Hi, I have a 250cc 4 stroke race bike, owner's manual recommends 100 octane unleaded gas. I'm in CA, and due to regulations pump gas is terrible (max 91 octane and ethanol nd who knows what quality) and race gas options are limited, few shops sell it anymore. It was suggested to me to try T4, I did and it runs OK but smells awful and the vapor just from the SEALED CAN set off the alarms in my hauler. (I've run C12 in the past and was not bothered at all by the smell of that, and it didn't set off any alarms, either.) With the bike sitting in the trailer the T4 smell is overpowering, is that normal for this stuff? I raced it last weekend and one of my competitors came over to ask me if I changed fuels since apparently the exhaust smells nasty, too. Since I am about to tune the bike I am starting fresh and can choose a fuel - VP is the preferred brand as that is what the suppliers here sell - any suggestions on what is best to use, whether oxygenated is better than non-oxygenated, and why the manual calls for unleaded fuel? Also what is common and relatively easy to find, and easy to manage for storage and smell? I called VP and they suggested C10 but nobody around here carries that, or VP100, either. Thanks in advance...
I presume that is your Moriwaki? We ran pump gas on ours other than when we went to Indy for the USPGRU race and we ran some F&L fuel. Unless yours was modified it is a stock CRF250L engine and people run those on pump all the time in the dirt. Granted they usually aren't wide open as much.
Does the manual say 100 RON or R+M/ ? There is a difference in how octane is measured in North America and the rest of the world.
Not if it is fuel injected. The lead can kill an O2 sensor. To further what I was saying about octane ratings. A fuel that is 100 RON can end up being 95 and even under depending on the MON rating of the fuel in North America. As an example, our Aspen R racing fuel is 102 RON, but when it is averaged it ends up being 97 the way it is done in North America.
Could you get away with just buying 91 octane pump and dumping some of this in the fuel jug at each fill up? It seems to get pretty decent reviews. Was watching a video on the Toobz the other day and they tossed some into a Dodge Demon on the dyno and did some massaging of the fueling and ignition maps and saw noticeable improvements compared to running regular pump. https://boostane.com According to their mixing chart it takes 2.29 oz of the regular (not professional grade) to treat 1 gallon of 91 octane to bring it up to 100. A 16oz can is $20.
Good question - it is RON, not R+M/2. I don't know if using an additive with pump gas is a good solution or not - it would be considerably more convenient (the toyhauler has a fuel station that we always have premium unleaded in) but I worry about what sort of junk is in pump fuel, and about how consistent it would be for tuning.
Yeah, RON is what it used mostly throughout the rest of the world....in the US we use R+M/2 aka Anti-Knock Index (AKI)....it's generally 4-6 units smaller than the RON value. https://en.wikipedia.org/wiki/Octane_rating#Examples So if its calls for 100 RON you are basically fine with 93 pump, probably would still be fine with 91 other than what you said, the unknown ethanol quantity. I run my bike on premium pump but every time I fill up my fuel jugs I treat them with this. https://www.summitracing.com/parts/luc-10576-1
So here is another question: oxygenated or not? I'm told that with an oxygenated fuel you need to drain the tank after every race weekend, that it is corrosive. Should I be looking for an unleaded, non-oxygenated, no ethanol fuel? If so VP MS93 looks like an option, or maybe C10, if those are readily available.
It's not an across the board thing, you'd have to check the specific fuel. Some oxygenated fuels like MR12 I think VP recommends to drain, their other oxygenated fuels I don't believe require it. Heard similar about Sunoco. Its not the oxygenation specifically since as you know there's plenty of pump gas that is oxygenated (that's part of what ethanol does to the fuel, it oxygenates it) and you aren't draining your car's gas tank right after every fill up. But again, it depends on the fuel....it may not necessarily be that its going to eat up your fuel system if you leave it in there, BUT it may deteriorate faster if its not sitting in a topped and sealed metal can.
No fuels like MR12 are highly oxygenated and when exposed to open air I.E a gas tank the fuel deteriorates quickly. Also due to the chemical make up if you leave MR12 in the system for an extended period without “flushing” the valves with pump gas, stalactite forms on the values and obviously cause all sorts of issues
There are so many variables with different fuels. Couple that with all the additives then top it off with internet "expert" advice and all you are left with is mass confusion. If you're not pinging and you're complying with the manufacturer's lead requirements I'd go with common available fuel. Be careful with additives. For example I just coated a steel tank with Caswell coating and they specifically warned against using Lucas ethanol treatment. Something in that witches brew that was no good for the epoxy. Stabil was OK....go figure.
Pump gas and this https://lucasoil.com/products/fuel-treatments/lucas-octane-booster if needed. I've got some small bottles that are perfect for one tank on a bike I can give you but honestly not sure how to get it out to Cali. If you really are interested I'll ask Lucas to ship me some to a track for one of our weekends.
Thank you - I'm almost certain I've seen that on the shelf at my local motorcycle shop so you don't need to hassle with trying to ship it to me, but thank you for offering that. I'll check it out.
Just out of curiosity, is it normal for T4 to smell really strong (as in, I can smell it from OUTSIDE the trailer0, and my whole garage smells like it) or did I get a bad batch? It smells very much like old, bad pump gas.