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Post by lain on Jul 25, 2016 3:53:25 GMT -5
I was riding my 92cc agility the other day when I heard a POP then it bogged to a complete stop. After taking it home I tore into it after diagnosing everything else, obvious the engine was to blame... I crack the top end open and what do I see? A part of the filter, a long piece of plastic found its way into my intake and was jamming the valve into the piston. There was only a piece of plastic melted to the top of the piston, but the valve was destroyed, the rocker assembly was all messed up from the valve jamming into it as well...
So I looked through my parts, luckily I had an unused regular big bore top end fully assembled and ready for install and a set of gaskets. I didn't want to just go for the "feel" like I did before (with great success) so I bought a brand new torque wrench... This is where it REALLY gets messed up... So I am happily installing my brand new top end... gradually increasing torque as I tighten the bolts of the top end... Then all of a sudden I get this gut feeling, I know it "FEELS" like it is over-tightening now but I continue to twist as the torque wrench was working thus far... SNAP! The top right bolt (the one that goes into the CVT side) snapped right out with part of the threaded porting inside the casing but nto protruding from either side (confirmed after further disassembly afterwards)...
So I am shocked, and just to make sure I was right about my gut feeling I went and tried the torque wrench on a car lugnut and at the lowest setting it still won't click anymore... Brand new torque wrench cost me my engine... I should have just used my elbow as a torque wrench...
So now I am trying to get my fave ride back on the road. I have another scooter (an adventure 50cc modded to 92cc as well), has a long case CVT with 13 inch wheels, and no plastics or anything just the engine wheels and seat and frame. The mounting seems to be exactly the same as the short case on my agility except with the rear shock eye being slightly further back.
I want to take the 13 inch wheel off because it is a disc brake with a damaged rotor and a missing caliper, and I want to put my 10 inch drum wheel on. Has anyone done this kind of backwards conversion before? Can I simply replace the final gear shaft for the rear wheel and pop my 10 inch wheel on and install the drum brake? Looks like it has a spot for a drum brake even though it has a disc on the rear.
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Post by cyborg55 on Jul 25, 2016 8:43:20 GMT -5
Who made the torque wrench?,,,HF?,,,,do yourself a huge favor,,,buy used snapon tools,,,they're real quality and when you buy used it takes the sting out of new retail
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Post by rcq92130 on Jul 25, 2016 12:40:57 GMT -5
Geeze Louise - don't toss the engine! Just drill the bolt stub and use an easy-out.
The stub should spin out with almost zero effort. You just gave to get something to grip it so you can turn it. Or, take your Dremel and see if you can cut a small slot in the top of the stub, then use a screwriver.
Only caveat is to very carefully cover holes so no shavings get down in the engine.
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Post by rcq92130 on Jul 25, 2016 12:41:31 GMT -5
And anyway, I thought you now had a big boy, 150cc scooter ...........
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Post by lain on Jul 25, 2016 16:04:45 GMT -5
I do, but who doesn't look at their first scooter with fondness? I loved that thing, haha. I still do.
Yeah I actually can't afford snap-on tools bro, each single tool of those is far more expensive than my entire tool collection. It was the advanced auto parts brand wrench... Now I know not to buy store brand there, I guess "store brand" no matter what kind of store just means "pieceofshyt."
There is no part of the bolt protruding, it is in there. I tried pushing it out with a smaller bolt but it won't turn and I feel if I were to stick my dremel in there it would ruin the hole before it would even dent the bolt because the case is aluminum and the bolt is steel..
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Post by rcq92130 on Jul 25, 2016 16:13:00 GMT -5
I know you know how to fix this, 'cause I remember you speaking of this before.
Option 1: Get a small drill bit and an EasyOut. Drill right down the center of the stub - need to go maybe 1/2" deep (you do NOT want to all the way since then drill chips would get down into the case). Stick the EasyOut into the drilled hole, turn counter clockwise and the stub will EASILY just screw out. I'm guessing it would turn so easily you could do so by hand.
NOTE: you can't screw another bolt into the hole, hoping to push the stub thru, since it will just bind against the stub and lock up.
Option 2: SMALL metal cutting bit on dremel, cut a small slot in the stub. Yep - it will also probably cut a slot on either side of the threaded hole - but so what? You are only going 1/16th inch deep. Flat screwdriver ... unscrew. Easy. A lot easier than Option #1, but if you don't want the ends of the slot in the case because you find it artistically crude, then go with #1.
ps: about torque wrenches. I know WELL exactly what happened to you. The tiny torque (17-ft-lbs?) is way too low for cheap clicker-style torquers. That's why so many people say we should stick with beam-style torque wrenches. A SMALL beam torquer is cheap and impossible to screw up with, though for larger torques it's less accurate.
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Post by lain on Jul 25, 2016 16:28:52 GMT -5
I know you know how to fix this, 'cause I remember you speaking of this before. Option 1: Get a small drill bit and an EasyOut. Drill right down the center of the stub - need to go maybe 1/2" deep (you do NOT want to all the way since then drill chips would get down into the case). Stick the EasyOut into the drilled hole, turn counter clockwise and the stub will EASILY just screw out. I'm guessing it would turn so easily you could do so by hand. NOTE: you can't screw another bolt into the hole, hoping to push the stub thru, since it will just bind against the stub and lock up. Option 2: SMALL metal cutting bit on dremel, cut a small slot in the stub. Yep - it will also probably cut a slot on either side of the threaded hole - but so what? You are only going 1/16th inch deep. Flat screwdriver ... unscrew. Easy. A lot easier than Option #1, but if you don't want the ends of the slot in the case because you find it artistically crude, then go with #1. ps: about torque wrenches. I know WELL exactly what happened to you. The tiny torque (17-ft-lbs?) is way too low for cheap clicker-style torquers. That's why so many people say we should stick with beam-style torque wrenches. A SMALL beam torquer is cheap and impossible to screw up with, though for larger torques it's less accurate. The easyout thing sounds promising, but I'm going to wait until I can borrow some QUALITY tools. I don't want to go out, buy some more cheap stuf, and wreck it more haha.... Kind of strapped for cash, moving very soon again and don't have a spare dime to drop, that's why I was contemplating using the other engine from the incomplete project scooter I have laying around. |
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Post by rcq92130 on Jul 25, 2016 16:40:05 GMT -5
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Post by lain on Jul 25, 2016 16:59:23 GMT -5
They won't damage the threads? |
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Post by rcq92130 on Jul 25, 2016 17:14:28 GMT -5
You drill a small hole, 1/2" deep, down the center of the stub. You put the easy out into the hole & turn counterclockwise. It has "reverse threads - ribs, really" that catch when you turn backwards. And the bolt unscrews out of the hole. Unless you drill toward the side, into the threads, nothing touches the threads.
But I would in a heartbeat use the dremel. Just did that with a stub on one of the intake manifolds of my Goldwing. Much faster, safer. Only "damage" is a tiny slot, maybe 1/8" long, on either side of the bolthole - which I could not care less about since it's no more than 1/16th inch deep.
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Post by lain on Jul 27, 2016 6:16:40 GMT -5
Well the cost of doing the recovery on the engine would be the cost of a new top end (for assurance it would work), new studs, new bolts, new gaskets, a drill, a set of bits.... So the engine with problems is going to just have to be put off till I have time and money for that.
Back to my original concern; has anyone done a backwards conversion before? The parts I have to work with is a working long case 139qmb with 50mm BBK and original head, 13 inch wheel with second shock and disc brake. Parts I can take out of the troubled engine are anything from cvt to wheel since they are all mostly new parts but the parts engine has a drum brake not disc. I don't think it's possible to use the 13 inch wheel with a drum brake since it is made for disc brakes.
Jus trying to get my fave ride back on the road with the parts I have at my disposal. I really need a secondary ride so I can feel safe about working on my main ride (needs new wheel bearings and valve stem). In my experience if I work on my main ride without having a secondary I end up jynxing myself and have further bad luck.. haha... life.
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Post by rockynv on Jul 28, 2016 8:03:49 GMT -5
Even expensive torque wrenches fail or go out of calibration with the cost of having them calibrated being too close to the cost of a new one. I use the Harbor Freight click type wrenches but always verify them against an old beam style wrench that I have been using for 45 years before using them. When the Harbor Freight torque wrench fails it still makes for a great breaker bar wrench.
For easy outs I prefer the stubby model Lysle from the Auto Parts store. If you go too cheap they tend to snap off and if the broken bit does not pop out of the broken bolt even the cheap ones will be extremely difficult to drill out and remove even with expensive carbide or diamond cutting tools.
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Post by lain on Jul 28, 2016 9:22:38 GMT -5
Really don't have the money to rebuild the engine, trying to use my engine from my project scoot.
While attempting to remove the rear wheel from the project scooter I discovered the previous owner pressed some odd piece of metal into the wheel and shaft to take up the space of a spacer, making it impossible to remove the wheel. So today I'm going to remove the final gear case section that attaches to the real wheel shaft, move the case and shaft from the other engine and combine them. Looks like if I do that I can just carry the drum brake over too. So far that's one of the few difficulties I have come upon.
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Post by lain on Jul 28, 2016 22:40:57 GMT -5
I finished working on my scoot today. I feel as if the longer engine case with a small tire is actually better than short case... Seems more powerful in the low end even though the engine size is smaller slightly (due to using stock head instead of BBK or big valve head). Will do tests tomorrow when I go back to pick it up in the daytime.
The slightly longer case fit in the frame without any problems at all and the wheel and final gear case from the short case fit as if it were made for it, which is expected since both engines are 139qmb. The muffler had to move from the old to new engine due to the fact the muffler for the engine was supposed to go with the disc brake I removed (was broken anyways). Drum brake carried over without any issues. All around minor to no issues at all equipping a short case engine frame with a long case engine of the same type. Hope others find this info useful.
I used a long case engine from a Jonway Adventure 50cc (modded to 92cc~) and put it in the frame of a Jonway Agility. I should mention though I removed the stock 11 inch rear shock from the agility and installed a 13.4 inch adjustable shock in the rear, which may have been a big factor in making it fit, but I had done it because I wanted an adjustable shock and it's what I had in the bin.
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