CBR250 extremely thirsty

[Toast]

Hey all.

MAte of mine just bought a CBR250R from Red Baron.

Seems a good bike, runs very smoothly, is in pretty mint nick overall.

He reckons he's not getting more than about 140kms to a tank (15L or so), and he's a learner, so is taking it pretty easy.

I used to get about 200kms, snotting it, on mine back in the day.

I haven't had a chance to check over the bike re: this problem, so can't provide any more info.

Any suggestions?

[vtec]

hmmm I like to think of myself as an expert. But this could be tricky.

Could be that it's running rich on all cylinders? Maybe red baron played with the carbs and adjusted all the pilot screws to 2 and a half turns, the CBR250R should be at 1 and 5/8 of a turn back from fully tightened. the MC22 CBR250RR should be at 1 and 3/4 backed off.

It could also be leaking out of the fuel tap, I've had a couple of taps play up on my RR's. (Really easy to notice this, cause the bike will stink of petrol).

Another thing, don't know if this will make it too much worse, but tell him it's pointless full throttling below 10,000rpm, and don't cruise with it below 6,000rpm. Max torque comes at about 11-12000rpm. Max power at 15,000rpm.
Here's a maintenance guide with al sorts of adjustments. There's another couple of pilot screw settings for slightly different models of the CBR, so just make sure he's got the right model setting.

If he wants a link to the full workshop manual with pics, tell him to do a search on www.cr-x.org/cbr250

[Toast]

Cheers for that mate.

Just leaking the stuff was my first thought, but as I haven't seen the bike since a few days after he bought it, I can't tell.

I think it's less to do with his riding style (brand newbie, so nana most of the time) and more to do with the bike.

Hopefully will get a chance to check it out later in the week. From memory, it didn't smell or behave like it was running rich at any revs, but I wasn't specifically looking for it, so maybe I missed something.

Hopefully get a chance to check it out later in the week.

[N4CR]

One of my mates who recently bought one from there has had it running rich and like shit, had it tuned heaps, mabey they just don't know what the hell they are doing there? Second time I have heard of this. And a few times with ZXR's as well.

[vtec]

Anytime, makes me feel smart offering my ideas

One other thing could be the choke might be playing up on the carbs, but if you're sure the power is pretty linear, then it might not even be a carb problem. That would just leave it at leaking petrol. Have a sniff around under the tank area.

[What?]

Clean or replace the spark plugs, then take it for a good, hard run down a quiet road, then kill it, coast to a stop and pull the spark plugs out. The colour of the plugs will give you a good indication of what the tuning scene is like.

http://www.theultralightplace.com/sparkplugs.htm

[Toast]

Anytime, makes me feel smart offering my ideas

One other thing could be the choke might be playing up on the carbs, but if you're sure the power is pretty linear, then it might not even be a carb problem. That would just leave it at leaking petrol. Have a sniff around under the tank area.

Yeah, first plan is to get the sniffer out...

Maybe it's not running as smooth as my first impression. After jumping from the bigger 'Blade to that one, it feels very linear, i.e. no acceleration the whole way. I'll give it a second snotting to see if I can notice anything else.

[Toast]

Clean or replace the spark plugs, then take it for a good, hard run down a quiet road, then kill it, coast to a stop and pull the spark plugs out. The colour of the plugs will give you a good indication of what the tuning scene is like.

http://www.theultralightplace.com/sparkplugs.htm

Great link. Cheers

[imdying]

Clean or replace the spark plugs, then take it for a good, hard run down a quiet road, then kill it, coast to a stop and pull the spark plugs out. The colour of the plugs will give you a good indication of what the tuning scene is like.

http://www.theultralightplace.com/sparkplugs.htm

Doing a plug chop like that would work best if it was a two stroke, which is probably why that link is for Rotax engines?

[imdying]

After jumping from the bigger 'Blade to that one, it feels very linear, i.e. no acceleration the whole way.

No, that's just how they feel. Honda did a pretty awesome job at making the worlds flatest torque curve It's nearly dead flat from <4000-15000rpm. Some pretty nifty tuning

[Filterer]

Maybe a silly suggestion but how does he know he is running out of petrol?

Does the bike have a fuel gauge and hes filling up when that comes on, maybe its not calibrated right

Otherwise perhaps the fuel pickup has moved and it can't suck out all the gas

Of course neither or these suggestions are valid if when he fills up the petrol pump says hes putting in 14+ Litres

[awesker]

Maybe a silly suggestion but how does he know he is running out of petrol?

Does the bike have a fuel gauge and hes filling up when that comes on, maybe its not calibrated right

Otherwise perhaps the fuel pickup has moved and it can't suck out all the gas

Of course neither or these suggestions are valid if when he fills up the petrol pump says hes putting in 14+ Litres

nah, they dont have fuel gauge, I run mine off the odometer.

another idea could be the way hes riding, cause when I started on my cib I was lucky to get 170 to a tank, including reserve.. while now I get 220 before resereve.. not sure what happened there, prolly just learning the bike and getting more experience.

[sAsLEX]

Clean or replace the spark plugs, then take it for a good, hard run down a quiet road, then kill it, coast to a stop and pull the spark plugs out. The colour of the plugs will give you a good indication of what the tuning scene is like.

http://www.theultralightplace.com/sparkplugs.htm

This aint a bmw with the plugs easily accessable! You need a trained anorexic monkey to get the third plug out of a cbr!

[Toast]

Otherwise perhaps the fuel pickup has moved and it can't suck out all the gas

That's a really good point, I never really thought of that...

Although, he did tell me that it was $25 (13ish litres I guess) that got him the 140km, so maybe that's not it, but definitely something worth checking out all the same.

As for riding style. After 2 years on my one, I got pretty confident, and could get it to live in 14k+ rpm range on a certain known, flowing road north of Auckland...still didn't get worse than 6l/100kms...

[vtec]

Yep, 6l/100km is while riding pretty hard. On Puke, I'm sure I was getting closer to 10l/100km, as that was just constant fully open throttle with between 14,000rpm and 18,500rpm.