Mikuni lean spot & pod filter #'s

[RADDUCK]

Hello Team,

Did the Mikuni swap a few years back with as set of BDST 38's from a 900SS. I rejetted and reneedled the carbs per Gehard's instructions. with the Y-6 needle jets, 5c19 needles, and the 37.5 pilots. I now have the jet needles in the 5th notch from the top. There is a circlip in this notch, then a plastic washer then a thin metal washer on the needles before they seat on the slides/diaphrams. the reason the needles are set so high (richest setting) is that there was a huge lean spot just off idle that was causing some poor rujnning, popping and backfiring just off idle. Bike idles great and runs really strong from 1/3 throttle and wide open. I have the 2in1 Gio.CA moto Exhaust and a homemade airbox with a 3x5" paper lawnmower filter. We seem to have overcome the lean spot but now run rich everywhere else (friends report gas smell & puff of black smoke when I get on it) and fuel economy has suffered. I've synched the carbs twice. Is there something I've missed? Its totally rideable but it feels like it could be much better. My set of BDST's do not have a fuel mixture screw. It is a fixed setting. I ride at sea level in San Francisco.

I am thinking of trying the original 900SS needle jets, needles and pilots and installing K&N or Uni Pod filters.

Can you give me your thoughts on the jetting issues and give me the part numbers for the K&N
or Uni pod filters you guys are running.

As you are probably aware its no fun to take the fairings/tank off these things for the 30th time and I don't want to pull them off just to take measurments. I would like to pre-order the appropriate air filters and have them ready to install next time I change the oil.

Thanks!
RADDUCK

[Foxtee]

Hi Radduck,
Sounds similar to the problems I had.
I've rejetted with a Dynojet kit for a 750 Monster, but still had the same issues as it state's to turn the air/fuel screw 3.5 turn out for a Monster.
Followed the instruction for a 750ss witch state's 2 turns out, now it runs fine.
My air/fuel screw's where covered by brass plug's which you drill out carefully to access the screw's.

[RADDUCK]

Thanks so much Foxtee!

I guess Mine has the brass plugs over the mixture screws and I thought that was the end of the road. I don't usually make a habit of exploring around a carb with a drill but I guess this time I'll have to make an exception. I'm going to attack it this weekend. I am positive that is the problem. Wondering though, Logic would have told me that 3.5 turns out would be a richer setting than 2 turns out. In all 4stroke carburetors I've had experience with, the mixture screw is a fuel screw, fully seated closes it and backing it out richens it, sometimes people refer to it as an air screw but that's only the case with 2 stroke carbs. Is this not the case here?

Also, are you running Pod filters? Do you recall the particular model number or dimensions of the filters I would need to purchase, inlet, height, style etc?

Thanks again and hope you had a great Thanksgiving.

[paso750]

Radduck, an airbox is always preferable but an effort. K&N pods that were mentioned in the forum are K&N SN 2530. I have the Unifilter UP4060A.
See recent FCR topic in the Sport section.
http://www.knfilters.com/search/product ... od=SN-2530
http://www.uniflow.com.au/contents/en-u ... 09%202.pdf
(p. 18 in the catalogue)
Correct jetting will depend on your setup specially airfilter and exhaust. That`s why in the FAQs I`ve only mentioned the original 750SS and 900SS jetting. When I ran the Mikunis I had a Dynojet stage 1 kit from a 750SS, the modified original airbox with the highest K&N filter and a Gio.Ca.Moto 2in1 exhaust. Stage 1 kit seemed to run better than stage 2. That could`ve been different on other bikes. The Dynojet kit numbers for the 750SS and Monster are different btw.
I have a couple of old Mikunis a friend gave me. One should have a Dynojet kit. If he doesn`t want that back you could have it. I just have to ask and disassemble the carbs to see which one actually has it installed.

G.

[RADDUCK]

Hey Gehard,

I would love the opportunity to try the Dynojet stage 1 kit if you wouldn't mind parting with it. Please ask your friend if he is ok with letting it go. I will obviously send you funds to cover shipping.

On a side note, I talked to one of the factory Honda race mechanics at the Baja 250 a few years ago when I had a few questions about proper jetting for my xr650r dirtbike. (They make a dynojet kit for this bike too). He reccomended against it saying factory needles were soft aluminum but dynojet needles were course and hardened and that they enlarge the brass seats over time. Like a miniture file going up and down every time you open the slide which eventually causes poorer running conditions. Ever heard anything like this before? I've never had one of their kits but I would imagine one would be able to tell just by the finish on the needles.

Thanks for your generous offer and all of your great insight.

Gunther

[Foxtee]

Just some more info for ya

Depending on what main jets you use there's not a lot of difference in the kit's , just which notch and how many turn's on the air/fuel mix screw .
I can't find a model on the pod filters

Hope the pic helps, my mate with a Guzzi 1000S run's the same filter's with no prob's.

Tony

[paso750]

good, I opened the carbs and one indeed had a Dynojet kit installed.
Dynojet kits usually come with 2 or 3 main jets. The kit installed was from a 900SS but the mains installed are 120 which also come with the 750SS kit. According to the 750SS installation manual:

Use the YJ124 main jet with stock exhaust pipe, or use the YJ128 main jets with aftermarket header or slip-on with high flowing baffles. If you are operating at high altitudes Use the YJ120 main jets

Guess you`d just have to try. The 900SS kit instructions say:

Use the YJ120 main jets with the stock exhaust ...

The rest is the same in the 750 and 900SS kit. In case you need other main jets you can order them i.e. at SUDCO. (You may need other ones if you run pod filters)
Btw. I asked my friend and he says you can have them. He has FCRs now and doesn´t need them anymore.
Pm me your address, I will throw them in my ultrasonic bath tomorrow morning so I could send them off thursday.

G.

[RADDUCK]

Go Paso Team. Thanks Gerhard & Tony for all your help here . I've gotta admit after all the Hype I thought the Mikuni's were going to be the holy grail for this bike. I've been kind of dissapointed for the past 2 years, and rode my TLS1000 more often. I had no idea there were mixture screws hidding under the brass knockouts, but I knew enough about carbs to know that was the circut I was wrestling with, I just thought there was no adjustment. Can't wait to really get her running right, actually loosing sleep over it (Yes I have the sickness). Thanks to G. looks like I will have a dynojet kit just in time for Christmas. I'm going to stick with the homemade air box deal for the time being, maybe spring for some pod filters later on but it seems the jury is out on that one. I'm concerned that I'm not getting enough air through the 4x6" pleated paper lawnmower filter but can appreciate the advantages of an airbox. May split the difference and see if I can get a K&N or Uni in a 4x6" size.

Anyways happy holidays. Will let y'all know how it turns out.

[paso750]

parts are on their way.

G.

[Mc tool]

I'm concerned that I'm not getting enough air through the 4x6" pleated paper lawnmower filter

It will probly be ok ............as long as you fit the lawnmower exhaust too
Radduck, maybe Im looking at this all wrong. I just dont understand why when trying to increace ( presumably) the performance of your motor you would fit an air filter ( probly not great quality ) 1/4 the size of the original.
I am watching with interest because I have a pair of mikuni's ( 900ss ) and now a pair of split FCR's.
What to do . On one hand we have Higgy's ( et all ) weberology which leads me to believe that a well sorted webber is a good set up , and it all ( of course ) fits, BUT I cant deny that the mikuni's, whilst still on the ( ill fated ) SS were better in every way, soooo stickin them on the paso should be an easy fix, except they dont fit , air cleaner wise, which leaves the choice of either filter pods ( Foxtee ) or a custom air box ( yourself ) both of which would require jetting mods ( fucking around ). My SS never had an air box cover( and none of the jets are standard ) so Im hoping that they will take to a pair of pods.One thing I have noticed tho , is that the radiator and related hoses have become an "issue" space wise in a lot of my planned mods ( 17" wheels , carb/manifold )..... SS motor is starting to look good

[RADDUCK]

MC tool - I too enjoy firearms so we have more in common than the Paso. A little more on this subject... I got my Paso in trade 4 years ago. I rode it 100 miles. Changed out the belts & rollers, got the Webber sorted (well sort of) sourced a set of rubbers, rebuilt the flopping gauge cluster and serviced the front forks with new seals & fluid, orderd a corbin gun-fighter saddle (figured you'd like that). 200 miles into my maiden voyage up highway 1 along the Oregon coast she tried to kill me when I passed a fully loaded logging truck and the countershaft bearing disintegrated (It sounded like a marble in a blender). I towed the whore home and sourced another Paso in Tennesse with some electrical problems through the help of another Paso.org contributor (Thanks Desmo_Demon ). I decided to do the Mikuni swap along with the engine transplant. The Redneck bike with the electrical problems had had the Mikuni swap done to it. The Mikunis were long gone but Officer Chuck Olive said he had made a home made airbox. I made sure it was included in the purchase. It may not actually be a lawnmower filter as it was purchased at Napa for $13 + change. It is pleated and has a foam surround with a metal backing. It does appear to be a quality product and would probably strech out to over 5' long if you pulled all the pleats apart. Regardless, this weekend I pulled off the panels, tank, and airbox to access the carbs and noticed a gaping hole (yikes!) on the bottom side of the airbox its probably 1.25" by 1.25" . I don't know when it appeared but the aluminum this guy fashioned the airbox out of seems to have gotten brittle and a big chunk blew out (could have been one of the many back fires through the carb) to blame with my mixture screws hidden under those brass plugs. Today I ordered a new Yuasa YTX14AH-BS battery and 2 Uni 4245ST pod filters from Phil at Moto Haven in PA. $119 shipped to CA. Gerard's Dynojet kit should arrive in the mean time and by next week the planets will have aligned. Shot a round of sporting clays with a nice browing citori featherweight on Sunday in Morgan Hill with the girlfriend . All in all a great weekend.

[Mc tool]

A corbin seat is definatly on the "to get " list
I used to do a lot of sporting clays , skeet and DTL, Miroku mod 10. But when the club found out that I could fix stuff and had the right electrical tickets to legally service the chuckers, I wound up spending most of most club days fixin' stuff and not shooting, in the end I just stopped going...... more time to waste on paso's

[paso750]

Radduck, maybe the pm notification isn`t working for you (as it isn`t for me unluckily). You have some and McTool, too.

...and 2 Uni 4245ST pod filters

Aren`t they too large ? Their ID is 63mm. The UP4060 are 60mm and imho should fit better.

G.

[RADDUCK]

I got them yesterday and yes they were too large. I told Moto Haven when I made the purchase that I needed the 4229ST but he knew it all and insisted I needed the larger ones. They had different part numbers here than what you had provided. Never the less they are in the mail on the way back to him. Just received your package from Santa Dyno Jet. Thanks! Is there some way I can send you payment for the shipping?

Thanks again and happy holidays!

I may go test ride a 2010 S1000RR tomorrow. They have a beautiful one at the local BMW dealer on consignment with only 2,315 miles on it. Not to worry the Paso is staying in the garage. I just may cheat on it from time to time.

[paso750]

ok, so they arrived, great. I saw you found the pms, too
The 4229ST would indeed be too small as they have an id of 55mm - they were right. 60 mm is what you need.
The ones I mentioned came from the catalogue I linked in one of the posts above.

G.