knockdolian wrote:Hi all, took my trike to work today and thought I'd show off by giving it a hand full of throttle on front of my workmates. Very disappointing result. It initially lifted the front end then cut out, cut in, cut out then in till I shut the throttle a bit. It's a 1901 carb. Any ideas ?
Thanks
Paul,
You're firmly in my territory on this one. LOTS of things it could be. Simple stuff first:
- Dirty/clogged air filter atop the carburetor
- Loose positive battery cable (yep, it can vibrate loose and cause that behavior)
- Clogged inline fuel filter(s) or filter in the carburetor body
- Loose wire connector on fuel pump
- Loose fuel pump-to-electric fuel tank selector switch-inline fuse housing (especially the old schoool twist-lock type with a glass encased fuse inside)
- Loose wire(s) on electric fuel tank selector switch (if you have one in conjunction with an auxiliary tank)
- Exposed electrical wire making contact with the frame (could be dry-rotted split in the insulation)
- Pinched fuel line
- Loose carburetor base plate (extra air getting in)
- Loose carburetor vacuum line
- Loose vacuum advance line at the distributor
- Loose spark plug on one or more cylinders
- Loose ignition wire on one or more spark plugs
- Crack in ignition wire insulation
- Loose wire harness on the distributor cap (your tach needle will bounce a lot if this is the case)
More advanced issues to look into:
- Failing ignition module (inside the HEI distributor cap)
- Failing distributor (remove the cap and pull up on the rotor cap while it's still fastened down. The rotor/internal distributor shaft should not budge upward at all)
- Failing fuel pump
- Failing tank selector switch (if you're running an auxiliary tank)
- Failing continuous duty master solenoid
- Sticking carburetor "butterfly" plates (if I am recalling the term correctly)
- Other internal carburetor problems
I have experienced every single one of these over the past 2-1/2 years, except the pinched fuel line and sticking "butterflies."
The trick is to look for the simple problems first, no matter how tedious and time-consuming (electrical especially). Throw money at it after ruling out the simple stuff, but make sure you've been methodical and positively ruled things out via test equipment and methods.