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Post by paydem on Oct 2, 2017 14:03:04 GMT -5
I recently bought Yamaha Jog R, 49cc, air-cooled. It has new top end, new carburetor, new rollers and some other stuff. When I bought it, the speedometer wasn't working, and it had compression leak because the muffler wasn't contacting the cylinder. Two days after experimenting, and I have it fixed now. I thought that after fixing the compression leak, if would gain more HP, but, no. I tried it today and the max speed was around 55-60 km/h. (34-37 mph) I looked up other people that has the same scooter, they claim it can go 75-85 km/h (46-52 mph) stock, only unrestricted. I took out the spark plug and it was dark. Wiped it off, tried to run it only to about half throttle, took it out again, no dark residue, clean spark plug (nice mixture). To about half throttle it feels sluggish, it reaches top speed quite slowly, and from half throttle to WOT it has no difference at all, the sound changes slightly, that's all. My call is that it has too big main jet, and something else is wrong.
Yes, I have the spacer out of the variator.
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Post by spaz12 on Oct 2, 2017 21:40:46 GMT -5
Welcome to the forum Not sure what the width of your belt should be, but there is a good chance that it might be worn out a bit causing your loss of speed. Buy a new plug and then check to see how it's running. You know you have rich jetting if it sputters and lean jetting if it bogs.
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Post by tsimi on Oct 3, 2017 1:07:20 GMT -5
Don't believe always what other people say. I have heard the same rumors of people doing 80 or even 90km/h on a stock setup. I have never seen a video though, wonder why that is. Maybe downhill with a lot of back wind but I don't believe it on a straight flat road.
A stock scooter doing 60-65km/h is pretty good.
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Post by neilvx on Oct 3, 2017 6:16:05 GMT -5
i had the same thing with my 1992 Yamaha BWS, i came to the conclusion people just talk shit lol. these 50cc are so weather dependent its funny, one day it will do 37mph and the other it will hit 42mph. Just use it and enjoy it
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yeska
Scoot Member
Posts: 85
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Post by yeska on Oct 3, 2017 23:14:05 GMT -5
Taotao 2014 all stock ,, except carb. kunfu brand 76 main 30 pilot , morning would top out 40 60-70 degrees after noon would be normal i guess ,35top 40 on the long way. Valves at 5 in 6 out ,all stock except carb ,i stay at 52 ft sea level. 45 plus down hill ,5 grams roller all chino brand ,,jaajjajajja at night runs faster more take off range , faster 35,, 42 top flat 1/2 mile run i think
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Post by aeroxbud on Oct 4, 2017 5:49:13 GMT -5
I had the Jog RR version. It's water cooled and has a bit more power. Stock with the restriction removed it would do about 40mph. With a decent pipe fitted, a Yasuni it would max out at about 50 mph on the speedo. Don't believe everything you read on the internet.
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Post by paydem on Oct 4, 2017 9:16:50 GMT -5
Well, the thing is, I have ridden scooters in the past that had the same engines, so I know it can go faster. The other day I took off CVT cover, discovered that the front pulley was wiggling in every way it can, and could spin independenly from the variator. Took it off, and from the belt marks noticed that the belt was not reaching the top of the pulley (about 20-30% of the width was unused). The front pulley's spacer was worn out and it wasn't contacting the crankshaft properly. I ordered new front pulley. I hope that the speed will pick up after when I change the front pulley. Sorry for my tragic English skills, as you may already noticed, it is not my first language.
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Post by AtariGuy on Oct 4, 2017 9:21:43 GMT -5
Everyones machine runs different. Even if you had 2 identical machines separated by 1000 miles, they'll run different. Things like temperature, elevation, humidity, barometric pressure, wind speed, direction, inclines or declines, road surface, rider profile, and even states of wear on parts, axle bearings, tire inflation... those all contribute to performance. I could try to compare my machine to another 2t, but in the end, my scoot is mine and i'll make it run well for me - and enjoy doing it.
Cuz you can never compare anything with what you read on the internet. No video/photos, no proof.
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Post by geoffh on Oct 5, 2017 15:43:10 GMT -5
Only just spotted this thread,my stock jog r will get to 30 rapid then climb to 40mph alittle more down hill,if you still have problems with the new parts fitted check the belt size it,s got to be 738mm x 16.5 Naraku sell one or get an OE one,3AA 17641 00.Don,t bother with a kelvar,racing.oversize belt a standard belt will last you thousands of miles.
geoff
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Post by paydem on Oct 6, 2017 13:35:49 GMT -5
I put on the new front pulley today. It feels like it picked up more acceleration. I can feel the weather difference in performance... During the day, the scooter feels pretty sluggish, and when I went for a ride on the night, it felt much more powerful, had more top speed and more acceleration. But to the next thing...
It still does NOT use full diameter of the front pulley, as well as the back one (I don't know what the back pulley is called). What I mean by that, is the belt does not reach top of the front pulley, and the belt does not sit at the very top of the back pulley. The belt looks in a good shape, i would love to try out a wider belt, but I don't want to spend time and especially money on those kind of things. It feels like it does 60 kmh and maybe 60+ on night time, when it's a bit colder.
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Post by tsimi on Oct 6, 2017 18:40:31 GMT -5
What you need is a longer belt. There are some options for the short case minarelli engines but for long case engines there are none that have the same width. For example, the stock belt has around 16.5mm width and 738mm length. The next best are BWS100 belts which have the following dimensions,
7019-SHORT-NS 17.7mm / 750mm 7019-SS 17.7mm / 757mm 7019-L-SS 17.7mm / 762mm
My Prebug also has a not so good belt situation at the moment, 5-8mm left to the edge front and rear, so I ordered the longest BWS100 belt. I will get the belt this weekend so let's see what's gonna change performance wise.
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Post by paydem on Oct 7, 2017 3:18:00 GMT -5
What you need is a longer belt. There are some options for the short case minarelli engines but for long case engines there are none that have the same width. For example, the stock belt has around 16.5mm width and 738mm length. The next best are BWS100 belts which have the following dimensions, 7019-SHORT-NS 17.7mm / 750mm 7019-SS 17.7mm / 757mm 7019-L-SS 17.7mm / 762mm My Prebug also has a not so good belt situation at the moment, 5-8mm left to the edge front and rear, so I ordered the longest BWS100 belt. I will get the belt this weekend so let's see what's gonna change performance wise. That's what I've been thinking. Once I have spare money for the belt, I will buy it. I think to buy Polini Speed belt, 747mm lenght, 16.5mm widght and 9mm height (overall only the lenght is 9mm longer.) I don't want to buy a belt too long because it will probably slip or other bad things will happen.
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Post by tsimi on Oct 7, 2017 6:19:39 GMT -5
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Post by geoffh on Oct 7, 2017 9:00:36 GMT -5
errmk,can you measure the belt you have,I used a piece of string around the outside lets see what you,ve got before you spend any money.
geoff
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Post by paydem on Oct 8, 2017 11:11:51 GMT -5
I noticed that when my warms up really good (after driving about 10 km's), it starts to lose power, does not idle, starts very hard, and I can barely get up a hill. That happens when engine is warmed up really good, it runs great at cold-mildly warm temperatures. I believe it's not a CVT related issue, neither is top end related to it, it's practically new. It has chinese 17,5mm carb on it. Should I spend money and buy OEM 12mm carburetor and put it back in?
And on the other note, it has terrible MPG's.
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