[puff336]

Hope I'm not "double posting"! My son had his first moto on a 2005 CRF50 Saturday. It is obvious we need to hop up this bike to keep him competitive. I'm new to this but think the first thing I need to do is ditch the stock exhaust. I have seen a few poor reviews on FMF and would like any feedback. Also, what about changing the rear sprocket going from a 37T to 39T? I should note that he is not great at shifting gears yet so we are looking for ways to give him quicker throttle response. He starts out in 3rd gear and even though he had the best reaction off the gate he was dead last after about 50 yds. This is fun but I want him to be a little more competitive so he doesnt get discouraged. We are working on the shifting. Thanks for any tips!

[willflyforfood]

I found this site while looking for some 50 stuff for a buddy http://www.50mods.com
Click on "Mods" for freebie stuff you can do to make a stock bike quicker.

[124]

Check out White Brothers, BBR, and fast50's. Between the 3 of those, you should be able to build anything you want...

[puff336]

Thanks for the help! I imagine I will try a couple of these. Any suggestions out there on aftermarket pipes for a stock engine? The best price I can find is on FMF but I have seen a couple of posts saying they don't do much for performance as compared to "White Bros." etc.

[Dan1981]

Hi guys i just checked out that site on free mods that you can do yourself and that awsome i will be doing the timming advancment and crankhose breather tube. Im not sure on the removing of the choke though. I like the Idea but what if i have trouble starting my bike, i cant choke it anymore after this right? The say to rejet after this mod, but on the stock carb all you can mess around with is the clip on the needle right??

[puff336]

When you replace the stock air box what do you do with the 2 tubes connected to it? Thanks!

[Dan1981]

ya i would like to know the same, i replaced my air box with a K&N clamp on and i just left that hose off, i beleive its a crank case pressure release, i may be wrong though.

[puff336]

Thats what I am thinking....appears to come from the crankcase then through a small black box which I take to be some sort of inline filter. I am wondering if I should slip a small piece of filter material over it to prevent any trash from getting into the crank case. Anyone know for sure?

[krylon]

There are a few companies that sell filters for the crankcase breathers. Uni sells them and Applied has one out there. I've seen a few on-line stores sell K&N filters to use for this also.... I am not fond of leaving it opn to the elements. If i were ok to do that, I would've thought Honda would have it that way from the get-go..

As far as the other mods. I am going to try the timing trick and the intake valve breather.

With the intake breather, 50mods.com just have the hose press in. Why not tap the cap and install a fitting so the hose s clamped on rather than take the chance of having it come off and dirt entering? Also, I feel safe with a filter/breather on the end of that hose also..

[puff336]

I replaced the airbox with a K&N filter and dropped the front sprocket to a 13T. Some change but not as much as I had hoped for. I was able to find an in-line fuel filter at a lawn mower shop that fit the crankcase hose perfect (to prevent trash from getting back in). I have a white bros. exhaust on the way but was wondering if I should go to a 12T front sprocket or up to a 39T or 40T rear sprocket. The front is a lot easier to change but I worry about getting too small. Thanks for any replies. I am looking to get as much throttle response as possible since he isnt great at shifting yet I want him to be able to hook up faster out of the turns in 2nd or 3rd gear.

P.S. This board is great! You guys know a lot more (or are just a lot more helpful) than the mechanics at my local cycle shop. If they would be more helpful I would be buying form them instead of E-bay and the Internet sites,

[flying finn]

Not sure if its legal for your sons class. But try a new rev box (CDI) about $27 from most retailers, really allows more rpm's, maybe he can get around in 2nd gear and let it wind out more and forget about 3rd that way.

Try gutting the airbox as well, very restrictive, you'll have to adjust your needle though as you'll be flowing more air.

[buldog]

You might want to check the rules with the association you run with. Where we race the 50 has to be stock suspension and stock exhaust. no point spending $$$$$ if you have to take it off.

[Zhack]

How do you richen up the mixture on these little guys (I have a 70F) after opening up the airbox?

[crfski]

I just performed the mod that saw's off the spark arestor screen on the baffle for my son. What a great
improvement ! Seems to run much better, gives it some grunt ! For zero dollars !