2000 CR 250 Jetting

[00Cr250]

Hi guys
I am having trouble with the jetting on my CR 250 and was wondering what some you guys were running. Ive found loads of info on 01 and 99 CRs but nothing on 2000s I have a pro circuit platinum pipe and factory sound silencer my elevation is like 0 - 999 ft and the temp is around 40 - 50 right now any suggestions would be great thanks

 

[anthony96rm250]

well whats the problem

 

[00Cr250]

If you feather the throttle and kinda slowly get it up to the powerband its fine but right off idle or high rpm powerband if you pin it it boggs right down and its really touchy if you give it to much gas at all

 

[bwood]

does it smoke a lot sitting still?
Is the bog like its rich, "loaded up"?

Try adjusting your air screw on the side of the carb in 1/4 turn incraments. Start with 1 1/2 turns from lightly seated. After each adjustment you will need to test it by riding it just to make sure it clears out. As you turn the screw out it adds more air to the slow circuit. The air screw and the slow jet work together at idle. If the bike runs rich at idle it could have excess unburned fuel in the crank area causing a rich condition and making the bike bog at throttle openings. The bike should be crisp at idle with light smoke at the exhaust. No smoke means your not getting enough fuel/oil mix to the crank/piston. Keep doing this until it it clears up. If you make it past about 2 to 2 1/2 turns you need to go to the next smaller pilot jet (I think, the smaller jet will allow less fuel at idle).
If this doesn't fix you prob, you might need to look at the main jet and needle. If both are worn (it will look like a grove cut at the pointed end of the needle) it will allow excess fuel to enter at 1/4 throttle and the bike will bog until enough air makes it in to correct the fuel to air mix.

BTW, which carb do you have, does the cap on top screw on (like one big nut) or does it have screws that hold it on? Check you jetting against stock. Stock should be in your owner's manaul. For an aftermarket pipe and silencer, you would need to be a little richer on the top end and mayne just a little on the bottom.

Also don't rule out mechanical issues:
Worn top end
Power valve timing/operation
Leaking right side crank seal
You might try a search or look at some prev posts, I think it was the same guy who replies first who was having some jetting issues and I went into some possible mechanical issues.

Also

 

[00Cr250]

I have the carb where the throttle screws on the top and i will play around with the screw and the the jets thanks a lot for the help :cool:

 

[bwood]

Here is a link to that above mentioned post,

http://www.dirtrider.net/forums3/showthread.php?t=168459

I'm not suggesting that your problem is the same just a list of other things to check and better descriptions of the mentioned mechanical issues.

 

[00Cr250]

I tried messing around with the air screw a little bit and it didnt realy solve the problem. like i said before the bike runs fine its just when you pin it that it bogs and it doesnt matter if it is right off idle or hight powerband. if you sort of feather the throttle or slowly bring it it up in rpm it has balls up the wall, also the bike was just rebuilt before i bought it (got the reciets with dates on them with the bike) from a honda shop and completely gone through. it does smoke a little bit. What exactly should i look for with the powervalve ?? One of my buddys said that could be the problem too. Thanks for all the help too eh!!! :)

 

[00Cr250]

I just took my powervalve cover off and looked at a site on the internet about cr250 powervalves and acording to the site my powervalve is working backwords :whoa: Would the spring down in the bottom do this?? it is supposed to be sprung closed in low rpm and off and open at high rpm and mine is sprung towards open when the bike is off. Or are they different for different years ??? although i dought they would leave everything the exact same but just reverse it :think:

 

[bwood]

I honestly have not had to work on or adjust anything on these motors. Is it the cable operated powervalve (two cables mounted on the side of the cyliner)? If so are they on backwards/reversed? I would definitely recommend a manual to make sure the adjustment is correct.

 

[00Cr250]

My powervalve is done by rods conecting inside the jug and i guess i did figure it out that my powervalve is workin right and im stumped. Ive messed around with the air screw and the jets and the needle setting and it still runs the same untill you pin it and it boggs :bang: :bang: im stumped

 

[whenfoxforks-ruled]

Then, replace the float valve. You can not reasonably inspect it, maybe with a microscope and comparator? It should be replaced yearly. If defective, it causes issues like you just described. If you are properly adjusting your jets, and it seems wrong, it is! There is another reason, mechanical. And of course, the reeds, crank seals, silencer packing, pipe condition, has it been ported or modified, correct sparkplug, air filter and of course the ignition!

 

[_JOE_]

Time to do some testing. Start with compression and leak-down to rule out cylinder scoring or crank seals. Check the reeds. I hope you cleaned the air filter before going this far.

 

[00Cr250]

I just got a brand new plug to try when im done with this and i will post if that happened to be it or not. The exhaust im pretty sure was put on right before i bought it though im not sure. what should i be looking for with the packing? I will check that out tonight to to see what that is like. not ported, bored or anything, it was rebuilt with a brand new jug right fom honda. The reeds are brand new. The air filter is just cleaned and oiled. and lastly what should i be checking in the ignition?? I havent heard of a coil that is only partially bad and not giving spark only in one spot but i could be wrong. Is there anything else i should be looking for with the ignition??

 

[James]

What jets are in it now?

 

[00Cr250]

The jets that are in it now are
180 Main
48 Pilot
screw 1 1/2 turns out
3rd clip position
Seems to be where it runs the best but it still does it

 

[00Cr250]

Also by float valve, do you mean needle and seat??

 

[00Cr250]

I just tried the new plug and now it ran for about five minutes and now i cant get it started. If i keep kicking it about every six or seven kickes it will fire for about 2 seconds and thats it. Pulled the plug and it has great spark and a little wet but not a lot. Bout 2 seconds away from just giving in and bring it to the dealer and telling them to fix it

 

[whenfoxforks-ruled]

Float valve and seat, if it is applicable. Is the packing oil filled, brittle? CDI box can cause weird issues sometimes? Sure sounds like its getting flooded. Take the plug out and turn the bike over, without the tank. Wrap a dry rag around the sparkplug cap and turn the engine over slowly. Any gas come out? Float valve and/or float height. Is the plug dark or sooty? Another thought, is your rotor and woodruff key secure?

 

[00Cr250]

Finally got some time to rip into the bike a little bit more and take the reeds out and yes they were shot bad. Cracked, week, chipped :nod: Any opinions on VForce 3 Reed systems??? Thats what im leaning towards but just wanna get some input first
Once again thanks for all the help guys :cool:

 

[skipn8r]

I prefer the Boyesen Rad Valve over the VF3.

 

[00Cr250]

Thanks for the input.. Ive usually hear the opposite about Boysen VS. VForce. Ill have to look into Boysen a little bit more and see what they got.

 

[whenfoxforks-ruled]

I believe the Tassinari valve hits a lot harder, and does not break up as bad on top.

 

[bwood]

I need to make a clarification, for some reason I thought the bike was an 02 therefore I was thinking of a cable operated powervavle.

+1 on the VF3. I used one on my 99 which was the same as your 2000. It made a world of difference.

 

[00Cr250]

I think i will be going with the VF3s and thanks for all the help with everything :) :cool: