bowls and it came around for remainder of season.there was some silty looking mung in both bowls and one air/idle screw was turned completely in,the other 3 turns out.Just want to check everything before putting back together.Really appreciate the help and or advice.It is a 1994 m-900/mikuni carbs,beleive its stock except for some carbon cans.
Quote from: wooden indian on February 10, 2011, 11:51:33 AM
Pulled carbs of bike for cleaning and have a couple questions...can anybody tell me stock jets and needle and float settings so i can check.Would also like to know what idle/air screws should be turned from bottom.Last fall pulling away from a stop sign bike lost most of its power and was running horrible including backfiring.I changed fuel filter and drained bowls and it came around for remainder of season.there was some silty looking mung in both bowls and one air/idle screw was turned completely in,the other 3 turns out.Just want to check everything before putting back together.Really appreciate the help and or advice.It is a 1994 m-900/mikuni carbs,beleive its stock except for some carbon cans.
US 900 Monsters from (1993-1996) ran BDST 38 B 132 Mikunis with 140 main jets, 70 starting jet, 5C37-3 needle (the -3 is needle pos-n 3rd notch from top), Y-2 needle jet, 40 Pilot/slow jet, float height is recommended at 14mm, The Dynojet and Factory Pro websites will recommend Idle mixture screw settings, (the FP and DJ jet kits I have say 3 1/2 turns out from lightly seated but they are for Euro spec carbs BDST 38 B 129).
When adjusting the idle mixture screws, go for the setting that gives the fastest and strongest idle with the motor well warmed up. Count the turns outward from lightly seated. I'm concerned one IMS was all the way in and one 3 turns out. Maybe you can set them both at 3 turns out to start with. It will be interesting to see if the float level on the carbs is the same.
The needle jets will often wear oval within 5-10,000 miles and are worth replacing. I like the Factory pro stainless needle jets if they still are available.
The float levels can be out from the factory, out of spec and each carb out from the other! The Ducati Suite site, Factory Pro site and this forum via the search function will show you how to set them.
When using carb cleaner, be wary of getting it on the carb diaphrams, just use it on the hard parts. I've heard stories of dissolving diaphrams with some brands of carb cleaner..
I'm assuming you're in the US, if you're not, the Euro/World spec carbs have the needle clip in the 4th notch from the top. Disclaimer: being Ducati, just because a certain model bike should have a certain spec on paper, doesn't mean it came out of the factory that way so check the carb numbers carefully and the float level, needle clip pos-n, etc.
Hope this helps out.
Cheers.
Stock jetting:
http://www.postdiluvian.org/~mason/moto/jetting.html (http://www.postdiluvian.org/~mason/moto/jetting.html)
W carbon/open cans, one step up in needle & main jet is recommended.
Float height 14mm, how to:
http://www.ducatisuite.com/jetkit.html (http://www.ducatisuite.com/jetkit.html)
Idle screws:
2,5-3,5 turns out fr screwed in is within normal/basic range.
Both should be within 1/2 turn equally set.
Otherwise, +1 on koko`s advice.
OMG,
Quote[I have say 3 1/2 turns out from lightly seated but they are for Euro spec carbs BDST 38 B 129/quote]
please tell me you still got FCR`s..... ;) ;D
Thanks Greenmonster, intersting your chart differs a little from mine. Slow jet was different and SS spec.
If WI's carbs are stock re: jetting, he may even consider a Factory Pro or Dynojet jet kit to go with his open pipes (and maybe open air box). I like a jet kit with open pipes, etc.
WI, you can get a jet kit pretty cheap and they make the bike more responsive. You may want to ask Ducpainter re his jetting set up as he runs the CV carbs and appears content with their performance .
Greenmonster. Yeah, still got 'em (FCRs) and would never go back. Would be first mod (with open A/B) on any carbed Duke for me. Best single engine mod besides increasing compression and porting, I reckon.
Just adding to the subject,
thought you`d be awake there down under. ;)
I tried my recommendations above and they seemed to work.
Just to add some confusion, there are air jets in those BDST`s, too....
A jet kit and, most important of all,
opening up the airbox lid is the best mod you can do.
Do the stock needles have as many notches as the DJ or FP?
I think they only have 3 or 4...but may be forgetting.
DJ have 5 IIRC.
Stock I forgot....
I could go out in the barn and look at my stockers...too cold. :P
Stock and FP needles have 5 notches, older DJ 7, newer DJ 6.
Showoff! ;)
Bed now, works starts in 6 hrs. [beer]
How old are we with our memories (and eyesight)?! I had to look real carefully to see how many notches were there. Mind you I'm looking at Euro/world spec needles. I was surprised the stock needles had 5 notches (Euro 5C 19-4).
Quote from: greenmonster on February 10, 2011, 05:16:30 PM
Showoff! ;)
Bed now, works starts in 6 hrs. [beer]
I'm on the couch, too sick to go to work today.
DP. You happy with your CV's (seriously)?
Quote from: koko64 on February 10, 2011, 05:28:57 PM
I'm on the couch, too sick to go to work today.
DP. You happy with your CV's (seriously)?
Happy as in are they good?
Nah.
They have no response and ice up at the worst times.
I'm not unhappy enough that the cost of flatslides seems worth it for my riding style.
The more engine mods I did, the more unhappy I became with mine. The carbs got left behind when I got porting and pistons. Before that with my first Monster on a stock engine it was only the freezing that annoyed me. It just annoys me when things don't run sweet and you can feel it. But when I bought a worked Superlight that came with FCR 39s I was a ruined man.
It's true, road and track styles are so different. Anyway, you need your money to feed that tyre eating 996.
Quote from: koko64 on February 10, 2011, 06:02:17 PM
The more engine mods I did, the more unhappy I became with mine. The carbs got left behind when I got porting and pistons. Before that with my first Monster on a stock engine it was only the freezing that annoyed me. It just annoys me when things don't run sweet and you can feel it. But when I bought a worked Superlight that came with FCR 39s I was a ruined man.
It's true, road and track styles are so different. Anyway, you need your money to feed that tyre eating 996.
Most of my street riding is sort of based on 'The Pace'. I live in a pretty rural area and can go for quite a distance without ever putting a foot down. Throttle response isn't really necessary. My motor is stock except for jetting and a swiss cheesed airbox lid with DP cans. The stock carbs work fine mostly.
The 996 likes it's tires. ;)
Thanks for the help in this thread... I'm not having this problem, but I'm getting ready to pull my carbs for cleaning and some of this stuff may come into play.
Given that I tend to destroy little rubber seals, washers, pins, and other delicate parts with my caveman approach to Duc maintenance... is my local dealer my best source for original CV carb bits, or should I be aware of online suppliers?
Thanks in advance.
Sudco handles Mikuni. You could try there, or there was a Yamaha model that used the same carb so you might be able to get a complete o-ring kit.
Someone here will remember which model it was. I don't.
Any Duc dealer should be able to get them if they don't have them. A long time dealer probably does have them.
Yamaha 850 TDM. Jets and needles will be different.
& TRX 850.