Not great low end on Modded 220

[C George]

I built up my sons 220 into a true 225 and it runs good but just doesnt have that low end monster torque. I runs very strong in the midrange.
Im just open to 2nd opinions as I could very easily be missing something
Mods
cylinder bored and nikasil plated to 70 mm
, intake ported and cleaned up , RB head with
180-190 lbs compression , 35 mm carb with 42 / 152 jetting , pc platinum 2 pipe , timing advanced past stock , VP 94 fuel , no kips detent ball and spring , 3/16 intake spacer
Thank you for any suggestions

[C George]

Im very open to the fact of over thinking , just not the torque i thought it should have , maybe midrange is so strong that it feels soft off the bottom ???

[C George]

I'd really like to try a woods pipe on it but maybe me just being brain dead

[bikeman2502001]

you didnt mention what needle and what position you are using and what elevation you ride in, You will lose a little of the low end torque when going to the 35mm carb but not too much and you gain alot more than you lose elsewhere. The torque pipe is not usually recommended for the 220 and will be overriding the mods you have done there if low end performance is the area you prefer. Im sure someone here is using the torque pipe and could tell you more about using it. Right now the cost is about the same for a different pipe or carb you will have 2 choices with your engine either way, Mine had the kind of torque you mentioned with the stock carburetor and fmf rev pipe. Your porting shouldnt hurt the power as you left the exhaust untouched ( I hope), With the stock needle 2nd is for motocross type power and the third is for more low end torque but is sleepy with shims you can have anything you want between those 2 points I count 3 additional positions can be made between 2nd and 3rd with shims giving a total of 5 overall and you can notice each one on roll on power and control the hit. Boysen 607 reeds are of good bang for the buck with good over all performance. The pro reeds are worse not better. Fredette racing also sells a torque ring that fits between the pipe and cylinder its only 7 dollars if i remember right.

[ericr]

You might be too rich on the pilot jet. I have the 220 with the woods pipe and run a 38 pj. If you haven't yet, follow the Jetting Guide.

[John_S]

Try stock timing also just to test. My 220 runs best right in the middle with RB head, 35 carb, VF reeds, and rev pipe.

[C George]

Exhaust port is un touched , any thoughts on preloading kips system one notch ? We ride at 500-1500 ft. When we had to ride a few miles to the next trail , running the bike at 1/4 to 1/2 throttle under a Lt load it stuttered something terribly , the only time the bike ran its best was under power and even then I dont think its that impressive

[C George]

I could have missed something on assembling the kips but I triple checked myself that the sub valves were opening and closing properly

[C George]

any thoughts on air striker carbs

[bikeman2502001]

Be sure and not go by the marks on the valves mine was off by 1 tooth, but you did say you set them visually right?

[oldmankdx69]

I recently purchased an air striker quad vent carb from Sudco. This was after much fiddling with jetting on the 15 year old carb on my 05 KDX 200. The difference was amazing. Well worth the $200+.

[C George]

yes set them visually , had the cylinder done by millenium and took a long time to reassemble

[C George]

This carb i bought off ebay supposedly off a kdx 200 ,,, dont know how old

[kdxdazz]

Trying putting the detent ball and spring back in. Its there to keep the power valves closed

[spl383]

I also think your slightly rich on the pilot jet. RB modded carb made a big difference on my bike in low end grunt.

[C George]

Ive never run a pilot smaller than 42

[C George]

Let me reword this thread since this old fart cant think straight . How can I clean up the low end stutter that seems to be horrible when taking the road for a few miles to the next trail ??

[C George]

I believe this 225 engine is so tight that im going to halve to lean out the jetting

[Malibu406]

The mods definitely take away the low end tractor-like torque the stocker had. I did the RB head, RB carb, airbox mod, fmf desert pipe, wiseco piston and pc 304 silencer.

It definitely hurt the bottom as would be expected. It hits hard in the mid range and stays through the topend. More of a motocross type of power now. To counter that I just have to slip the clutch more at the bottom.

I ride mainly tight woods in PA. I used to have a CR500 and also a ktm360 now. Those bikes, especially the ktm, benefit from a flywheel weight to tame them down and reduce compression stall. I never think a kdx220 with its low power output would benefit from a flywheel weight, but I think mine and maybe yours could. Reason, because the lowend is now poor and the midrange hits hard, smoothing out the transition should give more useable power there and less tendency to break the rear tire loose.

[C George]

Thanks for your input
I may be wrong but i believe the much higher compression / intake vacume has made the fuel ratio way too rich and dirrectly affects low end