Endurance racing a 1998 RS250 cupbike..advise please..

[TODDEROSSI]

What do the apriliaforum guys think? I have a 1998 Ape in great shape with many mods. I have raced in the CMRA in TX for 7 yrs. I now plan to endurance race for several yrs. Do you think it is a bad idea to endurance race an RS250? How often would the topend need service (Miles wise). Think the bike would over heat? (It gets a 100 degrees here during race season.) How long would a crank last? I have done all the work on Honda RS125's...how difficult is the engine work on a Ape in comparison to a Honda RS125? Any advice? Thanks (I will be in the LT WT Superbike class and refuse to race an SV650.)

TODDEROSSI
TX USA

[TODDEROSSI]

The races are from 4-6 hrs depending on the schedule/event. There are about 8 per season.

TODDEROSSI

[ysr star]

Interesting,

We at AF1 Racing were thinking of racing a RS250 in the CMRA endurance series next year. It would require alot of work to make the bike last every race, but they are a street bike in other countries, so it seems they can handle it. We of course will have to track down a bike, which we are looking for now, and do lots of testing to ensure it can happen.

I am looking for a street legal version which I will then ride the piss out of on the street. That will be some of the testing, but it won't be able to test the balls out for 4-6 hours that a race will be. The rest will just be trial at the track.

BTW the sooner we get a bike, the sooner testing and some serious R+D will occur. I promise we will make lots more usable power than stock, reliably. So if you have an RS250 to sell, let us know.

Jon

[micah apriliaforum com]

I do think it can be made to work. If set up on the cautious side it should last. I am thinking it could still make in the 60 bhp range on a dynojet and do the trick. Different pistons will be required as well as some serious head work to fix the stock (0 degree squish band) heads and reduce detonation.

[Roswell Rat]

AF1-
If you need an endurance rider for next season please let me know.
Also, I have a cup bike available.

[micah apriliaforum com]

hhhhmmmmm.....interesting. We are buying a bike when we find the right one becuase I will probably grenade it a few times before deciding on a tune.

[Roswell Rat]

Micah-
If you are genuinely interested you can contact me through email at jayson@asa-architects.com. I should be in the Austin area over Memorial Day weekend.

[wsmc667]

we've gotten like 1600~1700 miles out of the stock pistons/rings, so if you change them every event, you're good to go. put on pipes and run some thinner base gaskets to bump compression and you'll get 65 at the rear wheel. once the rings get worn, you'll be down to 58 or 59 hp...

hard part about endurance racing the RS250 is the high fuel consumption and small-ish fuel tank. never mind that you'll also have to fill the oil injector tank. you can probably sort out something for the oil tank, but i think the gas won't last an hour.

sounds like fun to me.
:D chris

[micah apriliaforum com]

I would machine my cases exclusively for premix use. I am no longer reccomending premix for stock motors without the addition of an oiling hole for the center bearing on the right side cylinder. It easy to do when the cases are split and then I could throw away the oil injection system all together.

[keean]

I dont have a set of crank cases infront of me at the moment (my spare ones are in the loft!) But whan I was flowing the crank on my RS250 I remember the layout of the oil injectors... There are three bearings on the crank, the left one (nearest alternator) has an injector, the centre one has an injector, it is the far right one, next to the gearbox that does not have an injector, but this should be lubricated by the gearbox oil - can't quite remember which side of it the rubber oil shield went...

Anyway the oil is injected through these bearings, so they must throw it all over the inside of the crank casings... the oil will then be picked up by the fuel/air mixture to lubricate the con-rod needle bearings. If you doubt that the needle bearings get any oil with the injectors, just look at the smoke from the exhaust - all that is caused by fuel/air mixture dissolving the oil from the crank cases and carrying it through to the combustion chamber (plus a little seeping past the rings)...

From my experiance there are two big dangers with lubrication, the first affects only injectors - the second premix as well. They are, oil metering valves on the injectors getting blocked (need to be free'd with a needle) and needle bearings 'drying out' - after which they dont attract the oil to them any more and start to wear rapidly. Both of these tend to happen when the bike is in storage and not being used.

I appreciate that there is a lot less worry about whether the oil is getting to the engine with premix - but remember the RS250 is a street bike in UK/Europe, and here there are plenty of bikes that go 10000miles without a single thing being done to the engine, and the oil injectors cause no problems at all (and that would likely include several journies on a motor-way where you hold the bike at max revs for over an hour)

Of course when racing the real advantage of removing the injector system is the weight saving from the loss of the oil tank, pump and tubes... Premix would also be better for endurance as you can use a quick petrol filler system with your premix.