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Post by prospero on May 6, 2006 11:28:47 GMT -5
Hello everyone,
I am a new member from Puerto Rico. There are many GY6 based scooters in the island. Lots of racing and audio mods. I have a red and silver 2005 UM Matrix 150, same as ScootDawg's. I love the scooter. I will take some pics of it and show them later. Mine is bone stock though.
I did Motoman's break-in method, and I am glad to say that my stock scooter beats other scooters off the line. I have to thank Motoman for that. After the first oil change I only use synthetic oil, due to the high heat.
I am interested in a mod for the GY6 based on a big bore piston (63mm or 64mm) with a stroker crankshaft, that I've heard gives the engine a near 200cc displacement.
I made a spreadsheet wish I will share later, which calculates the engine displacement based on the bore and stroke. I made some calculations with it and found ways to get the engine up to my 200cc goal.
I believe the hardest part to find for that mod is the stroker crankshaft. I have heard of 60mm stroke and even custom made 64mm stroke on the Yahoo! groups Vento forum. Have any of you found vendors wish can supply such stroker crankshafts? There is one based here in Puerto Rico, but it is only 60mm stroke.
I would also like to know what would be the best compression to have to achieve the fastest acceleration. And how high can I make it.
Since the heat and humidity in Puerto Rico is all year, I am also very interested in oil and water cooling for the GY6. The engine gaskets literally disintegrate from the heat. In particular the head and exhaust gaskets. A while ago I had to replace the stock head gasket with copper silicon (supposedly the best), in order to have a long-lasting seal.
The gasket issue I had a while ago cause oil leaking, and a spray of oil got inside the air intake which ruined the stock paper filter. I have read that the oil can leak through the "breather tube" and get inside the air intake. If someone here is experienced fixing this issue please let me know how to fix it.
I am currently having some charging problems with the battery. The stock battery lasted about three months and then died. I recharged it with a car battery charger at 2amps. The battery got charged, but the charge only lasted a couple of weeks. Right now I can only start the engine with the kick starter. I've become an expert at kick starting. Most of the time I can get the engine started in just one kick! Well needless to say, it is a pain, but I'm reading up on beefing up the charging system.
Finally I have two Hella HID bi-projectors. I will remove the stock halogen headlamp and install those two beauties. Each projector has low/hi beams by means of a solenoid with pushes a small metal plate. Each HID bulb consumes about 70-100 watts at start up, then goes down to 35watts after starting. That means that for both bulbs I need around 200 watts at startup, and 70watts after starting. This requires more current than the stock battery can give, so I am also planning on beefing up the battery system.
Well that is all for now, thank you for your time. ScootDawg I love your website and forum, keep up the good work and your great product reviews.
Sincerely,
Omar
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Post by Admin on May 6, 2006 12:50:17 GMT -5
Welcome to the forum Omar. You guys in PR are light years ahead of us on scooter knowledge. I've seen the videos of ralleys with all the scooters and guys doing wheelies. I seemed the vast majority of scoots were Phantom/Matrix clones. Keep us posted on your mods.
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Post by prospero on May 6, 2006 13:25:12 GMT -5
Thank you Lee, It seems there many racing enthusiasts in PR. I would say our racing performance levels are achieved by intense competition. It's fair to say that more than 80% of all scooters here are moded to race. Many also take their scooters to the drag strip to race. I have seen races on scooters with wheelie bars that go more than 100mph, that's scary! There are many brands here, fair to say almost ten, but the Matrix is not so widespread here. People here want better stock racing performance than warranties. Scooters here don't stay in stock form for long. I want to mod my scooter for faster acceleration and faster speed, but not to race. I bought my Matrix because of the three year warranty and because mine has front and rear disc brakes. I just want a better performing scooter with a good warranty. Regards, Omar Welcome to the forum Omar. You guys in PR are light years ahead of us on scooter knowledge. I've seen the videos of ralleys with all the scooters and guys doing wheelies. I seemed the vast majority of scoots were Phantom/Matrix clones. Keep us posted on your mods. |
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Post by Admin on May 6, 2006 13:57:53 GMT -5
I don't know if you have the same warranty in PR, but mine says that if you modify it you can void the warranty. Of course, they would have to be able to tell that you modified it. No way to tell that you've put a big bore kit on it without tearing down the head. If you have a friendly dealer who thinks the mods have nothing to do with your warranty issue is likely to overlook it anyway.
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Post by Admin on May 7, 2006 9:41:59 GMT -5
Hey Omar, I just remembered seeing an oil cooling unit on the parts for scooters site. Link is on the links page of scootdawg if you don't already have it. Look under full size scooter parts.
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Post by scootie on May 8, 2006 0:53:47 GMT -5
prospero, you can use the hi-comp piston thats being used on the 4 valve head, little grinding needed, regarding the stroker kit, i was told that it was designed for the taiwan gy6's(use in some kymco) w/c they say is made slightly different from our china made. what i did with mine is use a 60mm piston, port and polish, SKM straight pipe(from taiwan), re-jet, iridium plugs and motoman break-in method. .. so far an additional 15km/h was added to my top speed( sill in the break-in period).....wont putting an oil cooling system be more troublesome, more parts=more probbable parts that might go wrong
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Post by fulltilt1 on May 8, 2006 20:36:55 GMT -5
I've got a question. I'm running an MRP 2R pipe on a stock 150 GY6 and I can't for the life of me get it to run right. I've also got an MRP Foam type air cleaner. At idle my plug looks great. However where I used to get 8500RPM stock I can't get even 7000RPM now. The Scoot is running lean the plug is a dirty white after about 2 minutes flat out. I've re-jetted as far up as a 135 and made very little difference. When I raised the needle, it was at the second from the bottom groove, to the bottom groove it boggs badly and won't make even 5000RPM. This is the stock Carb is it possible to get this to run on the 24mm carb? I'm open to all suggestions, I may not follow them but I'll definately listen. Thanks in advance for any help.
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Post by 90GTVert on May 8, 2006 22:26:11 GMT -5
Have you increased your pilot jet? The CV carb isn't going to react much to increasing the main jet (unless it's too small), but the pilot jet controls the first 25-30% of the fuel delivery range, and also combines with the main beyond that clear to the upper delivery limit. You could also have an obstruction in the mixture circuit. If you can turn the air/fuel mixture screw mor than about 3/4 turn without a change in idle, you probably have an obstruction. Also be sure to inspect your manifold if you have a stock rubber type because they crack easily. Hope you find the problem. Stan
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Post by Admin on May 9, 2006 7:16:55 GMT -5
Stan is the man with knowledge. A 135 main is way more than you need. I'm settled in with a 120 main jet and whatever is stock idle jet in the 30mm carb. When I installed this stuff, MRP tech insisted that a larger idle jet was needed than stock either on the 24 or 26mm carb.
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Post by fulltilt1 on May 9, 2006 9:30:43 GMT -5
Thanks guys for the good words. Any idea on what the stock idle jet is or what I should move towards. I saw on Stan's site a jet kit of 38/120 is that for the stock carb? I was looking along those lines as my idle mixture adjustment is much further out than the stock airbox allows for. I just didn't figure it supplied that much fuel of the total mixture.
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Post by prospero on May 9, 2006 19:21:54 GMT -5
True, but lately I think sacrificing the warranty isn't such a big deal since the one doing all of the maintenance is me. I'll leave the big bore and stroker crank mods at the end. I'm going to focus first on reliability and later on performance. I don't know if you have the same warranty in PR, but mine says that if you modify it you can void the warranty. Of course, they would have to be able to tell that you modified it. No way to tell that you've put a big bore kit on it without tearing down the head. If you have a friendly dealer who thinks the mods have nothing to do with your warranty issue is likely to overlook it anyway. |
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Post by prospero on May 9, 2006 19:22:51 GMT -5
Great! I'll look into that. Thanks for the info. Hey Omar, I just remembered seeing an oil cooling unit on the parts for scooters site. Link is on the links page of scootdawg if you don't already have it. Look under full size scooter parts. |
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Post by prospero on May 9, 2006 19:25:10 GMT -5
Thanks for the info Scootie! Do you know in what country the United Motors' GY6 engine is made? prospero, you can use the hi-comp piston thats being used on the 4 valve head, little grinding needed, regarding the stroker kit, i was told that it was designed for the taiwan gy6's(use in some kymco) w/c they say is made slightly different from our china made. what i did with mine is use a 60mm piston, port and polish, SKM straight pipe(from taiwan), re-jet, iridium plugs and motoman break-in method. .. so far an additional 15km/h was added to my top speed( sill in the break-in period).....wont putting an oil cooling system be more troublesome, more parts=more probbable parts that might go wrong |
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Post by 90GTVert on May 9, 2006 19:46:38 GMT -5
If you have the standard 24mm carb (Walbro) on most 150cc GY6 engines, they have a 35 pilot and 107 main from the factory. 38 is the next size up for the pilot, and 40 is a bit too rich for the idle circuit. The CV design will pull the required fuel through the main at the rate the engine demands, so the main (unless way too small or way too large) isn't going to show much change. The idea is just to have the main large enough to supply what the engine can use efficiently. I've found the 38/120 to be about as good as it gets with the 24mm carb. MRP is now selling a 32mm carb in addition to the 30mm, but I think that's excessive on a generally stock 150. 28mm or 30mm should be about as close to optimum as you will get in most cases. Stan
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Post by scootie on May 12, 2006 2:05:45 GMT -5
i think it's china made, but i think u can make it work with minor mods...currently i'm having problems with my carb during 30-80% throttle....while cruising at around 70-80kph then when i suddenly release the throttle and let it slow down to around 50kph then twist it again suddenly, the carb sounds flooded, so theres a second of engine bogging. so i search the net and found out that i need to lower the needle jet clip(w/c will actually rise the needle jet), since my needle jet is currently in middle position, i lowered the e-clip....test it, and still the carb hesitates for a second if i twist the throttle hard at speeds of 50kph...what am I doing wrong??? stan? dawg? prospero? anybody? Thanks for the info Scootie! Do you know in what country the United Motors' GY6 engine is made? |
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Post by 90GTVert on May 12, 2006 8:38:31 GMT -5
Have you looked at your spark plug to determine if it's actually running rich/lean? Give a little background on the history of the condition also. Any mods? Was it running good, then changed? Often, the first place people look for a change is in the carb, when in fact it could be elsewhere. Diagnosis via email is tedious, so the more details you give, the better the chance of narrowing it down. Float setting too high? Coil breaking down? Leaking intake? Poor electrical connections? Have you replaced your filter, fuel lines and vacuum lines? If the scooter was running fine, then suddenly changed, it's not likely an adjustment problem. You have to find the source of the change, which is usually a part beginning to fail, or connection that is getting loose. Stan
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Post by Admin on May 12, 2006 11:13:08 GMT -5
I agree with Stan. The problem you are having could be caused by any number of things. Before you go changing all the settings on the carb, you may want to pull the plug and inspect it. It will tell you if you are running lean or rich. Also, it could be simply that you need a new plug. A lot of plugs that come with Chinese scoots are crappy.
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Post by scootie on May 12, 2006 21:08:17 GMT -5
thanks stan/dawg for the quick reply.....the things a did before the problem was re-install my aftermarket pipe/muffler and re-install my iridium plugs w/c i used for 350 miles only, and a 115 mainjet. i put back the stock parts during my break-in period after installing a bigger piston. I installed a bigger main jet because i noticed that after a long day trip(during the break-in period), the tip of my plugs are white. btw i'm using the stock carbs with a unifilter.
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