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Post by troy1896 on Feb 20, 2011 22:43:05 GMT -5
May I ask which bbk it was? I see that is was a single ring. Depending on the kit you should probably be at an 8 or 9 plug (occationally a 10 with an extreme set-up) based on manufacturers recommendations.
A 75 sure does sound lean but your motor and climate is different than mine so not sure there. The plugs could have been getting fouled from the needle or idle. Have you done any plug chops for WOT and half?
From the looks of the pic, the speckles on the top left of the piston appear that it was lean at least at some time, but not sure when since this piston has had multiple incarnations. Could just be the lighting on the carbon though I can't really tell. I agree with the others that think that some left over metal from the con rod fusing got wedged in there somehow.
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Post by motorhead on Feb 21, 2011 0:41:49 GMT -5
Either way. This bike has officially become a money pit. And once I get it running again I am just going to sell the dang thing and just get something brand new and just say :censored: 2 strokes. Because, this isn't fun anymore. I don't think I can ever get back on this bike without fear. I don't think anyone is this forum has been broke down by side of the road as many times as I have (6 total, 3 on the aprilia), waiting for their wife to drop everything and come tow them home.
Aprilia is supposed to be a good brand but... Any bike regardless of brand that was rode hard untill it broke probably wont be the same again or will drain your wallet till it runs right. I'm not the sharpest tool in the shed but the "G D" crank case was free of debris before I put it back together. whether or not something broke free and I just happened not to have found it yet, this is it for me and 2 strokes. The last one I will own and or work on. you would need more than a single friggin BB in the crank case to take down even the worst chinese 4 cycle.
I hate to vent here and go on a rant. Especially with everyone trying to help me. But I'm at my witts end. I can't go 3 days of riding without having to split the case. Thank you for all your help. You've been awesome. I'm just going to have to buy a 250cc to get what I want from a scooter.
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Post by 90GTVert on Feb 21, 2011 8:49:16 GMT -5
I don't think anyone is this forum has been broke down by side of the road as many times as I have (6 total, 3 on the aprilia), waiting for their wife to drop everything and come tow them home. My guess would be that I've walked the scoots home or had to get rides 20-30 times or more so far. I see it as me pushing the limits of what the scooter can handle, not a reason to give up on the scooters. It all depends if you enjoy learning and correcting problems. If you don't, I feel that you may be better off to stick with mild setups. Stock crank, sport kit, don't push the squish/compression, jet toward rich, etc.... If you are looking for 70MPH and suitable of a daily driver without a lot of hassle, I do agree that you'd be better off on a larger scoot like the 250cc you mentioned. |
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Post by motorhead on Feb 21, 2011 10:47:43 GMT -5
I'm not giving up on scooters. Just 2 strokes. And especially Minarelli 2 strokes. What really kills me is that I sold a fantastic TGB laser get this bike. My frustration comes from breaking down during a commute. Not form breaking down from trying to squeeze power out the engine, if the latter was the case I would feel different.
Motorcycles are ridiculous, I'll never own one. No 4 wheeled vehicle should ever get better gas mileage than a 2 wheel vehicle. 50mpg is the ceiling for motorcycles. You see bikers in a group, they might as well be driving a big rig on flat tires uphill. by 250cc I was thinking more Honda Reflex or a Linhai. or.
Who knows, maybe the guy that buys this aprilia from me after i fix it will never have an issue with it from then on. The reason I bought this bike was so I could cruise at 50, Yet still have a small enough bike to park it on the curb at the grocery store. I wanted 150cc performance in a 50cc package.
I don't know if I would classify this bike as an extreme setup. BBK, 20mm carb, race crank, tuned pipe and a stock airbox. Is that an extreme setup?
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Post by 90GTVert on Feb 21, 2011 11:25:26 GMT -5
Well, as I see it, no matter if an old lady rides it on the way to the tea shop or if you go out and drag race it... a single ring kit meant for the RPM you mentioned is pushing it. If you want a 2T that won't give you as much trouble, go for a sport level kit that revs to 10,000 or so. You won't be seeing the power and speed like the race kits, but you won't be seeing the back of a pickup too much either. 49cc scoots involve a lot of sacrifices to really go fast.
IMO the best way to make a minarelli a 50MPH cruiser and not have a lot of trouble is to go 90-100cc. You can keep the revs low (50MPH on my Venus 96cc is about 8,000-8,500RPM) and keep everything a lot less on the edge thanks to the extra displacement. 70cc sport kits aren't a bad option either, but they don't have the torque to keep larger riders cruising at 50MPH reliably when it's windy or on hills. Beyond sport level stuff, you just have to expect more problems and less life. Now, either way what happened to you sucks and it's possibly something that could have happened to even a mild kit after the initial incident.
I'm sorry this happened to you, but I hate to see it ruin your opinion of 2Ts. If you wanna get that new 4T and drop a BB in the spark plug hole before you fire it up, I think you might be disappointed. 2T or 4T doesn't matter much there. Debris bashing into the things is not going to do nice things.
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Post by 190mech on Feb 21, 2011 12:22:49 GMT -5
I just look at it as you are now a member of the 2 stroke piston club!I cant count the fried pistons I've removed over the years,but as you get to know a 2 stroke and its quirks,you'll find nothing as simple and powerful!!
I agree with Brent for a daily driver a 90cc&up is the best choice,fuel economy is not a strong point with 2 strokes,maybe a 4stroke in a larger size would fit your bill better..
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Post by motorhead on Feb 21, 2011 12:24:12 GMT -5
LOL, I didn't mean drop a bb into the cylinder. Just that on a 4 stroke, if there was a bb in the crank case it wont work its way into the combustion chamber through transfer ports.
The TGB laser I had before this had a morini 2t engine. It came with a seized crank. I swapped the crank and never had another issue with it. And having the experince on working on both of the major 2t scooter engines. I have to say that I like the morini set up a lot more. Maybe its because my experince with it was more pleasant.
You don't need a puller to remove the morini flywheel. The morini oil pump is easily accessible, it sits next to the reeds. And there is no starter clutch. Maybe I should just track down the guy I sold it to and get it back. The only reason I sold it was because I couldn't tune it. After market pipes made it run worst.
My problem with this bike (aprilia) could just be psychological. I bought it tuned expecting 70mph. The lore of super fast sr50s from other forums and youtube drew me in like a fly to a bug zapper. And since it was liquid colled I expected it to last longer. When you own a stock bike and you tune it as you go, you can feel what it want and doesn't want to do. Because you have a reference point. You know how it sounds. Either way, I don't think buying a bike someone else tuned is a good idea. A 250cc could be too big for me because I like the convenience of parking smaller scoots at the super market front door. Maybe a 150 Vino is what I need.
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Post by bigkahuna427 on Feb 21, 2011 12:42:56 GMT -5
I think someone on here has the saying the faster they go the faster they blow. Yes, trying to squeeze every last possible improvement in power does have it's consequences. You are pushing the envelope. However if you getting 100 miles out of a piston you have a problem.
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Post by 90GTVert on Feb 21, 2011 12:56:22 GMT -5
There are 250cc scooters that use the same size frame as the larger 50ccs (like the Triton). The downside there is that I believe they come with cooling issues from the factory, so again you'd need to be willing to work on it rather than just hop on and ride. For 70MPH, I think a 250+ is the best choice. www.liquidation.com/auction/view?id=3415667 |
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Post by motorhead on Feb 21, 2011 23:51:50 GMT -5
Okay, I just got done splitting the crank case for the 4th time. Crank shaft is all there. Rod and crank bearings are all there. seals intact. Wrist pin bearing is all there. Reed valve is all there. Every part is where it needs to be. And to anyone who has ever opened a 2t crank case... You know, there isn't any spare room in there, a BB wouldn't go unnoticed.
The only component I haven't eliminated is the exhaust.
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Post by 190mech on Feb 22, 2011 5:29:08 GMT -5
How about the intake/air filter?
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Post by lshigham on Feb 22, 2011 5:40:50 GMT -5
That's what I was thinking too.
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Post by motorhead on Feb 22, 2011 10:16:19 GMT -5
There is nothing foreign in the airbox, nothing out of the ordinary with the carb or intake. I did however find damage inside the crank case as seen in the picture. In person you can see that the gouge in the case is deeper and wider than the piston/cylinder scoring.
Well, in the spirit of the quote I have under my posts... S#%T happens. My scooter was just fine, it didn't fail me. No scooter would work that way. I'll give it another chance. I got 250cc performance out of it.
Has any one ever seen or thought of putting a screen between the cylinder and crank case ports to keep large objects from entering the cylinder? The screen would have to built into the gasket but it would help a 2t survive a reed failure or something like this.
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Post by lshigham on Feb 22, 2011 11:11:59 GMT -5
I would advise against it, it would reduce flow and become another thing that could come loose and cause damage.
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Post by troy1896 on Feb 22, 2011 13:10:39 GMT -5
You can always get some carbon fiber reeds if your worried about them breaking.
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