Correct...I bought my fcr after the bike and the ac pump didn't work. The diaphragm in the ac pump bowl was folded over and would sit right when folded back so i just sent it off to Jerry at Stroker. He cleaned it up and was asked to set it up and it came back perfect. No o-ring or any other accoutrments were added to seemingly affect the squirt.

 

I thought I posted this, but could not find it in the thread.

This carb is the *****. Not only can the acc pump be adjusted by start and stop the size of the squirt can be set by different nozzles.

From the link below
************************************************
The accelerator pump can be adjusted to inject
fuel into the throat of the carburetor over a wide range of
throttle openings. The rate at which it injects fuel can also
be controlled with different sized pump nozzles. Total flow
volume depends upon the pump’s beginning and end point
adjustments.
***********************************************


Read here, this is the best thing I have seen on tuning a carb.

http://www.zodiac.nl/instructions/234862.pdf

When I used to rebuild car carbs, there was a "Duration spring" that could be changed also. It set the time of the squirt.

Note, this carb has NO diaphragm for the acc pump, just a piston in a cylinder with spring and check valves Item 67 page 4.

Jets were shipped Jan 27. Today is the thirty first.... Maybe...

David

 

Thats like the 36 pumper I have. Never had to touch anything on that carb as it came set up and running fine. The fcr was messed with and when I got it, the ac pump didn't work. The bike ran fine but if you gave it full throttle, it bogged like you wouldn't believe.

 

The rest of the jets came in the mail today. I put the 15 pilot jet in and the P6 needle Jet. I also put in a 125 main instead of the 130 that came in it.

With the 12.5 pilot the mixture needle was hanging by a thread. I left it at 1 3/4 when I put the carb back on with the 15. It ran pretty good, so after the bike warmed up, I opened it up another 1/4 turn. The engine went from 1250 to 1500, so I went another quarter turn. Not much more increase in RPM if any . I left it at 2 1/4 which is what I was shooting for.

Now when I blip the throttle or turn it really slow the engine takes off like it should. No more stalling. I hit the kill a few times and it started back up on the first try every time.

I could not do second gear wheelies. At first I was thinking the P6 needle jet because I had changed it. On the way home from work I realized on the first test drive I didn't hook up the air box. SO the next test is pull the lid or remove the tube from the carb to the air box and go for another ride. If that does not do it I will put the P8 needle jet back in.

On this carb I can change the needle, the needle jet and the main jet with out removing it.

All in all the bike ran great. It only takes about 3/4 choke to start it. Full choke it will start but slowly looses RPM until it dies or I push the choke in part way or twist the throttle.

Edit: In first gear I could flip the bike over backwards like nothing. I went to turn and hit the throttle. The bike went straight until the front wheel came back down. This is going to be fun!

David

The temp today ended in the word teen measured in Fahrenheit, I was the only motorcycle on the road.

This is the fuel filter in a loop that goes below the carb so any water will not make it past the filter.

 

This morning I fired the bike up.

First I just pushed the starter. It went put put and that was all. This is a good thing. Then I pulled the choke out almost all the way and it started right up. It went to a steady 3500 RPM.

Once both radiators were hot, I added a little propane from an unlit torch into the snorkel. The engine slowed down a little which tells me not to go any richer for the IDLE mixture screw.

I then cranked it up to 4,000 rpm with no load and added the propane. The RPM went up a little then down (too much propane).

Next I bumped it up to 6,000 RPM under NO load. I just put my hand over the KDX snorkel a little and the RPM went right up. Too lean. I had marked the throttle and it was at 1/8, so I am thinking bigger pilot jet or smaller pilot air jet. I have the 117.5 pilot jet, so in it goes. I will post results after lunch.

David

 

You want to set the IDLE mixture screw for max rpm at idle with a warmed up engine. You may have to go back and forth between the mixture and speed screws to get it right.

A 117.5 PILOT jet????????

The idle mixture screw circuit works in parallel with the pilot jet. The pilot jet gets the mixture close and the idle mixture screw fine tunes it.

Ride on
Brewster

 

Eh, 17.5 pilot. Close

It runs better now, real snappy off idle when warm, but still a little lean at 4,000 to 6,000 rpm no load. (1/8 throttle) More changes to come I am getting closer. Its hard to tune a carb when I can't ride the bike.

Smaller pilot air jet or back to the P8 needle jet.

David

 

I was a little lean in the mid circuit when I was playing with my carb and went from the P-6 needle jet to the P-8….. The P-8 made things overly rich…..

ended up getting the richer needle 9EBY01-50 (middle position). This needle along with the P-6 was perfect.

Mikuni also states that “When using this Jet needle, the use of a larger pilot jet maybe required”

 

More fun today. I put the P8 needle jet back in. The too lean situation at 4,000 to 6,000 rpm is gone now. Idle mixture screw is at 1 1/2 or a little less. Bike runs really good in the shop.

After I replaced the needle jet, I pulled the choke all the way out and cranked it with out touching the throttle. It fired in 2 compression strokes and went right to 3,000 RPM nice and stable. (cold) If I pushed the choke in some it would speed up to 4,000 rpm.

I adjusted the accelerator pump so it does not squirt on the slide as its coming up with the engine running. This is about 1/8 throttle. It stops at about 3/4 of the slide opening. I also held the accelerator pump so it was disabled. Bike ran like crap.

I don't want to reinvent the wheel and I will not just copy some one else.

I have a "Leaner" Needle to try later on. I am also thinking of trying the #15 pilot jet again since it did not cure the 4,000 to 6,000 lean condition, the P8 needle jet did.

Not much more to do, the midrange and top end (needle and main) need to be tweaked, but I can't ride since there is snow on the roads.

New fork valves are in. carb is as far as I can take it till spring. I have a set of battleaxe tires for it. Stock ones have a few hundred miles left on them.

Thanks for watching

David

 

Is your Pump squirt splashing off the needle? It needs to splash of the needle for a more complete burn (this is in the HSR40 manual).