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post #1 of 1221 (permalink) Old 04-10-2007 Thread Starter
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MX650 mods?

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.
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Re: MX650 mods?

didn"t i answer that question for you on youtube.....

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post #3 of 1221 (permalink) Old 04-10-2007 Thread Starter
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Re: MX650 mods?

yah y ou did, and thatnks, but i didnt specify that i was goin to be using it on dirt, and i read that you might want to add torque and stuff?
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Re: MX650 mods?

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Originally Posted by filitup View Post
want to add torque and stuff?
you might want to talk to miker71 he is the expert on the mx dirt bikes... he did some mods to the rear forks and completely turned that dirtbike into a monster... he's the one that can really help you on your bike

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Re: MX650 mods?

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")
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Re: MX650 mods?

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
Attached Images
File Type: jpg 1200w 1.JPG (175.9 KB, 774 views)
File Type: jpg 1200w 2.JPG (171.5 KB, 614 views)
File Type: jpg 1200w 4.JPG (166.5 KB, 587 views)
File Type: jpg 1200w 5.JPG (185.0 KB, 694 views)
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post #7 of 1221 (permalink) Old 04-11-2007 Thread Starter
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Re: MX650 mods?

alright! sweet. thanks. i jst talked to my dad, and he said he knows a guy that could weld th e bike. What would the welding process be?
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post #8 of 1221 (permalink) Old 04-11-2007 Thread Starter
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Re: MX650 mods?

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.

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post #9 of 1221 (permalink) Old 04-11-2007 Thread Starter
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Re: MX650 mods?

oh and one more thing... with all these upgrades, will the bike still be quite? Becuase my area has regulations on the sound of the bike...
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Re: MX650 mods?

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.......

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Re: MX650 mods?

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
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post #12 of 1221 (permalink) Old 04-12-2007 Thread Starter
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Re: MX650 mods?

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?
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Re: MX650 mods?

Quote:
Originally Posted by filitup View Post
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... :-(

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Re: MX650 mods?

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..
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post #15 of 1221 (permalink) Old 04-12-2007 Thread Starter
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Re: MX650 mods?

oh okay. sounds good. thanks. i think that i might stick with the 750 which clips right in? And im having trouble findinga n mx500 in my area and so i uess i have t o go with th mx650 .

how fast will the stock 500 or 650 go with 48 volts?
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Re: MX650 mods?

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..
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Re: MX650 mods?

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....

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Re: MX650 mods?

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Originally Posted by aproldan View Post
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....

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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post #19 of 1221 (permalink) Old 04-13-2007 Thread Starter
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Re: MX650 mods?

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
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Re: MX650 mods?

Quote:
Originally Posted by filitup View Post
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.....
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