Rear tires on drx 50

[Nichols Atvs]

My Drx 50came with an 18 inch tire but every one said to run 16 inch snow hog, question is if i ran 18 inch snow hog would i get a little more top end or would it slow us down we need more top end running 19 tooth front sprocket and 32 tooth rear sprocket
and going to change clutch springs to 1500 big and small Need to keep engine stock. He has been running up front but we need a little more speed . Thanks

[kenjolly]

Im running 18in snow hogs and a 19 front 30 rear good top end and still get more than half the hole shots. no clutch work "stock"

we ran the 16 when we started but got stuck in the ruts,sits to low

[bulldogfallon]

I wouldn't mess with the torque spring in the back until you start making more power....This could fight the light roller weights in the front variator

Try running a 30T rear sprocket to get more top end along with the 18" snow hogs.....

Either one will help get you more top end...both should be more than enough

Keep 2 sets of tire set ups (16" and 18")for easy change at different tracks.....long or short vs flat or rutted tracks may require power in different rpm ranges and ground clearances


You may also want to look into a different belt---The 90cc belt is a little bit longer 787mm compared to 780mm.....

Heavier roller weights could also allow the front variator to push the belt higher into the pulley??? Stock is 3.5 gram....3.75 to 4.2 may be something worth trying


Keep me posted on what works best....I keep tinkering...sometimes too much and I lose what worked best :)

[ecmini1]

Bulldog great advise,
stay away from the torq spring upgrade specially if it a koso spring their 1500 is like mosts 2000. Stock machine dosent need it changed. I do rec to repl. the clutch springs to the 2000 spring better stall speed for better hole shots.

[Nichols Atvs]

So your saying not to change the big spring to 1500 and (i think its a Koso) and change the smalls to 2000 not 1500 and we need the rpms up more not lower? what is the stock spring big and small rpm wise more than 2000 . You think go down to a 30 tooth rear sprocket. and add the 18 inch tires. i have a HC head coming for it all so dose that change any thing .

[ecmini1]

Your correct go with 2000 clutch springs this will raise your stall speed, the torq spring is to add clamping force to the belt to keep it from slipping if its has to much force the belt wont pull low enough in the clutch and hinder your top speed. The belt shouldnt be slipping on a stock motor. The HC head will help with bottom end as-well.

[bulldogfallon]

I tried the 2000rpm clutch springs and didn't like the bottom end results, but it pulled better out of the corners...It seems to make the 50cc bog worse...I bet it would make the 70/90s rip though

HC head, 30T rear and 18" Sno Hogs and you should be pleasantly surprised

A new chain wouldn't hurt too....stockers tend to bind up ....



Best advice I have to offer(which I don't always follow myself)

Make 1 change at a time and document it, then try 1 more change......

Don't rush and make too many changes at once w/o comparing the results (easier said than done)

[#404's Dad]

Originally posted by bulldogfallon

Best advice I have to offer(which I don't always follow myself)

Make 1 change at a time and document it, then try 1 more change......

Don't rush and make too many changes at once w/o comparing the results (easier said than done)


GREAT advice, I made nearly 150 pulls on the dyno last night tinkering with every little small thing I could think of from full synthetic light weight oil in the trans, jetting and every air filter we had on the wall that would fit, change one thing at a time is right, other wise yuo will have no clue what did what lol.



Corey

[bulldogfallon]

Are you going to share any of the secretsresults??

We all use the "SOP Dyno" which isn't always accurate :)


That stands for "Seat of the Pants" for those that didn't get the joke :) :)

[#404's Dad]

Originally posted by bulldogfallon
Are you going to share any of the secretsresults??

We all use the "SOP Dyno" which isn't always accurate :)


That stands for "Seat of the Pants" for those that didn't get the joke :) :)

Sure, I have nothing to hide lol, The biggest disspointment of that testing session was the Malossi Reed Cage and Carbon Reeds.

This reed assy lost both Horsepower AND Torque over the stock setup with and w/o the red reducer.

Also, the biggest deal was the "Personality" the bike had lost with the use of the Malossi setup.

Only info...........

Corey

[dblacks]

I have heard of dissapointment with the Malossi stuff in track testing as well. DRR is pretty good with stock stuff in it.

[drr wizard]

Originally posted by #8trx450r
Sure, I have nothing to hide lol, The biggest disspointment of that testing session was the Malossi Reed Cage and Carbon Reeds.

This reed assy lost both Horsepower AND Torque over the stock setup with and w/o the red reducer.

Also, the biggest deal was the "Personality" the bike had lost with the use of the Malossi setup.

Only info...........

Corey

which carb were you testing with ? 21 oko or 16 mukuni?
drr wizard

[#404's Dad]

All testing was done with the stock OKO that has the recommended mods done to it.

Corey

[bulldogfallon]

Recomended mod is not recomneded....

I wouldn't do it or recomend it....

On the 50 the larger hole they ask you to drill is too big IMO


If I were to mod the carb it would be the .029 bit on both holes, which seems to work well.


or

Change over to the Keihin PE20 or use the Mikuni stock carb

There is an adaptor that will allow you to run the Mikuni with the new Koso style intake .....

This may be the best combo....not sure yet.....I will try to source this book and see if I can get you guys some for testing

Keep you posted

[#404's Dad]

Originally posted by bulldogfallon
Recomended mod is not recomneded....

I wouldn't do it or recomend it....

On the 50 the larger hole they ask you to drill is too big IMO


If I were to mod the carb it would be the .029 bit on both holes, which seems to work well.


or

Change over to the Keihin PE20 or use the Mikuni stock carb

There is an adaptor that will allow you to run the Mikuni with the new Koso style intake .....

This may be the best combo....not sure yet.....I will try to source this book and see if I can get you guys some for testing

Keep you posted

If you examine the AFR graph at the lower section of the page here you will see how nice and flat line it is, pretty rare to actually get a line this flat imo from what I have seen on the dyno and this IS with the 21OKO and the recommended holes drilled, Runs fine although as I have mentioned in other posts I am still not 100% happy with it, I like faster throttle response but that is just me.

http://img.photobucket.com/albums/v337/sidewaze79z/DRR50CC6-2007.jpg


Corey