Newby CRF50 Owner. Question about throttle limiter



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Hi All,


I just bough a CRF50 from a friend. I am buying this for my 5 year old to learn to ride and have a few quesitons\concerns...


So it's a 2000 CRF50 with the 88cc big bore kit aftermarket rear shock and extended forks. He says there is no longer a throttle limiter and in frist gear it is fine for the kids but once they shift watch out... His boy went flying through the desert like superman when the throttle stuck wide open, I do not want to repeat that with my boy on the bike...


So, is there an aftermarket or replacement throttle limiter that I can put on the bike? He says the throttle stuck wide open because the carb is all gunked up, does that sound right?


I am mechanically inclined but am completely new to the world of dirt bikes. I'll search the forms but would appreciate some feedback on this specific question.


I am paying $200.00 which I assume is a killer deal, any idea what it is probably worth? Cosmetically the bike looks excellent.



Edited by jeremywrags

first of all, I think $200 is a pretty good deal.  But just be aware that the bike sounds a little much for a five year old to learn on.  Not saying don;t get it, just saying to be aware that the few extra horsepower can be  lot for new guys.


It does sound like the bike needs a little love with a wrench.  I don't think the carb is causing the sticking, but it should still be removed and cleaned.  See some of the posts on here about how to do a complete job.  The sticking is most likely from a cable that needs lubed or replaced. I cannot think of an aftermarket throttle limiter, and if you get a stock one, you need to ensure it will mate up to the carb.  I am not sure if the 88 kit came with a different carb or it is still running stock.


Here are some things I look for with used bikes.  Before you buy one you need to understand one thing.  All used bikes have secrets.  Some of those secrets are small, some are big ones.  Some of the secrets the bike will tell you right away, some of them it will keep hidden for a long time.  In any case, remember that all bikes still have a secret that one day they will tell.


Check the bearings in the wheels.  lift the tire off the ground and try to wiggle it from left to right.  Any play means it needs replaced.  You can get those for about 20 bucks a wheel and replace them with a hammer and screw driver.   Check the swing arm bearings and bolt.  Kind of tough to do with the shock on, but lift up the back end and listen and feel for movement.  This one is tough to explain and better if its shown.  on any bike, look at the air filter.  if its dirty, that can be, but not always, an indication the bike isn't well cared for.  The good thing is the stock ones are cheap and easy to replace.  Also look at chain and sprockets.  the specific thing here are the teeth.  Do they look thin or have a rounded wear pattern on the tooth (the side, not the top.  basically the chain is cutting a circle on one side of the tooth).  if the teeth have any wear, both of the sprockets and chain should be replaced and that is about 40 to 50 dollars.  


All the work on these bikes can be done without issue.  Just get a book and let that be your guide.  Youtube also helps.


My only concern is the bike seems a little much for a new rider.  Don't get me wrong, in a few months of riding I am sure your kid will be comfortable and ripping up the dirt.  But its those two months before that point which usually create the most concern.  But if the carb is still stock, then pick up a used OEM throttle and stick it on there.  That will help out and you can back the screw (that is the actual limiter) out until he/she gets comfortable.


Let me know what else has been changed besides the over bore, shock and forks.

Wow thanks for all the great info. I did buy it in the end, I figure at $200 I can't loose...

So when I went to pick it up it would not start so my buddy and I tore the carb apart, it was gummed up and the jets were blocked. Cleaned it up, got everything clear and put it back together, started first kick...

As for the throttle, I'm not sure it sticks open because as soon as the bike starts it is already revving without touching the throttle, give it throttle and it revs higher and stays there. When we took the carb apart I noticed that the little rubber needle that the float moves up and down was rotted and torn, not sure that would cause the issue though?

As for the throttle limiter, I have an aftermarket throttle, fast50s brand, I tapped a 6/32 hole in the throttle housing and stuck a screw in it and it worked perfectly :-)

Besides clean and lube and replace float needle any suggestions on what I should look for?


That float needle is probably causing your problems, but also check the idle adjustment on the carb.  There are two screws on left hand side of the bike.  One controls idle and the other is a fuel/air mixture.  The one with the rounded head and has a visible spring is the idle.  Screw it in to make it idle higher, screw it out to slow it down.


I am going to go out on a limb and guess the bike has had a rough life not cared for that well.  However, a little love can go a long ways with these things.


here are my top things to consider.  If anyone else has some ideas, add them to the list.


After you are sure the carb is spotless, give it a valve check. I am not sure what it is with an 88 kit, but stock it is .002 on the intake and exhaust.  I have heard it different on this forum, but my book says .002 for both.

Clean the air filter, let it dry, oil it, and stick it back on there.

Depending on what kind of exhaust it has, clean the spark arrestor screen and ensure the exhaust is free flowing and clear.

Now, with those things done, adjust the fuel/air screw and idle on the carb.  It should be good to go from there.


If you do all the other things with bearings, sprockets, etc, you will have a little money in it, but the bike should be good to go.Keep it clean, keep it greased, and keep it maintained.  That is really the big thing.


Finally, have fun with the kid.  Riding around with your son or daughter is a ton of fun.  It basically gives you an excuse to be a kid again.

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