KymcoForum.com
Scooters - 50cc => Agility 50 => Topic started by: flextrainer on November 15, 2009, 02:53:19 AM
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I'm gonna start tearing down my engine tonight to install the 72cc kit that's been sitting on the shelf for two weeks. I almost don't want to put it on because she's finally running good. I'm gonna port and polsih the heads and work on the exhaust while it's down. I'll keep posting through the project to let you all know how it is going. So sad I just got all the bugs worked out and got her running 42-45 easily on flat just cruising. Have an iridium plug, but I'm gonna wait until I get it broken in and get the new transmission kit installed ( hi po vatiator & clutch ) so I can see if it really makes a difference. Otherwise I won't know what worked the best. Just curious on what everyone else thinks on the break in procedure. I always use the hard break in procedure based on the theory that the first few miles are when you can seat the rings to the cylinder best. Two full throttle pulls with letting off the gas ( till a rolling stop) and letting the vacuum in the cylinder pull the rings up to seat the top and bottom good. Then running fairly easy for 500 miles. Any other theories out there.
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First thing, if you are running on the oil injector pump; zip tie it wide open. You will need the extra oil to keep everything moving free. I would also add just shy of 1 oz. oil to the fuel. Most certainly run through the rpm range. Give it three-four miles around mid range, and run it up for a few tenths of a mile. varying the rpm's will prevent the new parts from taking a premature seat. I would say two tanks of fuel is PLENTY of break in for a piston/cyl. In moto-x there is NO break- in at all. The most important thing is to use quality 2t oil, and plenty of it. I have been running my injector wired open for a few months now (since i burned a piston) and am planning to keep it that way. I also add about 1 oz. of seafoam to every tank to keep it all clean. You may be a little disappointed w/ the jug kit alone. They don't do too much until you can get the engine to breath right, and start turning some SERIOUS rpm's. Please keep us posted!
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well my first snag is the end gap. they are about .006" too big. why couldn't they be too small, easy fix. now I have to wait for new ones.
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Huh, that sucks! I never even checked mine. :-\
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A little "point" file will cure that. Or did you mean the GAP is too big?
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the gap is too big. now I have to wait on new ones to get here. I have been trying to see how big is too big, but the verdict is pretty much the same all around. cylinder bore in inches x .004 on the top ring and cylinder bore x .005 on the bottom ring. which comes to .007 top and .009 bottom. there were wider recommended gaps for nitrous and high po apps. but none would give a .014 and .016 which is what I have. ex. of mine 47 ( bore in mm) divide by 25.4 to convert to inches = 1.8503. Multiply that by .004 to get your ring's end gap = .0074. too small of a gap and rings butt together and break too much and you have excessive blowby and oil consumption plus loss of compression/performance.
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I would put it together and do a compression test. That's going to give you the true answer to your question!
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Who makes the kit you are using? A 47 mm piston should have you at 70cc. What I dont understand is why the rings would'nt match the cyl. they were made for, unless the material they are made of is EXPECTED to expand. Have you contacted the MANUF., instead of the supplier? There will also be a different set of rings for a nicasil/ alum. cylinder vs a cast iron cyl. Just trying to throw some ideas!
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thanks guys. didn't think of the rings and aluminum cylinder material thing, just going by the general rule for ring gapping. I thought of doing the compression test but didn't want to have to tear it back down ( have to get new gaskets) if it was bad and compression usually drops a little after break-in becausee of wear on the rings and cylinder, so I figure if I start with too big of a gap it will only get worse. Good idea of finding out the manufacturer and contacting them. My supplier is ususlly the best at fixing things or explaining why they are right.
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Cool... Too much worry is a KILLER! Keep posti'n.
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Heard back from my supplier and he's sending out another set of rings. He's real good about customer service and is quick. Never had any problem, but now I know it's not a problem when I do have one...peace of mind. I get my stuff from www.enviromoto.com (http://www.enviromoto.com) and he can get pretty much whatever I need if it's not on his site. Y'all should check him out.
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Looks like a pretty nice website! Always good to have another reliable source!
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Should have my rings in two days, he sent them out first thing this morning. Got him looking for a trans kit for me too since I haven't got it yet. He has one I really want, but is out of my budget.
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Got my trans kit picked out. Now I just gotta get it ordered, get my motor broken in, and go.
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Do you have a link to post up for everyone to see what you decided on?
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Here it is guys. I think it is going to be way better than stock at lower than full racing price.
http://www.enviromoto.ecrater.com/product.php?pid=6055029 (http://www.enviromoto.ecrater.com/product.php?pid=6055029)
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Looks like a good kit, a good price as well! I've read good things about NCY stuff! The only thing that looks like is missing is the belt. You may want to ask, if you haven't already, if the stock belt will work well with that kit. It may be nice to start with a new belt anyways.
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That's a geat idea. By the way do you know the number of the belt cross referenced over. Mine just says bando and a bunch of numbers that I haven't found on any sites. most are like 669-18-30, or 729-18-30. mine has no numbers like this.
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This may be the site you are looking for http://www.heeters.com/Belts.shtml (http://www.heeters.com/Belts.shtml)
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I found this page while looking for the stock length when I did mine. It looks like your belt is 736mm X 18mm.
http://www.nypintl.com/pdf/Checklist%20of%20complete%20models%20of%20V-Belts.pdf (http://www.nypintl.com/pdf/Checklist%20of%20complete%20models%20of%20V-Belts.pdf)
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Thanks for the kind words guys. I am currently expanding my parts page to include Kymco parts so you should see me around more often.
Best regards,
Jeremy
www.Enviromoto.com (http://www.Enviromoto.com)
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Cool Jeremy good to see you over here. Kymco scoots are great and we need a good supplier, which you have proven to be.
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More better hod rod stuff! WELCOME! It's really nice to see some shop owners come around here. There is a ton of good info for all...
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That's awesome!! We need more reliable knowledgeable people to buy parts from! I think it's great when shop owners are active in their particular community as well! It's makes them privy to their customers needs and is a ultimately advantageous to both parties! ;D
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Agreed and thanks for having me. I promise I wont go spamtastic all over the board. ;D
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WHA??? Not be like US? Help and, advice is MORE than welcome! A new set of eyes...
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Got my rings yesterday and finished putting everything together tonight. Only rode four miles, but all seems well. Great throttle response, lots more power! Only went up to 35 and let her coast down a huge hill to pull the rings up in the groove and seat them. By the way that hill was hard to do more than twenty up before and I hit that at less than half throttle. So far I have the bbk, ported and polished the heads, opened up the exhaust and intake,open air filter, and 5.5 gram rollers. Next is the transmission kit. I'll keep you updated as I break it in and put the trans kit in.
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That's great! It's always nice when everything works out the way it should! Just make sure you do a couple plug chops to make sure you have the carb adjusted correctly! Did you happen to measure the new rings, I'm assuming they were within spec? Were the other rings the wrong ones, or where they just flawed?
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The new rings were pretty much right on. I took about .001" out of both to give a little extra room since these engines run hotter than a water cooled. So, they ended up at .008" top and .010" bottom. And yes it is nice when everything comes together nicely. I figure I will need a little tuning on the carb, but it seems to be right on I just upjetted two sizes. I haven't done more than about a 2 second full throttle pull yet, but I can tell that opening up the head, intake, and exhaust helped air flow tremendously. I also took the carb completely apart and ground down the throttle plate screws and sharpened the leading edge (of the throttle plate) to improve air flow through the carb The intake and exhaust note is louder and deeper. I have an iridium plug, but I'm gonna make sure I have the carb just right and the motor broken in before I put it in, so I can see how much of a difference it makes. I'm gonna order the trans kit tomorrow, have it in three days. I'll keep you posted of my progress.
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Any updates?
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Yes! Everything is working perfectly. I started with the wrong slots in the new clutch, but changed that and acceleration is twice as good. top speed by my chinometer was about 56. so, that probably equals about 50-51 mph. All in all money very well spent. I did use 6.3 gr rollers over the 9 gr ones that came with the clutch kit. I have about 700 Km on it now and it is running better every day. Up hill is very easy with the biggest one I ever go on slowing me to only 41 versus 33-35 before. Parts installed are enviromoto's 72cc bbk, and NCY performance trans. kit. Old average speed was 35 ( counting hills and flats) new is 44. That's a big difference in my book. I could get probably 4-5 more mph out of it ( with enough room) since the rpms seem pretty low compared to before even at top speed.
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Good to hear 8)
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Thanks. I think my next mod is going to be 5.5 gr Dr. pulley slider weights. That will pretty much cover everything but the ignition system. May put the other gears I have since the RPMs are so low now. The NCY clutch kit made a world of difference.
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I bought one of those ORANGE Ign. coils on ebey. High performance type. It cost 19.99, and it does deliver a hotter spark. I compared my stock coil w, a blue to yellow spark, and the hi perf. one gives a pure white spark. The only draw back is the plug boot. Theirs is made of hard styrene plastic and did not last 2 months. It will simply un screw from the wire, and you can trim back 1/2" to screw your factory boot on in its place. Glad to here you got your set up working well!
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I have opened up the exhaust some more and ended up with a 94 main jet with the needle one slot from all the way down. I didn't have a 92 jet, so I dropped the needle down. I also went with 6gr rollers and the most aggressive slots on the secondary slider ( NCY trans kit is awesome). I am cruising at 48 mph and top out at 54 on flat to very slight down grade. All of this is at fairly low rpms due to the trans kit. Haven't been on any big downhill pulls yet, but could probably get 56-57 easily. Final parts are bbk and NCY (extremely tunable) trans kit. Plus a lot of tuning. My speeds are GPS verified. I am working on a video to post on youtube.
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Badass ;D
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INDEED!!!
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I have opened up the exhaust some more and ended up with a 94 main jet with the needle one slot from all the way down. I didn't have a 92 jet, so I dropped the needle down. I also went with 6gr rollers and the most aggressive slots on the secondary slider ( NCY trans kit is awesome). I am cruising at 48 mph and top out at 54 on flat to very slight down grade. All of this is at fairly low rpms due to the trans kit. Haven't been on any big downhill pulls yet, but could probably get 56-57 easily. Final parts are bbk and NCY (extremely tunable) trans kit. Plus a lot of tuning. My speeds are GPS verified. I am working on a video to post on youtube.
Where are you located?(asking for altitude levels)
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Where are you located?(asking for altitude levels)
..flex ain't been around since december...