JS Motorsports Carbs

AussieCombat said:

If anyone is interested.....
Sorted out a fuel line setup today, seems OK, rode the bike and it was very crisp and the plugs
were quite light, Jim had set the needle clips at second from the top, so dropped them to the centre (lifting the needles).
Hopefully better, unfortunately upon starting Ed for the rerun, the right side muffler parted company from the flange.
Here's my setup.

It is great to be able to do quick changes to the carbs with 2 screwdrivers and 1 spanner.
Seat off, tank off, tilt the carb, top off, adjust, return.
Obviously / hopefully, once they are set then it won't matter, but it is good.
To remove the carbs is simple,... Seat off, tank off, tilt carbs and remove tops, right side filter off, carb off,
left side carb and filter off together.
Got some welding to do.
AC.

Click to expand...

Lifting the needles will make it run richer - not leaner (but go with whatever gives the best color & running.) - only check the plugs with a plug chop while riding (not after idling). Fuel line setup looks good as long as there are no kinks. Did you have any problems with the right side hose kinking? Can you provide left & right pics showing both petcocks.

I simply loosen the ring screw that encircles the carb to manifold and slip the carb off with cable still attached.
Very quick and easy, of course taking the air filter off first!
With the carb off the manifold in this manner you can do anything you want without taking off the seat or tank.

Hi Jim,
No kinking with the thicker rubber, and easier to handle than the plastic, seems to "give" a bit more.
Left side is identical to the right,....
Rounded 90 deg spiggot, T piece to T piece, with a line going down to the filters and carbs.
Gave it a good go at 4,500 up a long gentle hill, both taps on, no issue, then again with only one tap on
no issue, just a bit lean.
Tested flow through the bowls with one tap on then both taps on, seems plenty.
Yes I know lifting the needles will make it richer, it was lean, or appeared lean.
Time will tell, raining here at the moment.
I'm really happy, just tried a cold start, as much colder today than has been for months.
Chokes on, one kick, no throttle, beautifull, 1500 revs and settled back to my preffered 1200 with chokes off.
Neally as good as Mikuni's. heheheh.
Jim, are the slides chromed brass ?
AC.

AussieCombat said:

Jim, are the slides chromed brass ?
AC.

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Chromed but I don't know what the underlying metal is. The chrome is thin and can wear through at high spots but then seems to stop as I have had mine in for years that way.

PS - Concerning needles - I thought your earlier post mentioned the the plugs were dark.

No, he said the "plugs were quite light" lowering the clip, raising the needle.
Unrelated question, Jseng1. I want to go to a duel cable setup up. Do you know what the length of free cable should be for a for a setup of this nature?. It's kinda iffy taking an account for the junction box and all and I know they are not the same as a stock Amal setup.

You are both right,
But what I meant was the plugs were a bit dark at Idle, but quite light at middle revs.
Have ridden it now with needle clips in the centre notch, didn't like it, so they have been
returned to the original setting, second from the top.
Now for the open road, and our favorite long hill to test the Main.
Jim or Peter, do you have the eyesight to measure the distance between the notches on the needle.
I'm not wearing glasses yet but need them, and so use a magnifying glass.
Reason... There is quite a difference in fuel supply with just one notch adjustment.
If the open road results in really light plugs, I might shim the Needle clip and give it ago.
Of course it might be the Main not letting enough through but I doubt it. Main is 150.
One thing is for sure, the PWK's are a shorter body, atleast the amount of Slide travel is less.
Idle to full throttle is easily obtained with no contortions.
I like it, it's like a quick action hand piece, and needs getting used to on the roundabouts.
Short carbs can give the impression of better performance because they open more with the
same amout of throttle twist. I'm not covinced yet that the bike is performing better, but it is certainly
behaveing very well.
Thanks Jim.
AC.

If you are light at mid range then you need to raise the needle. Pilot jets run the idle. I run different pilot jets in the carbs. 42 in one and a 35 in the other, I believe you can go down to 25 but have not had to go below a 35. Jim has these for you if you need them.

Here is a couple of 38's for reference.

The plugs will always be dark at idle. If you lean the idle they are still dark - this misleads a lot of people. You want the smoothest idle regardless of plug color. The plug heat range is designed for a motor under load. You have to read the plugs after a chop while riding.

I only offer down the #35 idle jets because thats about the end of the effective range. Presently I am sending out the carbs with #38 idle jets.

I haven't messed with dual cables - you'll have to make some measurements - best to adjust the length to get them right (re-solder the ends).

I'm an idiot.
I must appologise if I misled anyone re... my newly aquired Quick action throttle.
When I reset the needle clips back to the original setting of...second from the top, I
noticed that the white plastic, spring retainer, was at the top of
the spring on one carb, instead of at the bottom. !
(which I had changed)
Obviously the spring was binding, which then felt like I was on full throttle, and
as I was really only checking Mid range plug colour at the time, and didn't need the extra,
I didn't think any more of it, except that I thought the bodies were shorter. Not so.
It feels about the same amount of travel now that everything is right.
And, there might be a bit better mixture than the Amals, as I've never seen Ed run
out to 7,500 before in third. (22 tooth sprocket, wha hoo)
The plugs are white at that, will try next size up.
Having fun.
AC.

When mounting the new manifolds that come with the kit, what is used between the new manifold and the head? Reason I'm asking is that in the photos on JS Motorsports website it doesn't look like there is a gasket

as I've never seen Ed run
out to 7,500 before in third. (22 tooth sprocket, wha hoo)

Click to expand...

Wooohoo! Now that's advertising.

Hey Snakepit,
just scroll back to my photo and you'll see the heat proof spacers.
AC.

Has anyone replaced the EMGO filters that come with this kit with anything else? The chrome cap on the end of my filter came off on one of mine and I need to replace and didn't know if there was perhaps a K&N filter that might be worth pursuing.

AussieCombat said:

If anyone is interested.....
Sorted out a fuel line setup today, seems OK

Click to expand...

You have the fuel filters on backwards.
They'll clog in short order if you don't flip them.

Johnnymac said:

Has anyone replaced the EMGO filters that come with this kit with anything else? The chrome cap on the end of my filter came off on one of mine and I need to replace and didn't know if there was perhaps a K&N filter that might be worth pursuing.

Click to expand...

I ran a dual flange but was to much of a bugger to get on and off.
Went with these instead. The most filter surface I could fit in there.
http://store.knfilters.com/search/produ ... od=RU-0982

pvisseriii said:

I ran a dual flange but was to much of a bugger to get on and off.
Went with these instead. The most filter surface I could fit in there.
http://store.knfilters.com/search/produ ... od=RU-0982

Click to expand...

Is K&N RC-2380 the dual flange you are talking about? Plenty of room but cannot turn right air screw lever.

Or did you try dual K&N 2850? and was that the one difficult to remove & replace?

Can you turn the right air screw with Dual setup K&N RU-0982?

jseng1 said:

pvisseriii said:

I ran a dual flange but was to much of a bugger to get on and off.
Went with these instead. The most filter surface I could fit in there.
http://store.knfilters.com/search/produ ... od=RU-0982

Click to expand...

Is K&N RC-2380 the dual flange you are talking about? Plenty of room but cannot turn right air screw lever.

Or did you try dual K&N 2850? and was that the one difficult to remove & replace?

Can you turn the right air screw with Dual setup K&N RU-0982?

Click to expand...

Yes, the rc-2850. The right air screw is never easy to get to but mine needs only a 1/4 turn one way or another between air filter vs no air filter and is assessable for that. The 0982 is good cause you can pop it on and off so easy to get to it if needed.

Jim, carbs are working great.... Heres a pic to prove it...




Crap.

"I'm sorry osifer I was just testing my new JS Motorsports carburetors, really!! I won't do it again."

Guys,

Since I don't get a lot of time to ride my Norton as mush as I would like, I do get out to my garage a couple times a week to at least start it up and idle a bit.

My problem is, when I do this, it really blackens the plugs. Is this normal? I only use the choke to start the bike, as soon as it starts, I shut the chokes off.