Ryca has never been known to show much common sense in the design of exhaust systems for there kits,the exception being the café which uses the stock header pipe.It has to due with wave tuning ,without getting into that subject to deeply ,I'll just say, If you have the stock header and you have room to put the supertrapp,muffler on the end ,it would go a long ways toward getting your bike to run normally.You would still have to do some carb tuning .Header length for our 650 should fall between 30 to 34 inches stock header is 32 ,yours is 45 and being larger 1 3/4 inch in dia. makes it even worse,the header on the bobber (Ryca) is to short and also poorly designed.

It is hard to judge if your running to lean or to rich as both will blue the pipe, the best way to check is to pull the sparkplug ,if the plug is covered with soot your very rich ,if it's bright white your lean. but the best way is to use a new plug ,run the bike at moderate high speed ,shut it of and then check the plug.I would guess due to the filter,intake, and the larger header pipe that you are running lean. Have you changed to larger jets or is your carb stock? I'm guessing your idle jet is ok(maybe)  ,but when you open the throttle your going very lean .you have the jet set from Lancer you need to use it,you might need to use a main jet in the 150 to 155 range and the spacer mod would also help.

You are probably way lean, but just to be clear, did the bike run properly before the conversion?  And are you using the stock petcock?

No, I did not run the bike when I got it, except to start it up and verify that it ran. I did the cosmetic work, checked the inside of the motor for cam chain problems, etc. but did no mods to the motor. I have a Raptor petcock.

I am in the San Fernando Valley. I made mine to look like a converted dirt track machine. At the Nostalgia Drag Races last weekend many thought it WAS a race bike. Asked if I had raced it. I think the alloy rims, Universal tires,  exposed filters and Supertrapp helped with the image.

I just couldn't get past the Ryca gas tank with the hole in the middle, or the fact that it had rear sets. Proper dirt bikes have the foot pegs under the motor, not behind it.

I see the reasoning behind their offerings and it might be a successful marketing venture. I think mine is truer to the street tracker concept. The obviously home made metal brackets also make it look like a non factory creation.

John in Kalifornia

John , Very nice , that looks good ! What tank did you use ? How much fuel does it carry ? Sorry for all the questions , but I'm a street tracker nut , ok just a nut !

I thought you posted bike up before??  Did you change user names?

John:

I used an oxygen sensor to jet my carb (both the stock carb and the Mikuni), and there was another member named Halvor that did the same thing.  I had an older narrow band oxygen sensor that has a single wire to the oxygen sensor.  These narrow band sensors are from computers trying to reach that magic 14.7 - and they have a very limited reading range above and below that mark....still it proved to be very useful and taught me a lot.

The reading will jump around a lot as you ride, and only at a steady throttle setting will the display be stable.  When you begin to open the throttle the vacuum in the venturi will drop, and it takes a short period of time for the engine and airflow to react - but for that short period of time the mixture will go lean (the lower vacuum in the venturi pulls less fuel though the jets).  If you "whack" open the throttle the vacuum drops and the lean condition is worse.....and this is why they put accelerator pumps on carbs to provide more fuel when the throttle is opened quickly.  There is no way to jet to eliminate the temporary lean condition on the Mikuni Round slide carb.....the stock CV carb tries to correct for this by having the slide vacuum controlled and never letting the vacuum drop too low.  (The Dial A Jet device is supposed to be able to adjust for this lean condition and add more fuel flow when it senses a lean condition).

A lean condition also is created when you let off the throttle and are slowing down or coasting.  The higher vacuum pulls a lot of air through the carb - but the slide needle is dropping and will reduce the amount of fuel flow through the jet.  This situation is what causes the engine to pop and backfire if you close the throttle completely when slowing down....there just isn't enough fuel flow to provide a mixture that can be ignited in the cylinder by the spark plug.

In both of the above lean conditions that occur during sudden throttle opening or sudden closing - the secret is to roll the throttle ON/OFF more slowly and never throw the engine into an excessively lean condition.

But back to the jetting - the oxygen sensor does a very good job of showing the steady state conditions at all throttle settings, and it is a very useful tool.  I jetted my bike so it was just a bit richer than "stoich"  The 14.7 is the best ratio for economy, and around 12.5 for power.....I am somewhere between those numbers.

When you weld in your oxygen sensor bung - I believe you should be up in the flat area between the curve at the head and the curve down by your footpegs.  Most factories put the oxygen sensor in the exhaust pipe very close to the outlet of the exhaust manifold - and some systems have a second sensor located after the catalytic converter.

I have a pipe with the sensor bung already welded in - you are welcome to use it if you pay shipping both ways (but you are on the opposite side of the country from me, and it likely is easier for you to get your own pipe made).  I had to drill a large hole in the outside pipe and a smaller hole on the inside pipe - and the bung is only welded onto the outside pipe.