Clinician
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Post by jhare on Sept 23, 2018 2:38:42 GMT -6
Grab a multimeter and start testing. Could be battery, could be a bad ground somewhere, or maybe even there's a short somewhere in the wiring. Sometimes wire sheaths will rub off and two wires or wire to metal will be in contact, so once you turn the ignition switch it can be shorted out by another wire or metal touching it.
Also, when the ignition switch is turn ON do other electrical stuff work? Lights, horn, indicator lights, etc.? If yes move on to checklist below, if not check battery voltage and replace if necessary or charge.
This would be my process:
-Examine the ignition switch wire and see if there's continuity. Also physically examine the wire and follow it, check to see if the sheath is rubbed off and the exposed wire is in contact with something shorting it out,
-Test battery voltage to determine condition,
-Check all grounds,
-Determine good continuity throughout electrical wiring and check condition of wires.
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Clinician
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Post by jhare on Sept 22, 2018 13:07:28 GMT -6
Cybord, great insight! The woodruff key was indeed missing!!! There was some shearing on the crank rod and inside of the flywheel. Luckily I had another part laying around, popped it in, sprayed some ether in the intake and the engine fired up! I'm going to reassemble everything and take it out for a short ride. Thanks everyone for your help with this.
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Clinician
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Post by jhare on Sept 19, 2018 3:03:33 GMT -6
I had time to work on my scooter today, so here's my update:
I replaced the spark plug and spark plug cap, got good resistance readings all around (coil, spark plug, spark plug cap). I can't get the engine to fire by pouring gasoline or ether into the intake. The spark plug has spark verified by grounding it to the engine block. Rechecked valve clearance and it's within spec. Battery is fully charged. I swapped out the CDI with one from my other scooter (same type of scooter and same type of CDI), but no combustion.
Thoughts?
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Clinician
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Post by jhare on Sept 14, 2018 12:36:02 GMT -6
Another example of my type of carb:  |
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Clinician
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Post by jhare on Sept 14, 2018 11:06:45 GMT -6
I see. The carb I'm working with doesn't have an accelerator pump (at least I don't think so). My carb is a Keihin pb20, here's an image I found:  |
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Clinician
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Post by jhare on Sept 13, 2018 10:49:02 GMT -6
czmdiver, do you mean to bypass the carburetor? For example, remove the carb and spray ether directly into the intake port?
ucwt, good point, I had already checked the enriching arm (which I take to mean the jet needle connected to the throttle slide/valve). The jet needle would move smoothly up and down the needle jet (i.e., the jet that delivers gas from the bowl) when the throttle was articulated. One thing I'm having a hard time figuring out what is the proper amount of turns out for the idling screw (i.e., the screw that adjust the placement of the throttle slide).
Update: Doing some more research I determined the spark plug I'm using is fuel fouled, the tip is completely black. When I ground the spark plug to the engine block it still sparks bright blue. I've read that a fuel fouled spark plug will spark but may misfire, maybe leading to my problem? Any insights on this issue is much appreciated.
I'm waiting for a new iridium spark to arrive.
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Post by jhare on Sept 12, 2018 12:48:32 GMT -6
Thanks, ucwt. One of the o-rings was compressed. I went ahead and changed both o-rings at the intake, but it didn't change much...
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Post by jhare on Sept 11, 2018 19:08:22 GMT -6
The sound you're describing seems like your engine is backfiring. If you have a carburetor then you need to adjust the idle screw, that will help with the engine turning off at low speeds/idling. To deal with the backfiring, it could be your fuel-air mix screw also needs to be adjusted. Follow the advice above and watch a few videos on carburetors, download the service manuals for your scooter and read them. Since you don't know much it could be worth it hiring a mobil scooter mechanic to fix some of these issues and sit with him/her to familiarize yourself with your scooter. Your last problem you described sounds like the the fuel tube connected to your carburetor popped off, thus leaking gas when you turn your petcock on. Reconnect the fuel line and you should be fine.
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Post by jhare on Sept 11, 2018 18:47:41 GMT -6
I have a 2002 Bajaj Chetak 150cc I'm trying to get running again and I've run into a wall, seeking your insight. I got it for cheap from someone that said it's been sitting 5-6 months and it had started fine back then.
Info I have collected so far:
OD reads 2200 miles
Spark:
-Compression is good at 170 psi
-valves are within spec (I had to adjust the exhaust valve, it was a bit too open)
-Verified spark by grounding spark plug to engine block and kickstarting, bright blue
-I replaced spark plug hood with NGK resister
-spark plug wire has good resistance (coils seem fine to me)
Air:
-Air filter and passages are clear
Fuel:
-Filled tank with fresh gas
-I cleaned the carbs and reassembled (they were pretty clean when I opened them up)
-fuel flows freely
-float height is within spec
-throttle cable is loose, it's stretched out and can't be adjusted, so there's some slack in the throttle cable
Fresh battery fully charged.
Problem: The engine will turn over but despite all my efforts it will not run. I have sprayed starter fluid in the carb before starting the engine and then another time while starting the engine and it still won't run. With the starter fluid the engine seems to have some ignition, but it's small and won't be long enough to make the engine run, even for a few short seconds.
Thoughts?
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