Help with carb or???

[scosgt]

2012 SYM HD 200 EVO 6000 miles.
It had a slight hesitation in the midrange.
I changed the petcock (tried both a GY6 type and a new original SYM) changed the fuel filter. Got worse.

Opened the top of the carb (Kehlin CV type) and sprayed it out. Diaphragm is intact. Got worse.

Adjusted the valves (really only two, and they were not off enough to make any real difference).

Pulled the carb and cleaned out the jets and float.

So here is the problem:
It starts instantly and idles SMOOTH. It revs like crazy on the stand. BUt as soon as I put a load on it, it bogs. I can barely hit 35 MPH, and it takes a while. Not sure if it is flooding or fuel starved.

So the very first question, is it possible to install the top parts of the carb (needle, needle seat, spring, guide, diaphragm) improperly? It does not look like it, but that is basically when my severe problems started.

Any ideas????????? Need help.

[bull]

yes, your problem could be a needle out of position or binding, but I would suspect the diaphragm is out of position, cracked, ripped or damaged in some way thus not providing a sealed chamber for proper operation.

To determine fuel status w/o feedback system- pull the spark plug and check the insulator color- if black too much fuel, white too little, slightly tan correct fuel

[blueboy5000]

Is your air-filter clean? Bogging usually indicates a rich condition.

[blueboy5000]

Also do a "plug chop" to determine if your mixture is correct. Sym usually sets their mixtures a tad lean, which becomes more noticeable as the bike breaks in.

[scosgt]

I had the carb diaphram installed wrong. Got it right, the bike runs again.
There is some hesitation but it does accelerate.
However, on right hand turns it hesitates and sometimes acts like it wants to stall. That is a real head scratcher.

One thing I did was snip off about an inch of the vacuum hose going to the petcock and use a better clip. That may have helped. But I still don't know why it wants to die on right hand turns. Once it gets going, acceleration is OK but not on a par with my 2009 HD 200.

Looks like a trip to the shop is in order so they can out some meters on it (now that I can ride it LOL).

[scosgt]

So here is an update:
Got the carb, fuel filter and new petcock (SYM original) all working fine.
Could not figure out the hesitation on corners. Increased the idle rather dramatically, it got worse.

So, just for the heck of it, I cut the idle down to where it stalls, then came up just a bit. VOILA. Got my power back (still a little hesitation at WOT at speed, but I hit 58 MPH on my test track, and I consider 56 to be "normal" on the other HD (GPS speed), so the acceleration is OK).

So here is what I think is the problem: I noticed, with the lowered idle, that the higher running gear does not release or downshift until between 13-15 MPH. I can actually feel the bike slowing with engine braking, then at about 13 it "releases". So if I take the corner from a standing start (stop sign), or slow to under 13 MPH, it works just fine. If I take the corner at 20 MPH (just for testing), I can feel the engine fighting with the gears - exactly how a car would feel if you tried to accelerate in 4th gear at 20 MPH. It does not stall, but it does lug.

When I got this bike at about 6K miles, it appeared the gear oil had never been changed. It came out silver metallic, something I had never seen before. I have changed it twice, the first time the it came out silver, the second time it was clear.

So I am thinking there is a problem in the gear box, which probably can not be fixed except by changing out the gear box itself.

I will try using a lower viscosity gear oil, maybe that will loosen it up a bit.

Any thoughts?