2003 CR250 observations

[motometal]

New bike! Here are my observations so far:

Weight: the bike FEELS way lighter than my 2001. I put it on the scale and it is actually 6 pounds lighter, but the 2001 has an o-ring chain and a skid plate.

Handling: Awesome! Felt right at home within 5 minutes!

Braking: Front brake is great (more power), rear I didn't really notice.

Gearing: Seemed ok but I don't like the idea of the axle being so far back so I am putting on a 50 tooth sprocket and report back later.

Motor: Softer on the bottom than the 2001, very quick revving in the middle and ok but not great over rev (jetting?). Not a beginner's bike, keeps you awake for sure! Lots of wheelies!

Also, at low rpms there is a knocking noise, probably from the piston, louder than engine noise on my 2001. I'm not used to this, anyone else notice this on their bikes? It goes away as the motor is revved a bit higher. This is independant of load (not detonation). Never heard it on the track, but was noticeable in the woods when lugging.

Suspension: Feels good so far, I was bottoming the front so I will add 10ccs and try again. Also the rear spring is a bit stiff for my 155 lbs, will swap for 4.9.

Jetting: Much better than I expected (based on reading threads here), a bit lean just off idle (surging but no bog) and rich from there on up, but very rideable and no plug fouling or drooling. This is in Iowa at 50 degrees. Float level is too high, don't think this was hurting performance but it did spew premix all over the rear brake :whiner: .

Clutch: Drags more than i'm used to making shifting tough sometimes. I expected this from my Suzukis, but most Hondas don't drag. Maybe it will quit after break in?

Overall it was fun to ride, doesn't hurt to have a set of brand new 755s either!

But, the 2001 is a great bike also and it will be a sad day when it's sold.

 

[James]

Originally posted by motometal
But, the 2001 is a great bike also and it will be a sad day when it's sold.

That's why I still have two....I need to stay out of the shop

 

[Faded]

Originally posted by motometal
Motor: Softer on the bottom than the 2001, very quick revving in the middle and ok but not great over rev (jetting?). Not a beginner's bike, keeps you awake for sure! Lots of wheelies!

Also, at low rpms there is a knocking noise, probably from the piston, louder than engine noise on my 2001. I'm not used to this, anyone else notice this on their bikes? It goes away as the motor is revved a bit higher.

Here at 4700 ft. the jetting is rich through the middle. A lot of guys I talk to are going to the 6BEY-31-75 Needle or S-8 Nozzle and 6BEY-3075 needle, clip #2 for both. 32.5 Pilot is good, I tried the 30 and was lean. 360-350 main is pretty safe, depends on the weather. Of course those needle #s mean nothing to you seeing how they changed everything...

The knocking was apparent on mine since new. I'm convinced that it was piston slap. It went away after my first top end. Of course a lot of stuff went away with my first top end, like excess cylinder base and bore material, power valve flap tips, and some extra aluminum in the combustion dome. :laugh:

Glad you're happy with your bike, it's always a treat to get a new toy. :thumb:

 

[SpectraSVT]

Originally posted by motometal
Not a beginner's bike, keeps you awake for sure! Lots of wheelies!

I'm a beginner and it wasn't enough bike for me. I would say its a PERFECT beginner bike. Motor doesn't have any hit at all so its easy to keep the rear wheel from breaking loose.

 

[James]

Originally posted by SpectraSVT


I'm a beginner and it wasn't enough bike for me. I would say its a PERFECT beginner bike. Motor doesn't have any hit at all so its easy to keep the rear wheel from breaking loose.

Something is wrong with your bike then. We ran across a guy that was saying the same thing a few weeks back. Turned out that he had his powervalve apart and put it back together wrong.

 

[motometal]

mine doesn't have enough power to wheelie over a log in 1st gear if the motor is lugging, but then when it goes...definitely a big hit! Better be pointed in the right direction.

Regarding the air box, I don't like the open cell foam gasket OR the minimal sealing surface on the filter OR the nubs that protrude into the sealing surface area. I was thinking about getting the MX Bonz kit, but then some are also going with the Twin Air kit that uses a different cage and element (over $100!) with more of a sealing surface. Or how about taking out the foam gasket and just using silicone? I know there have been several threads on this, still not sure best route to go.

Jetting: the pilot circuit seems ok but just above that it is on the lean side (maybe perfect in warmer weather) so since the needle jet (or needle diameter) affects this, I would think and S-8 would be too lean on my bike. A different needle length, taper, or clip position would affect larger throttle openings (mid throttle) and might be the hot ticket (along with a leaner main).

Faded, 350 or 360 main sounds really lean, but then you are at a higher elevation.

 

[Faded]

Originally posted by motometal

*mine doesn't have enough power to wheelie over a log in 1st gear if the motor is lugging,

*I was thinking about getting the MX Bonz kit...Or how about taking out the foam gasket and just using silicone?

*Faded, 350 or 360 main sounds really lean, but then you are at a higher elevation.

Gotta love that 48 tooth rear....:silly:

I was impressed by the quality of the MX Bonz kit, it was waaay better than the PC Racing. Not sure about the Twin air, haven't seen one in action. Becareful using silicon, the fuel vapors will break down the standard stuff.

Here's a plug chop with the 360 main @4700ft, 48 degrees, and high humidity (it was about to rain).

 

[motometal]

what type of silicone is ok to use around fuel? I normally use Ultra Black Permatex for general use, not sure about fuel resistance of this product.

I know the "ring" on the plug is what matters, but seeing a plug that white on the tip would scare me a bit, particularly if riding on a track with wide open sections. Was that a new plug just run briefly at WOT?

I'll try a 400 main tomorrow, I am at about 1000 ft elevation I think. Studying a magazine test (yes I know these are somewhat bogus), they went with a smaller diameter needle in the #1 clip position. That would remedy my situation of slightly lean off the bottom and fat in the middle. They were using a 6BHY38-70, of course this is at Glen Helen etc., wonder what the elevation is there?

 

[mx547]

the airport is 1157.

 

[Faded]

Originally posted by motometal
but seeing a plug that white on the tip would scare me a bit...Was that a new plug just run briefly at WOT?

Yes. It was only in the bike for about 8-10 minutes.

 

[Buzz Bomb]

For the airbox problem, everyone always says silicone is bad, but has anyone here actually tested and had gas break down their airbox junction? On my friends CR80 he used it before and never had a single problem. Maybe the fact that gas doesn't get into the airboot and the air would be pushing all the gas fumes INTO the engine (in other words AWAY from the silicone) is part of it. It's not as big a deal as everyone makes it out to be. If you insist on not using silicone, weatherstrip adhesive is the best thing.

 

[Faded]

Originally posted by Buzz Bomb
For the airbox problem, everyone always says silicone is bad, but has anyone here actually tested and had gas break down their airbox junction?

Yes, I have, that's why I recommended not using it. The stuff to get is Hondabond 4. It remains semi-elastic and resists fuel/vapors.

 

[SpectraSVT]

Originally posted by James


Something is wrong with your bike then. We ran across a guy that was saying the same thing a few weeks back. Turned out that he had his powervalve apart and put it back together wrong.

Bike is the same as was from the showroom floor. Others who rode it said it was the same as their 03 CR's so I think "you" got the freak CR (which is a good thing).

 

[James]

I do know how to jet mine and turn the throttle past 1/8th...nothing freakish about that. If you do those two things and it still feels sluggish, check the powervalve cable.

Looks like motometal got one like mine too.

 

[SpectraSVT]

I'm not saying the bike sucks and its slow just that it has a smooth power delivery so its good for beginners. If you think it has "hit" then ride an 03 RM250 or YZ250...thats a hit. I like this hit but others don't so it comes down to personal preferance and what you think makes you faster.

 

[Faded]

Originally posted by James
I do know how to jet mine and turn the throttle past 1/8th...nothing freakish about that.

lOl :laugh:

 

[Superchief]

Something definitly out of whack, nothing wrong with the hit on my 03. The bike is all stock and hates to keep the front end on the ground. You don't even have to give it more than a 1/4 throttle to do it, is that what you call sluggish? So since it's such a beginers bike, i guess i should let my 6 yr old daughter ride it since she wants to learn how to ride? i'd get the bike looked at by a qualified mechanic, cause there is definitly something not right with it.

 

[motometal]

Well, after much tinkering in the garage as it rained all day Sunday, got to ride the new unit today. Now has:

Softer rear spring (its a 4.8 or 4.9 from a 2001 CR)
400 main jet (stock = 420)
50 tooth rear sprocket (stock = 48)
general tweaking of controls and suspension

the suspension, handling and brakes feel great. the motor pulls a lot better with the mods I did, but seems a little flat on the bottom still then has a great midrange hit. My friend has a very healthy 2000 and we swapped, and he thought my bike ran really hard including on the bottom. Still though, I noticed his 2000 had more of a linear powerband and the 2003 had more of a responsive revvy hit to it. Just the opposite of what you would think considering the RC powervalve.

Can the RC powervalve incrementally open, or is it all or nothing?

MX Bonz airbox kit on the way, along with rad shrowds (keeping the stockers for whenever I sell it).

This bike feels like it has a very light flywheel, yet I never killed it. Starts fine in gear, but clutch still feels a bit draggy.

Any other comments on the low rpm piston rattle? This probably doesn't hurt anything, but is a bit annoying.

 

[mx547]

Originally posted by motometal

Any other comments on the low rpm piston rattle? This probably doesn't hurt anything, but is a bit annoying.

when i have that, i just remove all the silencer packing: no more rattle! ;)

 

[Superchief]

I believe the RC valve opens proportionately to the throttle opening.

 

[sigar]

I recall reading the 02 RC valve was all or nothing. I think I read it in MXA though so lend whatever credibility you think it deserves.

 

[psycho]

Going back to the Mx Bonz airbox mod.... I just installed it this past weekend and the instructions recommended Permatex Ultra Black so that's what I used. Guess we will have to see how this works out as far as the silicon breaking down. So far I am happy with the kit's fit. Just my thoughts on it so far.......

 

[VintageTech]

Any reason why the cover for the RC valve can't be removed for observation while operating the throttle? Seems this would give an answer to the question of how it operates.
Does it have a stepper motor? If so, I don't know why it would have one if it was just a 2-position setup.

 

[James]

The RC valve is incremental and you can take the cover off and watch it (that is how it is supposed to be checked periodically).

The Boyesen Pro Series Reeds should give you some more bottom end. If I am not mistaken, the 2002/2003 CRs come with single stage reeds. I have these on my 2000 and was planning on getting them for the 02 in the near future.

 

[Faded]

Originally posted by Superchief
I believe the RC valve opens proportionately to the throttle opening.

It opens according to RPM. The servo motor is set up in push/pull configuration so that it can open/close without a lot of lag time and be consistent w/varying RPMs. If it was all or nothing the exhaust flaps would probably have been spring loaded closed and have only one cable to snap them open.