jetting frustration

[ktm 550 mxc monster]

Hey guys, I need some assistance on my Rm, I can't seem to get the jetting on it right at all. Here go specs then I will get to the problem.
01 Rm250
Stock top end
V force 2 valve
Fmf fatty pipe
Stock silencer
Moose air cleaner
50% superfast fuel race gas,50% premium unleaded
927 castor @ 40-1
764' above sea level(dallas area)
160 main jet
48 pilot jet
needle n3wk on #2 or lowered one notch
air screw 1-1/4 out
powerjet carb
#7 slide
The problem is it loads up easily, spooges like mad and has sluggish 0 to about a little less than 1/4 throttle response, but the air screw achieves maximum rpm around the mentioned 1-1/4 leading me to believe the pilot is ok.
The top end just had a new piston put in about 5 hours ago.
The jetting didn't seem to bad before I put boyesens in and it went down hill from there.
In my never ending quest for more bottom end I put the v-force on trying to limp through till our racing summer break to get it ported by Eric.
This didn't make much of any differernce to the jetting from tbe boyesen reeds.
Bike doesn't like to idle well either.
Here is the funny part, the starter bypass on my bike is adjustable but acording to the manual( oem suzuki service not owners) you can only safely adjust it out a maximum of 24 clicks which leans it..
At about 30-31 clicks out it starts to be very snappy and idles ok, but it does sound a bit too lean and has some up down surges suggesting the same, 3 clicks in (27-28) and it goes down hill fast.
The manual suggest that the screw affects 0-3/8 throttle and is factory set at 12.
I would think if my pilot is so rich that I have to crank that thing out to 30 to get it to snap up some that it would not pick up rpm with the air screw at 1-1/4 but be sluggish and have to have the idle adjust slide stop screw in so far.
I don't know where to go with it now, it gurgles,spooges and stalls horribly when doing tight woods riding.
lower needle all the way? lean pilot more? throw bike off cliff??
The main seals are in good condition and I never loose trany fluid.
HELP!!!

 

[ktm 550 mxc monster]

anyone? I am at your mercy here, I just don't know which way to go now and I think my head might explode soon..lol

 

[RM_guy]

I had the same kind of problems with mine. I put in a smaller pilot (#45) and it helped a lot. I also played with the choke knob and had the same results as you. A friend told me that you should only use the choke knob to set the idle and use the slide stop screw to keep the slide from bottoming out on the carb. I haven't had a chance to try it yet but I hope to as soon as the weather breaks around here.

Good luck. You will really like Eric's Mo Power porting. It's amazing how much and how smooth the power is now.

 

[ktm 550 mxc monster]

I will try the 45, it might just be the ticket, I don't know about the advice from your friend though to quote the book"note: When engine idling is desired, make sure to adjust the carburetor with the idle adjust screw and not with the bypass(starter)". Makes me wonder if they have experiance with people getting stuck with the old school fact that you used to use the choke to make certain carbs idle as they had no screw adjuster. The book states it is to fine tune the full close to 3/8 seems redundant that that is what the air screw if for to though..
You are making me salivate thinking about how much smoother the bike will be with Erics work, he has done some before for me and always delivers great results :worship:
Let me know how things work out for you with your jetting and I am going to try the 45 as I noticed the air screw is more and more sensitive when the choke is screwed in less than 10 clicks so maybe the choke is masking?
I think I will try to jet with the choke around 10 and get good results with the air screw and go from there, if that doesn't work then there is always the cliff idea.

 

[RM_guy]

My Friend's suggestion to use the choke to set the idle is a bit suspect with me too but since he told me I haven't had a chance to try it. Let me now how you make out.

BTW, Eric porting gives a ton more over-rev too :)

 

[RM_guy]

OK.
I started the bike up and set the idle with the choke knob. I had to turn it out 31 clicks to idle for a few seconds before it died. The manual says 24 clicks max so I called my friend up. He agreed that 31 clicks was too much and suggested dropping the pilot down one more size. I already went to a 45 so I'm trying a 42 now. My throttle response with the 45 is good with the air screw at 1.5 turns out so I'm interested to see what effect the smaller pilot has on the air screw setting. I'll let you know next week how I make out.

BTW, even though the manual says not to set the idle with the choke knob, it says right on the knob to use it to set the idle. :confused:

 

[RM_guy]

Let me start out by saying I HATE jetting!!! :( :whiner:

I put in the 42 pilot jet and it didn't seem to make any difference with the air screw setting or the amount that I had to turn out the choke to get it to idle. I went back to 12 clicks on the choke and set the idle with the slide stop. I'm going to leave the 42 pilot in and try it on the track this weekend. I was going to try a 40 but the shop didn't have it in stock.

I WILL get this freaking thing figured out... :thumb:

 

[ktm 550 mxc monster]

I think the powerjet is confusing the issue, I hate powerjets. I am struggling too, I also couldnt get a 40..what a pain..lol

 

[Ojref]

Are you sure that you aren't leaking air into the engine? You've stated that you have done a top end and put in a V-force block, which is notorious for causing air leaks. If you have a air leak you will never be able to jet the engine properly, ever. From what you said about the surging at idle sounds like a air leak.

PS I used to live in Duncanville, major riding areas out there. Dallas is like heaven for dirt bikes.