Bike won't start after oil plug comming off while riding

[HELLAFLUSHED!]

Need help! I was at a stop light yesterday and once the light turned green I went, then my bike shut off. I found out that my oil plug came off. I bolted it back on but now my bike won't start. I checked my spark plug and it's good, checked my vacuum and carb and they're all fine. It starts sometimes for only like 2-3 seconds then dies again. I can't even try to keep it alive with the throttle. Any thoughts?

Btw, does anyone know what's the measurement of a stock SYM DD50 shock from hole to hole? Thanks guys.

[paulpauly7]

compression test is now needed

[Wheelman-111]

Greetings:

Pauly's simple, quick diagnostic test is the right call. When the plug came out, the engine was inhaling and exhaling a TON of ambient air. Without the cooling effect of the fuel mist, the top end can overheat in just a few seconds, cooking your bore/ring interface and reducing compression to levels below combustion.

[LMH]

Empty the carb out via the bolt on the bowl, ensure its refilled, then kick to the high heavens for a while. Same thing happened to one of my first builds. I was so excited to use a pump plug/blank, and took off with out using something to hold it in. I got about 2 blocks and found the plug near my engine mount. I had a heck of a time getting it to run again, but after draining the bowl and turning my kicker leg into a wind mill she fired up and stayed on. It was doing exactly like you're describing. It'll start for a few seconds but not well and will die shortly after.
Doing a compression test can't hurt, just be sure to use a good tester.

[HELLAFLUSHED!]

Alright, I'll try to check it out tomorrow or sometime this week hopefully. Real busy at work and by the time I get home it'll be time to go to sleep again. Thanks guys! I'll keep you folks updated on what's happening.

[HELLAFLUSHED!]

Found out what my problem was. Thetes a scratch on my cyclinder and piston and the top piston ring was stuck where the line was. Bottom ring was okay though. I free'd the top ring and used a piece of sandpaper to open up where it got stuck in to ensure that the ring moves freely and now it seems fine. I was gonna try to put it back together but it was getting late and I didn't have my honda bond cause a friend borrowed it a few days ago but I'm going to pick it up from him after I finish work. Do you think it's still runnable?

[HELLAFLUSHED!]

Found out what my problem was. There's a scratch on my cyclinder and piston and the top piston ring was stuck where the scratch was. Bottom ring was okay though. I free'd the top ring and used a piece of sandpaper to open up where it got stuck in to ensure that the ring moves freely and now it seems fine. I was gonna try to put it back together but it was getting late and I didn't have my honda bond cause a friend borrowed it a few days ago but I'm going to pick it up from him after I finish work. Do you think it's still runnable?

[HELLAFLUSHED!]

[bonesv]

It looks to me like something got sucked up into the cylinder through the transfer port and hung on to the side of the piston on the way up. You better find out what it was. You can't run that like it is.
Needs a re-bore and new parts.

[Wheelman-111]

Greetings:

What are you HondaBonding?
I recommend you find what ever caused that scratch.
If you put it back together as is with a little lube oil, it should start and run for at least several minutes.

[HELLAFLUSHED!]

Yeah I'm gonna clean out the block. I use honda bond to reseal when I reassemble the bore.

[LMH]

You probably sucked something up when the plug came undone. That's so unfortunate but at least you figured it out quick!

[Wheelman-111]

Greetings:

Hondabond on the cylinder base gasket? Or the case halves? Surely not the head gasket?

[HELLAFLUSHED!]

Yeah the base gasket. The head comes with that rubber o ring.

[patthesoundguy]

That's a gouge from a foreign body right there. There is a nice ding or two in the top of that piston. Even if you honed that up a bunch you will have basically no compression. For what you would pay to fix that cylinder I bet a new top end would be the right fix. I would be digging around in that crank case to find what ever did that. Maybe vacuum it all out.