JS Flatslide tuning

Dkt26 · Jan 9, 2015

Hey all
Anyone got the instructions for tuning these handy?
Seem to have lost mine. Am after the initial slide gap setting prior to fitting. Did a search and couldn't find anything yesterday. I seem to remember 10 or 15 thou on the manifold side as a starting point???
Thanks in advance
DKT

ashman · Jan 9, 2015

Jim be the best person to ask, I just installed mine and made sure the slides lifted at the same time, started it then set the idle and air mixture took less than a few minets and has stayed tuned for over 4 years now.

Ashley

Brooking 850 · Jan 9, 2015

What idle RPM did you set your motor at with those carbs?

xbacksideslider · Jan 9, 2015

With a strong ignition system, they'll idle down as low as 600 but, in the interest of the cam shaft's lobes and to ensure that it never ever stalls, I set mine no lower than 1500.

Dkt26 · Jan 9, 2015

I'm not sure what Ashley's runs at but I'm going to see how they go between 900 & 1100. Wherever it seems most comfortable and steady.

ashman · Jan 9, 2015

a 1,000 rpms is fine just as long as its a smooth idle, I run a Joe Hunt maggie and these carbies work so well with the maggie.1,500 is a bit high for idle, wouldn't go no more than 1200.

Ashley

mikegray660 · Jan 9, 2015

good carbs but be sure to do your fine tuning when engines warm

jrh2020 · Jan 9, 2015

My instruction sheet says 0.010" gap at bottom of the slide when looking through the manifold side. Adjust cables for 3/32 inch slack.

YouTube video says 0.020"

http://youtu.be/VSRH13c8dlk

Jim h.

jseng1 · Jan 10, 2015

jrh2020 said:
My instruction sheet says 0.010" gap at bottom of the slide when looking through the manifold side. Adjust cables for 3/32 inch slack.

YouTube video says 0.020"

http://youtu.be/VSRH13c8dlk

Jim h.

The important thing is that you start with both carbs the same. It doesn't have to be exact and you can just do it by eye without measurements. Approx .010 or .020" but its not critical because you will have to change it anyway to set the idle speed. Then once the idle is set you want to make sure both cables have the same amount of slack.

For instructions email me at:

Jim@jsmotorsport.com

Kvinnhering · Jan 10, 2015

I have a complet sett of 32 mm if somebody intrested. I have switched to 34 mm on my short stroke. Send me PM if somebody are intrested.

gripper · Jan 12, 2015

Jim, is there any value in fitting a manifold balance pipe on the PWK flat slides? Other threads recently seem to indicate that it's a good idea.

jseng1 · Jan 13, 2015

gripper said:
Jim, is there any value in fitting a manifold balance pipe on the PWK flat slides? Other threads recently seem to indicate that it's a good idea.

Definitely yes.
I have a good ear and never needed a balance tube - just tuned the carbs without the balance tube. But then customers started asking for them. So I tried one out and found it to be easier to adjust the idle - less critical. if you're a perfectionist and have a good ear, you can get these flatslides to idle around 800 - 900 RPM steadily and hit on nearly every beat continuously without the dying that you can experience with other carbs. Easy way to do it is below with 3/32 ID stepped brass tube. You can use two overlapping pieces of hobby shop K&S tubing and loctite them together. Use a red hot wire to plunge through the rubber or make a tubing drill by sharpening the OD of a piece of the K&S tubing. Practice on a junk piece of rubber 1st to check the fit.

Brooking 850 · Jan 13, 2015

Thanks all, I have a balance tube on mine , in fact looks like there was some there originally, but then filled, so I redrilled and matched very similar to the original look , with 1 x brass tube sub JB weld secured into each carb and a rubber tube between the two.
Mine idles at between 900 and 1000RPM , seems to drop to the lower when hotter.
Regards Mike

Cal · Jan 13, 2015

I have a set of 32's on my 750 and it starts on first kick, idles very nice and runs great!! But I have one cylinder (right) that seems to do a little popping on downshift/decelerating. Both cylinders are jetted the same and it runs so good I hate to mess with it. But this probably means I am a little lean. Which jet should be tweaked for this condition. Of course I will first check to be sure I dont have air leak or a little dirt in the carb.

Regards,
Clay

1up3down · Jan 13, 2015

Clay,

I know exactly why the right carb pops and has the lean symptoms you are talking about, even though it appears to be jetted properly.

If you are interested then you can PM me and I will tell you how to fix it.

John

bluepaul11 · Jan 15, 2015

DKT,
Starting point is 20 thou clearance for the PKW 32mm Flatslides. I am sure Jim will provide any other detail you need.

There was also a video on Youtube but is no longer accessible!!!

Paul C

cyclepsycho · Jan 16, 2015

bluepaul11 said:
DKT,
Starting point is 20 thou clearance for the PKW 32mm Flatslides. I am sure Jim will provide any other detail you need.

There was also a video on Youtube but is no longer accessible!!!

Paul C

The PWK carb adjust video has moved

The new link is

http://youtu.be/FM4b_88dKO4

Cal
To fix lean popping all you need to do is raise the needles a notch (or idle adjustment is too lean). Either that or you have an exhaust leak.

tomspro · Jan 16, 2015

cyclepsycho said:
Cal
To fix lean popping all you need to do is raise the needles a notch (or idle adjustment is too lean). Either that or you have an exhaust leak.

Sometimes, there is a further issues. Contact 1up3down for info.

JS Flatslide tuning

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