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93' CR250 Problems! Help!

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Hey all, I just bought a CR250 from a friend and it is bogging big time. When I got it it was spitting oil out everywhere, where the exhaust pipe meets the engine, and where the two parts of the pipe connect, and definitely out of the tailpipe itself! It was hard to start unless you held the throttle at 3/4, and it was smoking like there was no tomorrow. It was a pain to ride behind.

So I bought it for $750, tore it apart last night...

cleaned out the carb (didn't know what to set idle screw to?!?)

cleaned the pipes and repacked them

threw out the gas(thought it might have been too rich)

made up a new batch at 40:1.

and also changed the engine oil, thought it maybe had too much in it and it was blowing past the rings and not burning up (is this possible)

I try to start it this morning and it won't start with the kickstart but i got it started after rolling it down a hill. It was smoking and bogging but i thought this might be the residual cleaner and it just warming up. It wouldn't idle so i gunned it and it was very jerky. A little less bogged down than last night but not much. What's going on here? Jetting?

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I am far from educated in this so anyone please correct me but yes this does sound like your jetting is off.

What color is the smoke?

I run 32:1 mix myself on my 96 CR250

In regards to oil spitting from where the expansion chamber connects with the silencer, you need to purchase a rubber clamp that covers that connection!

Check Link Below For Pro Circuit Recommended Jetting

http://www.procircuit.com/jettingspecs.htm#1993

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What exactly is jetting, is it adjusting screws on the carb to certain amounts of turns? If so I couldn't make heads or tails of the values i looked up for 93 jetting settings...

main jet 175

pilot jet 55

needle clip 3rd

what do these mean?

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What color is the smoke?

I run 32:1 mix myself on my 96 CR250

In regards to oil spitting from where the expansion chamber connects with the silencer, you need to purchase a rubber clamp that covers that connection!

The Oil is a bluish , i haven't had it running long enough to warm it up or really check it out though i just glanced back as i was putting down the street.

I did have a rubber clam that covered that connection but it was ziptied does it need to be clamped?

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Sounds like you need a manual. We can only tell you so much, but you will need your manual to get you around. The manual for the 92-96 CR250 covers jetting very well. Has charts to help you figure out jetting changes. The oil you changed was the transmission oil. That does not come in contact with the engine itself unless you have a bad right hand crank seal. So, generally, it is not possible for that oil to get past the rings. Also, changing mix ratio does not fix jetting issues. When you change the ratio, you will also need to fix your jetting accordingly. Pick a ratio, stick with it, and jet accordingly.

Get this. Best $7 you will ever spend.

http://www.tradebit.com/filedetail.php/9347349-honda-cr250r-service-repair-manual-1992-1996-cr250

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What exactly is jetting, is it adjusting screws on the carb to certain amounts of turns? If so I couldn't make heads or tails of the values i looked up for 93 jetting settings...

main jet 175

pilot jet 55

needle clip 3rd

what do these mean?

the numbers after the pilot and main jet are sizes. fuel/air mixture screws are adjusted by number of turns and size and control your idle and very low-speed throttle. then it goes through the needle, which is determined by the size of the taper and the clip position. some needles have non-adjustable clips. this is your mid-range. the top-end is controlled by the main jet, which is adjusted by changing sizes. there is no other adjustment, you tighten them until they are snug.

i recommend you pick up a factory service manual. honda manuals are great and will explain everything to you that you need to know about working on the whole bike.

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Got that manual KCDavis, thanks a lot. Going to look into it more tomorrow and see what I can figure out. One thing i noticed was the sparkplug was not the correct one for the bike! So after fixing that it ran a LITTLE bit better. All in all it's getting better and better. Thanks everyone I'll keep you all posted

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I would also make sure you have a new air filter that is properly oiled. When buying a used bike who knows how old the air filter is or how it was cleaned by the previous owner(s).

An air filter is cheap but vital part of your engine.

You bike sounds like it is running very rich. Change your jetting one step at a time to limit your variables.

Your gearbox oil cannot get into the combustion chamber unless you have a leaking crank seal.

I would also suggest that you find out the model and type of carburetor that a 93 CR came with and compare it to the carb you currently have on your bike. It could be that a previous owner changed carbs to a different model and this could make jetting a bit difficult.

GET A SHOP MANUAL!! ebay or online sellers will have them.

Read this excellent post on jetting a 2 stroke bike:

https://thumpertalk.com/forum/showthread.php?t=412662

Do you have any friends that have any experience with 2 stroke bikes?

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Downloaded the manual, very helpful. I cleaned my carb and jetted it correctly! I hope, cross my fingers, I'll try it in the morning. :smashpc: As I was cleaning it I noticed that it was really green inside the carb. In other words it looked oxidized in there. Is this normal?

Also I cleaned my airfilter just to make sure that that wasn't part of the clog up. I cleaned it with soapy water first, and then kerosene. It didn't dissolve my airfilter so I think it went okay. Any thoughts on this?

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Downloaded the manual, very helpful. I cleaned my carb and jetted it correctly! I hope, cross my fingers, I'll try it in the morning. :smashpc: As I was cleaning it I noticed that it was really green inside the carb. In other words it looked oxidized in there. Is this normal?

Also I cleaned my airfilter just to make sure that that wasn't part of the clog up. I cleaned it with soapy water first, and then kerosene. It didn't dissolve my airfilter so I think it went okay. Any thoughts on this?

The green is from the ethanol in the gas. When gas is left in the carb it evaporates and the ethanol kind of tarnished everything up.

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Yep. If u r not going to ride a bike for several days, now u need to let it idle to empty the carb, or lay the bike on its side to get most of it...

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I have 94 CR 250 i mix 32:1, so is everyone i know. it could be one of the seals is bad (it will smoke like there is no tomorrow). to make start easy drain carb after each ride. just shut off valve and wait until bike dies(2-3min).

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Hey all, I've got an update for ya. Took the carb into the mechanic cause i was struggling clearing all the jets completely, they replaced a lot of jets and found a lot of things that were broken in it so that's the good news. So I put it back on the bike with a new airfilter, and carb boot. Mixed up some fresh 32:1 and I rode her around the block...

Still bogging... So someone told me I might check the power valve. So I did. To the best of my ability I took it all apart, and soaked it in gas, and then scraped off all the excess carbon. I only took out what i could find in the initial little box, I didn't take out the gov. or take apart the engine. When i put it together I felt like it needed some lube on somethings so I put a little 10w-40 on a few things (I know it will be burned up soon). Then put it all back together.

Took her for a spin and hmmm .... A little better, still sluggish on the low end but does pretty good on the top end. Plus it won't idle. At all. Period. Is the valve stuck open?

Do I need to clean the reed valve? What's next? Thanks guys.

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Something that old definately need a new top end (piston, rings etc.). You also need to pay close attention to the reassembly of the cylinder in relation to the power valve. If you reassemble the he PV wrong to the cyl. it will have no bottom end. If you are coming from a 4 stroke it will never feel like it has enough bottom end.

Good luck and post some pics.

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Something that old definately need a new top end (piston, rings etc.).

Its possible the top end has been done in the last few years. If it kicks over really easy then yes it will need rings at least. As for the reeds they could be chipped or warped so they dont seal off and could cause the issues you are describing.

You are taking the long route for diagnosing, but then you will find out what fixed it rather then doing 5 things at once and bever knowing what fixed what.

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Something that old definately need a new top end (piston, rings etc.). You also need to pay close attention to the reassembly of the cylinder in relation to the power valve. If you reassemble the he PV wrong to the cyl. it will have no bottom end. If you are coming from a 4 stroke it will never feel like it has enough bottom end.

Good luck and post some pics.

What do you mean if i reassemble it wrong? My problem seems to be that the PV doesn't switch from L to H even though it is clean. Something to do with how i set it up with the spring perhaps? My manual doesn't give much detail on this part :busted: I know that the PV should be in L position while it is off obviously but does it need to be sprung in L position as in, the spring pushing it into L and holding it there or do i want to set it so that the spring is not pushing it towards L or H? Thanks

PS It also won't idle... which is strange to me because the carb has been redone. totally... and the PV is stuck in low like it should be when it is idling yet it continues to die... what's up with that? does that leed me to believe it is something in my reed cage?

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Did you turn the idle adjust to see if that helped with the idle?

I haven't because on the first kick over from getting it back from the chop (the carb) it sat there and idled like a dream. I was afraid to mess with it. Should i?

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