strange issue

motor started hissing last night (and still does when I can get it started), pressing on the gear cover will silence it until you release it. I figured it was the small bevel gear screw again (and it very well could be because it still does it when it does start). Then this morning on my way to work it lost power, kicked back in, and then conked out one final time and I had to pedal the rest of the way to work (being sweaty and working in a freezer for 8 hours isn't exactly ideal). It's acting really really rich too. Putting the choke on wont let it start, but it will start if I dont touch the throttle, choke off. giving it ANYTHING past slight idle it will bog down and lose all power (essentially the same effect you get by holding the kill switch while moving). And yes, the fuel valve is open, I've done that silly mistake twice already, I wont do it a thrid

I figured it was a crank seal but I'm unsure now. I havent taken it apart yet and I'm hoping another member may have experienced this. Being that I work tomorrow morning I dont exactly have the time to take it apart completely. So if anyone has any ideas, I'd like to attack the suspected problem head on.

yeah, I thought it may be the carb. However as I said its acting rich, not lean, so there shouldnt be any blockage. Perhaps my jet rattled itself out? I'll have a look before I leave just in case. It's still got the power to move me if I just let it idle but that's less than ideal for obvious reasons so top end compression is still good, just once I open up the throttle it dies instantly. Only things I can think of is maybe my reeds gave out? or something got caught in the carb throat somehow

it's a continuous hiss as long as its rotating, though it's much more noticable when it's running, but still ran great the night the hiss started, it wasnt until the next morning when it started acting up. Even more odd (though probably makes sense if it's a crank seal) is the way the power comes. there's the occasional "poof" and it'll die for a second, then kick back in, it's especially common at high revs (rather than being every say... 15 seconds, at high rev it'll do it every 1-2 secs). It's like (onomatopoeia here) "braaaaaaaAAAA--braa-braa--brrrrraaaaaa-brraaaAAAAAA-*poof*-brrrrrrr-brraaa-braaAA"

Now that it's the weekend and I'm off work, I'll be able to check. It has symptoms like the fuel line clogged and it's not getting enough gas, at least when it was raining this morning (which would cool it off and cause a slight rich condition), on my way home when it's dry and warming up it started doing what I described above. So... yeah, I'll definitely check (and hopefully find a new one) the crank seal, I had a feeling that's what it was but I figured I'd have no power at all if that happened so I thought I'd ask. It's still got just as much power, when it's not "poof"-ing

EDIT: found the cause. Took the clutch cover off, lo and behold that same flathead bolt that bolts down the small bevel wheel (the same one that made me think my motor siezed last year) came off and stripped the threads... yaay, looks like I need another one, AND some loctite. Took the screw off, the hissing stopped, it had full power again, though I'm not sure if I wanna ride it without that bolt, I know they're press-fit and all but still. Also the metals wearing down on them, need some luuube haha.

Edit 2: turns out it wasnt the cause of the puttering, just the hissing.. I'm at a loss. Went and got more gas at 24:1 dino, and now it barely works at all. gunna check the jet... idk after that...

EDIT 3: only fires if I pedal up to at least 10mph, and only spontaneously (for a single rotation), any slower and it wont fire at all. replaced the seal, no effect. Replaced the jet, no effect, checked the gas line, flows nicely, checked the reeds, they're good... I really need help here :-\

Edit 4: drained the tank and cleaned off the filter (dear god was there ever alot of gunk on it) fuel flows well again, also diluted the oil in the gas tank from 24:1 to 32:1. Still wont start. This is quite the problem. I just... cant figure it out, I've checked everything I can think of that would cause the issue. Shouldnt be a sudden air leak, the seal wasnt blown but I still replaced it. Lots of oil (black oil??? weird) behind that seal, nothing on the outside. I'm running out of options short of a total rebuild, which I dont have the parts nor gaskets to do anymore. Anybody else think of anything I should check? Is there a way I can pour gas into the cylinder to check if it fires that way? I ask because I know the fuel needs to be atomized and pouring directly into the cylinder will prevent that. I suppose next on the list of things to try is if I'm getting a reliable spark...

Yeah, I'll give a new coil a try. It's a jag coil but the box the electronics are in isnt exactly water tight so the heavy rain the last couple days could have done it (it was pouring when the issue happened so its plausible). If I can find one. My roommate just bought a new kit so I might have one laying around.

ohhh you mean the magneto coil, I thought you were talking about the ignition coil (if you buy from JN Motors they include a coil with the CDI). I actually don't have another working one, but I'll be checking the CDI next, checking the coil will have to wait unless there's a way to test it without having a second one (I'm used to PC-style hardware troubleshooting, where if you have issues it's best to have a second compatible part to test)

you called it, sorta. It was the ignition, but not the magneto coil. Turns out my CDI wasn't secure enough and yanked the wire out of the ignition coil. fixed it, runs perfectly again. Still gotta get myself a new small gear bolt... They *look* like M8 with 1mm pitch but I tried my M8 1mm threaded rod and it wouldnt go in. Tried the M8 1.25mm as well and it wouldnt either. I was thinking if I could thread in that M8 1mm pitch into it, I could cut it shorter, then loctite a nut to it and maybe forever end the issues with that stupid screw.

fatdaddy said:

And ya might have "bugur'd" the threads when the bolt came out. I don't remember off the top what the thread pitch is, but I'm sure someone will chime in and tell ya. Thatsdax has the gear, key and bolt for $11.99.
fatdaddy.
http://thatsdax.com/ENGINE_KIT_PARTS_PAGE_1.html

Click to expand...

the unfortunate thing is that it's not the gear that's threaded... it's the crankshaft itself. Meaning if the crank's threads are stripped, I gotta get yet another crank. I'm alright with that though, if I can get one for cheap I can balance it properly before I throw it in. So far the small gear hasn't budged but I'm leaving the gear gover off so I can see if it move's at all (and so if it ends up working it's way off it's not going to cause any catastrophic failures) I did measure the pitch, thats why I figure it was M8 x 1.00P, stripped threads, unfortunately, would explain why my M8 x1.00p threaded rod wouldn't make it's way into it.

If I end up buying a bottom end, it'll most likely be the dax balanced one. I'm really intrigued by it from the raving reviews it's got already, and it costs $1 less than the bottom end you linked to. However you're right, a whole motor can be had for $30-$40 more, and a whole kit for $20 on top of that. So... if the bottom end goes, I'll go with the bottom end. I have a cylinder and piston here from a type D motor that are incompatible with my current motor, but with a dax bottom end, and the spare parts from my roommate's new motor kit, I'll have another running bike for $60.

As for learning about tuning, thats the whole point of this motor, once I get everything figured out the way I want it (and it'll be ugly by the time I'm done) I'll do a brand new one the same way, but clean. My motor has oil spilled, spraypaint (my roommate's old cylinder was spraypainted black), the odd sheared or stripped bolt, a clutch that barely grips anymore (I cant for the life of me figure out norm's instructions), pemetex copper gasket maker all over the head, gaskets that didn't fit properly (SBP copper gaskets)... sure I could clean it but just seems like more trouble than it's worth (yes I do value this motor less than the price of a cleaning product)

fatdaddy said:

The Dax bottom end is a better choice, I was just showing you that you HAD a choice. And tearing apart a bottom end is something everyone should do at least TWICE. Once for practice, then again to get it the way YOU want it. So it sounds like yer going in the right direction.
As for the slipping clutch, Lets try to solve that one. The FIRST thing ya wanna do is inspect the pads. If the pads are worn out or oil soaked then they're never gonna work. If they look thin, replace them. If they are spongey from being soaked in oil, replace them. They should be pretty much rock hard. (about $10 to replace.) Just remember that there are two types, Round and square. Order appropriately.
Then look at the clutch itself. The clutch back is smooth, but the outer clutch plate should have what looks like dents, (or whatever,) in it. Just choose the newest looking plate.
Then when you put it back together, screw the flower nut in untill the clutch, when engaged, is tight enough to lock the rear wheel to the engine. It's easier to turn the flower nut with the clutch arm pulled in. So, Pull in the clutch arm, spin IN the nut, release the clutch arm and test. Do this untill you have a good lock with the rear wheel. If nothing else is wrong, sheared key, ect, Then you should have a working clutch.
Also, While you have the clutch apart, TRY to get A DAB, AND ONLY A DAB, of lube in the very small clutch center bearings. Grease is best, But a little heavy oil is better than nothing, But ONLY a drop or three. Too much will only wind up on the pads. I've been doing it like this for years and NEVER had to replace a clutch on any of my personal bikes, Just pads once in a while. Then just a dab or three of grease around the big clutch and little bevel gear. It'll help it last longer and quite it down some. AND AGAIN, just a dab.
You lucked out to have a practice motor. Most have to chance it with the expensive one. But C'mon, $3 or $4 for some stripper or degreaser.LOL. (Straight gas and a wire brush even?)
fatdaddy.

Click to expand...

The issue with the clutch is a bit more complicated than it's just not gripping, it'll grip fine (ish), but the handle is unusually easy to pull and the plate will only retract if the tire is moving, so I think it's the main spring that needs to be tightened.

Yeah, This is actually my second motor, the first one I've had the chance to modify. My roommate had a motor before me but we couldn't get it started after an apartment fire destroyed his bike, so I've been harvesting parts. I do plan on eventually getting this one all prettied up too, but after I get a new motor on my other bike. Then I'll get a new cylinder (or maybe whole balanced motor from dax? I'd really like to try balancing on my own and compare them though). and get both these bikes running great.