Weird 2 stroke question

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omegaunderground

New Member
Ok here goes nothing
The seal on my engine is letting oil go into my mag case on the left hand side of my motor (left hand as in standing over the bike looking down). I know I need to replace the 2 black seals on the crank, at the same time I was planning on buying a gasket kit, and allen bolt engine kit and rebuild the whole engine while I have it off. My question is as follows...

Would it be a horrible idea to (temporarily) drill a hole at the bottom of my mag cover, attach some rubber hose and attach it to a oil capture bottle stored under my bottom bracket. To better explain what I am doing I've attached a picture I created in paint, its horrible looking but it gets the point across. Do you guys think this will work? I am just sick of getting oil on all my jeans/shoes, and cannot afford to fix this for another month. Thanks in advance for any advice.

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as your piston is on the down stroke some fuel mix is being pushed out the seal, on the up stroke unmetered air is being sucked into the engine. both causing a lean condition. if it's leaking bad enough to get your foot wet you probably shouldn't be running it untill it's fixed. it could cause the motor to seize up.
 
the seals are only about $6.00. As for the screw kit couldn't you find the metric screws at your
hardware store? They would be cheaper and just as good no shipping and handling charges.
Running with a known problem is asking for more trouble.
 
I am going to invest in the seals and a new gasket kit at the very least. Its strange the oil leak went away for a few months after I drilled a hole in the exhaust tip to bypass the catalytic converter. I was on a 4 mile or so ride and the bike was doing well, halfway back on my way home the engine just stopped wanting to rev, top speed went from 32mph to maybe 17mph. My car had just done something similar (2001 impala dual cats plugged up) so I figured drilling a hole wont kill it... if it didn't work I could weld it closed.

I went home drilled the hole in the exhaust and the engine never ran better, it also stopped the oil leak. After the leak was stopped I cleaned the engine and continued to clean it weekly (makes it easier to spot a leak) until this week I opened the mag cover and it was half full of oil. Its not my primary mode of transport so I can curb it for a while and wait for parts. The engine has about 1800 miles on it, its probably due for a rebuild anyways. Thanks for the advice guys.

Also when it did leak it was about a drop of oil every 5 minutes or so, not gushing but still not good either

On a side note I took my old Trek Easton frame (whole bike weights about 15lbs), put a rear rack on it and mounted a goped friction drive 23cc engine to it... Pics soon to come after I get the wheel/drive wheel ratio proper.
 
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omegaunderground said:
Ok here goes nothing
The seal on my engine is letting oil go into my mag case on the left hand side of my motor (left hand as in standing over the bike looking down). I know I need to replace the 2 black seals on the crank, at the same time I was planning on buying a gasket kit, and allen bolt engine kit and rebuild the whole engine while I have it off. My question is as follows...

Would it be a horrible idea to (temporarily) drill a hole at the bottom of my mag cover, attach some rubber hose and attach it to a oil capture bottle stored under my bottom bracket. To better explain what I am doing I've attached a picture I created in paint, its horrible looking but it gets the point across. Do you guys think this will work? I am just sick of getting oil on all my jeans/shoes, and cannot afford to fix this for another month. Thanks in advance for any advice.

Untitled-1053.jpg
[/URL][/IMG]
Click to expand...
If it isn't dry inside of your mag cover your seal is leaking...That is no good. You can change it easily by removing the lower coils. They're the thin seals so it takes care to get them to fit properly without leaking. I got a set for sale if you need some. ..dnut
 
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I didn't know I could change the seal without having to tear apart the entire engine that is a huge relief. I didn't want to have to replace all the engine gaskets (wouldn't be a bad idea) if its not completely necessary. Thank you guys for your advice
 
those seals from usabikemotors have 2 lips instead of one, and work way better than the stock ones. you should change the other side too.
 
foureasy said:
those seals from usabikemotors have 2 lips instead of one, and work way better than the stock ones. you should change the other side too.
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The one's I have do have the double lip. MUCH better than what most sites sell. I went to the usa site and engine parts look good there. The electrical parts are priced high. Still looks like a good place to shop for engine parts. BIKE-ENGINE.COM is a good place for parts. dnut
 
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I'm gonna go all out and rebuild the motor this week. The engine has probably 1800+ miles on it, 200 or so while the oil was leaking, it runs great still to this day. Anyways thank you guys for the pics and info about the double seal rings I am definitely going to upgrade and not just replace, save me repair work in the future for sure. Now if I can just do something about it being about 95 degree's in my shop lol... summertime in California oh yeah
 
Well I ordered the parts I needed from USAbikemotors for really cheap thank you guys. Got the following....

2 oil seal thick gaskets 2$
2 oil seal thin gaskets 2$
2 Gt4 Gasket kits (every engine gasket to rebuild engine) 9$ (4.50$ each)
2 brass collar stop for clutch cable (the bolt on my clutch handle broke) 0.90$

with shipping and all I was at 17.16$, man I was expecting it to be a lot more haha. Thanks everyone for their input and help.
 
omegaunderground said:
Well I ordered the parts I needed from USAbikemotors for really cheap thank you guys. Got the following....

2 oil seal thick gaskets 2$
2 oil seal thin gaskets 2$
2 Gt4 Gasket kits (every engine gasket to rebuild engine) 9$ (4.50$ each)
2 brass collar stop for clutch cable (the bolt on my clutch handle broke) 0.90$

with shipping and all I was at 17.16$, man I was expecting it to be a lot more haha. Thanks everyone for their input and help.
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Make sure your crank spins free when you reassemble it with the new center case gasket. I've had gaskets that were thinner and the crank dragged due to improper clearance.
 
Thanks for the tip motorhead, I am going to take the bike to my father in laws to do the rebuild he is a lot better with motors than myself. All the parts I got are for the GT4 engine so I am hoping I don't hit any snags along the way. I am excited to get the brass colars for my clutch arm as I was using a brake cable bolt/flat plate off a set of 990 U brakes on a BMX, the bolt sometimes hit my leg and drove me nuts lol. I went out and got new brake pads and a cable lock this morning, cable lock came with 5 keys insane right? Have a good one now.
 
I opened up the mag side today, removed the coiled mag part, I am not 100% sure how to remove the rotor itself, I know there is probably something on the other side of the engine (maybe that small gear that runs on the clutch, I can attach a wrench/screwdirver to so it will stop spinning and let me remove that nut on the mag rotor. The seal was actually not fully seated in the hole its supposed to go in, I used a zip tie cut flat to push the seal back in all around and re-assemlbed.

Went for a ride a few minutes after and the engine's bottom end power is back and runs great. I am still going to replace the seal and rebuild my engine as it probably needs it very badly but I got the leak to stop for now. During the whole ride the engine would run smoothly at 30mph, which is something I havent been able to do for a while it seemed to lack power with that oil leak maybe it had something to do with crank pressure too I donno. Thank you everyone for your help
 
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By the way, ordered my gear on Monday @ 10am, got it Wednesday at Noon.... very very fast shipping (I selected cheapest shipping option to boot) Arrived well packed and super fast couldn't ask for anything more, great job USAbikemotors.com Will definitely do business with them again.
 
omegaunderground said:
I opened up the mag side today, removed the coiled mag part, I am not 100% sure how to remove the rotor itself, I know there is probably something on the other side of the engine (maybe that small gear that runs on the clutch, I can attach a wrench/screwdirver to so it will stop spinning and let me remove that nut on the mag rotor. The seal was actually not fully seated in the hole its supposed to go in, I used a zip tie cut flat to push the seal back in all around and re-assemlbed.

Went for a ride a few minutes after and the engine's bottom end power is back and runs great. I am still going to replace the seal and rebuild my engine as it probably needs it very badly but I got the leak to stop for now. During the whole ride the engine would run smoothly at 30mph, which is something I havent been able to do for a while it seemed to lack power with that oil leak maybe it had something to do with crank pressure too I donno. Thank you everyone for your help
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Ace Hardware sells a faucet handle removing tool/puller, that works great for removing the magneto rotor/magnet. It is thin enough to fit behind the rotor and you simply tighten the puller down against the end of the crankshaft and the rotor will come off nice and square without the usual wobbling associated with trying to pry it off with screwdrivers or other tools. I think the Ace puller is about $5.00 and found in the plumbing section. It's even chrome plated :)
 
I repaired the seal late at night so no luck getting a puller, I have one around my shop that would work perfectly but cannot find it. I have PC repair screwdrivers that came with this tool kit my wife bought me years ago, they have about 1/8" plastic coat all around the shafts, I used that to pry the mag rotor off. Surprisingly it didn't take too much effort to pull it off.

Had issues getting the seal to re-seat properly I wound up taking a 14mm socket and putting it on top of the seal and tapping the socket with a rubber mallet... worked perfectly and seal went on even. While all this was going on I noticed my chain guard support on the back had been rubbed clean through by the chain, the chain guard fell and hit the ground as I was working lol. I am going to fab something to fix that tomorrow, today I am sick and taking a break from all this. Thanks for everyone's input I appreciate it, I am very excited to get this thing back on the road.
 
You might want to set the seal just a hair below flush with the surface. That way the rotor should not rub the seal.
Norman
 
Its in there a bit farther than being flush, I wanted to make sure the mag didn't pull the seal out... when I removed my mag rotor the old seal was stuck to it..eeek lol. I went to the hardware store here in town and got Allen head bolts for the clutch cover, mag cover, and clutch arm side. Got the bolts I needed for about 4$... just one on the clutch cover side I have to grind down a 1/4" because its too long for the hole its going into.

Tomorrow time permits I am going to fix my motor side chain guard, have some plumbers tape to make a new bracket, possibly use a spacer on my back wheel to bring it away from the frame a hair to avoid future chain/frame rub. Thanks for all the comments and input guys I appreciate it.
 
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