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Post by bigmatthew86 on Mar 2, 2023 16:44:17 GMT -5
I had a Zuma 70 several years ago that I ran the stock carb on. This time I ran a 17.5 & honestly I couldn’t tell a difference. Now maybe if I had them side by side you could have. I opted for the 17.5 because I wasn’t willing to give up oil injection or auto choke. If you get bored with those find a Zuma 125. I did & after a 158 kit on it my Zuma 70 is gone. The 125 does everything better & is larger so it’s more comfortable for us big guys. Mine will do around 65 with me sitting upright on a flat road. I’m thinking of swapping gears so it’ll do 70 but I don’t really need it as I can keep up the speeding traffic on 55mph roads. Modding a 2 stroke is sure fun but if you just want a rider the 125 is the way to go. Hard for me to say that because I’ve always been die hard 2 stroke.
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Post by TuneGoon on Mar 23, 2023 18:25:47 GMT -5
I had a Zuma 70 several years ago that I ran the stock carb on. This time I ran a 17.5 & honestly I couldn’t tell a difference. Now maybe if I had them side by side you could have. I opted for the 17.5 because I wasn’t willing to give up oil injection or auto choke. If you get bored with those find a Zuma 125. I did & after a 158 kit on it my Zuma 70 is gone. The 125 does everything better & is larger so it’s more comfortable for us big guys. Mine will do around 65 with me sitting upright on a flat road. I’m thinking of swapping gears so it’ll do 70 but I don’t really need it as I can keep up the speeding traffic on 55mph roads. Modding a 2 stroke is sure fun but if you just want a rider the 125 is the way to go. Hard for me to say that because I’ve always been die hard 2 stroke. I would need to take a written and road test to get an endorsement on my license, as well as plates and insurance if I got anything bigger than 100CC here in MI. This is where my attraction to the 50cc scoots began and just evolved into my hobby soon after. I recently bought a Honda CH80 for scooting around on with others while my Zuma is being wrenched on. |
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Post by TuneGoon on Mar 23, 2023 19:14:18 GMT -5
Im waiting to see if I can find a press locally for cheap, but Im not having much luck so I may just buy a 12 ton press from HF and throw some casters on it so I can move it easier since my work space is so tight. Im getting antsy to get these up gears installed and see if I can hit/exceed 50mph. I did decide to bypass the oil injection on the Zuma. Last time I rebuilt the top end, I dont think I primed the pump enough and I dont think it was getting oil to the carb which is why I believe it soft siezed last time even with a fat main. When rebuiling the top end last week I pulled everything apart to find no oil in the line that goes from the pump to the carb. Considering theres no real way to tell how much oil (if any) is getting to my carb, I decided to just move to pre-mix. It just seems a safer bet at this point with all of the mods I've done. The oil bypass mod was literally one of the easiest I've done on this entire scooter since owning it, and it only cost $4 and took less than 5 minutes. This is what I did: I purchased these rubber vacuum caps at the local auto parts store.  The only ones needed were the 1/8" and the 3/16". I removed the line from the oil reservoir (careful to keep all of the oil in the line) and plugged the reservoir with the 3/16" rubber cap just until I can get everything bypassed and remove the oil reservoir. I then removed the oil line from the carb and ran this small line inside of the larger oil line that came from the reservoir (making sure both are full of oil with no air in either line) and it was a perfect snug fit!  I used the original clamp from the reservoir hose for extra precaution holding them together. This thing isnt going anywhere and the pump can continue to recycle the same oil in a "loop". This way I dont have to remove the pump or block off any holes on the case and yet the pump never runs dry. As for the inlet on the carb, that still needs to be blocked off. Before I inserted the small oil line into the larger one in the previous step, I snipped about 3/8" off of the small line. I used the 1/8" rubber cap on that snippet I took from the small line. This takes up the difference in size between the tiny barbed inlet on the carb, and the smallest 1/8" rubber cap I could find. What an absolutely perfect fit!!     OIL INJECTOR BYPASS MOD COMPLETE!!With no additional costs, I can revert everything back to stock in less than 5 minutes if/whenever I choose to do so. |
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Post by bigmatthew86 on Mar 23, 2023 19:18:50 GMT -5
I’d pull that snorkel out of the airbox & jet accordingly.
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Post by TuneGoon on Jun 12, 2023 3:02:18 GMT -5
Its been a minute since I have updated. After getting everything tuned and dialed in, I hit just shy of 50mph on flat ground....and I havent even put the upgears in yet! I purchased a benchtop press and will be doing the gears this weekend. Im thinking I'll hit 55 with ease considering I can hit 49.59 mph @ 9940 rpm on stock gears. My rpm can go higher still but I didnt want to push the stock crank so Im eager to see these high rpm converted into mph! GPS verified:   Not too shabby for a large 330# dude, but its STILL not the 50+mph I was shooting for. |
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Post by Zino on Jun 12, 2023 7:06:08 GMT -5
nice work
4 -7 mph is what most see when they swap gears
because of the wall of wind you fight through as you increase speed
when you swap gears your peak rpms to drop a little bit .
you will probably have to drop your weights a half gram or so to get the same shift points in your transmission .
This will also keep your spunky yake off the same
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Post by hellish100 on Jun 12, 2023 20:32:05 GMT -5
Fun thread! It's fun to see the progression. Do you use this daily, as a commuter, or just for fun?
I think you could get away with more revs. Word on the street is that the stock crank holds up to 11k rpm. When you start getting into corsa revs, that is when they say cranks might go. I have no experience on that though. A friend with a corsa rags his pretty good and its still in one piece.:shrug:
I am confident you'll get into 60mph.
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Post by Lucass2T on Jun 16, 2023 0:17:57 GMT -5
Upping the ignition timing a few degrees does a TON for acceleration which will get your quicker to that illustrious 50mph area. Grind out the stator holes and turn the stator a few mm's counter clockwise. Free mod!
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Post by TuneGoon on Jun 16, 2023 3:39:33 GMT -5
Upping the ignition timing a few degrees does a TON for acceleration which will get your quicker to that illustrious 50mph area. Grind out the stator holes and turn the stator a few mm's counter clockwise. Free mod! My dude!! This is the tidbits Im looking for to squeeze every bit of juice from this scoot! I'll search the subject now, but would gladly follow a link to info/writeup if you happen to know of any? Im really trying to get my low end takeoff completely maxxed out in preparation to putting in these upgears. Ive heard more than once that the upgears really sacrifice some of the low end. Fun thread! It's fun to see the progression. Do you use this daily, as a commuter, or just for fun? I think you could get away with more revs. Word on the street is that the stock crank holds up to 11k rpm. When you start getting into corsa revs, that is when they say cranks might go. I have no experience on that though. A friend with a corsa rags his pretty good and its still in one piece.:shrug: I am confident you'll get into 60mph. Thanks, the Zuma is just for fun and I also picked up a couple other scoots that I can putz around on while the Zuma is being worked on. I think if I were to put a new carb along with an overrange (after upgears) I could probably be nearing 60mph on this w/ stock crank. I'll eventually split the case and put a 13K+ crank in, but I'll rip this stocker til I have no choice but to do that lol nice work 4 -7 mph is what most see when they swap gears because of the wall of wind you fight through as you increase speed when you swap gears your peak rpms to drop a little bit . you will probably have to drop your weights a half gram or so to get the same shift points in your transmission . This will also keep your spunky yake off the same Thanks, I appreciate all your help and advice. Your estimate is about what I was expecting for realistic gains in mph. I havent had the chance to update my signature info prior to this post, but I wound up going to 5g sliders already like you mention as well as replacing the white contra that came with the Multivar (1000 rpm?) with a Malossi yellow 1500 contra as my belt was beginning to slip on acceleration. I also bumped up my clutch to grab at about 6000 and she rips now without the slippage. |
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pili
Scoot Enthusiast
Posts: 278
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Post by pili on Jun 16, 2023 8:02:30 GMT -5
Upping the ignition timing a few degrees does a TON for acceleration which will get your quicker to that illustrious 50mph area. Grind out the stator holes and turn the stator a few mm's counter clockwise. Free mod! This definitely caught my eye and thanks for this tip I hadn’t considered. A few like 3 mm? Good thread TuneGoon |
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Post by Lucass2T on Jun 16, 2023 10:21:15 GMT -5
Upping the ignition timing a few degrees does a TON for acceleration which will get your quicker to that illustrious 50mph area. Grind out the stator holes and turn the stator a few mm's counter clockwise. Free mod! This definitely caught my eye and thanks for this tip I hadn’t considered. A few like 3 mm? Good thread TuneGoon 2-3mm is about right. Best is to measure it one way or the other though. |
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