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Post by chadcollings on Apr 16, 2011 19:48:17 GMT -5
Well from the great help I got on my '88 Jog and it officially up and running, I guess its time for me to be over confident and attempt my next project. I have a 2001 Aprilia RS 50 (Hopefully you guys are ok with this style of scooter- being less of an upright scoot) About 2 years ago I went out to start it for the season - and nada. Thing wouldnt start via electric start (12.5 volts coming out of the battery) Could not bump start Ended up shelfing it as this is when i bought my Ducati, and havent really been back to it til now. I had a mechanic friend tear it apart last season, he didnt get to far into and diagnosed that it was seized. (I question his diagnoses, which is why I am here) As of current I just hooked up a fresh battery (12.5 v output) to it and gave it an attempt at starting. All I can hear is a low buzz/hum. No cranking. Advice from here would be fantastic!! Keep in mind I am not savvy on alot of mechanical terminology. So speak slow and use small words Pics of anything upon request. Thanks guys! Chad
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Post by D-cat on Apr 16, 2011 20:16:42 GMT -5
Remove the spark plug and try to turn the engine by hand. If you can't, your mechanic was right.
I sometimes is possible to unseize an engine but it will never be reliable again until you do a top end.
This bike is powered by a Minarelli AM6 (2T Liquid Cooled) engine equiped with a 6 speed manual transmission. Nice bike. Even nicer, it's a vertical piston so you won't need to remove the engine first to see if this works.
Assuming it is seized: Simply, spray a couple cc's of penetrating lube into the combustion chamber (I like the PB Buster). Wait about an hour, then try to break the engine free by the shaft (may require some force, kickstart isn't going to do it... pipe wrench might (try not to cause more damage)). repeat if necessary. 3rd try let it sit over night. If you can't free it after 3 tries, it probably isn't going to happen.
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Post by chadcollings on Apr 16, 2011 20:38:00 GMT -5
D-cat Spark plug removed. But honestly I am not even sure how I would go about turning it by hand? Cause as you have noticed.. I am not the mechanic in the family.. Here are some pics labeled.. cause honestly.. I dont know whats what down here...
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Post by D-cat on Apr 16, 2011 20:54:04 GMT -5
What a mess, no wonder you put this on the back burner.
I'd remove the round cover on the transmission side (bottom photo), I think that's your best bet for safe shaft access. If it's still legible, might want to read that label... I have no idea what it says.
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Post by chadcollings on Apr 16, 2011 21:19:00 GMT -5
I took the panel off and it can be rotated with a socket wrench. I I am not sure what "normal" resistance should be? But he can be rotated easily with the socket for about 3/4 of the turn, then there seems to be some more resistance for about 1/4 of the turn, then it smooths back out.
I also disconnected the starter motor and hooked it directly to the battery, and it was turning freely.
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Post by Beachy on Apr 16, 2011 21:53:08 GMT -5
So, could you hear air flow from the spark plug hole when you turned the crank? Stick your finger in there and see if you feel air flow (compression).
If it's not seized I wonder if the hum is from a bad starter relay? That would be a cheap fix. Can you crank it over with the starter with the spark plug removed?
Cool looking bike, I'd like to see you ride it someday soon. If you'd like to donate it to a charitable cause, I'd love to take it off your hands.
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Post by chadcollings on Apr 16, 2011 22:15:26 GMT -5
I am getting compression when it spins.. I ended up putting a drill to it and spinning it. The 3/4 spin the drill would push it i did feel the "suction" over the plug hole. BUT, the drill didnt have the torque to break that 1/4 turn. I would then throw the ratchet back to it and 1/4 turn then lose again. I also took off the air box to get to the carb and reeds. And WOW this is not a Jog carb lol. I am still figuring out the best way to even remove the carb. As far as that 1/4 turn of heavy binding? is that seized? or is there somethign i can do to "loosen" that up? I have been getting people wanting to buy it even broke down for years this thing is a scream when its up and going. can hit about 65-70 just with everything stock.
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Post by Beachy on Apr 16, 2011 23:03:24 GMT -5
As someone else mentioned, spray some PB Blast in the cylinder and see if it turns easier.
I would start with a compression test, you will need to have the ability to crank it via electric starter or kick start with throttle fully open to get a good read.
I don't know the specifics of this engine, but I would guess 150-200 PSI is normal. (Someone please correct me if I'm wrong). Most 2-strokes will not start with less than 125 psi from my experience.
It's a very cool ride and considering it's ten years old you may have to rebuild the engine. But, it will be worth it and 2-stroke's are easy and fairly cheap to rebuild.
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Post by Beachy on Apr 16, 2011 23:10:56 GMT -5
I don't want to confuse you with too many ideas, but I just thought of something else which could cause the binding 1/4 turn.
If 2-strokes run too rich you can develop a lot of carbon build-up in the exhaust. I think the simplest way to diagnose this would be to remove the exhaust and turn the crank the same way you did previously
Just a thought.
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Post by chadcollings on Apr 16, 2011 23:21:39 GMT -5
just to verify, are you saying spray the pb blast into the spark plug hole?
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Post by chadcollings on Apr 16, 2011 23:35:03 GMT -5
Just pulled off the exhaust and gave it some turns... it seems like maybe it loosened it up a tad?? im also getting a little fluid out of where my exhaust was hooked up?? just a few drops on each spin.
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Post by chadcollings on Apr 16, 2011 23:46:50 GMT -5
Well i took an educated guess/risk and sprayed it into the spark plug hole.. in which it immediately started coming out where the exhaust pipe should have been hooked up.. so i cranked til the piston was all the way up and sprayed some in there. guess ill let that sit for a bit.
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Post by Beachy on Apr 17, 2011 0:13:23 GMT -5
Well i took an educated guess/risk and sprayed it into the spark plug hole.. in which it immediately started coming out where the exhaust pipe should have been hooked up.. so i cranked til the piston was all the way up and sprayed some in there. guess ill let that sit for a bit. That's ok Chad, Let that PB Blaster soak-in. Do you have the reed valves out? Not a big deal, just wondering considering it's pouring out of the exhaust port. Could you crank it with the starter?
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Post by chadcollings on Apr 17, 2011 0:23:27 GMT -5
I cant figure out how to get the damn reed cage off! been trying for an hour.
I currently dont have the starter motor even on the bike, I took it off to test it, Cause as of now when i start it (electic start) I get nothing but a soft hum/buzzz. from the starter relay(i think)
Side note. I am not getting a spark - so i need to figure out the electical next.
So next steps
Beat reed cage off with a hammer Then follow the voltage.
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Post by chadcollings on Apr 17, 2011 0:24:18 GMT -5
side note to side note this bike has no kick start (for future knowledge)
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Post by chadcollings on Apr 17, 2011 0:36:43 GMT -5
Well got the reed cage off.. now off to the electrical.
ugh
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Post by Beachy on Apr 17, 2011 0:43:00 GMT -5
Alright, so no starter and no kick start? So, how are you testing for a spark? I know it's late, are you drinking beer? It's ok if you are because I am too:)
Step away from the hammer. The reed valves should pull right out, maybe a little light prying...
Are you sure you don't want to sell it?
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Post by Beachy on Apr 17, 2011 0:56:57 GMT -5
Chad, you and I must have been typing at the same time.
I don't want to tell you what to do, but if you were my friend I would say slow down man....
I'm not sure what you are trying to accomplish by removing the reed valves and tackling electrical issues. Troubleshooting is difficult when a bike is torn apart. One step at a time...
Just my .02 cents.
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Post by chadcollings on Apr 17, 2011 1:00:46 GMT -5
LOL. Im just trying to diagnose as much as possible before i lose interest on this thing again and it sits for another 2 years. Ive moved on to electrical because im waiting for the PB to soak over the piston. So i figure while thats doing that, May as well figure out where my spark is. There is no kick start, but there is an electric start. Problem is electiric start doesnt turn anything over. Like i said all it does is make the humming noise... Which is coming from a little red box (which i assume to be the starter relay) there are half a dozed wires hooked to said box and the pug wire is on it too.
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Post by chadcollings on Apr 17, 2011 2:57:40 GMT -5
OK so I manually cranked the fly wheel putting the piston up into the top position. I then sprayed some PB Buster into the plug hole. Let it sit there for a few hours, then did it again. gave it some more manual cranking, and it seemed to be spinning a little more freely. Still holding up for about 1/4 turn, but it seemed to be not as bad. So while it was soaking and lubing i decided to start putting some things back together.
I followed the power from battery terminal to the starter motor. had voltage running the whole way. So I hooked the starter motor back up (I had taken it off to test it as instructed earlier) and gave it a spin. The electric start turned it up until its "1/4 dragging point" i gave it a few more tries each time watching the starter motor engage the gear and stick.
This is where i think I messed up.
I then manually turned the flywheel to get past the bound up point to see if the starter had a little more momentum (that being the 3/4 free turning area) if it could burn through the 1/4 binding part. Well... im guessing i WASNT supposed to try and manually turn the flywheel with the starter motor attached. Cause now the starter motor wont engage. It wont shoot forward.. It just spins back there behind the flywheel. From reading the other forums im thinking that i broke the "starter clutch" can anyone confirm or deny this for me? or give me any other input. Thanks much in advance.
Chad
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Post by D-cat on Apr 17, 2011 9:03:50 GMT -5
Possibly, but if you're only moving forward, it should have just snapped back like it's supposed to do.
Did you get those reeds out yet? I have concern for this 1/4 dragging point that it may not be the piston but rather the crank running a foul of a foreign object, like a piece of reed valve.
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Post by chadcollings on Apr 17, 2011 13:59:40 GMT -5
Honestly I dont remember if I was moving forward or backward??? Im pretty sure it was forward, but it was like 3am. I did get the reed valves out. All good and intact. Any way to test the starter motor?? Any way to check if the crank is snagging something?
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Post by D-cat on Apr 17, 2011 18:16:50 GMT -5
It sounds like you probably need to take the engine out and do a full disassemble. If you can get a service manual for this engine, I suggest you have it handy in hopes of being a little less lost.
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Post by chadcollings on Apr 17, 2011 18:49:09 GMT -5
Going to take the top end off and check for scoring. is it ok to spin the flywheel once the top end is off?
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Post by D-cat on Apr 17, 2011 19:07:31 GMT -5
Yes, and it will be a good check to find out where the drag is. Just turn it back to TDC before putting the jug back on. It's a 2-stroke so there's no timing considerations to worry about.
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Post by chadcollings on Apr 17, 2011 19:39:27 GMT -5
Well cylinder is off, there is Zero scoring in the cylinder or on the piston and rings appear to be intact. Leaving the piston attached, and spinning the flywheel, there is much less resistance (obviously) but still a small amount during that quarter turn, zero resistance during the other 3/4.
So I am assuming that its bottom end? '
If this is the case, where do i go from here?
Do I need a new engine? Can the bottom end be rebuilt? Is there anything else to troubleshoot before i go that drastic? Is there some magical fluid that i can dump in there or fairy dust i can sprinkle on top??
Thanks for the help Chad
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Post by chadcollings on Apr 17, 2011 19:41:31 GMT -5
on a side note, the rod that attaches to the piston is not straight.. appears to have a small bend in it, is this normal?? or imortant?
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Post by Beachy on Apr 17, 2011 20:36:02 GMT -5
Bent rod, you need to split the case. Not as scary as it sounds especially since you've torn it down this far. I'm surprised it didn't push the piston into the cylinder wall.
There is no magical fluid to fix this, and yes it is repairable. I would replace the rod, rod bearings, piston, piston pin and rings.
Any pics of the bent rod?
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Post by Beachy on Apr 17, 2011 20:37:58 GMT -5
It sounds like you probably need to take the engine out and do a full disassemble. If you can get a service manual for this engine, I suggest you have it handy in hopes of being a little less lost. +1
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Post by D-cat on Apr 17, 2011 20:57:28 GMT -5
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