wont start

Mini Bike & Go-Kart Parts

#1
Hello everybody, I have A sachs 80b that wont start. It did once and died out, now nothing. has good spark, clean points, I even removed the motor and turned it upside down to get excess gas out of it. not flooded. the carb is NOS, so is the motor. i am stumped. could the condenser be bad? It has spark. any help would be great. Thanks.
 
#4
I have tried straight starting fluid spay in to the cylinder, also with carb removed. not even a pop. 4 spark plugs, all with strong blue/white spark. nothing, all plugs fire when out of the motor and grounded. even left a plug on the coil wire and set it over the plug hole. had a nice little fire show :censure: points are clean adjusted, timing mark is dead on. the carb is supplying fuel. 16:1, and 32:1, also regular and 93 octane. has great compression, and good intake draw. getting ready to :2guns: it!
 
#5
Make sure plug is brand new and properly gapped. If plug wire is in anyway questionable, replace it.
Do specs call for a resistance plug?
Also, spark can blow out under the compression stroke...even with a new plug.
 
#6
I don't know anything about Sachs engines. But on my West Bend, I had the same problem. Great spark, ether and gas shoved in the hole, wouldn't even pop.

Ended up being a PTO seal being blown out which prevented ignition due to zero crankcase pressure.
 
#7
OK, some great suggestions here, thanks for the help. Another new plug and i tried a new gap, .019 instead of .035 started up and ran for about 30 seconds then just stopped. would not start again. the motor cooled off and started, then stopped again. :hammer::surrender::freakout::freakout::freakout:
 
#8
I have a Kawasaki 50cc 2-stroke motorcycle that behaved similarly. It had great spark, compression and the carb looked fine. It would not start by kicking but it would pop if I pushed it. I finally discovered that the flywheel key had sheared and the timing was way off. I used an ez-out to extract the remaining part of the key, dressed the galled shaft and flywheel surfaces with some valve lapping compound and put it back together with a new key. It lit right up.









 
#9
I finally discovered that the flywheel key had sheared and the timing was way off. I used an ez-out to extract the remaining part of the key, dressed the galled shaft and flywheel surfaces with some valve lapping compound and put it back together with a new key. It lit right up.
Tom,
That's an excellent point about checking the flywheel key. Also cleaning up the shaft with some lapping compound to ensure the flywheel mates even. I've never seen a flywheel key quite like that before, it's more like a pin.
 
#10
I had a Honda MT 175 with a starting problem...pulled my hair out but then it came to me to check the crankshaft seals(because it had backfired once) One was blown out JUST enough to not allow enough crankcase pressure. Also it leaned out the A-F mixture. Also if the engine is worn ( big piston and ring clearances) the it won't run. I had a Maico 490 that was worn out. If the RPM got too low it would die! I put a new top end on it and that cured it. 2 strokes are picky about piston and ring clearances. It's all bout the pressure under the piston!
 

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