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Discussion Starter · #1 · (Edited by Moderator)
Ok. I guess the into thread went a bit overboard, and it got locked. Understood.

Anyway, to continue on, I took both the bikes out yesterday with the little one. My bike, with the built engine is a bit faster, as it pulls slightly more revs. I need to find the carbon fiber or fiberglass reeds for it. It moves me pretty well to be 250lbs.

I also need to drill some bolts still I can lock wire them. The header bolts keep coming loose on the kiddos bike. And my muffler fell apart. Lol. I swear, it's just been carb and exhaust problems lately with these things lately. I want to look into a better exhaust, but packaging on these bikes don't leave any options.
 

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Ok. I guess the into thread went a bit overboard, and it got locked. Understood.

Anyway, to continue on, I took both the bikes out yesterday with the little one. My bike, with the built engine is a bit faster, as it pulls slightly more revs. I need to find the carbon fiber or fiberglass reeds for it. It moves me pretty well to be 250lbs.

I also need to drill some bolts still I can lock wire them. The header bolts keep coming loose on the kiddos bike. And my muffler fell apart. Lol. I swear, it's just been carb and exhaust problems lately with these things lately. I want to look into a better exhaust, but packaging on these bikes don't leave any options.
We all have had these same problems for the exhaust I go to the hardware store ( ACE ) and get new bolts then with a new gasket I use loctite red.

The problem is the Chinese bolts are made out of soft steel and they stretch so no matter how tight you tighten them the vibration will stretch them and they will come loose sooner than later they will snap off inside the thread causing you much hate and discontent it's best to replace them now while you can...

For the gasket I make my own out of gasket material ( cometic #C15180 ) ( Mr Gasket 77 )
made for automotive headers once you cinch down the bolts and this gasket material is crushed it will not crush anymore and heat will not affect it unlike the Chinese gasket that gets soft from high heat.
 

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Discussion Starter · #3 ·
Awesome! I never thought of making my own gaskets. I just reused the originals because they're doubled from the factory. Just used one, and kept the other for a spare. And I'll take your advice and just go ahead and replace the exhaust bolts. I still really want something drilled for safety wire, though. I don't pull the exhaust off that much, but want the extra safety. Vibrations are a real killer here.
 

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I would imagine you could buy some high quality hardware and then take that hardware to a fabrication shop and have them cross drill it for you on the cheap it should only be a few dollars per fastener ( quality carbide drill bits are rather expensive ) of course you could always take the venture into your own hands and get a small hobby drill press a vee block and small machinists vise. Which these tools are all very handy to have...
 

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I have never had the bolts back out. I just use a lock washer. But they are two strokes and every bolt should be tightened before and after a ride. And out of 20+ bikes, I guess I got lucky, no Chinese bolts ever broke off.
 

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I have never had the bolts back out. I just use a lock washer. But they are two strokes and every bolt should be tightened before and after a ride. And out of 20+ bikes, I guess I got lucky, no Chinese bolts ever broke off.
I would say you're very lucky person...

The ones that I have had snap off I got lucky and snapped off on the heads and was able to get vice grips on them and get them out.

I always replace the head bolts, the flywheel and clutch bolts that thread into the crank and the exhaust bolts.

The cost of about $8 for all the hardware is in my opinion extremely cheap insurance.

If I'm going camping or anything like that I have a small tool kit that I bring with me it includes all the tools to basically rebuild the entire machine some extra hardware in case something comes loose and falls off extra spark plug, carburetor, reed peddle sandwiched in between some thick cardboard and a complete pull starter ready to go...

If my camping trip is going to be more than a couple days I'll just bring a spare engine.
 

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Damn!! That is prepared. Lol
Replacing the bolt with stainless is a great idea. On my longer kept engines I definitely swap in stainless. Always lock washers and I have yet to do locktight. Except on the clutch bolts.
 

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Discussion Starter · #8 ·
On my son's bike, bolts are constantly coming loose. I've swapped the engine mount bolts with stainless, lock washers, and red loctite. I tried blue loctite on his exhaust bolts. Mine has been trouble free, bolt wise.
 

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Yeah I honestly think that the stainless bolts back out way easier than the cheap Chinese want to do. More of a slippery material I suppose. That has been my experience the lock washers I have always worked for me. But I also check them every time I run the engines.
 

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Discussion Starter · #10 · (Edited)
Yeah I honestly think that the stainless bolts back out way easier than the cheap Chinese want to do. More of a slippery material I suppose. That has been my experience the lock washers I have always worked for me. But I also check them every time I run the engines.
Yeah I understand that. I can get better torque with the stainless. Stainless Allens are hard to find for me, though. I'm thinking of knife edging or lighting a crank to experiment with. I'm also thinking of looking for a vertical engine to play with.
 

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Very nice, definitely think you're correct on more torque with those stainless. And yes do some experimenting with the crank. Quite a bit of threads on here about knife edging, I actually have an engine that the crank in the middle was hogged out. Extra light, lots of volume. Haven't ran ot yet.
 

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Discussion Starter · #12 ·
Awesome. Yeah, I'm looking for a few more revs. If I could throw in an aluminum rod, that'd be even better. LOL. At that point, It'd be useless for me to ride. I'd have to let my 7 year old take the helm, as he'd be able to take better advantage of the RPMs. I honestly need something super torquey for me. I can carry speed okay, but I can't launch to shoot out of corners at all. Especially since I'm about 5 times the weight of the bike. lol.
 

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You could send the crank to hot rods and have them put a custom connecting rod on it then send the crank to a machine shop and have it balanced at 50% balance factor and do all ceramic bearings with a wiseco piston build a custom plate for the coil so you can adjust the timing keep in mind though there is a limit that the clutch that we can put on these can hold... Right around 6.5HP that's going to be the two shoe steel clutch for the Piston ported engine...
 

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Discussion Starter · #14 ·
Shoot!! 6 HP would be amazing!!! I probably would only do ceramic crank bearings. I don't think ceramic needle bearings would hold up for long under that much repetitive shock. I could be an interesting build. Maybe I'll do that for my kids bike. He'll get more use out of that engine than I could . lol.
 

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Awesome! I never thought of making my own gaskets. I just reused the originals because they're doubled from the factory. Just used one, and kept the other for a spare. And I'll take your advice and just go ahead and replace the exhaust bolts. I still really want something drilled for safety wire, though. I don't pull the exhaust off that much, but want the extra safety. Vibrations are a real killer here.
Making your own gasket is a huge step up in the modifying process
 

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Shoot!! 6 HP would be amazing!!! I probably would only do ceramic crank bearings. I don't think ceramic needle bearings would hold up for long under that much repetitive shock. I could be an interesting build. Maybe I'll do that for my kids bike. He'll get more use out of that engine than I could . lol.
Dude, Full circle crank, port and blueprint the case and cylinder. It will have plenty of low end power to get you off the line. High compression will keep you going in the long run.
Do light clutch work with some HP springs and leave the Flywheel alone. All that balancing is not needed on these engines. Don’t send it out to anybody and spend two or three or $400. Couple cheap parts you can get plenty of low end power to get you off the line and run it. Does anybody really want to run these things more than 30 mph? If you do you’re probably insane and shouldn’t be on a pocket bike. Haha
 

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There was a member on here that used an SPX cylinder he custom fabricated his entire dirt bike himself lol he couldn't keep a clutch in the thing even with a double clutch it just made way too much power...

With these engines you can go mild to wild anything that fits your fancy 👍
 

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Discussion Starter · #18 ·
Dude, Full circle crank, port and blueprint the case and cylinder. It will have plenty of low end power to get you off the line. High compression will keep you going in the long run.
Do light clutch work with some HP springs and leave the Flywheel alone. All that balancing is not needed on these engines. Don’t send it out to anybody and spend two or three or $400. Couple cheap parts you can get plenty of low end power to get you off the line and run it. Does anybody really want to run these things more than 30 mph? If you do you’re probably insane and shouldn’t be on a pocket bike. Haha
Well, the knife edging isn't for balance. Basically lightening the counter weights to get more revs. Won't be as effective as in a normal engine, as I don't have to worry about windage as much. Blue printing it's really needed either. The tolerances are good enough as they are. The only other thing I would do would be to get a custom piston and some total seal rings, as I don't like the stock rings that much. The full circle would be for the torque build, though. Might do that for my bike, as I can't get off the line for crap. LOL. And 40 mph would be suitable for me, seeing as I'll be in full leathers and on a track when I do decide to take it that far. I just need to figure out a fork than can take the stress, as these are pretty much spaghetti noodles with springs in them.
 

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Discussion Starter · #20 ·
Yeah they are noodles. The mototec.36v 1000w electric dirt bike has fluid front forks. Otherwise a crf50 forks might fit on.
Thanks for letting me know about that bike!! It looks like it might, if I swap the fork clamps. Researching that bike, I also found the MotoTec 60 Hooligan. It's literally my bike (Holeshot X), but with a 60cc 4 stroke on it. Same wheels, better fork. They sell the legs Individually, and I can't find the Fork clamps for the life of me, but I'm looking. That will definitely solve my noodlely fork issue. I can even swap them on my kiddo's bike also. His is actually better prepared for jumps because of the DH bike shock I put on the back of it.
 
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