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Post by sirtokesalot on Feb 26, 2011 12:37:59 GMT -5
i recently bought a jonway scooter with he yy50qt-28 and im wondering whats so different between it and the yy50qt-6 other than mines slower and my freinds is twice as fast with all the same mods. does it have somtihng to do with the tire size being 2 inches bigger than with the short case? its realy confusing me i cant get the thing to go faster than 35 on flat ground while his does 55 with all the same mods.
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Post by buiditright on Feb 26, 2011 14:36:57 GMT -5
what mods have you both done?? Are you sure that you have both done transmission mods, carb mods, BBK or any other mods??
Bill
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Post by sirtokesalot on Feb 26, 2011 16:13:30 GMT -5
we both have the 4.5g roller weights both are using the same pod filter mounted directly to the back of the carb all restrictions were taken off my scooter came with a #90 jet his has a #84 jet thogh his does run slightly better with my jet in his carb mine still runs like crap using his 84 jet so i took my 90 back.
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Post by sirtokesalot on Feb 26, 2011 17:13:41 GMT -5
the odd thing is that when i get to 30 my rpm's are still very low at full throtal however on his at the same speed if u give it wot it takes off and leavs me there like i was sittin still. going downhill i can keep up with him and hit 60mph.
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Post by buiditright on Feb 26, 2011 17:24:21 GMT -5
The tires will make a little difference but it could be that your carb is made different then his. even thought your both running 4.5 gr rollers if it was me I would not tell him and I would put a set of 6gr Dr Pulley sliders in. Thy are kickin and would give you a world of difference in how your scoot will runhave you adjusted your carb??
Bill
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Post by sirtokesalot on Feb 26, 2011 17:34:14 GMT -5
the rollers are the odd shaped ones that i have in there. i think it had 6 or 9 g rollers stock and those seemed worst rpm were too low all the time. i have tryed tuning the carb but it seems that no matter how i turn it it runs like crap or it runs like a bag of crap ive tryed to restrict the amount of air going in but when i do that it bogs out around 20. i have the stock carb and a new carb i just bought im using the new one because the stock one wouldent idle. at a stop if i give wot it stutters before comming to life then slowly gets me to around 35 unless im going down. uphills it bogs down to around 25 sometimes 20. ive tryed using a few parts form his such as his exaust and his cdi box with no gains in speed i even tryed using his carb with no luck. maby its all the tire size and im never gonna fix it unless i do a big bore kit witch i dident wanna do because i dont wanna have to register it.
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Post by sirtokesalot on Feb 26, 2011 17:39:10 GMT -5
what is the effects of lighter or hevyer rollers?
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Post by edfr on Feb 27, 2011 4:23:36 GMT -5
Are you sure there isn't a restrictor in your Variator like a washer on the BOSS. How high is your belt climbing up the Variator. Easy to find out mark it and see how much of a mark is left after a wot throttle run. Heavy Rollers will get you more top end because they will close the Variator more with Less Rpms. Lighter Rollers require more Rpms to close the Variator and May Not close the Variator as much as it can. Also Lighter Weights your RPMS will be higher than with Heavier Weights. Lighter weights will keep the Belt lower much longer until your RPMS climb high enough to push the Lighter weights out. So your take off will be quicker but you may loose top end. Heaver weights will push the Belt higher much quicker with Less Rpms but your take off will be slower because the belt will climb up the Variator quicker out of the lower part of the Variator. So you have to try different weights to find the one that you like for take offs and mid-range and top end. Lefty Mark it like this:
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Post by tomcas on Feb 27, 2011 7:35:23 GMT -5
A 90 main jet is way to big without a BBK. You say his 84 was no better. Maybe you should try something even smaller and double check your float level setting.
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Post by sirtokesalot on Feb 27, 2011 10:26:02 GMT -5
im fairly sure the variator is working because it revs out far when i take off and then changes to a low rpm. today i checked the timing it was set on the f mark i changed it to the t mark and tryed it that way and it got worst. still runs just worst. i think im gonna sell it for profit and buy a smaller scoot that will go fast. was a 100 doller scoot and put like 85 bucks into it.
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Post by sirtokesalot on Feb 27, 2011 10:28:28 GMT -5
also the new carb i bought had a 78 jet and it still wouldent get over 35 mph however it did slow me down on the downhills.
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Post by sirtokesalot on Feb 27, 2011 15:34:07 GMT -5
ok now its retimed back to the f it still runs real slow it doesent seem like trans issues it seems like the engine isent making the power it should. theres alot of compression it just extreemly confuses me. it has no throtal responce at all when i give it wot it slowly bogs up to 25 or 30. do u gus think its worth trying to figure out or should i sell it and try to get a different scoot?
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Post by larry001964 on Feb 27, 2011 15:38:34 GMT -5
ok now its retimed back to the f it still runs real slow it doesent seem like trans issues it seems like the engine isent making the power it should. theres alot of compression it just extreemly confuses me. it has no throtal responce at all when i give it wot it slowly bogs up to 25 or 30. do u gus think its worth trying to figure out or should i sell it and try to get a different scoot? May I ask is there a weight difference between you and your friend ?
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Post by sirtokesalot on Feb 27, 2011 15:44:23 GMT -5
im only bout 10 pounds heavyer.
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Post by Bong on Feb 27, 2011 15:58:50 GMT -5
The speed limit of around 30-35mph sound like there is still a restriction somewhere IMO. Maybe a rev limiting CDI, If you open it up to WOT and the revs drop or you hit a wall and stop revving higher it is restricted. As others have said the washer on the variator may still be in place limiting top speed. Every engine is a little different. The same mods that improve one scoot may make another one run like crap. You need to experiment with what works on your engine!!! Maybe a #88 jet will get the performance you want. Thats what I run with a Pod filter. BTW 55 on a 50cc seems a little to fast and 4.5 rollers seem a bit to low. Just my 2 cents
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Post by sirtokesalot on Feb 27, 2011 16:14:14 GMT -5
the variator washer is gone the belt is ridin up the varitor almost to the end if i go down a big hill it does go out to 55 but the revs never get higher untill around 45mph. ive been debating takin a few vids of the scoots running and how har dhis pulls on me its realy sad. it slowed to around 13mph going up hill i actualt jumped off it and started running faster then it could go uphill on its own.
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Post by sirtokesalot on Feb 27, 2011 16:49:09 GMT -5
it basicly feals like its making a half a horse maby even less but yet feals like lots of compression.
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Post by Bong on Feb 27, 2011 17:04:39 GMT -5
45-55 mph is all a 50cc can do!! Some have a hard time getting that quick unless its a 2 stroke. Thats another animal entirely. 13mph uphill is a problem. If you make a video, I would personally like to see the one of you running at 13mph next to the scoot (joking) I do think the rollers/sliders are to lite IMO. At those speeds I agree that there is no restrictions but, Your rollers maybe the wrong weight for your engine. Again just my opinion. I am wrong at times like everyone else!! Good Luck Brother!!! Keep On Scootin On !!!!!
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Post by buiditright on Feb 27, 2011 17:56:40 GMT -5
i just happened to notice what you said about your rollers. If I can quote you said the odd shaped so that tells me you may have sliders in but the main thing is that if your not familure with those they have a certain way they have to go in your varator.
If they are in wrong that will make your scoot run really slow. Just FYI.
Bill
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Post by sirtokesalot on Feb 28, 2011 8:10:50 GMT -5
i put the slider weights in witth he smoother edge facing out. i looked at some pics before putting them in. what causes these engines to lack power?do they make smaller heads or cams or somthing to restrict the engine? it realy does feal moter related. i did pull the head off it when i boght it for inspection the cylender walls still appears to have the crosshatching the valves were a bit dirty but cleaned them. the moter seems to be in perfect working order but just dont make the power.
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Post by buiditright on Feb 28, 2011 8:57:01 GMT -5
yes as long as you put them in like the photo says then you will be ok but if they go in the wrong way it will make you lose power. If you have 4.5gr in there they are way too light. If you put a set of 6gr sliders in you will see a big difference.
Bill
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Post by texastea51 on Feb 28, 2011 9:40:26 GMT -5
ok, im his friend with the yy50qt-6. hes got virtually identical setup to mine. 4.0g sliders installed correctly. new belt of the proper size, no restrictions in the transmission or cdi. we tried one of my cdi's which rev over 10,000rpm digi tach confirmed. no difference regardless of what we do. mines setup with a 20mm carb, #84 jet pilot screw turned out way beyond normal spec 7-9 turns. the diaghram needle is set to the 5th richest setting and has hobby washers under it for more fuel. my 84 jet is too small the 90 is almost big enough. same air filter as my friend, stock exhaust. same cam and ignition timing, great low-mileage compression on both. both engines idle great and run smooth at all revs. in the end my scooter takes off on his from beginning to end. the engine just isnt making power mine is.
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Post by texastea51 on Feb 28, 2011 9:48:52 GMT -5
when i took his scooter for a ride the throttle response seemed delayed/sluggish. not any hesitation or misfiring though. it starts easy as well. it doesnt really run any better with my carb on it either. i know different scoots need different setup but the diference shouldnt be this drastic. i can set mine up to run like absolute ass and it'll still pull on his scooter at its best
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Post by texastea51 on Feb 28, 2011 10:08:57 GMT -5
which brings me to why were baffled. we both have several years of experience with scooters and cars and other small engines. ive just never seen a problem like this before its mystifying. im sure were just missing something, that last little peice of the puzzle that'll make this engine work properly
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Post by texastea51 on Feb 28, 2011 10:14:02 GMT -5
please help i want a riding buddy for the summer haha
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Post by edfr on Feb 28, 2011 13:22:59 GMT -5
What is his compression, not all engines run the same, some produce more power than others. I know you said it has good compression but what are the compression numbers. I bet your scoot has a higher compression than his. Also if his is sluggish have you tried LEANING it out, it seems that you guys just want more fuel but it may be to much.
Also i understand yours has 12" tires and his 10" tires and because of that your scoots have different Gears in the Tranny which has nothing to do with power but the one with the 12" tires will almost everyday outrun the 10" tire unless taller gears are put in. Lefty
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Post by fast150 on Feb 28, 2011 14:14:04 GMT -5
yea, the 10 inch tires will never be as fast as the 12 inch without changing gear ratios...
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Post by sirtokesalot on Feb 28, 2011 19:16:00 GMT -5
ok so the bigger wheel means mine should be faster but thats just it. it isent.im a day or 2 away from returning it back to stock making it run up to 30 and selling it to buy another one with the short case moter.
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Post by fast150 on Feb 28, 2011 19:23:17 GMT -5
Yea... I dont blame you, thats probably what I would do too...
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Post by texastea51 on Feb 28, 2011 19:42:34 GMT -5
were gonna start with a 79 jet and move up from there. got a whole set of jets in the mail today. tuning time, its gonna be some long afternoons after work
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