Loud Bang/Mini Explosion, Now it Won't Start

[panchothedog]

If you watch the videos from Red Beards Garage and the Grey Goat Garage
they show and EXPLAIN in great detail the right way to hop up the 196 and
212 cc engines. Those are the most common engines found on mini bikes
today and are very similar to each other. One has a slightly larger bore but
other than that are almost the same.

 

[desert rat]

Thank you. That's great advice. And yes, that would be a costly zip tie.
Now admittedly, most of my mini bike knowledge is from YouTube videos (I know, I hear myself and how dumb that sounds in retrospect), but are you saying that I shouldn't try to modify these mini bikes at all? Or, if I modify one thing, I need to strengthen other things to compensate?

If you want more out of your bike you need a bigger motor or better parts. The gov. keeps the motor at a max RPM that the current parts can take. If you did not put a screen door in the block then the parts you broke will be replaced in a proper upgrade. More horsepower cost money, there is no cheap power.

 

[old shed finds]

I'd pull the flywheel first and look at your flywheel key ....
Sheering it in half will throw the timing off and backfire a loud explosion.

Throwing a rod would have ," I'm most cases spray your legs with oil and make a oil mess".

And you say you get back home and it pull starts fine but won't fire? Most cases a thrown rod will lock the engine up in pull start mode....

 

[SAS289]

....

If you watch the videos from Red Beards Garage and the Grey Goat Garage
they show and EXPLAIN in great detail the right way to hop up the 196 and
212 cc engines. Those are the most common engines found on mini bikes
today and are very similar to each other. One has a slightly larger bore but
other than that are almost the same.

It's best for someone new to minibikes and small engines to get as much information as possible before making changes. This forum is great for that.

Wouldn't it be funny if the OP came back and said "Red Beards garage? That's where I learned the zip tie trick!"?

 

[MrBPrice]

Problem found...but first of all, thank you all for your help and suggestions. I got back in town last night. I woke up with an upset stomach and had to call off. I figured I would go ahead and pull the motor in between bathroom visits. After getting it on my bench I noticed a lot of damage to my flywheel cover. I removed it and found the flywheel magnet and some other pieces laying in the cover. Those pieces also put a nice penny sized hole in the engine block. So it's toast. Time to start motor shopping....

 

[MrBPrice]

....


It's best for someone new to minibikes and small engines to get as much information as possible before making changes. This forum is great for that.

Wouldn't it be funny if the OP came back and said "Red Beards garage? That's where I learned the zip tie trick!"?

This is very true, but unfortunately I found this forum after I destroyed my motor. Live and learn....

And no...it wasn't Red Beard. I actually watched his video on removing the governor internally because I figured that would get me close to the control rod and in that video he mentions that removing the governor will raise the rpms to a dangerous level and that the Flywheel could shatter and kill you.

 

[Mariah]

You are sooo lucky a chunk of that shrapnel missed your leg! That wire tie on the governor spring was a serious mistake.

 

[toomanytoys]

And there is why we preach what we preach here. This post should be stickied and titled why you don't zip tie or otherwise bypass your governor without proper parts.

Glad no one was hurt.

 

[massacre]

That was a close call!

 

[Mark Brown]

That was a close call!

I might say "This a was a near miss!" - which if you look critically at the words, actually means a hit.

 

[MKW]

Question...Are Briggs flathead motors as likely to come apart as the Clones are when the governor is removed??

 

[mustangfrank]

Problem found...but first of all, thank you all for your help and suggestions. I got back in town last night. I woke up with an upset stomach and had to call off. I figured I would go ahead and pull the motor in between bathroom visits. After getting it on my bench I noticed a lot of damage to my flywheel cover. I removed it and found the flywheel magnet and some other pieces laying in the cover. Those pieces also put a nice penny sized hole in the engine block. So it's toast. Time to start motor shopping.... View attachment 286464 View attachment 286465 View attachment 286466 View attachment 286467

Looks like the coil mounting boss/coil took a lot of the energy and probably save your leg taking a hit. Lesson learned, glad you reported back with your findings.

 

[kayde]

Even though I don't know you I'm glad your ok, as that incident had the potential to be way worse.

Hopefully this thread opens the eyes too some of the younger crowd that seems too think the zip tie trick is the way to go cause it's so cheap and easy.

Call you lucky as that coil probably saved your butt.

 

[MrBPrice]

Even though I don't know you I'm glad your ok, as that incident had the potential to be way worse.

Hopefully this thread opens the eyes too some of the younger crowd that seems too think the zip tie trick is the way to go cause it's so cheap and easy.

Call you lucky as that coil probably saved your butt.

I'm going to mount the coil and Flywheel shroud above my workbench. They definitely saved me from injury. I started out just wanting some mechanical advice, but as things developed, this brought to light some serious safety issues. I learned a lot from this experience and hopefully others will too.

 

[FOMOGO]

I'm going to mount the coil and Flywheel shroud above my workbench. They definitely saved me from injury. I started out just wanting some mechanical advice, but as things developed, this brought to light some serious safety issues. I learned a lot from this experience and hopefully others will too.

It could have been worse. Glad it wasnt.

Hemi_Flywheel

• FOMOGO
• Jun 23, 2017

 

[Strigoi]

If you get a new motor you will most likely need a new clutch. Most new engines are 3/4" shaft. The crankshaft on the 196cc HiSun on the coleman is 16mm. People say it is 5/8" but not exactly. Look on Facebook marketplace for a Coleman engine if you need one. People are always wanting to put torque converters on their bikes but the 16mm crank is hard to find parts so they just replace the engine. If you do need a new engine, the 212cc predator at Harbor freight is on sale. Basically find any engine with a 3/4" shaft. A torque converter is going to be one of you best upgrades. You can find one on Amazon for $65. Get one with a 3/4" driver and the sprocket for #40 or 41 chain. The torque converter will increase your takeoff and top end speed. To run one on the Coleman you need to raise the engine up about an inch. Use square tubing. Watch youtube videos but don't get all your info from 1 source. Watch a few and you will be able to sift through the BS.

Not all of those engines run the smaller crank. Some do have the standard 3/4" one. You need to measure before doing anything.

Question...Are Briggs flathead motors as likely to come apart as the Clones are when the governor is removed??

Yes. The risks are exactly the same. If a flathead lets a rod go it comes out the front of the block though. Not straight up at you. Watched a friend's 5hp Tecumseh shoot a chunk of rod a good 40' from the bike when it let go, making a nice hold in the case while doing it. Cast parts are cast parts. You want to run billet if going for anything more than those stock parts were designed for. I think it's even more prudent in an engine like a 5hp Briggs that's not being made anymore. I've only got one bike with a flathead in it, but I have a couple of spare blocks that are usable after some light machine work should I need them.

I know a lot of people don't agree with me, but do it right or don't do it at all. The minibike sub on Reddit is terrible when it comes to that.

 

[DeathStarJanitor]

Not all of those engines run the smaller crank. Some do have the standard 3/4" one. You need to measure before doing anything.



Yes. The risks are exactly the same. If a flathead lets a rod go it comes out the front of the block though. Not straight up at you. Watched a friend's 5hp Tecumseh shoot a chunk of rod a good 40' from the bike when it let go, making a nice hold in the case while doing it. Cast parts are cast parts. You want to run billet if going for anything more than those stock parts were designed for. I think it's even more prudent in an engine like a 5hp Briggs that's not being made anymore. I've only got one bike with a flathead in it, but I have a couple of spare blocks that are usable after some light machine work should I need them.

I know a lot of people don't agree with me, but do it right or don't do it at all. The minibike sub on Reddit is terrible when it comes to that.

The older Colemans had ¾" cranks. I assumed that since he just bought it that it would be a new one.

 

[Phil1958]

one year at winber during the parade i was riding next to doug wulff, he was on a powell with a 5hp flathead briggs. heard a decent kaboom, his motor popped like a zit, aluminum and oil went flying out in front of him. could have been a lot worse!

 

[old shed finds]

Problem found...but first of all, thank you all for your help and suggestions. I got back in town last night. I woke up with an upset stomach and had to call off. I figured I would go ahead and pull the motor in between bathroom visits. After getting it on my bench I noticed a lot of damage to my flywheel cover. I removed it and found the flywheel magnet and some other pieces laying in the cover. Those pieces also put a nice penny sized hole in the engine block. So it's toast. Time to start motor shopping.... View attachment 286464 View attachment 286465 View attachment 286466 View attachment 286467

I was close at the flywheel key sheared... But blown apart flywheel.....

 

[MrBPrice]

I picked up a Predator 224 yesterday. I never wanted crazy speed, so running this stock should be plenty for me. (And for those talking about it, yes, I needed a new 3/4 clutch)