[1Blackwolf1]

  Considering all options equal at this point am wondering about the 30MM performance carb kit available from our host.  Catalog item number Z91227, looks like it contains all the necessary jets, mounts, etcetera to make easy installation.

  Is this easier to dial in than the stock Mikarb currently on my military?  Figure I'll ask the pro's here istead of stumbling around trying to make the stock unit work better.  Have installed a free flow air cleaner, and duckbill breather so far.  Will probably install a Dunstall replica BSA muffler or cocktail shaker in the future.  Any and all help is appreciated.  Will.

[ace.cafe]

I don't use the 30mm, but it's a good carb, and it has it's advantages.
It's a flat-slide, and flat-slides are generally better than round-slides.
You will get more power, from around the midrange and higher.
Idling stability shouldn't be adversely affected.
I don't know about how hard it is to jet, but some people here seem to be having a hard time getting any information from others about jetting.
It's a copy of the Keihin PWK, which is a very good carb design, so it's not a slouch.

One thing that I'm not too wild about, is that it is a solid flange mount carb, like the Amal.
I'd prefer one that mounts on the rubber hose. I know the rubber hoses have their issues too, but the carb is in a better working environment on the rubber hose.

Once you have a good exhaust and air filter, it's the carb size that is the restrictor on the engine, and the 28mm will take you almost to 5000 rpm in top gear(17T), but starts to weaken a bit earlier. The 30mm will take you as high as the stock cams can give, and give better power from mid to top rpm. It would be particularly better if you have changed to an 18T sprocket, and will allow better top end with the added loads you'll see at higher speeds when using the taller gear.
The 30mm isn't quite enough for a highly modified engine, but it's a very good "all around" carb for a mildly modified bike that uses stock cams or re-phased cams.

[NJ Riff Raff]

Hi Blackwolf.

I just want to be clear you are talking about this carb?

http://store.royalenfieldusa.com/30mm-performance-carburetor

I am currently trying to dial in it on my iron barrel military. Do you also have an iron barrel?

There are some things to keep in mind. First off is if you are ordering it from the CMW parts catalogue the description says that it comes with a 140 main and 19 pilot. The 19 pilot is a misprint. It is really a 38 pilot. I think some people here think that they are running a 19 pilot when really they are running a 38. (I have this info from the manufacturer of the carb) The extra supplied 25 pilot would be leaning things out at idle if you went that way. I found that my bike did not like the 25 at all. The 38 seems to work really well for idle, using the choke for a 1st kick start.

The other thing to keep in mind in terms of jets is that unlike other carbs and carb theory 101 the main jet has a great effect on the lower throttle openings. (I also have this info from the manufacturer of the carb) At a 140 main I think it is way too rich. I started with the carb out of the box. 140 main, 38 pilot (at the time I thought it was a 19) and needle in middle position. As I started to reach the higher RPM in 1st and 2nd gear there would be a huge hesitation, enough that I just turned around and headed back to the garage.

I installed the leanest jet supplied, the 132 and leaned the needle into the second clip position from the top. That improved things dramatically with a slight hesitation in the same spot. However when I've got into a situation with some long idling and prolonged 1st and 2nd gear movement I would start to get popping in my exhaust when I would engage the throttle and have to pull over and let things cool down. Just to see I leaned the needle to the top clip position. It eliminated the flat spots but worsened the popping problem. I then richened it up putting the clip in the middle position and hesitation at the top of 1st and 2nd got a lot worse and I turned her around and headed back to the garage.

This now leads me to believe that the 132 main is still too rich. I'm waiting on delivery of 130, 127 and 125 mains. My next move will be to drop the main by one step and keep the needle position in the middle and err on the side of rich with the needle position to eliminate a lean condition at the smallest of throttle openings.

The supplied blots are in my opinion too short. If you screw them all the way into the head then put on the carb with the gasket, what's left is barely a couple of threads for the nut to grab onto and that's without using the supplied washer. I went to home depot and got a couple of longer M8 - 1.5 bolts, sawed the heads off and am much more confident in how much more there is to grab onto. The supplied bolts also had a hard time screwing into the head. Not so with the blots from home depot. You do not need to use the O ring.

I do have high hopes for this carb as start up is great, idle is great and when I was close with a very lean needle position perhaps compensating for a too rich jet, things really ran well with some real punch in 3rd and 4th gear. I just have to eliminate the lean condition at very small throttle as New York City is unforgiving in its stop and go traffic.

I should say that I have the classic 50's exhaust, K&N 28mm pancake air filter and am close to sea level in the New York area.

What trouble did you have with your stock carb?

Here are some of the answers I received to a very long email I wrote to JRC, makers of the carb. I'll spare you all the email I wrote them.

Answers -

On this carburetor the main has very large affect at 1/4- and up throttle. It is a bit different than a conventional round slide carburetor in that respect.

The main jet has a very broad affect on the midrange unlike most carburetors. I think you will find it may help to work down in size.

The O ring is an additional seal on the inlet manifold, it is a redundant feature and isn't required for proper used of the Carburetor.

[Slider]

I had the dealer install my flat-slide (along with the pancake filter, British exhaust, and Power Arc ignition). I also thought it would be a solid mount, but it wasn't. Here's a picture of the finished package...

http://i217.photobucket.com/albums/cc22/russ5288/IMG_3097-1.jpg

[Blltrdr]

I had the dealer install my flat-slide (along with the pancake filter, British exhaust, and Power Arc ignition). I also thought it would be a solid mount, but it wasn't. Here's a picture of the finished package...

http://i217.photobucket.com/albums/cc22/russ5288/IMG_3097-1.jpg

Slider, you might try supporting your carb/filter set up. Without support it most likely will lead to a premature failure of the intake rubber. Also you should be able to find a hoses the right diameter to press fit so you could lose all those hose clamps.
 
I tried the rubber mount on my flatslide but put the solid mount flange back on, It seemed to me that there wasn't enough of a lip on the carb to properly clamp the hose.

The support idea is just a suggestion, but given with prior experience. Just trying to help out.

Blltrdr

[Slider]

I'm not sure how to rig up a support. But it does seem very strongly mounted, no movement except for a slight bit of flex in the rubber when I push on the carb.

[Blltrdr]

I'm not sure how to rig up a support. But it does seem very strongly mounted, no movement except for a slight bit of flex in the rubber when I push on the carb.

Slider you could fashion a  strap out of metal, etc. to do the trick. At one end bend a 90, this will slip under your filter clamp with the tang facing the intake. Then have the top of the strap attach to your rear tank mount bolt or some place else that will support it. What ever you decide to use for the strap make sure it is something that isn't brittle. I'm sure some other member will weigh in and give you couple of suggestions. Any way it is something you should consider doing no matter how stout you feel it is now.

Blltrdr

[ace.cafe]

Blltrdr is right.
If you let that carb and filter hang on the hose for its support, the hose will prematurely fail.
A simple piece of 1/8" thick aluminum bar stock, 1/2" wide, from the hardware store, bent on each end, will make a simple strut bracket.
Attach one end to the filter mount, under the hose clamp, as Blltrdr described, and drill a hole in the other end to mount to some frame bolt in the vicinity.
Bend the bracket so that when it's installed, it doesn't push or pull on the carb, but just provides it some support to hold it where it's supposed to be.
That's all it takes.

[otteryboy]

Hi Blackwolf,

Not sure if this helps as I bow to the experience of others more knowledgeable and I am not even sure what the flat slide carb is but........................................

For what it is worth the previous owner of my 1992 500 fitted an Amal monobloc.

Maybe, if he had fitted a concentric I would not be writing this. The bike did not run sweet at all. I went back to the original Mikarb, re jetted it and dialled it in ( as you Americans are prone to say) and hey presto:

Excellent starting
Excellent running
Excellent tickover
Excellent economy

I am so happy with the bike. I guess I wonder if over tinkering is a good thing?
Was the factory so daft when they put the bike together as it was?
Like everyone else I am tempted to go for a louder exhaust, free flow air filter etc, etc but the more I ride my bike the more I feel I want it to run well to original spec.

Of course these are troubled times in merry old England and after many years of "New Labour" the country is turning back to more conservative values. Maybe this is rubbing off on me!

Whatever you decide I wish you well!

Otteryboy

[baird4444]

  Blackwolf- I'm very close; I think.....   I've got the 25 pilot jet and 125 main jet in.
This carb is a little harder for me to get dialed in. Maybe because of the mount makes it harder to remove and change the needle setting. The jets can be done by removing the bowl. as far as the studs, I  Had to buy  2 -  31mm  M8 x 1.25 studs and nuts at ACE hardware.
   The xtra torque is a real kick in the ass!!  One thing nobody is talking about is your gas economy will suffer a little. I'm down to somewhere between 50 and 60 mpg. I can live with it so long as it is above 50. I'm going to track 1,000 miles for a better idea...
  I looked at the Dyno sheet for almost a year b4 I did it; DON'T wait  a  year...
             - Mike
                     

[1Blackwolf1]

  Thanks for all the input guys.  I guess I could always try and tweak the original carb but not a big fan of Mikuni.  Would go to an Amal, but not at that price..and I know they are cheaper here than other sites.  Wish I would have kept all the Amals I had from my old Triumphs/BSA's.

  How much more can I get out of the stock unit is also a question.  I suppose I'd have to just order the whole set of mains and start experimenting.  It seems to currently stumble at mid-range..not die but labor to accelerate past about 45.  Since I'm considering a dunstall or cocktail shaker I am wondering if maybe I just need to change main jets.  Idles and kicks over fine, air-fuel seems really close if not near perfect.

  I don't want to do the overkill thing since I know that cruising speed is only around 55 mph, but don't want to starve the girl either.  I think this might be the first plan of attack..what size main/pilot jets do these things run stock?  And am I right that if I raise the needle valve I will make the engine run richer?  Thanks again.  Will.

[ace.cafe]

  Thanks for all the input guys.  I guess I could always try and tweak the original carb but not a big fan of Mikuni.  Would go to an Amal, but not at that price..and I know they are cheaper here than other sites.  Wish I would have kept all the Amals I had from my old Triumphs/BSA's.

  How much more can I get out of the stock unit is also a question.  I suppose I'd have to just order the whole set of mains and start experimenting.  It seems to currently stumble at mid-range..not die but labor to accelerate past about 45.  Since I'm considering a dunstall or cocktail shaker I am wondering if maybe I just need to change main jets.  Idles and kicks over fine, air-fuel seems really close if not near perfect.

  I don't want to do the overkill thing since I know that cruising speed is only around 55 mph, but don't want to starve the girl either.  I think this might be the first plan of attack..what size main/pilot jets do these things run stock?  And am I right that if I raise the needle valve I will make the engine run richer?  Thanks again.  Will.

The stock main jet on a Mikarb is 110, and that's way way lean for most applications.
A 125 main jet should do you fine on the stock carb after changing the exhaust and air filter. Worst case you might have to go to a 127.5 main.
Pilot jet should be a 25(stock) or a 27.5(next size up).
If you get a weak midrange symptom, go to a P0 or P2 needle jet.

With proper jetting for your elevation above sea level like this, with the freeflow fliter and exhaust, the stock carb should get a single-rider Bullet 500 up to about 75 mph(real mph, not speedo mph). The speedo will probably read somewhere over 80.

Set your air bleed screw(small screw on the side) to 1.5 turns out from fully seated.
Set your needle height to the middle(3rd) groove with the e-clip.
Get it started up, and warm it up with a moderately fast idle set by your idle screw(big headed screw on the side)
When the bike warms up good, set the idle to the highest you can find by screwing the little air bleed screw in and out. When you find the highest idle with that screw, then lower the idle to normal with the big headed idle screw.
That should be perfect for starting and idling, and coming off idle into riding speed.

Then if you experience issues in the midband, you can raise or lower the needle position until you get it right.
Plug chops help you to know which way you have to adjust the needle at the various throttle settings.

[1Blackwolf1]

  Thanks for all the input guys.  I guess I could always try and tweak the original carb but not a big fan of Mikuni.  Would go to an Amal, but not at that price..and I know they are cheaper here than other sites.  Wish I would have kept all the Amals I had from my old Triumphs/BSA's.

  How much more can I get out of the stock unit is also a question.  I suppose I'd have to just order the whole set of mains and start experimenting.  It seems to currently stumble at mid-range..not die but labor to accelerate past about 45.  Since I'm considering a dunstall or cocktail shaker I am wondering if maybe I just need to change main jets.  Idles and kicks over fine, air-fuel seems really close if not near perfect.

  I don't want to do the overkill thing since I know that cruising speed is only around 55 mph, but don't want to starve the girl either.  I think this might be the first plan of attack..what size main/pilot jets do these things run stock?  And am I right that if I raise the needle valve I will make the engine run richer?  Thanks again.  Will.

The stock main jet on a Mikarb is 110, and that's way way lean for most applications.
A 125 main jet should do you fine on the stock carb after changing the exhaust and air filter. Worst case you might have to go to a 127.5 main.
Pilot jet should be a 25(stock) or a 27.5(next size up).
If you get a weak midrange symptom, go to a P0 or P2 needle jet.

With proper jetting for your elevation above sea level like this, with the freeflow fliter and exhaust, the stock carb should get a single-rider Bullet 500 up to about 75 mph(real mph, not speedo mph). The speedo will probably read somewhere over 80.

Set your air bleed screw(small screw on the side) to 1.5 turns out from fully seated.
Set your needle height to the middle(3rd) groove with the e-clip.
Get it started up, and warm it up with a moderately fast idle set by your idle screw(big headed screw on the side)
When the bike warms up good, set the idle to the highest you can find by screwing the little air bleed screw in and out. When you find the highest idle with that screw, then lower the idle to normal with the big headed idle screw.
That should be perfect for starting and idling, and coming off idle into riding speed.

Then if you experience issues in the midband, you can raise or lower the needle position until you get it right.
Plug chops help you to know which way you have to adjust the needle at the various throttle settings.

  I'll try that first Ace..seems cheaper and less confusing with your rexplanation.  So raising the needle valve makes air/fuel richer correct?  At least thats what I remember from other Japanese carbs.  Thanks a lot everyone, really good ideas suggestions.  WIll.

[ace.cafe]

  Thanks for all the input guys.  I guess I could always try and tweak the original carb but not a big fan of Mikuni.  Would go to an Amal, but not at that price..and I know they are cheaper here than other sites.  Wish I would have kept all the Amals I had from my old Triumphs/BSA's.

  How much more can I get out of the stock unit is also a question.  I suppose I'd have to just order the whole set of mains and start experimenting.  It seems to currently stumble at mid-range..not die but labor to accelerate past about 45.  Since I'm considering a dunstall or cocktail shaker I am wondering if maybe I just need to change main jets.  Idles and kicks over fine, air-fuel seems really close if not near perfect.

  I don't want to do the overkill thing since I know that cruising speed is only around 55 mph, but don't want to starve the girl either.  I think this might be the first plan of attack..what size main/pilot jets do these things run stock?  And am I right that if I raise the needle valve I will make the engine run richer?  Thanks again.  Will.

The stock main jet on a Mikarb is 110, and that's way way lean for most applications.
A 125 main jet should do you fine on the stock carb after changing the exhaust and air filter. Worst case you might have to go to a 127.5 main.
Pilot jet should be a 25(stock) or a 27.5(next size up).
If you get a weak midrange symptom, go to a P0 or P2 needle jet.

With proper jetting for your elevation above sea level like this, with the freeflow fliter and exhaust, the stock carb should get a single-rider Bullet 500 up to about 75 mph(real mph, not speedo mph). The speedo will probably read somewhere over 80.

Set your air bleed screw(small screw on the side) to 1.5 turns out from fully seated.
Set your needle height to the middle(3rd) groove with the e-clip.
Get it started up, and warm it up with a moderately fast idle set by your idle screw(big headed screw on the side)
When the bike warms up good, set the idle to the highest you can find by screwing the little air bleed screw in and out. When you find the highest idle with that screw, then lower the idle to normal with the big headed idle screw.
That should be perfect for starting and idling, and coming off idle into riding speed.

Then if you experience issues in the midband, you can raise or lower the needle position until you get it right.
Plug chops help you to know which way you have to adjust the needle at the various throttle settings.

  I'll try that first Ace..seems cheaper and less confusing with your rexplanation.  So raising the needle valve makes air/fuel richer correct?  At least thats what I remember from other Japanese carbs.  Thanks a lot everyone, really good ideas suggestions.  WIll.

Yes, raising the needle(by lowering the position of the e-clip to a lower groove in the needle) will richen the midrange primarily.

BTW, if you don't change the header pipe, the restrictor in the tail end of the header might be enough restriction to not need as much enrichening of the jetting.
It will also hold back your power potential.

The approved procedure would be to get a free-flowing header pipe when you change the muffler. Or else carefully use a correctly sized hole saw to "core-out" the restrictor from the back end of the header pipe. That way you can keep your header pipe if it's in good shape.
It will make a difference in jetting and power, whether that restrictor is left in the pipe, or removed. It's not hard to do.
Much better to get that restrictor out of the pipe.
The jets I recommended would be appropriate for AFTER you remove the restrictor from the header.

[1Blackwolf1]

  I had planned on taking the Dremel tool to that little beauty as soon as I have the muffler and jets on site.  I basically just want to let the engine breathe and exhaust.  I know these aren't over powered but I'd at least like to have the 23 hp they are built with.  I figure I'll do the poor mans upgrades first then save up for the big $$ items.  Thanks Ace.