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Post by dollartwentyfive on Dec 22, 2015 12:10:03 GMT -5
the pickup becoming misaligned is not very likely.
judging from the info i have so far i would guess either the coil isn't hot enough or the fuel being poured in through the vacuum hose is flooding the plug.
this is why i said to use a spray bottle.
you wouldn't need to remove the carb, but then you still need to remove the fuel line and plug it, plus you would need to WOT the throttle, then spray into the carb inlet while cranking.
another tip would be to keep your battery on a tender when not working on your ride.
also, your engine should start almost as soon as you hit the start switch.
surely within 5 seconds.
anything longer than that indicates a problem somewhere.
i'm not sure of your particular garage setup, or even if you have one.
i'll read the thread to get the back story so i can better help you.
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Post by dollartwentyfive on Dec 22, 2015 12:31:07 GMT -5
I did and i didn't get any reading this was your answer to if you checked the compression. no compression indicates stuck, broken, or burnt valves, or some type of piston problem (hole in it, rings are completely gone, connecting rod broken) i'm sorry to say it but your engine will need to be dismantled. if you do not have good mechanical aptitude then i would defer to a mechanic if i were you. do not proceed if you do not feel confident in your abilities. if you know the difference between a rocker arm and an idler arm, then you should be okay. BTW, one is an engine part, the other is a chassis part. a couple other causes would be blown head gasket or a cracked head or cylinder. |
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Post by murkyapricot on Dec 22, 2015 13:19:59 GMT -5
I did and i didn't get any reading this was your answer to if you checked the compression. no compression indicates stuck, broken, or burnt valves, or some type of piston problem (hole in it, rings are completely gone, connecting rod broken) i'm sorry to say it but your engine will need to be dismantled. if you do not have good mechanical aptitude then i would defer to a mechanic if i were you. do not proceed if you do not feel confident in your abilities. if you know the difference between a rocker arm and an idler arm, then you should be okay. BTW, one is an engine part, the other is a chassis part. a couple other causes would be blown head gasket or a cracked head or cylinder. The battery was low, after i charged it and rechecked compression i got 30psi Im a bike mechanic so I have a nice size shop to work in The plug is def getting spark This isn't a new scooter to me ive had it for a year and a half and done all the maintenance myself I have a spare head and piston set ready to put on I just didn't want to jump the gun and replace something for no reason |
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Post by dollartwentyfive on Dec 22, 2015 19:29:53 GMT -5
i've been doing some searching, trying to come up with some answers for you. i found the following thread interesting, for a few reasons. it mentions the scooter not starting, it mentions the same compression(30psi), and it was posted 3 years ago. scooterdoc.proboards.com/thread/6698my scooter refused to start on a number of occasions, and they were always solved by scoping out the scoot. the valves needed adjustment, or the intake was cracked, or a wire was grounded. my advice to you is just hold your nose, and dive in. let us know what you find. BTW, 80% of the problems with my scoot was the direct result of crappy wiring/ switches. so i rewired it, and i didn't have a schematic, i had to come up with my own. |
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Post by cyborg on Dec 23, 2015 0:14:21 GMT -5
Couple things come to mind 30 psi is a no go in this engine,,,either a valve is hanging open ( funky rocker arm ,bent valve,,spring lost a coil wrap and hanging open) rings frozen in the piston or you holed a piston,,,,
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Post by murkyapricot on Dec 23, 2015 8:05:52 GMT -5
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Post by murkyapricot on Dec 23, 2015 8:08:53 GMT -5
Video, still getting same 30psi compression  |
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Post by murkyapricot on Dec 23, 2015 8:15:02 GMT -5
So very disappointing, the top end rebuild seemed to have no effect on the problem
What do I do now?
Another question, if you look at the rockers closely the small letters are upside down when installed. This is how it originally was, I'm curious to know if they have a top and a bottom? Or are they interchangeable?
Also i still found the Freewheel to be a bit difficult to spin to set TDC
In the videos I watched they span pretty freely but mine has decent resistance, is this the root of my problem?
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Post by pistonguy on Dec 23, 2015 11:11:15 GMT -5
So very disappointing, the top end rebuild seemed to have no effect on the problem What do I do now? Another question, if you look at the rockers closely the small letters are upside down when installed. This is how it originally was, I'm curious to know if they have a top and a bottom? Or are they interchangeable? Also i still found the Freewheel to be a bit difficult to spin to set TDC In the videos I watched they span pretty freely but mine has decent resistance, is this the root of my problem? Well I saw this coming. a shame Couple things. Thanks for the pics, they help You have replaced the Cylinder and Piston assy and NOT the Cylinder Head or "Head". From the pics of the Old Piston could use one from the Skirt Sides, Front and Back. (Thrust Faces). From what I could see looked like Allot of Trash went thru the Motor, thats all that stuff stuck in the Piston Skirts. Although Not Good will Not cause your Motor to Go South and Lose Compression the Way You Described. A Valve Issue Will. Along with the New Cyl, Piston Assy a Typical "Top End Re-Build" will and heck, Must Include a Valve Job, New Valve Springs, Seals and a close Valve Guide Inspection, I have Little Faith anymore in sourcing a Local Valve job, Complete New Cylinder Heads are Cheap. You Need One with the Milage you stated. In the back of my mind has always been it need a valve adjustment and has been continually Adjusted and Checked on Overlap Stroke. I hope Im wrong there. that'll give ya bout 30 psi |
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Post by murkyapricot on Dec 23, 2015 12:08:59 GMT -5
So very disappointing, the top end rebuild seemed to have no effect on the problem What do I do now? Another question, if you look at the rockers closely the small letters are upside down when installed. This is how it originally was, I'm curious to know if they have a top and a bottom? Or are they interchangeable? Also i still found the Freewheel to be a bit difficult to spin to set TDC In the videos I watched they span pretty freely but mine has decent resistance, is this the root of my problem? Well I saw this coming. a shame Couple things. Thanks for the pics, they help You have replaced the Cylinder and Piston assy and NOT the Cylinder Head or "Head". From the pics of the Old Piston could use one from the Skirt Sides, Front and Back. (Thrust Faces). From what I could see looked like Allot of Trash went thru the Motor, thats all that stuff stuck in the Piston Skirts. Although Not Good will Not cause your Motor to Go South and Lose Compression the Way You Described. A Valve Issue Will. Along with the New Cyl, Piston Assy a Typical "Top End Re-Build" will and heck, Must Include a Valve Job, New Valve Springs, Seals and a close Valve Guide Inspection, I have Little Faith anymore in sourcing a Local Valve job, Complete New Cylinder Heads are Cheap. You Need One with the Milage you stated. In the back of my mind has always been it need a valve adjustment and has been continually Adjusted and Checked on Overlap Stroke. I hope Im wrong there. that'll give ya bout 30 psi Thanks for the response, so what I'm gathering is I also need a replacement head  Should I also replace the rocker arm assembly? Sucks that what I replaced didn't work but it was a great learning experience |
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Post by ricardoguitars on Dec 23, 2015 12:48:33 GMT -5
Well I saw this coming. a shame Couple things. Thanks for the pics, they help You have replaced the Cylinder and Piston assy and NOT the Cylinder Head or "Head". From the pics of the Old Piston could use one from the Skirt Sides, Front and Back. (Thrust Faces). From what I could see looked like Allot of Trash went thru the Motor, thats all that stuff stuck in the Piston Skirts. Although Not Good will Not cause your Motor to Go South and Lose Compression the Way You Described. A Valve Issue Will. Along with the New Cyl, Piston Assy a Typical "Top End Re-Build" will and heck, Must Include a Valve Job, New Valve Springs, Seals and a close Valve Guide Inspection, I have Little Faith anymore in sourcing a Local Valve job, Complete New Cylinder Heads are Cheap. You Need One with the Milage you stated. In the back of my mind has always been it need a valve adjustment and has been continually Adjusted and Checked on Overlap Stroke. I hope Im wrong there. that'll give ya bout 30 psi Thanks for the response, so what I'm gathering is I also need a replacement head Should I also replace the rocker arm assembly? Sucks that what I replaced didn't work but it was a great learning experience I would replace the rocker arm as well, if you already have a new cylinder, piston and head, it doesn't make sense to put the old rocker arm back on; it is cheap insurance that it won't fail next. After that if you still have low compression, I think is time for a new compression gauge, lol. |
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Post by crawford on Dec 23, 2015 14:10:01 GMT -5
Did you set timing marks with cam and piston? it sure sounds like out of time?
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Post by murkyapricot on Dec 23, 2015 14:47:36 GMT -5
Did you set timing marks with cam and piston? it sure sounds like out of time? Yes i did, the "t" on my fly wheel with the big hole on the cam (the two small holes line up with the head) Ive set TDC a few times from doing the valves, but never removed the cam before, so did I do this correctly? Originally when it was new tdc didn't like directly up on the free wheel |
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Post by geh3333 on Dec 23, 2015 14:54:43 GMT -5
if the chain tensioner somehow came loose , then it would be possible for the chain to skip a tooth or more. if the timing is off , then another valve adjustment will need to be done after setting the timing.
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Post by geh3333 on Dec 23, 2015 14:58:19 GMT -5
i just saw the top end work. i was also afraid of that.
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