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Cr250 1991 running problems

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hi i am new to the site, can any one tell me what is up with my bike it just wont rev at top end it started second kick the other day when i opened the throttle it just bogged out and splattered:banghead: i have cleaned the carb & blown it out. jetting is 175, 55, R1370N, needle position 2nd, air scew 1.5 float level is fine. running 30-1. getting a good consistent spark. but when i took the plug out it was wet with oil & fuel, cleaned the plug and popped it back in tried to kick her over & she started then cut out with a splutter so took the plug out again & it was dry fuel is on & choke & idle screw work fine. got a new plug & gonna pop that in to see if that has caused any of the issues of not running right.

could the hpp cause any of the problems?. bike is not at home & need to travel to see her so before i get over was hoping if any one might have some tips for me.

she is not leaking any oil from the seals and the compression is very good, not long had a re-build.

any help would be great:worthy:

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sorry kc i work nights, reeds are fine have checked them & they are boysen and are seated fine & in good shape. i have just replaced the expansion chamber to a fmf gnarly (second hand & in very good condition) & have gone buy there jet settings apart from the needle being R1370N & fmf say R1369N & i have not got that size. would there be much difference?.

what would you recommend jetting to be to lean it out?

going to check powervalve on Sunday put new plug in and see what happens.

thanks for the reply much appreciated will let you no the outcome.

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I am not sure how much difference the needle can make. Sometimes needle position can help clear things up a bit too, with a mid to top bog. If your jetting is rich up top and causing the black plugs and bogging, I would get the next couple of sizes smaller main jets, and just experiment with a little trial and error.

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Gonna check the powervalve tomorrow and clean carb out again & pop new plug in & see what happens..... fingers crossed will run ok

if no luck then I will go to Honda & grab some different size jets & experiment with jetting.

will keep you updated on what happens tomorrow

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checked power valve all OK, fuel getting there now played around with the jetting like you suggested no oil just fine fuel residue. think its a ignition problem as the spark is weak now. going to change the stator coil & magneto (looks pretty naff) & the coil/ht lead assembly. (got both of them of another 91 cr250 I have which are in like new condition) hoping the cdi is OK as my spare has a broken wire right where it comes out of the black box.

when i get a chance to play around with her again I will let you no my progress........

cheers kc for your advice

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The problem I am having is getting the thing to start now, it was running but with no top end and would not clear.

checked the carb & float all perfect nothing blocked & float hight spot on.

followed kc advice & checked powervalve, reeds are all good.

but still running with standard jetting.

changed magneto etc etc etc and all electrics are running how they should.

thinking about breaking the engine down and seeing if there is anything gone wrong inside................

previous owner done a re-build and am not that confident about his work now as i have come across a few problems, cluth, magneto housing etc.

any advice is knowledge thanks guys

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Right quick update on what i have found to be the problem.........

started to strip the top end down & got to the reeds to find that one of the little buggers had snapped cant find it anywhere so can only assume it has come out of the exhaust.

all these things had been checked of course when starting issues had arisen, so just waiting to see what happens when new reeds arrive & I rebuild my baby.

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new update,

put new reeds in & she started on second kick.

sounded really sweet & crisp, then cut out after a couple of minutes.

just ordered a new plug br8eg as the one i have is not the correct one it is a br9 would it make much difference?.

and also would a br8eix be any better?.

plug was wet and oily when i took it out, going to play around with the jetting & go leaner.

would running 40/1 be to lean?

or shall i stick to 32/1?

would it be wise to wait for new plug before i play with the jetting?.

thanks for all your help guy's almost got her running right

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Hi kc, just going trial riding for the time being as work commitments wont let me go out for the full day & it has got really hot over here the last couple of days up in the 40+.

November when I have more spare time I will be taking it to a few tracks.

just had another problem the pin that holds the magneto in place has broken and magneto retain bolt has come off, another headache.

think it is due to timing be out slightly!?.

what ratio is good for the style of riding i am planning for the time being?.


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The pin was the woodruff key.

i have made one till the original part arrives just to make sure it is down to this.

so put it all back together started second kick with no problems at all, give it a good blip on the throttle great response.

everything seems sweet, so cut the engine.

when original part comes and have put all back together will be out there to see what this bike has got.

its been a long pain full task but i no it is well worth the money and time spent.

any one who might need the woodruff key it is

Honda part number 13331-360-000 if any one else has this problem cos it took me a while to find this out.

my next post will hopefully be the one how i tell you everything is sorted and running spot on all the way.

cheers for all help much appreciated

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Keep us to date with your work as you have in the past. I own a 1990 cr250, I will learn from you. I actually ordered new springs from my power valves. I haven't installed them yet, because the bike runs well now. I do have clutch dragging, which I assume that some the plates are warped. Already clutch cable to the max. Annoying....


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Hi bob, i have been getting most of my parts from Ebay which i find pretty cheap.

also there is another site which has near enough everything, mr motorcycle.com

Took bike out for a quick run today everything is running perfect, just need to move needle as not enough throttle response at bottom end.

front wheel is lifting & back wheel all over the place so i am a happy boy now.

just a few more tweaks and job done.

then i can start rebuilding the other cr250 91 that i have

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