What do you think

Funky I'll let CDNTX650 help you troubleshoot this problem from hereonin he clearly has much more experience than me.

Besides all of my posts only attract the worse kind of element on this forum that are dead set on flaming me and causing me grief at every opportunity.
I don't want to give them the opportunity to drag down your thread mate so I'll leave you in the very capable hands of CDNTX650

good luck buddy :thumbsup:
 
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ok mate no worries sorry to hear your getting flamed i for one appreciate your input but i understand.
All the best Funky
 
Hi all:thumbsup: this is the jetting of my Carbs BS34s 1981 special pamco ignition 707cc iridium plugs High voltage coil :D
Issue running rich. Carbs have been stripped and cleaned as per advise on this forum :thumbsup:
Needles 51x11 was set at 3 notch from top now second notch.I tried top notch but ran bad cut out when turned throttle but idled lumpy
Air pilot jet r130
Main jet 132.5
pilot jet under rubbers next to main 42.5
mixture screws 3 turns out
Your advise will be greatly appreciated
All the best funky:thumbsup:
 
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OK chaps have been reading most of the weekend this may help anyone in the future This is from Mikuni:thumbsup:
Follow steps in order:

1. Top end (full throttle / 7.5k to redline) - Best Main Jet must be selected before starting step 2! Select Best Main Jet to get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the highest top speed / pulls hardest at high rpm:

a. If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.

b. If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small. In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use! Do not pay too much attention to the low end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low end / cruise later - after step 2.

2. Midrange (full throttle /5k-7k). Select best needle clip position to get the best power at full throttle / 5k-7k rpm, after you have already selected the best main jet:

a. If the engine pulls better on a full throttle roll-on starting at <3k, when cool but soft when at full operating temperature, it is too rich in the midrange and the needle should be lowered.

b. If the engine pulls better when fully warmed up but still not great between 5k-7k, try raising the needle to richen 5k-7k.

If the engine pulls equally well between 5k-7k when cooler as compared to fully warmed up, the needle height is probably properly set. Do not pay too much attention to the low end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets that produce the best power at high rpm. You will deal with the low end / cruise next.

3. Low end (full throttle / 2k-3k) Float height (AKA fuel level & how to..)
To get best low end power, set float height so that the engine will accept full throttle in 2nd gear from 2.5k to 3k rpm at minimum. Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.

Base settings are usually given if a particular application has a history of fuel level criticalness. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm. Reference: a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. Check out and RESET all: Suzuki (all), Yamaha (all) and Kawasaki (if low speed problems occur). Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!

If there are low end richness problems, even after lowering the fuel level much more than 1.5mm from our initial settings, also check for needle wear and needle jet (part of the emulsion tube). See Worn Needle and Worn Needle Jet diagram. It is VERY common for the brass needle jets (in the top of the "emulsion tube") in 36mm, 38mm and 40mm Mikuni CV carbs to wear out in as little as 5,000 miles. Check them for "oblong" wear - the needle jet orifice starts out round! Factory Pro produces stock replacement needle jets / emulsion tubes for 36mm and 38mm Mikuni carbs.

4. Idle and low rpm cruise. Fuel Screw setting (AKA mixture screws)
There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs use a special "D" shaped driver, usually supplied in the carb recal kit. Set mixture screws at recommended settings, as a starting point.

For smoothest idle, 2nd gear 4000 rpm steady state cruise, and 1/8 throttle high rpm operation: Pilot fuel mixture screw settings, float level AND pilot jet size are the primary source of mixture delivery during 4000 rpm steady state cruise operation.

a. If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.

b. Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm 0 to 1/8 throttle maneuvers. B. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem. NOTE: A rich problem gets worse as the engine heats up.

c. If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture. NOTE: A lean problem gets better as the engine heats up.

d. If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen the mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!

All the best Funky:thumbsup:
 
straight from the horses mouth eh !:wink2:

I am surprised that the correct proceedure is to test and fit the main jet first and work backwards. It seems counter-intuitive to me but just goes to show how wrong you can be.
I've never checked and always assumed it would be logical to get the idle stable first so that you can ride the bike safely whilst testing the rest of the throttle range.

great post Funky I have printed it out for future reference :thumbsup:
 

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It appears you're running the adjustable "Canadian" needle. You'll need to check your needle jets to insure they are the matching Canadian versions as well (336-Y-0). The two components are supposed to be run as a matched set. The combo is richer than the U.S. stock components but that extra richness is achieved with the needle. The Canadian needle jet is actually slightly leaner than the original. If you're running the Canadian needle with the stock Y-0 needle jet, that could be responsible for the black plugs.

The stock Y-0 needle jets have rows of 3 and 4 air bleed holes down the sides. The Canadian 336-Y-0 has rows of 4 and 5 air bleed holes .....

StockNeedleJets.jpg


 
There ya go.

The plugs really shouldn't be that black with stock mains and pilots jetting on bs34. The carb guide gives good advice on how to check float level with the clear tube which is the only way I use if I can...and that also let's you see the Condition of the needle and seat oring. If it's leaking you'll always be rich with high float level.
 
Heres some good reading in laymens terms Thanks smed speed http://www.dansmc.com/carbs2.htm
I cant really use this while im running in the engine so i will have to improvise until i can go to 7500rpm ... and im going to check my needle jet or emulsion tubes as they are called. Thanks 5twins
I am off to the USA florida in four weeks so i may treat myself to some bits from over there I need to source some air pilot jets and pilot jets to. It seems there is more selection over there.also waiting on some advise from smed speed and Haiden tuning If its not one thing ist an other.Its got to be a labour of love or total madness with these bike lol...
All the best to all Funky:thumbsup:
 
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It appears you're running the adjustable "Canadian" needle. You'll need to check your needle jets to insure they are the matching Canadian versions as well (336-Y-0). The two components are supposed to be run as a matched set. The combo is richer than the U.S. stock components but that extra richness is achieved with the needle. The Canadian needle jet is actually slightly leaner than the original. If you're running the Canadian needle with the stock Y-0 needle jet, that could be responsible for the black plugs.

The stock Y-0 needle jets have rows of 3 and 4 air bleed holes down the sides. The Canadian 336-Y-0 has rows of 4 and 5 air bleed holes .....

StockNeedleJets.jpg



My needle tubes have 4 and 5 holes :confused: I think that right based on your post, I am hoping that with the main jets i have oredered i can lean the mixture off .
 
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Well, they may be the right ones but reading the number off them would be the best way to be sure. Then again, MikesXS is the only place I know that sells these (well, maybe Heiden as well). I'm thinking they aren't originals, probably repros, so who knows if they even have a number on them. I never bought any so I couldn't say for sure.

A few more things to ponder ...... the stock 5HX12 fixed needle measures 50mm from the fixed clip to the tip. The 5IX11 "Canadian" needle measures 50mm from the top clip slot to the tip. That means you would have to run it in its lowest, leanest position to equal the stock needle. Running in the middle #3 slot may be too rich. You may want to try slot #2. Also, you reported finding a #130 pilot air jet. That's 2 sizes smaller than the 135 that was stock. That will reduce the air flow to the pilot circuit and make it richer.
 
I bought a set of 336-YO's then realized the Oceania models have the 5IX11 Needles and the 336-YO as standard on our BS34's.

Here is a pic of the 336-YO i bought off Mikes, has the number and genuine Mikuni symbol stamped on them. Mind you i bought these a few years ago.
 

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These are all the sizes of the different jets in the carbs bs34..... I have fitted new float valves and Gaskets set the float hight to spec and checked with clear tube to the float drain, Just waiting for new main jets should be here tomorrow
IMAG1542_zpsvqj0iuxe.jpg

IMAG1544_zpsatsynpog.jpg

IMAG1545_zpsqtfo9t9s.jpg

All the best funky
 
Ok an Update received my new main jets today 130 and 127.5:D
I fitted the 130s and went for a ride:thumbsup: bike went well no back firing did about 12 miles, returned to my man cave and checked the plugs:shrug: they were much better but not right:banghead: they were still slightly fouled, not as before more around the outer bent bit of the plug and more to one side :wink2:.
I then bit the bullet I checked the needle settings and they were on the second notch from the top as i thought:thumbsup: so i went on and fitted the 127.5s cleaned the plugs checked gap 30thou:thumbsup:
The bike started went for a little ride took the plugs out and they were again better I kept the bike at about 4000 rpm as im running it in still ,,,,but gave it a little few second blast to about 5000 to see if the main jet coped which it did.:thumbsup:
I took plugs out and they were almost there, I have a sneaky feeling that i need to reduce my air pilot jet as i think the fouling is probably happening there to I.E that circuit is running on the rich side as i have never used the choke to start the bike.:thumbsup:
I intend on going for a longer ride tomorrow and i have ordered some more jet 125s and 122.5s. just incase
Summery I have gone from needle postion three from top and from a 132.5 to a 127.5 and it could probaly do with a little more tweeking.
:DOh if anyone has some airpilot jets for BS34s 120 110 100 90 i will buy them I looked in the UK spec for that carb and it says an 85 :thumbsup:

All the best funky
Oh if anyone has some airpilot jets for BS34s 120 110 100 90 i will buy them I looked in the UK spec for that carb and it says an 85
 
That is the same set up in my BS34's. I have original filters and reverse cone mufflers.
Intresting Skull or any member of the forum who knows If i am running rich on idle do I change the air pilot jet or the pilot jet or both.
all the best Funky
 
edited to remove incorrect information
 
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If you want to lean the pilot circuit, you don't reduce the air jet. That makes it richer. It delivers less air to the circuit with a smaller jet. The jet used for the air jet in the BS34s isn't anything special, it's actually the small round main used in the BS38s, but in this application, it flows air.
 
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