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Post by Deleted on Oct 3, 2021 19:56:35 GMT -5
Hi everyone, I recently bought a used Yamaha Zuma 50cc from 2005 but unfortunately do not have very much knowledge about scooters. At least some of the threads I read are hard to understand for me, so apologies if what I am asking has been asked before! The scooter currently goes about solid 35mph and I would like to know how to improve performance. I know that there are different steps and possibilities, but I have no idea where to look or adjust things first. Also, I would like to start off by improving the performance without buying a lot of new parts (only if possible of course). The only knowledge that I have so far, is that I can take out a variator ring (but how do I know that has not been done yet) or adjust the motor weights (what is ideal?). And I am not sure if there might be some other restriction like a CDI maybe? I am thankful for any advice and feel free to ask me to provide more details if that helps. Thank you very much in advance! I always love to learn more  Manu |
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Post by Zino on Oct 3, 2021 21:17:55 GMT -5
welcome to the forum
I have built a few zumas up .
2005 zuma
Stock goes between 35 and 40 mph
So you have a some room for improvement.
There is not a restricted variator ring or a restricted cdi.
I would check the belt width .
16.5 mm is stock replace at 15 mm.
Swap in a fresh Plug it is a performance part NGK BPR7HS
Check carb responsiveness
Play with the throttle
Is it very responsive at 1/4 throttle 1/2 throttle full throttle or does it hesitate at any of these spots ?
How fast do you want to make it ?
Whats your budget ?
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Post by Deleted on Oct 4, 2021 9:07:12 GMT -5
thank you very much! I will check the belt width and plug
I noticed driving that it reacts quick and accelerates well up until about 15mph but then is much slower between 15 and 25 mph and takes a lot of time to accelerate. After that, at around 25,30 mph it reacts quicker again. So I would say it hesitates quite a bit at half throttle.
45mph would be very ideal for me but of course only if possible!
Regarding the budget around 100 right now but maybe more in the future. I am no in a rush and maybe with time i will have more budget.
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Post by x7rocks on Oct 4, 2021 9:19:37 GMT -5
thank you very much! I will check the belt width and plug I noticed driving that it reacts quick and accelerates well up until about 15mph but then is much slower between 15 and 25 mph and takes a lot of time to accelerate. After that, at around 25,30 mph it reacts quicker again. So I would say it hesitates quite a bit at half throttle. 45mph would be very ideal for me but of course only if possible! Regarding the budget around 100 right now but maybe more in the future. I am no in a rush and maybe with time i will have more budget. Sounds like the rear torque pulley is causing this dip in power. Stock zuma ones have notoriously bad guides that kill acceleration. Change the rear pulley sheave to one with smoother guides and you'll solve that issue. |
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Post by Deleted on Oct 4, 2021 9:24:24 GMT -5
thank you! is there any particular one that you recommend?
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Post by x7rocks on Oct 4, 2021 9:31:28 GMT -5
I think ncy has a sheave that fits the stock rear pulley not 100% sure of the name but I think it's ncy
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Post by Zino on Oct 4, 2021 16:45:17 GMT -5
With your budget focus on making sure it runs as good as possible as is . That shift you talk about in the mid range is from the torque driver swapping it out will not increase your speed . To make sure you are maxing out the gear ratio When you open your cvt see how much belt travel you are getting Take a sharpie and run down the road full blast and measure how much sharpie is left. The stock zuma variator will get down to 3mm or less when it is maxed  This is a ncy variator that is maxed out to less than a mm.  |
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Post by Zino on Oct 4, 2021 16:57:10 GMT -5
Next steps after maxing out variator is power adds.
Pipes
A Good Street Pipe
Looks like stock adds power for Take Off and more Top end MPH .
They are easy to tune transmission slighly lighter weights and stiffer clutch springs for and small up jet on Carb make a big difference
tecnigas Silent pro, Malossi Wild Lion ,Polini Speed are good examples.
Expansion Pipes
Adds the most Top Speed and Power
Harder to tune for requires bigger jetting in the carb and requires alot lighter weights to spin up in the narrow power band and way stiffer clutch springs .
Yasuni Z ,Yasuni R are good examples .
If you get a pipe get a good tempature gauge to protect your investment.
A good pipe and the jets and springs ,weights ,and temp gauge has you between 200- 300 bucks .
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Post by Deleted on Oct 4, 2021 20:08:32 GMT -5
thank you! I appreciate your help a lot! I will try to follow all the advice you gave me when I get to it and will keep you updated!
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Post by Deleted on Jan 25, 2022 19:01:42 GMT -5
Hi sorry for the long wait for a reply! I followed some of your advice over the time and exchanged the spark plug and most recently also the belt. After that the scooter already started reaching 45mph. So I didn’t change anything anymore as I thought that is all I need. Now recently however I encountered a new problem. There is a rattling and almost screechy noise in the area of the variator (I opened the cvt to check). But the noise is only in idle and goes away as soon as I accelerate over 5mph. At the same time however, it feels like this noise is also slowing down the engine in idle because it now turns off almost any time I stop at a red light for example. I researched a bit and read that it might come from the variator weights but I am not hundred percent sure. Side note: one of your advices for the later tuning stage was an extension pipe. The scooter came with an extension pipe when I bought it. But as you mentioned they require special tuning, so I thought maybe the problems also could come from the higher speed and missing adjustments in variator and clutch. I apologize if this is the wrong thread, but I was unsure where to post it as it turned from a performance question into a troubleshoot question. I appreciate any help! Thank you |
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Post by Zino on Jan 25, 2022 19:30:13 GMT -5
45 mph is very strong for mostly stock
Can you take a video with it running so we can hear the sound and see the belt .
The belt may be slapping around at low rpms and as soon as you pick up speed it tightens up .
Please post a picture up of your pipe so we can see which expanionpipe it is.
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pili
Scoot Enthusiast
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Post by pili on Jan 25, 2022 21:04:55 GMT -5
Hello. I ride an 03 Zuma with a 70cc Malossi cast iron Sport kit with a stock carb and exhaust. I upjetted to an 82 main and a 46 pilot jet and moved the enrichment needle up one notch. All of this took not a lot of mechanical knowledge and a total of about $175. That got the Zuma to 45mph and accelerating much quicker than stock. I recently fitted an Athena 15:50 final drive gear ($75-$80) and it now does do about 50mph with still very good acceleration. It is the perfect commuter; I pass cars on most streets as opposed to trying to keep up, and the Malossi kit is good for at least 10k miles. Something to consider depending on what you're looking for.
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Post by Zino on Jan 26, 2022 9:23:15 GMT -5
pili
Malossi 70 cc sport kit with upgears is a fun and solid combo , power on demand still looks like stock.
This is the way I wish they would come from the factory .
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pili
Scoot Enthusiast
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Post by pili on Jan 26, 2022 13:45:55 GMT -5
pili Malossi 70 cc sport kit with upgears is a fun and solid combo , power on demand still looks like stock. This is the way I wish they would come from the factory . I totally agree! |
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Post by Deleted on Jan 27, 2022 18:37:23 GMT -5
Hi guys thanks for the quick response. I am adding a picture of the exhaust and a video of the open cvt with the engine running. Hope you can hear the noise well. Also I think that the noise is actually still there when I accelerate! And as I said before sometimes it makes the scooter stop when running in idle. Video: imgur.com/a/WWsmmIoPicture  |
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