Bought a CRF250R kart. Looking for advice

Mike Wood

I was on my way to get a WF etc. when a great deal came up on a shifter. It's a 2006 CRF and is stock with the stock carb but with pump-around. It has an airbox with no filter and I am wondering if I should get a nice K&N to replace. Might need to rejet? It's been sitting for years but does have new gas in it and starts up with a tie-strap pull on choke but won't idle. I guess I should check the manual (hard to get the 2004-2009 manual it seems) Wondering if I need to clean the carb idle paths out. Hoping I can do this without a gasket set or anything.

Other questions are what temp should I operate at typically? Its got a reasonable sized radiator and uses the internal water pump.

I've been starting this thing in 4th gear on the stand. Not as easy as the 125. Plus first start seems to need a lot of pulls - I tried my old trick of pressurizing the fuel tank (with my mouth) but this is the first pump-around setup I've owned. Is there a better way to "prime"?

Does not have the slipper clutch but neither does the new HPD CRF250 kit so thinking I should be OK. I've always thought this shock absorbance spin-up stuff could be better handled on the axle sprocket side anyways but only see the shock absorbing carriers out there - and for 219 stuff.

Otherwise in terms of maintenance should I just stick to the Honda manual for the bike?

Cheers,
Mike.
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GP8 CRF250R shifter
Top Kart clone (for the dirt oval!)

Rodney Ebersole · Posted: Sat Mar 23, 2013 6:02 am Post subject:

Mike to prime it by blowing into the tanks vent or vents the return line from the carb to tank needs to be pinched off. 120-130 H2o temp.
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Rodney Ebersole

Mike Wood · Posted: Sun Mar 24, 2013 7:38 am Post subject:

Thanks!

I also found out why it doesn't idle. Every single vacuum hose on the carb had a few holes on the top of the bends. Guess 6 years of sitting around would do that.

I was reading some people like to put gear oil (80W) in the gearbox instead of using the same 10W-30 oil. Others say just don't use synthetic in the clutch. I know you don't put Moly oil in there gearbox but pretty sure fully synthetic should be OK. I am wondering if the kart demands are any different from MX. I was given some GN4 Honda semi-syn 10W-40 oil with it which is what the bike racers use. I was thinking about switching to Amsoil 10W-30 after that.
_________________
GP8 CRF250R shifter
Top Kart clone (for the dirt oval!)

Rodney Ebersole · Posted: Sun Mar 24, 2013 2:07 pm Post subject:

Mike all them vacuum hoses hoses on the carb where bowl vent hoses that need holes on top of the bends. The only vacuum hose it has goes to the fuel pumps and probably starts from a barb coming out from behind the reed cage.
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Rodney Ebersole

Mike Wood · Posted: Sun Mar 24, 2013 3:01 pm Post subject:

oooohhhhh. That's embarrassing! They looked sort of uniform position-wise but like someone had just slit them with a blunt knife! I almost thought they were critter bites.

One thing I'm discovering is that the 4-stroke has things that are hard to get to with the seat being in the way. Hard to turn the stiff throttle-stop, hard to get to the oil etc. I did get it to start idling way too low - 900rpm but since it's hard to get a stubby screwdriver in there to adjust idle up it stalls out - then it won't start warm. Got to figure out the warm start lever... while pulling the tie strap I guess.

Thanks for stopping me fixing something not broken!

Update: got a nice idle around 1900 only once it's in neutral. Guess it does not like the flywheel load of axle and wheels. Man this thing is hard to start warm though. Cold it starts first pull.

Mike.
_________________
GP8 CRF250R shifter
Top Kart clone (for the dirt oval!)

Rodney Ebersole · Posted: Mon Mar 25, 2013 5:48 am Post subject: carb

Mike, I messed up too and missed the fact that it's a 4 stroke and not a 2 stroke. So scratch the part of my post about the vacuum line coming from a barb from behind the read cage.
I have noticed guys with 250 4 strokes and they seem to have hard times with starting them also.
Generally when a motor is cold it needs to be very rich with the fuel air ratio in order to start and warm up, the reason they have jokes for cold starting.
When warmed up the motor doesn't need the richer mixture and starts well with out a choke or will flood if the choke is used.
If your not using a choke to start it cold and it starts easy, then I would bet that your start/idle circuit is too rich for warm starts and is flooding out when warm. Throttle position controls a lot of the fuel/air ratio of the start/idle circuit. Also the idle circuit air and fuel passage ways are the smallest holes in the carb which generally clog up first with dirt.
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Rodney Ebersole

Brian Degulis · Posted: Tue Apr 09, 2013 7:41 pm Post subject:

I put a CRF250 on a kart a while back check out the thread http://www.ekartingnews.com/viewtopic.php?t=119106&sid=3f5be020a5225aa09e2207bf1aa4ca0d

The best way to start it without getting to involved is to make a fixture to go into the axle with a bolt on it then use a coleman starter in 5 th gear. K&N filter is easy to find. They idle @ 1900 you might have to go a little higher. Temp should stay below 170 When they sit and idle they get very hot very fast. Mine stays below 140 in FL but will hit 180 after maybe 5 minutes at idle and continue to climb and thats with a big radiator.

When you get it going your going to see one hell of a diffrence in power compared to a WF. Mine is geared for a short track and if I accelerate to hard in 1st I'll lose traction on the front wheels. Awsome power and low end torque.

Brian