Fuel type and mixture.

[TommyD]

Hi there - sorry it this seems a draft question, but I've just got myself a CR250 and would appreciate some advice on suitable petrol type and the oil/fuel ratio to use, as I haven't a clue.

Cheers

[Trakxntrials]

Hi Tommy D, welcome to KB - I can't help you there, but if no-one else helps you through the day - check back here tonight and I will ask Terry for you - he will know. Where did you get your bike from - could they tell you what they used in it? If not, check here tonight, I will have some info for you. All the best

[cowpoos]

ring your local honda dealership...they will happily tell you what you need to know.

are you new to motor bikes??? or just 2 strokes???

[Cary]

Hi there - sorry it this seems a draft question, but I've just got myself a CR250 and would appreciate some advice on suitable petrol type and the oil/fuel ratio to use, as I haven't a clue.

Cheers

Been a while since i've owned a 2 stroke (KX250) but here goes;

Use 98 if you can get it mix at 33:1.

For some good advice try private message to XTC, knows his stuff and would not mind giving the advice (I hope )

But 33:1 is the general mix & use a good quality 2 stroke oil.

Hope this helps, it's not a silly Q we've all got to start somewhere.

[Brian d marge]

I have a cr 250 91 ..
Yes It runs quite happily on the cheap Sh$%&'

I use 40 to one reasonable quality oil

pilot jet #55

needle # 1369 in the 3rd position

main # 175

This is a good starting point for a 91 cr .... If yo tell me the year I could be more of a help

Stephen

[WRT]

I got an '01, I normally run race fuel (or 98 if race n/a) at 40 to one with Motul oil (the one that smells like strawberries . . . . mmm). I'm no expert tho, I just go off what the guys I go riding with run . . . this is my first two stroke too.

No probs so far tho . . . after several months of regular and prolonged use.

HTH

[Flyingpony]

Excuse me, but aren't all 2-stroke bikes self mixing?
Why are you worried about oil|petrol ratio's?

Just ensure the right grade of petrol in the fuel tank and good quality 2-stroke oil in the other tank. Being self-mixing, the bike does the rest for you.

Well at least that's how it's worked on all the various Suzuki 2-strokes dating from the 70's right through to the 90's I've encountered. Surely it's standard on other brands too.

[Ixion]

Excuse me, but aren't all 2-stroke bikes self mixing?
I've encountered various Suzuki 2-strokes dating from the 70's right through to the 90's, and all were self mixing.
Why are you worried about oil|petrol ratio's? Just ensure the right grade of petrol in the fuel tank and good quality 2-stroke oil in the other tank. Bike does the rest for you.

Older 2 smokers, and some modern racing/competition ones use petroil.Dunno about the CR250. But competition riders sometimes remove the oil feed system even if it has one, to save weight and the power needed to drive the pump

[Wellyman]

Run Race fuel or 98 and use Motul 2 smoke oil. Motul is the best brand I recommend

[Brian d marge]

Older 2 smokers, and some modern racing/competition ones use petroil.Dunno about the CR250. But competition riders sometimes remove the oil feed system even if it has one, to save weight and the power needed to drive the pump

The Cr range ,,use petroil ..and you can chan the mixture strength by varying the oil ..ie richer leaner , by adding subtracting oil ...,,Also you would be suprised how much wieght you notice ,,,A full tank feels like a ton of lead bricks ,,,I usually mix only what is Neccessary ,,,ie for changes in suspension ...I mix a litre ,,,that gives me enough time to think about the changes I have made ...

On a lighter note ,,I use the cheap crap fuel syphoned out of me truck,,,have been doing that for a a year or so now ,,,and after many enduro , MX ,,and this will be coming up to the second rebuild this year ,,Last check the ring pegs showed signs of moving ,,so the piston is up for it soon ,,,I will screw this engine into the ground over the summer and rebuild both spare and Race engine ,,,end of october ...
Anyway there were NO signs of detonation ,,,,,,surely the gas in NZ cant be that bad???

What the race fuel in NZ like ...highly oxygenated?? or 98 with a ton of additive ...Snake oil ??

curious ...( thinks ,,,Hmm crusty demons ,,,,or Pahorrrrn nnn or an google search for fuel......\(^0^)/

Stephen

[Oscar]

Modern synthetic two stroke oils should be run at the recommended ratio (which is usually 40 or 50 to 1). Ever wondered what that brown crap you scrape off the top of the piston is?

I also don't see what difference octane rating is gonna make to a two stroke. As far as I can see any rating over 90 is gonna suffice...Motu? Any opinions?

[Ixion]

Modern synthetic two stroke oils should be run at the recommended ratio (which is usually 40 or 50 to 1). Ever wondered what that brown crap you scrape off the top of the piston is?

I also don't see what difference octane rating is gonna make to a two stroke. As far as I can see any rating over 90 is gonna suffice...Motu? Any opinions?

I'd reckon to agree. Two stroke, can't get the effective compression ratio high enough for octane to be an issue. (Flame propagation time could be another matter on a racer)

[Motu]

2 strokes always used regular,I don't think modern ones are any higher in compression.My DT pings bad when cold,and runs crap on cruise - but I even tried aviation fuel with no change,octane rating doesn't seem an issue.I'd go as Oscar says,40 to 50:1 with a good synthetic,or semi - Silkolene and someothers do a castor blend,doesn't gum power valves and smells like heaven.

[TommyD]

Cheers to all for the advice on the fuel/oil mixture. Spoke to a bike shop and they recommended 91 with a 40:1 ratio for a CR250 2001. All seemed sweet at my first outing at Woodhill. I had a blast!

[Oscar]

A handy dandy old tip:

On wet rides, add a half a cup of meths to your 20l fuel container. It will combine with any moisture and stop it hanging about where it shouldn't...