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New member a gyro that won't fire

Posted: Wed Jun 17, 2020 10:34 pm
by Johnthemann
Hello..Sold a lot of Sprees, Aero 50's and Elite 80's back in the 90's as a Honda salesman. Well move forward more than a few years and I just acquired a 1986 TG50 with 900 miles in near perfect shape. Perfect except it won't run and I am completely buffalo'd. It cranks over good, getting good spark, meticulously rebuilt/cleaned the carb (including emulsion tube) 3 different times now, compression is over 100, reeds look good. Won't fire period..even with a puff of wd in the combustion chamber, starting fluid in the air cleaner doesn't do it either. Totally lost..any tips would be greatly appreciated unless you mention crank seals...just went thru that on an RD350 and never want to do that again :smile:

Re: New member a gyro that won't fire

Posted: Thu Jun 18, 2020 12:08 am
by bonesv
What does the spark plug tip look like? It may have oil seeped past the oil pump into the crankcase causing it to behave that way?

Re: New member a gyro that won't fire

Posted: Thu Jun 18, 2020 6:55 am
by vintagegarage
Starter fluid has no place in a scooter shop.. At least you are keeping the air filter box in place. Instead of using starter fluid, simply fill a pump oil can with gasoline and a small amount of oil. Leave the air filter box in place, then unscrew the cap on the top of the carb where the throttle cable goes into the carb. Lift the cap slightly without removing the throttle slide, squirt a pump or two of your gasoline/oil mix into the slide, put the cap back on the carb, and hit your starter button.

Re: New member a gyro that won't fire

Posted: Thu Jun 18, 2020 9:26 am
by Johnthemann
Spark plug tip is clean..I just did a top end so all of that is good. When I say I used starter fluid..I used it with filter in place and just a puff..Im aware of the oil cutting abilities of ether..I use it to clean my tools :). Tried your method of gas thru the slide still nothing...If I didn't have spark I would swear its a safety switch somewhere...Totally lost. Thanks for the suggestions though.

Re: New member a gyro that won't fire

Posted: Thu Jun 18, 2020 6:15 pm
by motormike
I keep starting fluid around...it's the kind with "Upper Cylinder Lubricant"
Maybe you should look for that vintagegarage.
I have a two Gyros Johntheman...and both start very good.
My '85 requires a hand over the air intake on the filter box usually.
My latest "hard-start" situation was cured by a new spark plug...good luck sir...motor...:)

Re: New member a gyro that won't fire

Posted: Thu Jun 18, 2020 10:54 pm
by harleyracer59
if you just rebuilt top end, im guessing vacuum leak somewhere. do a leak down test. se whats leaking. also, 100 is low for a fresh rebuild. check head gasket

Re: New member a gyro that won't fire

Posted: Thu Jun 18, 2020 11:33 pm
by bonesv
harleyracer59 wrote:
Thu Jun 18, 2020 10:54 pm
if you just rebuilt top end, im guessing vacuum leak somewhere. do a leak down test. se whats leaking. also, 100 is low for a fresh rebuild. check head gasket
Yup. It may be an intake gasket also leaking in air unwanted. Use a sealant on these gaskets and be sure of correct torque. Check all vacuum hoses as well for cracks/leaks. Also oil pump o-ring. :wink:

Re: New member a gyro that won't fire

Posted: Sun Jul 19, 2020 3:02 pm
by wentwest
My Gyro was the same, really hard to start. I finally stripped the carb down and soaked it in a mixture of soap and ammonia and water in an ultrasound machine, and now it starts. There must have been a blockage in the idle jet passages that I never got to.