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Question -
Hello Mike,
Being a car and bike builder for over 30 years, I don't often get stumped. I have just finished building a '99 Evo Sportster, with a custom built softtail frame, for my wife. The engine is bacially a '99 model, (freshly rebuilt- 883 bored to 1200), although the rockers, pushrods and all top end covers are off a '92 model. Likewise with the cam and timing covers. It is equipped with Andrews N4 cams. It uses a stock type '84(?) to '99 softail oil bucket and the cam gearcase breather line is connected to a return port in it. I opted to use a DYNA S type dual fire electronic ignition with a mechanical (only) advance- the reluctor is integral with this item- it came with the unit when I purchased it. The coil is a Midwest supplied dual fire coil for electronic ignition- mounted in the softail location. The plug wires are brand new blue streak wires for a softail. The carb is a stock '99 883 CV unit- #42 pilot jet and #160 main jet. I drilled out the cover over the pilot adjust screw and have been adjusting it at anywhere from its original setting of 1 1/4 turns to up to 4 turns.( all that this did was raise or lower the idle speed). I am running a mid '90s FXDL gas tank with a stock petcock- the fuel flow seems to be about the same as on my dyna.
Now for the real problem- the bike runs well when leaning ever so slightly to the right and will run okay when standing straight up- as long as it is revving in the 2000 plus rpm range. However, when leaning left-especially when on the jiffy stand at initial startup/warmup- it is not running on one cylinder. I am quite sure it is the rear one. You pick the bike up off the jiffy stand and lean to the right, the cylinder cuts in and it sounds fine. You straighten to vertical and it starts to miss, although revving it up seems to keep it running on both cylinders. You lean it back on to the jiffy stand and it cuts out completely - and does it consistently. It does this with or without the air cleaner installed, with or without the cam gearcase breather connected to the oil tank (and plugged or open). It also does this with a spare carb from a '93 Evo softail 80 incher. I have run my hand along every inch of the spark plug wires while grounding the back side of my hand and no shorting to ground. I have played with the float level (gone higher, gone lower, gone correct, gone way higher), made sure the float bowl vent is not blocked, drilled out the pilot jet by .003" - nothing changes. Revving it when leaning left causes atomized gasoline to reverse a little out the carb airhorn and while revving it, leaning over to the right causes way less gas to reverse out the air horn. Do you have any ideas
Answer -
Do you have the tilt switch installed?
Mike
Hello Mike,
I don't know what a tilt switch is. I custom wierd the bike myself. It has 2 load circuit breakers, a main circuit breaker, all the (baically stock type) handlebar switches, a mechanical speedo and a stock type dash mounted ignition switch. It does not have a fuel guage sending unit installed. (I used a shallow expansion plug and used the guage unit to plug the left hand hole- no it doesn't leak)The wiring port into the fuel tank is plugged. I am pretty sure that, unless a tilt switch is hidden within anything I have itemized.
Further to the first correspondence, I went on to Andrews Cams' website and tried a few things from their install data. Mostly, installing a 65 pilot jet and setting the idle screw to 2 1/2 turns... no change. The exhaust just smells fatter, thats all.
Any further ideas?
Thanx
Dave
AnswerYour question really has me stummped. I have never heard of a problem like this.
Since you have changed the carb and the same thing still happens, you can elimate the fuel problem. Since you are losing a cylinder when you lean the bike I would say its an electrical problem. Since you say you custom wired the bike yourself you probably didnt install a tilt switch. what a tilt switch does is kill power to the bike, if the bike goes past a certain degree. Like when the bike falls over.
I would start by removeing the plugs, turning the bike over while somebody leans the bike and make sure its only firing on one plug. If it is I would test the plug wires or replace them with good ones that you know work. Same with the plugs. Even though they are new, they might be bad. I would test the coil also. If That doesnt help, then I would check the wiring to see if anything is touching when you lean the bike over.
Good luck and happy riding
Mike
