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MX650 mods?

591K views 2K replies 212 participants last post by  MrKitty 
#1 ·
hey im about to buy an mx650, and i was wondering what my best bet would be to go faster. Should i just change the sprocket size, get a different motor, or change it to 48V? What would the best option be for the best price. Im plannin to take it out on dirt jumps.

Thanks.
 
#5 ·
Hi Filitup!
Yes, Aproldan is right, I took my son's regular mx500(500w 36v) and turned it into a MX1200 Monster(48v 1200w motor).
Expert? Ok, well you forgot to tell Filitup I got most of my expertise from the master, aproldan himself... LOL ! I just honed aproldan's advice, and engineered it a bit further...
According to your note in the forum, and it seems you are about to buy a mx650(or did you already buy one?). If you have not already bought it, you could save a bunch of $$ by buying a mx500, and upgrading that one(The mx650 is >$100 more than the mx500). If you are going to upgrade to a "monster" mx1200 (or mx750), then you are basically paying >$100 for yellow paint.. LOL. *The only differences from the mx500 to mx650 is the paint color and, the mx650 has a 650w motor(the mx 500 has a 500w...)
So, the first question is, are you willing to spend the time to(and are you able to) "re-fabricate" the rear swing arm, to fit the large 1200w motor - this option requires cutting & welding(*I can send pictures of mine, and help you through the steps)? Or, would you rather go with the 750w motor, which is the biggest that will fit right in, with out modifying the rear swing arm?

(*check out my son's mx1200 vids on youtube. search for "mkroberge") :)
 
#6 ·
Filitup,

Ok, based on your private messages to me, you would rather not cut and weld, so the 1200w motor is out.. *I don't blame you - it was quite a job, and if it were not for a good friend of mine to do the brunt of the fabrication(with his spare scrap metal, MIG welder, and grinders/cutters) I don't think I would have bothered..

With this decided, you are going to want to go with the 750w/36v motor, and pump 48v to it - for max power..
Unless you want the yellow mx650, save yourself $100, or more, and buy the MX500, because you are going to replace the motor in either one, anyway..
Chris at TNC Scooters is great for all the parts you will need(~about $170 total in upgrades):
~$20 Extra 12v/12ah battery.
~$40 100a/48v controller
~$38 48v battery charger
~$65 750w/36v motor(*Swaps right in w/no modifications)

*Ok, How fast can you go with this setup? My Son(65lbs) saw 31mph max, using a 15 tooth front sprocket(not stock)/80 tooth rear(stock)=5.33:1 ratio. When we tried any larger front sprockets(to lower the gear ratio) it wouldn't go any faster. Probably because we exceeded the capability of the motor(Horse Power). *I weigh 175lbs and I maxed out between 26-28mph, so you would probably see ~28mph if you weigh ~135lbs...
*Now here is the deal. You have to decide how you are going to use the bike. If you want top speed, you will have to ride on flat hard surfaces all the time, because if you run a 80t/15t=5.33:1 ratio on dirt, jumps or hills, it will feel sluggish, and you may end up frying the motor.
*I tried the top speed thing for fun, but if you want to go in the dirt/jumps small hills(like my son rides) I would suggest a higher ratio.
Before we upgraded to the 1200w/48v motor, we had the 750w/36v in his bike. We tried a 8t front sprocket(80t/8t=10:1) and the thing popped wheelies, had killer acceleration, and had top speed as fast as a stock mx500/36v, 17mph - but believe me, it was way better than a super slow lame stock 17mph mx500 !!! We ride on this dirt course(see my vids), and my son had such acceleration, he left his buddies stock mx500's in the dust!
*Now, the stock gear setup is 80t/11t. This is a fairly good combination for the best of both. It went ~24mph top speed, and had better acceleration than stock mx500's.. *But, if you are going to ride on hilly/dirt courses where you never get near the 24mph top speed, you will have to monitor you 750w motor.. It can overheat.. *Remember, you are pumping 48v 50-100a to a 36w motor.. (*But, we never saw the motor get hot, no matter how my son rode it - when we had 9t or 8t front gears...)
*Now, lets get to my photos. They are of my son's MX1200. He rides this just like a 70-90cc dirt bike. Jumps it like heck, spins dirt out of the corners, ect... It's allot of fun, and you can pretty much get the same out of a 750w upgrade. *About the only difference is, you need to pay attention to the 750w motor. It will be getting the same power as my son's, but it is smaller, and can get warm/hot. If you take care of it, it will be fine.

*When you buy the MX Dirt Rocket, and the upgrade parts, - let aproldan and I know(by posting here) and we will help you through the upgrade process. When you are ready to start, I can send photo’s of where I put what(Extra battery,48v controller, ect) and step you through the process.

- miker71
 

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#514 ·
Greetings fellow mx upgrader.

We have a sluggish mx650 that can't keep up with our MX500.
I am about to buy all the parts and do the upgrade in your post.
Parts I can buy, procedure is what I need. I don't know what I don't know.
Pictures were a big help.

Are you still interested in giving advice?

Best regards,

David

813-263-7621
 
#10 ·
miker71 our mx dirt bike expert.... btw your boy qualifies to be in the 30mph club... it's up to you if you want to submit a pic of your boy and his bike so street can post it up on the club site... street, miker71 and i been communicating for some time now i i do believe his boy hit the 30+ cause he used the same setup i did and his boy weights the same as aj.... and aj went over 31mph on his dirtbike.... so he gets my vote...i'll take this to members only section to vote.......:thumbsup:
 
#11 ·
RE:
alright! sweet. thanks. i jst talked to my dad, and he said he knows a guy that could weld the bike. What would the welding process be?

sweet. ill be heading by pep boys soon and i already have enough for the MX500. I am probably going to be doing the welding procedure, as i want top performance. How much would that cost again? And ill post as soon as i get it.

oh and one more thing... with all these upgrades, will the bike still be quite? Because my area has regulations on the sound of the bike...



Filitup,

Ok, so you want to do the monster 1200w deal instead, way to go! The only difference in the upgrade, will be the 1200w 48v motor, which is ~$90, so that’s ~$25 more than the 750w upgrade plan.

Welding process: Take a good look at my photos… Print them to bring them to the guy your Dad knows… Basically, we cut away the top and inside left of the stock swing arm boxed steel, where the longer 1200w motor needs to protrude into – so the chain sprockets on the right side will still line up with the rear tire sprocket... So, we had a “box” originally, but now we have a “L”. The “L” is much weaker than the box, so my friend took a piece of “L” shaped angle iron, cut it to size, and welded it to the stock “L”, making it a super strong double “LL”.. from the pics, you can see the new “L” piece is taller, so we could also then use it as the left side motor mount…
*Now, I’m not going to kid you, or your friend doing the welding… This was quite a job. My friend and I are not welders by trade, but he knows what he’s doing, and it took us quite a few hours to fabricate what you see in the pics… I don’t have any idea what it will cost you, but maybe this guy can do a good job quickly…
* You’ll want to take the swing arm off the bike. Leave the stock 500w motor and rear tire attached to the arm, with the chain on. Bring this to your welder, with the new 1200w motor also. Show him my pics, and tell him to make it so the new 1200w motor is where the 500w one is, and make sure the sprockets are lined up, and the chain is straight! If he is successful, you’ll be able to just reconnect the “new” 1200w motor/swing arm assembly to the bike when you get it home!

*If, after thinking this over you would rather just try the 750w first, no problem. You would still enjoy the performance gain over a stock MX500/MX650.

*The electronics – the extra battery & new 48v 100a controller is another step, which aproldan and I can walk you through when you are ready. This will require some wire splicing, and soldering. “Cake”, compared to the swing arm modification….

*Noise? What noise? It’s electric!!!! J That’s the best part of this! It’s like a 70-90cc mini dirt bike, without the noise! We live in a neighborhood, and a real dirt bike driving up and down the road would be a call to the cops for sure… But, My Son can cruse all day, and no one even notices… :)

Ride time: You haven’t asked yet, but if you are wondering how long you can ride between charges, it’s like 25-45min continues ride time, then 3-5hrs to charge.


Aproldan: I forgot about the 30+mph club, when My Boy did 31mph… Sure, that would be great if he could join that club. Where do I send a Pic? Can I e-mail it to you, and you send it to street? OR, should we just wait until I put the 20t front gear on the new 1200w motor, and then start a 40+mph club? :)

-miker71
 
#13 ·
alright! thanks. and wehen you mean swing arm you mean the back part of the bike?

Sorry im new to this. Is there a way to prolong performance time?
Filitup,

Yes, the silver rear part of the bike that holds the motor & rear tire. It "swings" as the rear shock compresses, thus a "swing arm"...

Ride time performance: To get more ride time, you need bigger batteries, but this equals more weight(you don't want), and more room(you don't have). There might be "better" batteries, but they probably cost a fortune. Ideas aproldan?

*A higher ratio(less top speed, but more torque/quicker acceleration) also gives longer ride time. I believe this is due to the motor requires less amps to "GO". Can you expand on this aproldan?

*But this is electric and batteries can only do so much, so you won't see drastic gains - no mater what you do.. If you want to ride all day,
I think you will have to go Gas... :-(

-miker71
 
#14 ·
re: thanks! aweomse. so my total cost in upgrades would be....?

Filitup,
Ok, I think about 8 posts ago, I estimated ~$170. So, if you go with the 1200w motor, you will have to add ~$25 for the motor. *How much $$ for the welding / metal fabrication work? That's between you and your Dad's friend.. *Also, there will be some incidentals you will need, like 12 gauge wire, an Automotive fuse-able link, New On/Off switch, ect... So, I'm guessing ~$240 upgrade parts & shipping, not including $$ for the welding...
*So, if the welding is going to bust your budget, you could just go for the 750w motor for now, and costs would total around ~$215...
*You could even not replace the 500w motor, and just go 48v/100amps to start off, then you would be around ~$150. *Going to 48v with the stock 500w motor will definitely make it way better than a stock MX500....
I guess what I'm trying to say, is - you don't have to do everything all at once, and go broke. In fact, part of the fun of upgrading is doing one thing, and seeing the gains, then later trying something else.. One thing you don't want to happen, is you rip the whole bike apart, and run out of $$ or time, in the middle of the upgrade.. :)
 
#16 ·
Filitup,
I don't know about the 650w motor specs, but I bet it's pretty close to the 750w. My Son's bike went like ~24mph with the stock MX dirt Rocket gears setup(80tooth rear/11tooth front = 7.27:1 ratio)
*Because you are now going to buy the MX650(650w motor), this would be a good candidate to first just try the 48v upgrade(without trying the 750w motor at first). It's only advertised at 100w less than the 750w motor... If you go onto the unite motor web site, they don't even list this motor? I am personally wondering if the MX650 may really just have the 750w motor in it.
Filitup, this might be worth holding off on the 750w motor, to see if you get the same performance at aproldan and I did, before you spend the extra ~$65 on a new motor, that you may already be getting with the mx650...
If you just go without the motor for now:
~$20 Extra 12v/12ah battery.
~$40 100a/48v controller
~$38 48v battery charger
~$45 for incedentals, and shipping..
~$140 - ~$150 total for your initial upgrade.. :)
 
#17 ·
ok i just read up on the mx650 and the mx500... basically the same bike like miker71 first posted... the replacement parts are the exact.... only one difference is the mx500 has a weight limit of 175lbs. where the mx650 has a weight limit of 220lbs. so miker71 is right, your really paying extra for the color... it still has a 500watt in both... even thou the yellow on looks pretty cool but not worth paying extra....
 
#18 ·
Aproldan,

I think the MX650 does come with a 650w motor…. Several months ago, I was on the phone with Razor for warranty parts, and I asked the rep about the differences in the MX650. He said the Yellow paint and a 650w motor was the only difference, and that the bigger motor allowed for bigger/heaver riders.
*But I will agree that searching on the web for info shows neither the 500 or 650 bikes are documented consistently..
* I just got this pic off of the Amazon.com web site. I think it is a picture of the MX650 box. It says here, it has a 650w motor, too….
*Regardless, an extra $100 for 150watts and yellow paint is a poor deal! But, if that’s all Filitup can buy without driving too far, than that’s what he should probably get..

*I still wonder if it is really a 650w motor, or is it a 750w motor, because the unite motor web site does not show a 650w motor????

-miker71
 

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#19 ·
okay. well you see, ive thought about this, and im going to mostly use my bike for taking it out to the jumps. Since any form of pocket bikes on public roads is illegal, i wouldnt be using it for transportation. So which upgrade would be the best for dirt? Is there a specific sprocket size i need to get?

Thanks
 
#20 ·
okay. well you see, ive thought about this, and im going to mostly use my bike for taking it out to the jumps. Since any form of pocket bikes on public roads is illegal, i wouldnt be using it for transportation. So which upgrade would be the best for dirt? Is there a specific sprocket size i need to get?

Thanks
Filitup,
The best thing for dirt & jumps, will be a higher ratio. A higher ratio will give more torque and make less heat on the motor. Stock, the MX bikes come with 80t rear / 11t front = 7.27:1 ratio. You should be able to go 17mph as soon as you buy it.. When you upgrade to 48v, the motor will spin faster, so you will probably end up seeing ~24mph..
Sprockets / ratios: There are a few ways to get a higher ratio. Unfortunately, none of them are direct bolt/screw on's, because the 80t rear sprocket is the biggest direct bolt on, and the 11t front sprocket is the smallest direct bolt on.. But, I have had some success modifying smaller front sprockets, to lower the ratio. You can buy 25P(the size) 9tooth & 10tooth 1/4 in diameter front sprockets from the surpluscenter.com web site for <$2 each, then tap them to screw onto your motor shaft. *For dirt, I would go with the 9t, 80t/9t=8.9:1 ratio... This combo at 48v/650/750w motor will give results like my youtube videos, and go ~18-19mph top speed... You can also buy a pre-taped 8t front sprocket off of ebay for ~$10 that will screw right on. But this 8t sprocket is a re-reversed(tapped twice) sprocket, and therefore it is a bit loose and the threads are week. My 8t worked fine at 36v, but when we went to 48v/750w motor it stripped out the second day. :(
Now, the other option is to buy a Currie scooter 90t rear sprocket, ~$20, this would give you 90t/11t-8.2:1 ratio - and ~20mph top speed. *The 90t Currie rear sprocket will need the center hole enlarged to fit your hub, which will require a little bit of drilling, and patience with a jig saw..(*I'm actually getting this sprocket today, and next week I will be modifying it to fit, so I can give details as how I modified it, later).
The deal on the sprockets is this: The front ones are less expensive, but need to be screwed onto the motor shaft. The threaded shaft was not originally intended for sprockets, it is for the lock nut... I have not yet had a threaded shaft snap off, but we haven’t had that combination on long enough to see how it holds up long term... The Rear 90t Currie Sprocket seems like the best way to go for peace of mind, because after you put the time into modifying it, it will just bolt onto the hub where the original does - and should be exactly like the original 80t stock one, in terms of reliability.. *I'll be able to let everyone know how the 90t sprocket works out for us, in a week or two...

Now, on another note. Aproldan is still not sure if the MX650 really does come with the 650w motor(Because it is not on the unite motor web site)... If it does not, you are in fact paying an extra $100 for yellow paint. :(
Maybe, you, filitup could call Razor to verify the MX650 does come with a bigger motor? *It might be that Razor contracted with Unite motor to make this size motor, just to be supplied to Razor for the MX650..... :)
 
#23 ·
yah i went to the store yesterday and i read the specification son the box to the mx500 an dit said 650W motor.

hmmm.

so if i keep the same stock gear ratio and 48v will that be okay or od i have to cahnge it?
Filitup,

Yes, I think you will be ok with the stock ratio… The bike should go 17mph stock, and ~24mph @48v. It will be up to you to take care of, and monitor your motor…
*For example, if you are riding in an area where you can only go 10-15mph, and you are always pegging the throttle, then the motor will get hot, because it cannot spin up to full speed, but you are sending a full 48v and 50-100amp surges to it… *If you take it easy in these situations, you’ll be ok. Now, when you are on a flat hard surface – you should be fine letting it all hang out. But, it is always a good idea to stop now and then, and check/touch you motor, to see if it’s getting hot – and let it cool if necessary.. If, later on, you want to “higher” the ratio, you will see a snapper bike and less heat to the motor..
I would suggest just to leave it stock at first, it’s still a great ride the way it comes! Then, when you do go 48v, you will see a significant difference that will really put a smile on you face!:)

-miker71
 
#27 ·
miker71 - Thanks a lot for sharing all this info, it is really appreciated. aproldan popinted me to this site and the information here has been great. I plan on doing some of these mods to my MX500 (and eventually my wife's bike) in the near future, I'll let you know how it all works out.
 
#28 ·
miker71 - Thanks a lot for sharing all this info, it is really appreciated. aproldan popinted me to this site and the information here has been great. I plan on doing some of these mods to my MX500 (and eventually my wife's bike) in the near future, I'll let you know how it all works out.

TiddlerRacer,

Glad you are finding this MX Dirt Rocket upgrade info helpful! We look forward to hearing about / seeing your modified MX500, once done. If you need any help along the way, let aproldan or myself know, we’d be glad to help!
My son absolutely loves his MX1200. He’s always buzzing around like it’s on fire! The other day, I took him to a place where there were 3 foot dirt piles, and he was getting 5 feet of air, and landing his MX perfectly!! He was upset at Dad for not having the camera to video it for PB & Youtube, LOL!! We’ll catch a video of that next time… :)

- miker71
 
#34 ·
hi,

I also have a mx650. I am attempting the 48volt hop up based off of this forum and need your knowledge of where you put the 4 battery. Any suggestions would be great.
Also, I need 12 gauge wire, and an automotive what?
Tera,
When I had an extra 12v battery, I mounted it on the upper battery tray. I bent all 4 battery tray tabs down, turned the batteries 90 degrees, and mounted them side-ways. Check out my How to 2 12v batts.jpg.
-miker71

Also, I have had quite a few people also ask me how I mounted my controller, ran wiring, mounted my battery charger port, 50amp on/off toggle switch, how I got the MX500 plastic fake engine case to fit back on, ect... Also, A few people have inquired how I mounted my $8 Wal-Mart bicycle speedometer.. So, I am posting .jpg photo's that should answer all of these questions. Hope this helps
-miker71 :)
 

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#35 ·
I flattened the batterybox sides, turned the bat 90 degrees, added the 2nd bat, but they do not fit. In the pics you posted, it doesn't show 2 bats on top. How did you do it? Cut the battery box frame? My batteries together need 7 3/4", which exceeds this. Also, why did you add a different on/off switch?
 
#36 · (Edited)
I flattened the batterybox sides, turned the bat 90 degrees, added the 2nd bat, but they do not fit. In the pics you posted, it doesn't show 2 bats on top. How did you do it? Cut the battery box frame? My batteries together need 7 3/4", which exceeds this. Also, why did you add a different on/off switch?
Tera,
My Bad..:( I forgot one step with using two batteries in the upper batt tray. After you have turned the batts 90degrees, you then also have to turn them on their sides. (*See photos*). Once they are on their sides, they just barley fit - good enough to tie-wrap down. (It's ok to turn these batts this way, because they are sealed batts.).
I had these batts in my son's bike this way for one season - and they worked fine. *Currently, I have a different battery combination than most of you. I have one 36v block batt in the lower tray(got this on close-out), and one 12v batt in the upper tray - for 48v total. But, I had the combination I described (*two batts in upper tray - two batts in lower tray, before, and it works fine) - without cutting any frame away.

I added a different on/off switch(50amp, bought at automotive store) because the stock Razor on/off switch is rated at 30amps, and if you upgraded to the 100a/48v controller, you may melt the stock flimsy switch, or start to have contact problems. The rugged 50a switch I use works fine, and never gets hot. Also, I did some current measurements with this combination, and what I saw was: When you PEG the throttle, the motor gets a spike of 40-50amps, then as the motor spins up, the amps decrease to 5-10 amps continuous

I relocated both the Battery charger port and on/off switch up to the fake gas tank, so when I need to take the fake black engine covers off, they don’t have wires attached to them – and now you have easy have access to everything..

Hope this helps,
-miker71 :)
 

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#37 ·
I would of never figured that out. Thank you for helping me. I really apperciate your time & knowledge.

I now have the batteries mounted and the controller mounted in the same spot as you.

I am having difficulties understanding how to correctly wire my YK42-4 controller. The diagram that came with it doesn't show how to wire in the brake wires, charger receptacle, on/off switch, fuasble link.
Think you could explain how to do this?
 
#38 ·
I would of never figured that out. Thank you for helping me. I really apperciate your time & knowledge.

I now have the batteries mounted and the controller mounted in the same spot as you.

I am having difficulties understanding how to correctly wire my YK42-4 controller. The diagram that came with it doesn't show how to wire in the brake wires, charger receptacle, on/off switch, fuasble link.
Think you could explain how to do this?
Tera,
Sorry for taking so long to get back with you, - been busy!
The YK42-4 controller is a basic controller. There are no brake or battery charger port connections (you don't really need them anyway, if you can be careful. (*They are safety features).
Brakes: These 2 wire connections went to your stock mx500 controller so that if you press the brake, the motor will cut out. *I just cut my brake wires at the brake handle. *Now, my son can hold the front brake, and goose the throttle to do burn outs! (*not recommended on a regular basis, but fun once and awhile, if the pavement is wet). (*Oh yeah, I swapped the front brake handle to the left handle bar!)
Battery charger: Just connect this across your final configuration of 48v of batteries in series. Connect them right off of your batt terminals. Don't connect either wire on the other side of your on/off switch! *You want it so when your bike is switched off, you can plug your charger in, and it will directly charge the batteries, not the controller. *Also, put a 5a fuse inline with the positive lead of the battery charger port.
ON/OFF Switch & Fusible Link: Take the positive lead off of your 48v's of batteries - run it to the fusible link - then from the fusible link to the on/off switch. Then, run the wire from the other side of the on/off switch to your controller.
-miker71 :)
 
#39 ·
Jesseforlife said:
Hi miker, my name is jesse and i just got a mx 500 1 month ago. My town has great streets with so many of them i hope to discover with my mx 500. However, i've always thought that my mx 500 could give me more speed than what it gave me at first. So i found this site luckely for me i found this site. I have an unlimited budjet to spend on my mx 500. I want to get the most speed out of my mx 500. I do not use my mx for offroad purposes, only for speeeed!!!! I do not want to make any welding to my bike, however i am willing to spend on the motor, controler and ext... I was just wondering if you would be kind enough to answer my email as i have seen how busy u are through this site lol! I have visited the tncscooter.com website, but i would greatly appreciate if you would make me a complete list of the things i need to get tthe most speed out of my mx 500. also i have a question would this 900 watt motor fit in my mx 500 without welding link: http://cgi.ebay.com/BRAND-NEW-900-W...ryZ22703QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Jesse,
The part#'s from Chris at TNC that I bought to first upgrade my son's MX500 to a MX750 48v are:
~$20 Extra 12v/12ah battery #101160
~$45 100a/48v controller #101215
~$38 48v battery charger #101158
~$65 750w/36v motor #106150


For Speed, see answers to sprocket change questions:
http://www.pocketbikeplanet.com/118-electric-pocketbikes/33003-question-about-mx500-please.html

As far as that question about that 900w motor. I'm not familiar with that one. It appears to be of correct size, but not sure of the mounting holes?
I know the 750w motor from TNC fit's right in, with no cutting or welding.

-miker71
 
#42 ·

Jesse,

I'm not sure what happened to this link(post#39) when I posted it, but it seems one cannot click on it to go directly to it..

*So, if anyone wants to check out discussions about MX sprocket changes for speed/torque, just scroll through the forum list, and look for the one called "question about mx500... please answer".
*Read the posts for info.


-miker71 :thumbsup:
 
#40 ·
trueawoodstar1 said:
hey, could you send me how to connect the extra battery to make a 48 volt and is there any thing else i would need to buy other than a 100 amp controller?
trueawoodstar1,
The extra 12v battery goes in series with the other 3 12v batts the mx500 came with.
As far as what you will need, or how/where to hook stuff up, read the mx650 forum.
-miker71 :)
 
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