97cc running issues, looking for input.

[ebrammer252]

I know, I know, just swap it out for a 212. But I already have the 97 and I'm trying to complete this one on the cheap.

Before I got it the motor hadn't run in years. The gas tank and carb were gummed with varnished gas. I grabbed a replacement carb off Amazon and a new gas tank.

The motor runs, it idles okay, mostly steady, with the wheel off the ground it'll rev up no problem (albeit it will sometimes backfire).

With the wheel on the ground and me standing over the bike, if I twist the throttle it'll stutter and struggle to get the front wheel off the ground. If I'm on the bike (220lbs, I know it's not going to be happy about that) the bike will get moving some but the throttle will stutter and cut in and out. If I persist I can get it up to speed and it'll run decently.

Sometimes on low speed running around it'll die and need to be fired back up.

I do know that for a while it was struggling to fire up. Pulling the plug and bridging it on the block shows a small spark, wondering if maybe my coil is going bad and this could be a weak spark issue?

I've removed the cylinder head and the cylinder, piston, and valves all *look* good, but I haven't compression tested it

Any thoughts on what could be my issue?. Can I simply move the coil pickup slightly closer to the flywheel to try and get a stronger spark?

A few videos of it idling etc

http://imgur.com/a/Fv9EqDl

 

[River Rat Ron]

I’ve owned a few of these motors that were used. Not one could I get to run consistently. Didn’t waste much time trying….newcarb about it.
I’ve been dicking with mechanical devices for 40+ yrs. Maybe when new and carefully maintained they were worthy. But I doubt it.
Wire the governor, run it wfo and pray it grenades. Video it I think we would all enjoy it. I’ll start a go fund me for you and we’ll all pitch in some change for a 212….….it has to catch fire, huge oil spill, plumes of black smoke. Slow mo is a bonus.

 

[Ginz61]

Good stuff. I’m in.

 

[ebrammer252]

I’ve owned a few of these motors that were used. Not one could I get to run consistently. I’ve been dicking with mechanical devices for 40+ yrs. Maybe when new and carefully maintained they were worthy. But I doubt it.
Wire the governor, run it wfo and pray it grenades. Video it I think we would all enjoy it. I’ll start a go fund me for you and we’ll all pitch in some change for a 212….….it has to catch fire, huge oil spill, plumes of black smoke. Slow mo is a bonus.

Brb setting up a GoFundMe haha

 

[River Rat Ron]

Brb setting up a GoFundMe haha

Oh man you’re quick….doh

 

[Harquebus]

Be neat to get it running right, as an alternative to all the guys running 2, 3 and 4 hp flathead engines on their vintages, and I mean that as a modern analogue.

Sure, check your spark and flywheel to coil gap, but it’s running good enough seemingly...

if it’s particularly gutless, can we ask what your gearing is? If you’re gearing is wrong, the strongest of motors won’t move the bike so much as it destroying the clutch in one go.

I dont know anything about these engines except that they come on base model Chinese doodlebugs And people grenade them or swap them out and/or both.

 

[Bird Brain]

Id check and make certain the choke butterfly hasn't separated away from the stem shaft if the choke stem is plastic on the carb you purchased. Ive seen this happen on Honda GX models before on numerous occasions. The point it clips onto the shaft is weak in securing the butterfly and comes loose so when running its sitting in the opening and kinda doing its own thing causing a run situation similar to what you have shown at idle. Just something else you might want to rule out.

 

[Bigjake]

Check coil gap to business card gap I'm sure you got a new plug to with all the other shiny stuff
Another thing check the muffler se if it's not plugged up