Honda CRF250X - Maintenance

November 4, 2005 version

 Introduction 

 My Modifications 

 BigBore/TopEnd 

 Maintenance 

 Jetting 

 Gearing 

 Comparo 

 Pictures 

Setup, break-in and maintenance log

3/1/04 - I drained the engine and tranny and refilled them when I was installing the first mods on the 250X.  

Drained the engine oil and refilled with GN4 10W40.

Drained the tranny oil and refilled with GN4 10W40.

3/4/04 - I went for my first break-in ride today. I put about 20 miles on the bike. The suspension is stiff (no surprise) and the engine is tight. But it sure runs nice.

Somethin' tells me I'm into somethin' good.

3/6/04 - Rode at Texas Cr today; put on 30 more miles. The suspension is feeling better. The engine is starting to run better, also (if that's possible). Texas Cr is mostly 4WD and ATV routes, so I didn't have much of an opportunity to check out how the 250X responds on tight trails. But it sure rides the ATV routes nice. In the sand wash, I noticed I was loafing along, so I picked up the throttle, and the 250X got light in the front and shot ahead. Wow, I coulda' used this performance when I rode high desert in NM back in the 70s and 80s on old XRs.

The low seat height brought about by the KoubaLink and the lowered front end really made the 250X easy to ride. I'm only 5'6" tall, and the stock seat height gave me nosebleeds ;-)

I AM into somethin' good!

   

3/7/04 - Rode at Texas Cr again today; 35 miles. The suspension is just beginning to stroke smoothly now. I continue to be impressed with throttle response. When I loaf along like one tends to do on a 4-stroke, the ride is fine. But then, twist the throttle and the bike leaps ahead and goes all aggressive. And it's fun to ride this way. I'm going to ride some tight trails next week and see how it does. I haven't put the 13T front sprocket on yet, and may not have to.

Several people remarked how low the 250X looks, but I didn't let on about the link.

I checked the spark plug at 85 miles, and it looks pretty good to me.

The bike is getting 37.4 MPG; about 84 miles per tank. I hope it gets better.

 

3/11/04 - Rode at FourMile Area today; 30 miles. I got a chance to try some single-track trails. The 250X performed without a hitch. I could bend into the turns effortlessly and body english was effective at avoiding low-hanging tree branches. The bike pulled cleanly up several small hills without wheelspin. I was pleasantly surprised how easy the 250X was to ride on these trails. Still no need for different gearing, but the big mountain test won't be for several months...

3/13/04 - Rode another 30 miles at Texas Cr. I was able to ride the single-track trail and some steep hills; the 250X handled everything with ease. Is there nothing it can't do? It seems like the bike has more power in the sandy stuff. It may finally be totally broken in or I may just be getting more used to riding it like it wants.

   

3/14/04 - I did a break-in service at 146 miles to get the break-in oil and metal particles out of the engine and tranny.  

Drained the engine oil and refilled with GN4 10W40. Installed a new oil filter.

The tranny was full before I drained it. Refilled the tranny with GN4 10W40.

3/16/04 - Rode my 230F and my 250X at Texas Cr. On previous rides on my 250X, I had noticed an occasional clacking sound coming from the area near my left foot. It sounded like the chain was slapping against the chain buffer, and because it only happened occasionally, I dismissed the noise as of no consequence.

I rode my rebuilt 230F on 3/15. It has a 1.5mm larger piston than stock, and it's high compression also. It was pinging/detonating badly on hills, so I decided to address the issue. I went up one on the main. I read in the 230F and 250X Owner's Manuals that Honda recommends 91 octane for each bike, and I've been using 85 and 87 octane. So I drained all the old gas from both bikes and filled them with new 91 octane gas.

The clacking sound disappeared on the 250X, and the bike seemed to run better. On this ride, I tried winding the engine out more. In the sand washes, I was able to wind out 4th gear till I didn't want to go any faster (the terrain got too blurry). I don't think I could tap out fifth gear in a sand wash.

The results on the 230F were mixed; it ran ok on the level but it still detonated on steep hills. I eventually increased the main jet 4 sizes and raised the needle one clip position. Now it runs great, too.

Lesson learned: read the manual, at least to see what octane to run in the bikes.

3/31/03 - Rode my 250X on some mid-elevation ATV routes and parts of the Rainbow Tr and it did just fine. At 84 miles on the trip odometer, I had to switch to reserve. I got back to the van with 100.1 miles showing on the trip odometer and the bike was sputtering. A fill-up fixed it, so I think it was pretty close to dry. I calculate that my 250X is getting 44.4 MPG; this is about the best I expect to get, and it's plenty for the rides I do. I don't expect to buy a larger aftermarket tank. I ordered the stock cylinder for the 270 kit.

4/27/04 - I had Jeff Slavens (Slavens Racing) shorten the fork travel by installing 1.5" travel limiters on the fork damper rods. When I rode the 250X after installing the shortened forks, I couldn't believe the difference. With the bike now level and the wheel-base a bit shorter, the bike turned crisply and with ease. Previously, the front end was always pushing in the turns, and I was always tense, waiting for a fall. This very bad tendency completely disappeared.

The shorter forks resulted in the triple clamps / steering stem being lowered 1.5" from stock. This matches the 1.75" lowering of the rear end pretty closely. Jeff also changed the damping when he worked on my forks, so now I can have some adjustment on the clickers; before, I was running them full soft. The 250X is even more fun to ride than before.

4/28/04 - I finally rode some technical trails at 9,000' elevation, and found that I needed lower gearing. There was enough power on tap for me to run up short twisty uphill sections at a brisk pace, but I wanted to go slower because of the muddy conditions. So I installed the 13T front sprocket and tried again. No problems. I could go as slow as I wanted. I have no idea how much I lost off the top end because I can't ride the bike tapped out in 5th gear anywhere except on a smooth dirt road; it still does over 60. The K-dub switch gives me the giggles ;-)

With 400 miles showing on the odo, I checked the gas mileage and it's 44.3 MPG, consistent with an earlier check.

   

5/5/04 - 500 miles showing on the odometer and time for a service session. Yes, I know the book says 600, but it's easier to remember 500 (and multiples).

ART = 25:00, average speed = 20.0 MPH.
(ART is accumulated real time which I call wheel time; it is the time that the front wheel is turning and is very close to the engine run time.)

 

Drained the engine oil and refilled with the same stuff; GN4 10W40. The dipstick oil level was between the R and N before I drained the engine; a bit below recommended, but I'm ok with it. The oil looked normal black, with no burn smell. Installed a new oil filter. At this rate, I'll use up the first 20 I bought by the time I get to 10K miles, sometime next year.

The tranny was full before I drained it. The oil came out looking less black than the engine oil, and no burn smell. Refilled the tranny with HP Transmission Oil, one of the Honda recommendations in the Owner's Manual. A CRF450 rider friend says he likes the HP in his 450, and I'm looking for smoother shift action, so I'll try it.

The valves were within spec, so no need to buy shims.
Intake L .005  R .006     Exhaust L .011+  R .010+

A check of the bike didn't reveal any problems.

7/17/04 - 1000 miles showing on the odometer and time for another service session.

ART = 51:00, average speed = 19.6 MPH.

 

Drained the engine oil and refilled with the same stuff; GN4 10W40. The dipstick oil level was at the top because I've added oil several times; about 4 ounces in all. The oil looked normal black, with no burn smell. Installed a new oil filter.

The tranny was full before I drained it. The oil came out still looking red, and no burn smell. Refilled the tranny with HP Transmission Oil again. I couldn't tell that the HP in the tranny was any better than the GN4 I had used earlier, but I'll stick with it for now.

The valves were still within spec, so no need to buy shims.
Intake L .005  R .006-     Exhaust L .011  R .011

Cleaned the air filter.

A check of the bike didn't reveal any problems.

9/3/04 - 1500 miles showing on the odometer and time for another service session.

ART = 76:01, average speed = 19.7 MPH.

 

Drained the engine oil and refilled with the same stuff; GN4 10W40. The dipstick oil level was near the top because I've added oil several times; about 2 ounces in all. The oil looked normal black, with no burn smell. Installed a new oil filter.

The tranny was full before I drained it. The oil came out still looking red, and no burn smell. Refilled the tranny with HP Transmission Oil again.

The valves were still within spec; they actually haven't changed any measurable amount since the last check.
Intake L .005  R .006-     Exhaust L .011  R .011

The air filter was clean and still had plenty of filter oil on it, so I didn't have to clean it.

The clutch still works fine, so there was no need to inspect it.

A check of the bike didn't reveal any problems.

10/16/04 - 2000 miles showing on the odometer and time for another service session.

ART = 103:37, average speed = 19.3 MPH.

 

Drained the engine oil and refilled with the same stuff; GN4 10W40. The dipstick oil level was near the top because I've added oil several times; about 2 ounces in all. The oil looked normal black, with no burn smell. Installed a new oil filter.

The tranny was full before I drained it. The oil came out still looking red, and no burn smell. Refilled the tranny with HP Transmission Oil again.

The valves were still within spec.
Intake L .005-  R .005     Exhaust L .011-  R .011

The air filter was clean and still had plenty of filter oil on it, so I didn't have to clean it.

The clutch still works fine, so there was no need to inspect it.

A check of the bike didn't reveal any problems.

11/28/04 - 2287 miles showing on the odometer and time to install the big-bore kit.

ART = 120:28, average speed = 19.0 MPH.

 

The valves were still within spec.
Intake L .005-  R .005     Exhaust L .011-  R .011

Engine compression was 57 psi.

I cleaned and lubed the rear shock linkage. It was still more than adequately greased from new. Installed a new oiled air filter. Installed filters on carb vent lines that went to the air box.

Installed the big-bore kit and the '05 R head; see the Big-bore page for details.

2/2/05 - 2348 miles showing on the odometer. The big-bore break-in is finished.

ART = 123:29, average speed = 19.0 MPH.

 

After the new head and big-bore kit were installed and break-in completed, the left intake valve was tight, so I re-shimmed to the next size smaller. All others were still within spec.
Intake L .005  R .005-     Exhaust L .011-  R .011-

Drained the engine oil and refilled with the same stuff; GN4 10W40. The oil looked normal black, with no burn smell. Installed a new oil filter.

Check out the pictures of break-in rides.

Honda parts and manuals

I order all Honda parts from Service Honda, 800-828-5498.   My parts 11/11/04.

I ordered the following Honda 2004 CRF250X manuals from Helm, Inc:
  Owner's Manual - $16    Service Manual - $48    Parts Catalog - $32     shipping and handling extra.


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