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Post by 2strokd on May 19, 2009 22:22:40 GMT -5
Got a new shock and a set of carbon fiber reeds with a better cage from Autotech on ebay. I was very happy with the shipping time, i ordered Fri. and it was here Mon. at 2pm . My new shock is great. It is made by Prodigy 250mm bolt to bolt and is well worth $45 IMO. I knew my old one was bad, but i didnt think it was that bad until i put the new one on . The reeds and cage with a Verts homemade spacer idea worked great . I noticed a little better throttle response, and some more midrange. I was still a little flat up top(above 9,000rpm). I ended up doing some tuning. I moved my needle clip back to center. Since i was already using my biggest jet (85 mikuni) and it didnt like a 82, i took a 72 i had and drilled it to a??? all i know is the drill bit was 1mm and after i drilled the jet it appeared to be just a tad bigger than my 85. Im guessing its around a 87-90 range. It liked more fuel combined with the reeds, spacer, and cage thats for sure Carbon fiber reeds can be a good power adder is tuned right And a good shock helps a ton. Especially when your old one is 8 years old
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Post by 2strokd on May 20, 2009 22:50:44 GMT -5
Bad night tonight. My uncle and i went on a 35mile round trip ride to a local town i used to live in to see a friend. On the way there i was cruising along about 40 then went to speed up when it just fell out, dropped power bad. I stopped on the side of the road thinking it was hot or not getting fuel (more hot), it was idling high. I went to shut it off with the key and it kept running With the key off! It sounded almost like it was dieseling, or running back wards at about 4grand? Weird, never had that happen. I turned the key back on, then off and it killed the motor finally. I was as puzzled and worried as could be. I checked the fuel line, it was full. I sat there for a few puzzled then kicked it over slow to see if i still had good compression. It felt good so i hit the start button and it fired right up and sounded good. It seemed to run fine, so we finished our trip. Maybe a bad call but it ran great the rest of the way. Trust me, i was paying attention . All was good until i got home, pulled it into the garage, shut it off, then went for a restart and nothing . Good spark, getting fuel, oohhh nnoooo!! The compression feels low . I took the head and cylinder off to find a set of nice Polini piston rings stuck to my piston . Did it get to hot? Not enough oil? To lean? Never got to hot before when i road it WOT for 4,or 5 miles straight. I run Klotz Techniplate oil at 50:1 (more like 45:1), is that a bad idea? Ive had people tell me Klotz is only good for race use.?. Well i race the rat snot out of my scoot sometimes, thats close right? According to my plug readings im not lean at all. What a bummer of a way to end a day !!!! It was running so good to. Any input would help . Be nice though, im hurting already
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Post by 90GTVert on May 21, 2009 5:51:08 GMT -5
That sucks. Is the cylinder and/or piston scarred or are the rings just stuck?
If the rings are just stuck it could be from carbon and you may be able to clean it up. You could try popping the rings out as gently as possible. If they're really stuck you may need to soak the piston/rings in some penetrating oil, like PB Blaster. Once they're out you could use a very find sand paper to go over the top and bottom (not inside and outside) of the rings just enough to be sure there is no buildup there. Use a razor to carefully remove any deposits that may be in the piston's ring lands.
If there is damage you'd need to hone the cylinder and replace the piston and rings. Heat, port sizes, improper oiling, and other things could cause cylinder and/or ring damage.
I don't know anything about Klotz. I have heard it's a good oil, but I've never looked into it any beyond just seeing it mentioned as a good oil. I know that sometimes when people say something is good for race use it doesn't necessarily mean that you need that oil if you rev high a lot etc... When people think of race use they think of high revving, hard accelerating, diving into turns, and all that and forget another important fact about race engines. In many cases race engines are rebuilt regularly so wear isn't always an issue for them like it is for a street motor. I don't know if that has anything to do with this case though.
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Post by 2strokd on May 21, 2009 9:24:27 GMT -5
Thanks for the input Vert. I soaked the piston in PB all night. Im gonna drop Klotz a line and see what they think about there oil in a daily driver scooter, cant hurt to hear what they think. The way these little motors run, they(the scooter motor) dont know we arent racing. The cylinder and piston still look good, and i think i can save the rings. Uncle thought it should run with that much compression, that got me thinking about my loose flywheel when i took it off. Im gonna look at that too, maybe i sheered the flywheel key and it jumped timing? Its got spark but it might not be at the right time
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Post by 90GTVert on May 21, 2009 11:38:25 GMT -5
I'm not sure how you'd get enough compression to run when the rings are stuck in the lands. If the rings can't be pushed outward how are they supposed to seal the cylinder?
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Post by 2strokd on May 21, 2009 11:47:13 GMT -5
I'm not sure how you'd get enough compression to run when the rings are stuck in the lands. If the rings can't be pushed outward how are they supposed to seal the cylinder? your right, but the top ring wasnt completely stuck so it still had alittle. I have the piston soaking now, but its not looking good. Lower ring is stuck as hell . Tons of blowby, i played hell just getting the wrist pin out from all the buildup. I dont know were i went wrong on this one yet Ill go take a few pics and see what you think. I need a copy of Bells book bad Also need a good source for new gaskets. I remember a post for a good place but forgot to bookmark it.
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Post by 90GTVert on May 21, 2009 12:07:22 GMT -5
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Post by 2strokd on May 21, 2009 12:11:00 GMT -5
Thank you Sir
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Post by 2strokd on May 21, 2009 15:01:53 GMT -5
I talked to the tech guy at Klotz today, real nice guy. I told him that i had a scooter with a 70 kit and it stuck the rings on me. Right away he started asking the right questions. He asked if i premix, how i run it (WOT) for miles, or stop and go mostly? My app is mostly stop and go but it quit running after a long WOT run. After a short but sweet conversation he told me that the blend i am using is more for alcohol and race apps. Its got a 20% caster blend and he said it will gum up in daily use, and that my long WOT run cooked the gummy caster into solid carbon. I gotta tell ya, after looking at the way my piston and head looked i think he was right. He recommended i run there r50, or there motorcycle techniplate. They are both fully synthetic and better for street use. He said if i raced the scooter at 9 or 10 grad almost all the time this oil would work. Here is a pic My cylinder still looks good Piston not so good. Any good solvent suggestions. I have been soaking it for about 4 hours in some bike chain cleaner.
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Post by 2strokd on May 21, 2009 22:43:42 GMT -5
Well im back to 49cc,s for now . The rings on my Polini piston are so stuck im not sure they are gonna come off. I need wheels and still had the stock cylinder and piston, so i cleaned them up and put it together without a base, or head gasket. I made a set of intake gaskets for the reed spacer, and the CF reeds. It runs way better than it did when it had the stock 49cc before. I did remove the rings and clean them and the grooves well. The reed spacer, and CF reeds are the only thing different from when this top end was on before. It definitely doesn't run like a 70cc, but good enough for now. It will still run 50mph . As soon as i can afford it am going to get a new pipe thats tuned for a 70cc like i should have done to begin with (big mistake on my part ), maybe a new set of rings, a 10x14x15mm rod end bearing, a new set of gaskets, and a manual choke, ohh and of course some R50 Klotz instead of the techniplate. Im running the old gas out in this motor. It wont be in long so it should be fine.
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Post by 90GTVert on May 21, 2009 23:34:26 GMT -5
You can try diesel fuel on the rings. Never tried it, heard it works.
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Post by 2strokd on May 21, 2009 23:58:28 GMT -5
BTW i have a tach update for everyone that is interested. Its turned into a POS. It will just shut off, or reset itself out of nowhere. It worked great until yesterday. It started acting up right before the motor did. I rode today after i put it back together and it did the same crap. Yesterday was just a bad day for Skeedr all around. Im going to call the place a got the tach from tomm. see what they say.
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Post by 2strokd on May 22, 2009 0:02:20 GMT -5
You can try diesel fuel on the rings. Never tried it, heard it works. The chain cleaner i have it soaking in smells like diesel fuel. I bought it years ago when i had a ATV, used a little on that chain and its been sitting ever since. I figured now would be a good time to use it .
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Post by 90GTVert on May 22, 2009 8:44:07 GMT -5
If that doesn't work, medman's chemtool suggestion sounds good... or see if Polini sells a piston kit.
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Post by 2strokd on May 22, 2009 8:52:46 GMT -5
Polini does sell there 47mm piston separate. Hopefully i dont have to that route though. Looks like i can get a set of rings for about $25, and a new piston for around $50. That is if i cant get this piston back in order.
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Post by 2strokd on May 22, 2009 9:18:09 GMT -5
im still running strong enough to wheely down the road with all 49cc,s of it. The reeds, spacer and cage, along with a good piston cleaning, and no cylinder gaskets must have really woke this stock motor up. I didnt have the power to ride a wheelie before. Not that im so impressed that im gonna leave the Polini on the shelve, just surprised thats all.
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Post by 2strokd on May 22, 2009 22:23:53 GMT -5
Piston is done, ring were just to cooked in. I tried oven cleaner, still wouldnt work. To top that off, i thought Dr.moto had me hooked up on a new piston until i measured mine and found that its a 46mm piston, and not the 47mm i thought it was. Now im looking for a 46mm piston
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Post by 2strokd on May 26, 2009 8:32:04 GMT -5
Still no luck getting the rings off. My piston is pretty clean now, and i cant see anything other than carbon that would be holding them in. The rings arent scored or pinched in by the piston. Today i have all day to work with it so i am thinking i will get nasty with the rings. If they break, they break. A set of rings is cheaper than a piston. If all fails and i cant use the piston, ohh well its just sitting in a coffee can soaking away, not doing the scooter any good anyway . A new piston from Scoot-attack is $60 and im not sure if it even comes with rings, and that not even including shipping . Ive also been thinking about having it bored to a 47mm setup. Finding 47mm pistons, rings etc. is allot easier and cheaper. What do you all think about having it bored? Good, bad idea?
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Post by 90GTVert on May 26, 2009 10:26:30 GMT -5
I'd do as you said and try to get those rings out to replace them if possible. If not, you prob can bore it but you'll want to try and find a piston very similar to what you had. A piston with different characteristics can affect compression and timing. Considering you had to use a spark plug with a mor shallow reach to eliminate detonation, I'd think you are on the edge already. Depending on the angles that your ports come into the cylinder, boring can change the port timing a little as well.
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Post by 2strokd on May 26, 2009 11:54:45 GMT -5
GOOD NEWS ;D After days of soaking and praying i finally managed to ease the rings off. I used a very small 1mm wide flat screwdriver and allot of patience, but they finally came off unhurt . I still have some cleaning to do to the rings and grooves, but i think i will be ok
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Post by rallyrrr on May 26, 2009 12:06:06 GMT -5
I think you would be time way ahead if you just and got a new piston and rings. I've experienced a similar failure and wasted a lot of time trying to get the old piston to work. Take the old cylinder and piston to a motorcycle mechanic/machinist with experience with two strokes and get his opinion about re boring. Then order the appropriate piston and rings. It may turn out almost as practical to get a whole new big bore kit. I just put on my new Top Performance 74 cc kit and am very happy with it. Just got back from a 120 mile camping trip (about 50 was gnarly gravel... great "fun" with my street treads). I got a puncture in my rear tire but it didn't leak down til the day after I got home.
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Post by 2strokd on May 26, 2009 12:27:28 GMT -5
I think you would be time way ahead if you just and got a new piston and rings. I've experienced a similar failure and wasted a lot of time trying to get the old piston to work. Take the old cylinder and piston to a motorcycle mechanic/machinist with experience with two strokes and get his opinion about re boring. Then order the appropriate piston and rings. It may turn out almost as practical to get a whole new big bore kit. I just put on my new Top Performance 74 cc kit and am very happy with it. Just got back from a 120 mile camping trip (about 50 was gnarly gravel... great "fun" with my street treads). I got a puncture in my rear tire but it didn't leak down til the day after I got home. You dont think i should go ahead and put the polini piston back in? Glad to hear your 74cc Top Performance kit is working out well for you ;D. Whats the Top speed with Top Performance?
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Post by rallyrrr on May 26, 2009 16:25:06 GMT -5
I haven't really checked it for top speed. I can tell you that it will run 50 - 55 with between 1/8 and 1/4 throttle. I think one real steep hill got me down to 40 with my 200+ lb. butt and about 50 lbs. of cargo.
When I was running my Airsal T6 Aluminum kit (it probably had about 3000 mi. on it) some of the Nikasil plating came loose and galled itself between the ring and land. The ring (sing. ring piston) was stuck in the land. I finally worked it loose with the help of a razor knife. I carefully cleaned the land and found an old ring that showed a good end gap. I even lapped an old ring in the land with valve lapping compound to try to smooth out the land but could never get enough compression to start the engine. You're luck could be better but I wouldn't count on it.
The best thing about running 50 cc is the gas mileage. I'll bet you're probably back up to around 70 mpg.
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Post by 2strokd on May 27, 2009 7:18:29 GMT -5
I haven't really checked it for top speed. I can tell you that it will run 50 - 55 with between 1/8 and 1/4 throttle. I think one real steep hill got me down to 40 with my 200+ lb. butt and about 50 lbs. of cargo. When I was running my Airsal T6 Aluminum kit (it probably had about 3000 mi. on it) some of the Nikasil plating came loose and galled itself between the ring and land. The ring (sing. ring piston) was stuck in the land. I finally worked it loose with the help of a razor knife. I carefully cleaned the land and found an old ring that showed a good end gap. I even lapped an old ring in the land with valve lapping compound to try to smooth out the land but could never get enough compression to start the engine. You're luck could be better but I wouldn't count on it. The best thing about running 50 cc is the gas mileage. I'll bet you're probably back up to around 70 mpg. Those are goods speeds at the throttle positions you mentioned. I bet you are happy to have the power of more cc,s . You sure are right about the mileage , i thought the gauge was broke for awhile. I did manage to get her going again last night, so i guess luck was finally on my side .
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Post by 2strokd on May 27, 2009 7:28:16 GMT -5
After allot of cleaning i ended getting the rings back on the piston. They felt good as new on my worn out looking piston lol, its my sleeper look. This is what i ended up with.... I got that far and couldnt help but go up and get some oil and fuel so i could put the cylinder back on and give it a shot
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Post by 2strokd on May 27, 2009 9:37:49 GMT -5
Well here what i ended up with....
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Post by rallyrrr on May 28, 2009 13:43:36 GMT -5
That is great man! ;D You just saved yourself some serious cash. Sorry I was so pessimistic. It just goes to show you that you never know til you try. Pat yourself on the back for me. ;D While I was "breaking" in my new kit I guess I was going too fast(about 60) too soon for too long and it "soft" seized apparently. Kind of made a kind of metallic "ping" and died. (I thought the drive belt had broken but I knew it was in good shape. I pushed it to a convenience store about 1/4 block away and it started right up. I didn't want to push my luck on my trip so I tried to keep it between 50 and 55. My mixture on the low end is way rich. I kept thinking the idle jet was too small since the air screw could be closed completely and idle was always the best there... even on the 50cc cylinder. At least I have a new intake on. I have very poor idle/power transition. I think I've drilled the idle jet out to about 70 now. The old Derb won't hardly run right (four strokes) til I'm doing around 40. I need to make sure I'm not getting too much leakage through my cable thimble at the top of the carb. It's great to be highway/hill capable now though.
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Post by 2strokd on May 29, 2009 6:45:34 GMT -5
Thanks rally . I sure am happy that i got it back together without the big dent in the wallet that these situations usually leave us. I switched to Lucas semi-synthetic for now. I will got a pint of Klotz R50 next, its fully synthetic. No more caster oil for Skeedr! I have idle problems with my bb kit. It idles great with the stock jug up top, but with my 69cc kit it i cant get a good idle until its warmed up. When i do get it to idle good all i have to do is lean it to one side or the other and it will stumble and die. It doesnt matter were i have my idle air set. I am getting a few more pilots to try soon. For now im just happy to have the bb kit back on
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Post by 2strokd on Jun 3, 2009 7:39:44 GMT -5
With the same setup my scoot used to get to 50mph pretty quick(1/8 mile or so), now it gets to 45 pretty quick then just mopes its way to 50+, not so much + anymore . Like i said before, the compression isnt what it was before i made carbon ring toast out of my piston. I guess that kinda makes sense though . I am thinking about adding a base gasket today to raise the ports a bit and see if i get some more power back up on the top end. I havent had one in sense i got it back together. The problem with adding a base gasket is that at TDC my piston is still a millimeter or so in the barrel. Should i add a base for better timing, and then have the cylinder machined so im getting full use of the stroke?
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Post by 2strokd on Jun 3, 2009 17:17:26 GMT -5
I made a base gasket out of some .75mm material i have. That put the piston about 1/2mm from the deck at TDC and im clearing the exhaust port almost all the way at BDC. Thats better than i thought it would be with a base gasket that thick. After i put it in i was reving it on the center stand and it seemed to be running rich, and was floating out about 9,000rpm or so. I dont recommend reving your scooter way out to the redline on the stand without a load on it, i was doing so in short bursts. I tried moving my clip down one on the needle and that helped a little, but not enough, so i switched my 85 main out for an 80 and that helped out more. I figured since the piston isnt coming up as high now, and the compression should have dropped i might try a long shank plug again, so i put one in also. I went for a short ride and it pulls better throughout the whole range. I didnt notice any spark knock this time ;D. I was so having so much fun i almost ran out of gas....Thats why my ride was short lol, plus its rainy, chilly, nasty here today .
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