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2012 CRF250 Athena 280 Kit On the Way

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Since I race in an open class, I've decided to go for the extra 30cc of displacement vs. installing the Wiseco 14.5:1 Racer's Choice Piston kit.

I have added an FMF 4.1 RCT Full Exhaust System, and used VP110 Race Gas for my last race (2 hour hare scramble) and the bike was noticeably stronger than stock, but I'm looking for more pull out of corners vs. ultra top end even with the stock ECU map.

So, I'm looking for an ECU Map for the Athena 280 kit and high altitude (5500 ft) and race fuel. VP110 is available from a local dealer's pump at half the cost per gallon of U4.4 and I can't find a Renegade Fuel distributor anywhere close to Colorado.

Anybody out there running this combo?

Who has a proven ECU map for this combo?

My Wiseco Piston Kit is for sale - PM me if interested.

Edited by Grinstead_77G

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My son has a 280 crf he races in College Boy and 450/0pen classes. We had to machine the cylinder surfaces on the Athena Kit, it just wasn't right. Your crank needs to be ballanced with the 82mm piston. This kit really gets good when you have the head worked and put a good cam in it. We use the Vortex ignition the bike really ripps and is very smooth.

The VP 110 is not your best choice of fuels, try the newer VPR it is oxygenated at about 100 octane. It should be pretty cheap, less than U4.4. You will probably only need a good consistent fuel with about 92 octane to avoid detonation on the 280 kit. We run sx4+ at the races and it is 92 octane, but the map is different than the map for other fuels.

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Appreciate the insights. What model year is your son's CRF250R?

Are you running one of the "out of the box" Vortex maps, or something special?

I will checkout the availability of the oxygenated fuels. VPR is about $15/gal, U4.4 is almost $18/gal in 5 gal mini drums. VP110 out of the shop's pump is a little over $7/gal. Since we are at altitude, our compression ratios are already down about 18%, and my previous engines were pretty happy running Shell Pump Premium (91-92 Octane) even with 14:1 compression ratios.

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Appreciate the insights. What model year is your son's CRF250R?

Are you running one of the "out of the box" Vortex maps, or something special?

I will checkout the availability of the oxygenated fuels. VPR is about $15/gal, U4.4 is almost $18/gal in 5 gal mini drums. VP110 out of the shop's pump is a little over $7/gal. Since we are at altitude, our compression ratios are already down about 18%, and my previous engines were pretty happy running Shell Pump Premium (91-92 Octane) even with 14:1 compression ratios.

It is a 2011, and we are running our own maps but the Vortex maps that come with the ECU are actually really good. Another really cool thing is the ability to adjust fuel in the low, mid and high throttle positions without hooking up the lap top.

At your elevation I bet the higher oxygen content fuels would be good. I would try MR12 at almost 10% oxygen and mix it 3/2 with your VP 110. I think the MR12 is about 18/gal so your net would be about $13.6 a gallon. Our big bore can reach detonation easier than the stock bore race bikes.

When we ran MR12 we allways mixed it with MRX01 to get the octane up to about 92 and it worked really well. Allways been afraid of the MR12 straight in our motors except in the stock class.

We keep less expensive non-oxygenated fuel like Renegade 98 around just to put in the bikes after a race. After the race we drain the good fuel and put in some of this and run the bike a few minuites. We then put the motor at TDC and plug the exhaust and it can be stored that way. You dont have to worry about any issues and if someone were to start or ride the bike the fuel wouldnt cause an issue.

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Again, I very much appreciate the advice.

With pre-fuel injection,I remember having to run leaner main jets with big bores... Counterintuitive, but someone explained with the higher velocity of air being pulled through the carb, a jet can push more fuel for the same size vs. with a standard bore. With fuel injection, do you run something near stock, or does your map boost the fuel slightly across all RPM ranges?

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With the big bore we could not get enough fuel using the oem ECU and the OEM software. Once you reach a point, the oem software quits adding fuel even if you tell it to add more. Everytime we added fuel we picked up hp and torque until it quit adding. The Vortex allows a significantly higher percentage of fuel to be added at each throttle position. We were able to get the big bore fat up top with the vortex. The Vortex also allows you to change the timing throughout and raise the rev limit. We have the rev limit set to 13,600 on the big bore and 13,700 on the standard bore mod motor. They both pull right to the rev limit with no significant drop.

Allthough I have the software for mapping, , I don't do the mapping myself, it is initially done on the dyno and then fine tuned on the track. I will make changes based upon conditions using the three 0-10 pots for low, mid and high on the outside of the ECU.

Just the Athena 280 kit makes more power and torgue especially down low but it is really flat up top until you do the head and cam.

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I've done my own head work since 1968, so I plan on doing a general blend and polish. I've heard good things about the Builder Series and Stage 2 cams for big bores. Which cam are you running and what additional spark advance. I plan on doing a weight comparison to the stock piston... did you have to do any crank balancing to compensate for the Athena piston?

Sorry for all the questions, but very few folks seem to have much experience in this domain. You appear to be quite the trailblazer!

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My big bore 2012 Honda CRF285R is up and running!

82mm Athena cylinder and 13.5:1 piston kit, mild port/polish on the head, rebalanced and trued OEM crank, stock cam (so far) FMF RCT 4.1 full exhaust with megabomb header and a Vortex X-10 Ignition.

I have to recognize GYD for his patience in answering all my questions. Thanks, GYD!

First race tomorrow!

Edited by Grinstead_77G

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I had the Athena 280 on my '06 and absolutely loved it. Im seriously thinking about one for my '10How are you liking it? What gearing are you running with the 280?

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I have only had the opportunity to run the big bore kit with my head porting and the stock cam for about 35 min (break-in and race time) on Jan 15, 2012 before I had a freak mechanical failure - the right side camshaft bearing outer race cracked. Fortunately, all the metal fragments were contained in the head, and nothing got into to lower parts of the engine. It did, however, cause me to go through the engine completely to check every bearing and seal just to make sure. So it was less than $50 in replacement parts and about 20 hours of my time.

The start was uphil about 150 yars to first turn, deep tilled dirt, and with the assistance of a first turn pile up, I was 4th out of my class in the wave of 40 riders to the first turn, and 2nd in my class by the time we cleared the first tabletop and the second turn. So, I was very impressed! I'm no lightweight at 185 lbs, but the bike hauled me aound very well... All this with stock cam and my head porting. The bike was great from low through mid, but ran out of steam in the upper ranges with the stock head and cam.

All I can say is, with the big bore kit, my ported head, stock cam and valvetrain, Vortex ECU map #8 (tweaked a bit richer) and the FMF exhaust... The little bike pulled off idle very strong, unfortunately the cam bearing failure gave me a DNF about 3/4 way through the first lap.

For the past two races, while I had my 2011 TUF head out for intake mods to work with my 2012 46 mm throttle body, I've been running my head porting, Ron Hamp's cam and stiffer valve springs, and a stock bore Wiseco 14.5:1 Racer's Choice piston kit. It revs to the moon, and from mid to top produces phenomenal power at the expense of low end. it is much more of a challenge to keep momentum and the revs up. Still, it is still a ton of fun to ride.

Now that I have the TUF head back, I plan to swap out the stock cylinder, cam, valvetrain and head and get the big bore set-up ready for the final race of the winter hare scramble series, Even with the one DNF, I'm sitting 4th overall out of 33 in my class after the first 7 races with one to go, and the final is double points.

So, all-in-all it's been a good season. I'm a bit bummed that I haven't had the chance to run the TUF head with the big bore kit yet, but am looking forward to finally getting it installed. If I get everything back together tomorrow or Saturday, I may run a 1.5 hr Grand Prix event this Sunday down near Colorado Springs as a shake down.

And if you want to see the video...

http://contour.com/s...senior-start--3

Edited by Grinstead_77G

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This is not meant as in insult, but since you are no where near the rev limiter on this bike, you may want to focus on getting more bottom end power out of it. I race the vet classes on a '10 250, so I kind of feel your pain against the 450's. Since you like to lug and not rev, you may also consider a stroker crank with the bb kit, to get more grunt out of it. In the corner where you past 3 or 4 riders, you fanned the clutch, the bike looks like it is begging to be revved, and maybe caught you a little off guard. Maybe a different cam grind? I know I am viewing the video and it is different than being in the seat, but your style and that bike didn't look like you were gellin' imo.....

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This is not meant as in insult, but since you are no where near the rev limiter on this bike, you may want to focus on getting more bottom end power out of it. I race the vet classes on a '10 250, so I kind of feel your pain against the 450's. Since you like to lug and not rev, you may also consider a stroker crank with the bb kit, to get more grunt out of it. In the corner where you past 3 or 4 riders, you fanned the clutch, the bike looks like it is begging to be revved, and maybe caught you a little off guard. Maybe a different cam grind? I know I am viewing the video and it is different than being in the seat, but your style and that bike didn't look like you were gellin' imo.....

No insult taken at all.

Since that was my first ride with the 285 kit, I was being very (overly) cautious during the first lap just to get things checked out. I will see if I can post some video of the later portion of that first lap that shows revving the motor out a bit more. Unfortunately, I didn't get the chance to run it long enough to be comfortable pushing the motor and really getting the opportunity to see what it might do.

Since that race, I have also raised the engagement RPM for the Rekluse clutch which helped a great deal with getting off the corners on my standard bore set up and I hope it will do the same for the big bore kit. That setup was also with a stock head and cam (my mild porting) and it ran out of steam by about 11K RPM. I'm hoping the Tuf Head porting and the Ron Hamp cam will allow it to breathe better and rev more freely.

Next race opportunity is April 22. So stay tuned!

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You're going to need a custom-burned properly programmed ECU to get that mix/match combination of parts to work right.

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