I just got a RS250 track bike, and I have a couple of n00b questions. 1. I see the rev-limiter is adjustable, and it's set to 6K ATM, what's the optimum RPM value for trackdays? 2. The mechanic who tuned it up suggested that I use pre-mix gas, instead of filling the injector with oil. I am too lazy for this... has anybody had problems using the oil injector at the tracks? Thanks!
I assume you mean the shift light.. there is no rev limiter. Do NOT rev it over 12k or you will be rebuilding your top end. try to shift about 10500 and you'll actually be shifting about 11000 the injector system works fine.. and has to be used if you plan to run WERA. call me when your done with it, i'm looking to buy one
feel free to double check but if your running clubman it's superstock rules and I don't see where it states you can omit the oil injection
Just run the injection system on the RS250. It's way easier and on this bike not an issue. Set the shift light at 11,500 so you have 500 RPM warning before 12k. The RS250 will remain super reliable if it is kept pretty much stock and shift no higher than 12k. Going over 12k shortens the crank life big time.
There was at least one guy on the Ape forum a couple of years back who advocated keeping the injection system. Unfortunately, one of his oil lines popped off at some point and he seized. I think there was one other guy who had the same problem (or maybe it was a clogged line). So, if it is legal for the class you are racing, I'd run premix. Yes, the chance of a failure of the pump system is very low but if you pre-mix, you know the oil will get there. I used to just dump the measured amount of oil into a 5 gal jug and fill with premium pump gas on the way to the track. Easy-peasey. And the synthetic oils don't separate out so that pre-mixed gas is good for months. (now undoubtedly some pedantic prick will come along with info about fuel going bad in a month and synthetic oil separating within xx amount of time and I have no idea what I'm talking about. Whatever).
I'm picking up a 2003 250 Cup bike this weekend to replace my GSXR600 track bike. I started racing a TZ 125 last year and quickly realized I was hooked on 2 strokes!
I think the premix discussion was about it being legal for Clubman... Unless there has been some exemption I'm not aware of you have to run the injectors NOT premix
From what I've read you are correct. It gives no performance enhancement and it's probably just never come up as an issue to make it part of the rulebook. There's really no violation in the spirit of superstock and if someone wanted to protest on the grounds of someone using premix vs. injectors, well, they've got issues.
Being able to tune the mixture via premix can net 1-3 hp, about as much as any other mod on an APE. On a 55hp bike you bet i'd protest a close race over that. cheating is cheating 1hp or 10.... as far as someone having "issues" over calling out a cheater??? I guess kind of cheating a little is like being a little pregnant?
Can you not make the same tune by adjusting your pump mix and re-jetting? Are you not allowed to change jets in superstock? Nobody is going to win or not win based on gas/oil premix ratios. Do the rules say you can adjust your mix ratio with the pump in place? Tuning by mix ratio is a fallacy. If you actually want your engine to run at all, the range of workable fuel/oil mixes barely equals a jet size up or down. Meaning, to think you're significantly leaning or enriching mix by adding or removing oil is bunk. You premix your fuel/oil to a certain ratio for lubrication and cooling and adjust _jetting_ for power. Just like you'd do using the oil pump. More oil=more cooling=more power to an extent; whether it's by pre-mix ratio or oil pump settings.
It's more a matter of consistency. Premix is always 100% the same for every piston cycle. Oil injection can be a bit sloppy with a slightly different ratio each time in the combustion chamber.. think dirty fuel injector. given the low state of tune in these motors it isn't that noticable. Just think back to the old Aprilia cup days when guys were running $90 spark plugs that gave a tiny bit more compression and maybe 1/2 - 1 hp. add enough of that stuff up and you end up with 4 or 5 hp on the other guy. That WILL make a big difference between 2 equaly matched riders. That being said I would have no problem with the rules allowing premix. 6 of one etc as long as evryone is playing by the same rules..
I'll add my $0.02 here. I've had one for about 6-7 years now. I kept the injectors in because I'm lazy too. My advice, keeping it as stock as possible will go a long way in keeping it reliable. You can do a lot of mods to grab an HP or two, but you will sacrifice reliability. With parts getting harder to come by and more expensive, keep it simple and you'll be happy. Some pipes and a better air-filter are your best/safe mods. Besides, there is nothing more satisfying than tearing around guys on 100+hp bikes on a bike that makes 55hp's on a good day. If you want to spend $$, spend it on the suspension. Stock is not bad, but its where you'll get the most bang for your buck. One other thing to check - pull the powervalves and make sure the center blade pin is in good condition. These pins are pressed in and are known to ovalize the receiving hole and fall out. If that happens its bye, bye engine. Its a simple and easy to check regularly. Or get some billet center blades and never worry about it. Finally - Lazy or not, expect to spend time wrenching. Its not a like a TZ, but its not four stroke either.
