Drr 50 lowend bog

[jakesdad6]

I have a 2010 Drr 50 that when you take off it doesn't rev up as fast as I think it should. It has a pwk 20 mm carb with a 50 piolet and a 105 main. It has a stack 6 adj clutch wit red clucth and shoe springs and 782 belt with 3.5 and 4.0 roller stager. The motor does have some port work done by Tom Alley. I but a 1 mm shim in it and it help a little but I am thinking it's in the carb are my jets off. It doesn't brake up starts right up. I always had a issue with it being slow coming out the turns if not high enough in the rpm. I have change the the clutching all new so I don't no if it's the set up or the carb. Like I said have always had this problem since built just delt with it when my son raced it because he always keep it wide open Now that my daughter rides it just don't seam like it's as snappy as others I have seen is it because of the porting???

[jerkyboy]

Your pilot is a little big. Id try litening the rollers to maybee 3.0's. I never had much luck with the 782 belt use the stock 780. With the clutch tighten the springs till only 2 lines are left showing. What cylinder is in it?

[FRAN Z]

the porting could be it, our 2010 didnt run great with a ported jug. I went back to a stock one.also ran a stage 6 clutch with red shoe springs, with a red hebo and 3.2 rollers or 3.5 depending on the track.We jetted 50 and 105ish. I would lower your roller weights.Also i would go back to the stock belt.

[jakesdad6]

It is a stock ported cylinder with ported cases. I will try and lower the roller weights. Don't understand why the stock belt will help when I put the shim in it seam to make it better so if I put stock smaller width belt in what will that do. And now I don't no what to do about the jets one says lower and the other runs the same setup any other option???

[jerkyboy]

Whatever you do only make 1 change at a time. The 782 belt is longer but not as wide as the 780. 782x16x30 stock belt is
780x16.5x30 so you might have you might have to add 2 shims if you decide to try the stock belt. Going with a smaller pilot was just somthing to try since I cant hear it run.

[jakesdad6]

What size piolet would u try had a 52 in it first then I drop to a 50 the only other one I have is a 42 is that to lean or would you recomend ordering some more jets

[FRAN Z]

Originally posted by jakesdad6
It is a stock ported cylinder with ported cases. I will try and lower the roller weights. Don't understand why the stock belt will help when I put the shim in it seam to make it better so if I put stock smaller width belt in what will that do. And now I don't no what to do about the jets one says lower and the other runs the same setup any other option???
I would listen to Mike, he knows his stuff.that set up worked on my bike but may not on yours.what pipe are you running?

[jakesdad6]

Stock 90 3 pieace pipe and cdi box

[jerkyboy]

The 50 pilot you have in there might be ok. How many turns out on the air screw? If your out 3 or more turns then maybee try a 145. For now just mess with the rollers.

[selbygirl]

did you try lighter wghts i see you have 3.5 put them back and leave one roller out or even 2 rollers out end see if that helps we had a 50 i was running 2.8 rollers in it i allways noticed if it s a week spring or if the wghts are to heavy the bike feels like a sling shot you can feel the motor building up but not moving untill your in a higher gear then the bike shoots out allmost feels like your stuck in mud hole

[nitrofish]

Your jetting sounds ok, we usually ran 52 pilot and 100 main with that carb and pipe combo. You should pick up a tach and set your stall up to about 7500 that should help with your takeoff. With the 90 pipe you should plan to peak out at around 10500 or so with the stock ignition. 782 belt, 3-3.5 on the rollers with a red mallossi spring. We ran a small carb 16mm, for a long time with our set-up until Jack started keeping it pegged. The smaller carb gives you a little more bottom end but hinders your top end a bit. Matt.

[jakesdad6]

I left the jets where they are. I put a red hebo spring in and 3.5 and 3.25 stagger rollers. It seams to take off slitly faster no major improvements but lost some belt travel it doesn't seam to go as high on the varitor as befeore maybe 3/16 difference. The belt is a 780x16 when I used a shim I lost even more belt travel is this normal.

[selbygirl]

did you put new shoe springs in it i had one go bad it felt like carb problems and i had a bad coil wire on one of my bikes the bike felt slugish on bottom the bike was always slow out of the turns put a pvl on it gave better responce out of the turns if the bike feels better with lighter wghts what sprocket s are you running is it geared to high

[nitrofish]

Use a 782 belt to get your travel back, shim as needed to keep your belt from dropping to soon.

[jakesdad6]

I meant to say I was running a 782 not a 780. The sprokets are 32 18. I will try a differnt coil now I am use a bando orange coil.

[EthansDad]

some good ideas on here already, let us know if any of this fixed it or got it in the right direction. A few other things to consider:

- rollers VS spring - 4g is heavy for a stock 50. should be 3.0-3.75 range, maybe lower depended on rpms. you did not mention what spring you are using, maybe the rate is to high (too stiff)?

-ratio 18/32 might be a bit too high a gear. we run 19/35 so its 1.777 VS 1.84. if you run a higher final gearing, it will effect the load on your CVT and ultimately not let you shift out as much, unless you have the motor to pull it, which in the case of a 50 is generally no. we have a higher top speed with a 19/35 than we do with a 19/32 because the motor turns a bit more rpms (less load due to mech advantage of final drive) and therefore makes the bike go faster. and its better out of turns too.

-belt travel - don't get too hung up on how high it goes. I know the sharpee test is cool, but really doesn't get you much. more travel = more top speed, but pre-travel (shifting before take off) = sucky launch. if you take an average mx track, your kid is going to be going 0-20mph a lot more than he is 30+mph. if you shim, yes you loose travel (top speed), but you usually keep the bike in a lower gear longer. its a trade off. I shim different per track myself to get best feel when im in between roller sizes, and no I never get the belt to the top, don't even try.



so, with all this said, what is the bike doing or not doing now in your tests?

[jakesdad6]

I am running a red hebo spring. Never thought of it like that with the gearing but hearing it like that make sence I have a 19 but need a 35 sproket does any one have one for sale on this forum before I spend on a new one thanks again

[EthansDad]

yea, add a new chain to the list too. damn DRRs, usually can't get the same chain to run two different ratios like that.....

on the springs, I run the red hebo on one of our bikes, but it needs a lot of motor to pull it. that is one heck of a stiff spring for how small it is. also, the hebo being short doesn't put a lot of initial tension on the belt, so it slips out of first gear easy.

Ever see this handy spring rate chart? can see the red hebo puts 44lb/in in rate, but initially (at take off) only 70 lbs on the spring. the max rpm 1500 by comparison is a bit softer (can run lighter weights), and puts a heck of a lot more initial force 90lbs on the spring so it stays in first longer. can see from the chart maybe a few others to try, but lowering your spring rate is a good idea unless your 50 motor is ported to the max.

-EA

https://spreadsheets.google.com/ccc?key=0Av3_8nTLRJqTdHBfaS05S2FBQmg2dFRlRUhLMm9Yc 3c&hl=en#gid=0

[rmuscle]

was having a similar prob and i dropped my needle clip down one and solved the problem . spent hours thinking it was clutch and it was just my needle