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View Full Version : what we have done with our aircooled 90 so far...



AFROracing
04-03-2007, 12:14 AM
With an aftermarket filter (unifilter) and 4.5g rollers I thought the 90 aircooled was running pretty awesome.
With the "2nd version" exhaust, just by changing the rollers it allowed the bike to pretty much stay on the power but still lacked on holeshots.

I finally had a few minutes of free time last night and I changed the head to 180psi. it woke this thing up. Not much testing yet, but it was a very noticable difference on low end and massive up top!

Next step for us will to play with some springs....

forgiven
04-03-2007, 09:01 AM
yhpm afro

AFROracing
04-05-2007, 10:52 PM
got the wheels done finally....

Stilling deciding on nerfs, wait for the DRR's or weld some on now??

ntmx
04-10-2007, 10:31 PM
update!
after the head, and rollers, we had to change the jetting big time! and this is what we call the apex killer kit! im afros lil helper, and im telling you this thing is serious. if you have a cracked pipe, go to a welding store, buy two slotted welding tabs, weld one to the expansion chabber and one to the frame, throw in a bolt and walah!
whatever you do , do not go back to the old pipe, it was ok at the time, but this new pipe is way better.
next on the list was going to be porting, im not fond of that exhaust port, but with the outcome of this one, im not sure that i want to touch anything.
btw, first on the list is the airfilter! dont even chance it, throw a uni on and go to a bigger main. not only for the gain, but to save your engine. stock airfilters have never been designed for the demands we put on these machines.
i believe afro has a kit, air filter, jet, and rollers. im telling you, this will do the trick.
dont forget, disconnect the injector pump, it removes 50%of the tention on your little ones thumb.
or before you order one, call afro and tell him to just do it and send you one. for an extra 300, it will scream, have a high quality filter, and outerwear, rollers, head, disconnected oil injector, throttle cable, and welded pipe supports that are easy to unbolt and remove your pipe.

AFROracing
04-17-2007, 11:41 AM
this weekend my son was wornout and didn't wanna race his open class, sowe put NTMX's son on our DRR. Colton is an experienced MXer on bike and we wanted to see what the DRR's could really do!!

Getting a bad start and catching up, he put almost 1/4 to 1/2 a lap on the other riders in our open class, quads ranging from hopped up 140 typhoons, Apex's, honda, and polaris..

This thing was flying and it was good to see an agressive rider that is willing to pass the other quads ...


my 6yr old son playing:


http://media.afroracing.com/images/NTMX%20Gallery/Fly%20Spring%20Series/Albums/Album1/Large/IMG_0039.jpg


Colton passing the 140cc typhoon that nobody everpasses:
http://media.afroracing.com/images/NTMX%20Gallery/Fly%20Spring%20Series/Albums/Album3/Large/IMG_0002.jpg

passing the Apex:
http://media.afroracing.com/images/NTMX%20Gallery/Fly%20Spring%20Series/Albums/Album3/Large/IMG_0006.jpg

riding4fun
04-17-2007, 12:27 PM
Afro,

That's good news,

Our local track just closed for the summer before we even got to try it out.

Maybe I will rent a backhoe and take it to the desert and make my own track?


Is your son kicking his leg up? It looks like he is gonna fly off that thing.

AFROracing
04-17-2007, 01:04 PM
yes he's been doing tricks, he watches the big quads at our track, he's got 1 footer and X-ups down pretty good... Momma hates it!! :D

WOLFPACK
04-17-2007, 06:31 PM
AFRO,

Are you going to the WPSA nationals? It's sounds like you have the DRR90 motor down. If your going to be there look us up so we can talk motors. Caston McConnell rides for us and is currently leading the ATVA 90cc CVT. We do fair at building motors so we could probably help each other out.

Shane

AFROracing
04-17-2007, 11:41 PM
not sure if my boy is ready....

AFROracing
04-18-2007, 12:16 AM
or even old enough for nationals on a 90...

forgiven
04-18-2007, 02:07 AM
What are the stock roller weights and what is the main difference going to the 4.5's as far as characteristics felt to the rider?

I am pretty sure I am going to do the koso head too.

Plan on doing the Rath nerfs and waiting for the DRR rims.

AFROracing
04-18-2007, 10:43 AM
Originally posted by forgiven
What are the stock roller weights and what is the main difference going to the 4.5's as far as characteristics felt to the rider?

I am pretty sure I am going to do the koso head too.

Plan on doing the Rath nerfs and waiting for the DRR rims.

I think the stockers are around 7 or 8g...
just by changing to 4.5 it stretches out the shift point allowing the motor to stay on the pipe longer...

When I changed them I ask by boy what he thought, I got a big smile... LOL!

77racerdad
04-18-2007, 01:05 PM
afroracing did you put a tranny saver in i just dont know witch way to go drr or apex

drr wizard
04-18-2007, 09:30 PM
If you decide to go with Apex make sure you get a tranny saver , they are breaking alot of gears. its not a bad idea on the DRR but it is a must on the Apex. you can also machine the case and add a bushing for extra support .

AFROracing
04-18-2007, 11:25 PM
Originally posted by AFROracing
I think the stockers are around 7 or 8g...
just by changing to 4.5 it stretches out the shift point allowing the motor to stay on the pipe longer...

When I changed them I ask by boy what he thought, I got a big smile... LOL!

I haven't added any to my boy's... To tell you the truth I haven't heard of a DRR busting.. I am sure they will eventually...

I was on my son's DRR "testing" it on the stepup tabletop at the track. I assumed I would need WTF open to clear the top. NTMX said I landed about 3/4 downside.... This thing soaked it up.


I wanna build me one, I will prolly add oftermarket shocks and the tranny saver for my weight and my poor ability to let off the throttle!

ntmx
04-28-2007, 11:59 PM
Originally posted by 77racerdad
afroracing did you put a tranny saver in i just dont know witch way to go drr or apex
thats why we didnt go with apex, we had a dad at our track with a broken apex, and he said that he was going back to drr, he was done with apex.
as for the weights, whit the slight stall from factory, and the heavy weights, when the rear clutch comes in, the front variatr with heavy weights is allready shifting the belt halfway out. with the light weight 4.5's its like taking off in 1st gear rather than 3rd. and yes, it launches like crazy with the 4.5's if you go that rout, there is no reason to add more stall. add the head, and a little tuning on the carb...wow it will scream. if you can do the work yoursealf, its less than 150 in mods.

ntmx
04-28-2007, 11:59 PM
Originally posted by 77racerdad
afroracing did you put a tranny saver in i just dont know witch way to go drr or apex
thats why we didnt go with apex, we had a dad at our track with a broken apex, and he said that he was going back to drr, he was done with apex.
as for the weights, whit the slight stall from factory, and the heavy weights, when the rear clutch comes in, the front variatr with heavy weights is allready shifting the belt halfway out. with the light weight 4.5's its like taking off in 1st gear rather than 3rd. and yes, it launches like crazy with the 4.5's if you go that rout, there is no reason to add more stall. add the head, and a little tuning on the carb...wow it will scream. if you can do the work yoursealf, its less than 150 in mods.

miniquad
04-29-2007, 08:35 AM
The DRR and the APEX have the same gears, cases, bearings,and sprockets. I have an APEX and my buddy has a DRR he broke his gears shortly after getting his DRR. So if you are buying one bike over the other because you think the trans is better you are mistaken. Just a thought.

drr wizard
04-30-2007, 09:27 AM
Originally posted by miniquad
The DRR and the APEX have the same gears, cases, bearings,and sprockets. I have an APEX and my buddy has a DRR he broke his gears shortly after getting his DRR. So if you are buying one bike over the other because you think the trans is better you are mistaken. Just a thought.

miniquad the drr gears are the same style and ratio as the apex , but they are not the same . I am not at liberty to discuss the difference .
drr wizard

forgiven
04-30-2007, 10:09 AM
It is my understanding that DRR uses hardened gears and Apex does not. If THAT is confidential...someone PM me and I will take it down.

AFROracing
04-30-2007, 01:30 PM
Originally posted by forgiven
It is my understanding that DRR uses hardened gears and Apex does not. If THAT is confidential...someone PM me and I will take it down.

I have heard rumors, but can't say forsure!

miniquad
04-30-2007, 03:06 PM
The gears are not the problem it is the needle bearing that supports the gears hardened gears may mask the problem but eventually they will break too.

drr wizard
04-30-2007, 04:34 PM
miniquad ,
apex is a good product and I'm not bashing it but I know several apex owners and all but one have broken gears most of them more than once , I also know several drr owners and I own several myself and I personally have only ever heard of 1 that broke gears. now lets be reasonable something must be different.

maybe I just don't know how many drr breaks there are.
How many of you drr owners out there have broken gears? lets do a survey post your answer. thanks
drr wizard

ecmini1
04-30-2007, 05:05 PM
Im a dealer for both drr and Apex and we also do the transmission mods (bushing) I have transmissions sent to me from all over the country 50cc-90cc all makes and the reason for the apex breaking more is more power, being jumped further and rode harder. All the cvt style trans use the same gears that DRRs do. Put more power in your drr and it will brake sooner or later.

Not trying to stir any thing up just tring to give more info to you on the transmission.

Thanks

drr5
04-30-2007, 05:30 PM
my opinion is that until now we gradually built our bikes ,kasea eton predator etc and our kids learned on these bikes generally in stock form,now that the apex came out in basic race trim minus a little tweaking you have kids that have yet to understand that being smooth over the jumps is what save tranny gears, ive seen it at our local tracks most of the new kids to the mods keep the throtle pinned in mid air ,alot of the kids ive personally seen havent riden a modified bike they have only been on a stock till the apex.but ive also seen plenty of them hold up without breaking a trans, i believe its mostly rider error not weak parts.

miniquad
04-30-2007, 06:42 PM
I agree with you DRR5 most of the failure is rider error but if you have a chance to look at the bearing after gear failure you will see the needle bearings are beat into the stamped steel cage allowing play in the gear mesh.DRR WIZARD DRR is agreat product and the backing from the company is awesome but it is not were the APEX is in performance stock for stock. But DRR is improving their product to make it the best it can be. I am not pro APEX my son rides one because it was the best at the time and I feel is still better than the DRR at this point. I only wish the APEX had the backing that DRR has. The most important thing is the smile on our kids face, sometimes us dads seem to forget that this is the reason we do all of this.

ecmini1
04-30-2007, 07:52 PM
Originally posted by miniquad
I agree with you DRR5 most of the failure is rider error but if you have a chance to look at the bearing after gear failure you will see the needle bearings are beat into the stamped steel cage allowing play in the gear mesh.DRR WIZARD DRR is agreat product and the backing from the company is awesome but it is not were the APEX is in performance stock for stock. But DRR is improving their product to make it the best it can be. I am not pro APEX my son rides one because it was the best at the time and I feel is still better than the DRR at this point. I only wish the APEX had the backing that DRR has. The most important thing is the smile on our kids face, sometimes us dads seem to forget that this is the reason we do all of this.


Well put miniquad.:D

bulldogfallon
04-30-2007, 10:47 PM
DRR is closing the gap on Apex for sure....and for a lot less money too!!!

What price can you put on the backing of their product?

I think the 2007 DRR product is a much better value than the 2006 models...

Water cooled, wider stance, longer swingarm, 4 whl disc brakes, bigger carb and intake manifold, new levers, dual a-arms, better tire set up etc....

Not bad for a model year change.....and I don't think the prices went up that much if at all


I am always a fan of the underdog...so DRR is my choice

ecmini1
05-01-2007, 05:27 AM
Bulldog,
Im with you on this DRR is a great product and reliable. I think when the new head comes for the liquid cooled model we will see a whole otherside of the DRR.

77racerdad
05-01-2007, 10:55 AM
that what i want too see is the smile. just want to up grade from our 05 polairs 90 . i dont want to keep pushing them back after ever moto . when are the new heads coming any other change

sldhd700
05-01-2007, 11:55 AM
We had a DRR lose the gears in the tranny last friday night. Like it was posted earlier we believe it was caused by the weak bearing and rider error. The rider made a charge at the finish line for first, The finish was a double that big quads B class could barely make. Needless to say the mini didn t make it either. He landed short full throttle and that was the end of the night for him. DRR has a bearing upgrade available for 34.00 dealer cost. I ve got one ordered for my sons bike. We ran against an Apex last week and I have to say these two bikes are very comparible. The Apex would just barely pull away in the long strecthes. This seems to be the big competition right now its between bike manufacturers. I just need to figure something out for the exhaust bolts Ive lost two sets. This is the only problem I ve had so far. This bike is an awesome piece of equipment with alot of potential.


Shayden Housley #39

AFROracing
05-01-2007, 12:26 PM
Originally posted by sldhd700
We had a DRR lose the gears in the tranny last friday night. Like it was posted earlier we believe it was caused by the weak bearing and rider error. The rider made a charge at the finish line for first, The finish was a double that big quads B class could barely make. Needless to say the mini didn t make it either. He landed short full throttle and that was the end of the night for him. DRR has a bearing upgrade available for 34.00 dealer cost. I ve got one ordered for my sons bike. We ran against an Apex last week and I have to say these two bikes are very comparible. The Apex would just barely pull away in the long strecthes. This seems to be the big competition right now its between bike manufacturers. I just need to figure something out for the exhaust bolts Ive lost two sets. This is the only problem I ve had so far. This bike is an awesome piece of equipment with alot of potential.


Shayden Housley #39

have you lock-tite the bolts? I lost afew at the cylinder side until I lock-tited it

sldhd700
05-01-2007, 12:39 PM
Yeah I used green loctite with a flat washer and a lockwasher. Ive been told to try red loctite. I m also trying to find some bolts that the heads are drilled for safety wire and wire them.

ecmini1
05-03-2007, 09:59 AM
Use the red with lock washers and shouldnt have an issue.

sldhd700
05-03-2007, 12:08 PM
I put the exhaust back on last night with red loctite and lock washers. We l see what happens we have a race tommorrow night.


Shayden Housley#39

Full Throttle00
05-10-2007, 12:11 AM
Originally posted by miniquad
I agree with you DRR5 most of the failure is rider error but if you have a chance to look at the bearing after gear failure you will see the needle bearings are beat into the stamped steel cage allowing play in the gear mesh.DRR WIZARD DRR is agreat product and the backing from the company is awesome but it is not were the APEX is in performance stock for stock. But DRR is improving their product to make it the best it can be. I am not pro APEX my son rides one because it was the best at the time and I feel is still better than the DRR at this point. I only wish the APEX had the backing that DRR has. The most important thing is the smile on our kids face, sometimes us dads seem to forget that this is the reason we do all of this.

I could not of stated it better my self. well said...
I know that my son was on his DRR 50cc and no gear problems for 7 months.
But now as a 70cc for the first 3 months, more power he went thru his 1st set of gears. He had it pinned all the time. Indoor MX rough scrambles are also really hard on these gears. Starting, stopping, breaking, & roosting out of each corner is brutal to these mini's. All that torque when the rear tires hit at full throttle will just tear those gears & needle bearings up.
Since then, he has learned to change his riding style over the jumps & let off a bit before the rear tires hit the ground and guess what......no more problems!!!:D