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Post by dijux123 on Feb 28, 2021 10:56:40 GMT -5
Hello, I have this Yamaha Jog R, it drove pretty well for a few years, until today I changed it rollers to a bit heavier, before they were 3 and 5 grams mixed, and now I have 4.8 grams inside. The problem is that now, when I try to go WOT at certain point it bogs down, when I release the throttle a little bit it continues to accelerate and when I try to go WOT again, it bogs down again, what could be the problem?
It is a derestricted stock engine with Leo Vince TT exhaust on it.
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Post by Zino on Feb 28, 2021 11:24:47 GMT -5
That is a big jump in weights from 4 grams average to 4.8
When you raise your weights you are up shifting faster causing the engine to work harder .
Just like If you are riding a 12 speed bike and up shift to higher gears you will bog down until you get pedaling fast enough.
If you want to try a weight between 4 and 4.8 grams take your 3 gram weights and cut 6 pieces of aluminum foil the same size and fold up and stuff inside each weigh them .
Run all 6 of the new 3 grams plus aluminum foil then run 1/2 aluminum foil and 4.8 gram weights.
Compare performance with each
Take your favorite , Buy weights that are closest to that weight .
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Post by dijux123 on Feb 28, 2021 12:17:02 GMT -5
That is a big jump in weights from 4 grams average to 4.8 When you raise your weights you are up shifting faster causing the engine to work harder . Just like If you are riding a 12 speed bike and up shift to higher gears you will bog down until you get pedaling fast enough. If you want to try a weight between 4 and 4.8 grams take your 3 gram weights and cut 6 pieces of aluminum foil the same size and fold up and stuff inside each weigh them . Run all 6 of the new 3 grams plus aluminum foil then run 1/2 aluminum foil and 4.8 gram weights. Compare performance with each Take your favorite , Buy weights that are closest to that weight . Isn't there a way to somehow adjust the carburetor or something to make it run smooth again? The problem is that the 4 avg. rollers were just too light, and my friends with similar setups use 5grams and they run smoothly. |
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Post by Zino on Feb 28, 2021 12:52:45 GMT -5
First law of scooter tuning change one thing at a time .
The only variable you changed was weights and you made a big jump and it started to run poorly.
If you want to dial in the carb switch back to your original cvt weights a 3 and 5 mix .
You will need jets above and below your current jet.
When is the last time the carb was cleaned ?
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Post by dijux123 on Feb 28, 2021 13:05:08 GMT -5
First law of scooter tuning change one thing at a time . The only variable you changed was weights and you made a big jump and it started to run poorly. If you want to dial in the carb switch back to your original cvt weights a 3 and 5 mix . You will need jets above and below your current jet. When is the last time the carb was cleaned ? I cleaned the carb yesterday actually, surprisingly it was almost perfectly clear. I blew some compressed air in every hole and put it back together. Is it possible that some mixture screw adjustments could fix the problem? |
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Post by aeroxbud on Feb 28, 2021 13:33:10 GMT -5
Different variator, contra spring, belt and exhaust can make a big difference to a bikes needs. Even two stock bikes will run slightly different.
If your friends bike isn't identical. It could use very different weights.
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Post by dijux123 on Feb 28, 2021 14:40:22 GMT -5
Different variator, contra spring, belt and exhaust can make a big difference to a bikes needs. Even two stock bikes will run slightly different. If your friends bike isn't identical. It could use very different weights. It is an aerox, as I know the engine is the same. |
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Post by aeroxbud on Feb 28, 2021 14:58:14 GMT -5
Different variator, contra spring, belt and exhaust can make a big difference to a bikes needs. Even two stock bikes will run slightly different. If your friends bike isn't identical. It could use very different weights. It is an aerox, as I know the engine is the same. It's not the same. The aerox is water cooled, and makes more power. I had the jog RR, which is water cooled. That's still not the same as an aerox. Even Yamaha quote different power, and torque figures for them. The radiator is much smaller too. What revs are you hitting to think it's too high? Somewhere between 8,000 to 9,000 should be about right, till the variator is fully out. |
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Post by Zino on Feb 28, 2021 15:13:34 GMT -5
Different weight in riders also makes a difference .
I actually have 2 identical vino's same pipe same cylinder and run 1/2 gram different variaitor weghts between the two simply because one has a new stiffer contra spring so I need heavier weights to over come it .
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Post by dijux123 on Feb 28, 2021 15:20:53 GMT -5
It is an aerox, as I know the engine is the same. It's not the same. The aerox is water cooled, and makes more power. I had the jog RR, which is water cooled. That's still not the same as an aerox. Even Yamaha quote different power, and torque figures for them. The radiator is much smaller too. What revs are you hitting to think it's too high? Somewhere between 8,000 to 9,000 should be about right, till the variator is fully out. Before changing the rollers, the belt would have 1,2cm free space to move out, I checked it with the marker method. So is it possible to stop the bogging somehow? Changing the jet size? |
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Post by aeroxbud on Feb 28, 2021 15:24:07 GMT -5
If the rollers are too heavy, no carb tuning will sort it unfortunately.
Try putting the old rollers back in. Then if it's still not pulling cleanly, you have another problem.
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Post by dijux123 on Feb 28, 2021 15:38:16 GMT -5
If the rollers are too heavy, no carb tuning will sort it unfortunately. Try putting the old rollers back in. Then if it's still not pulling cleanly, you have another problem. But what about the belt not rising the full way up? |
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Post by Zino on Feb 28, 2021 15:50:41 GMT -5
If you had that kind of belt travel wit the lighter weights that is close to ideal.
Iwould keep your original setting.
When your weights get too light they spin past the power band and have a hard time getting any belt travel .
When you go to heavy they fling out to soon and stay below the power band and than catch up to it and show full belt travel .
Since you cleaned the carb .
It might be running a tad richer .
What position is the needle and how many turns out is the air screw compared too before .
If you are falling on your face at wide open and using the same main jet .
Trying lowering the needle clip one notch .
That will make it richer .
If it runs worse then original position .
Go one up from original position on the needle and see if that runs better .
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Post by Zino on Feb 28, 2021 15:55:31 GMT -5
Just verifying .
Was the pipe on the scoot with the lighter rollers and dirtier carb running well ?
We are trying to make sure we are not chasing down too many gremlins at once .
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Post by dijux123 on Feb 28, 2021 16:24:07 GMT -5
Just verifying . Was the pipe on the scoot with the lighter rollers and dirtier carb running well ? We are trying to make sure we are not chasing down too many gremlins at once . The original reason I tried to change the rollers was that the scooter would accelerate gradually and sound well until like 60-ish km/h, and then it would kinda drop rpm (judging by the sound) and stay there, if there would be a slight downhill, it could reach 70 km/h, big downhill 80 km/h, but a slight uphill would be like 40 km/h maybe 35. So after I weighed the rollers I noticed that they are quite light, because from my friends experiences and google I found out that around 5grams are perfect, so I changed mine to 4,8. and here we are. Also, with the previous rollers when the weather was quite cold, it would bog down at WOT too. |
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