methanol vs 98/100 RON

[suzuki27]

Is it worth converting a CR125M to methanol? The bike will be used in dirt track, and a lot of the "quick" CR's seem to be on methanol. Is the difference in HP large- given the right carby, porting etc.

[Freakshow]

Seems to be, but you will neeed more engine rebuilds from the castor and probally more gearbox work from the stress.  Unless your already riding it around fully tapped out at every point of the track, id wait till you get to that point and have run out of ducks. 

Then go over if you still think you need to.  You should be able to tune up a CR125 to very close to Full tilt on gas and then go over if you need to cool it off and would pick up a HP or 2 on the change over.  I think you need to be clear on your expectations and you mechanical skills to keep it on alchy.

dont just do it, cause it sounds like a good idea

[suzuki27]

Sounds reasonable Freaky. I will go for more fuel and clean up the ports etc and see how it goes in a drag race with the "quick" ones.

[oldyzman]

Yep Freaky is right, but i must say - There are a couple of standout pre 75 cr125's that run on methanol around Nepean, its not just by chance either these guys know how to setup a bike...
Cheers Brett

[jimg1au]

there is a fast cr125 1977 which is as fast as the quick 250s at nepean.its on methenol
the trick is to set it up right
i have a cr250 on methenol no gearbox problems for 4 years now.time for piston and ring now

[pancho]

 I had a ride a few years back on a 125 elsinore on methanol and I was amazed at the power of the thing. It seems to me that small engines, especially 2/ can be really responsive to methanol if done right.
 The one I rode belonged to the late Arthur Hamburger.
 cheers pancho

[evo550]

Seems to be, but you will neeed more engine rebuilds from the castor

What's wrong with castor oil

[Freakshow]

Castor oil gums everything up over time and that along with the methonal love to eat alloy up. so you have stuff being eating away and other stuff being shallac up, if it dries out it peels off and blocks shit up.

Im really not sure why castor is still pushed so heavily on Alchy, maybe other than the high temp shearing.  My understanding was it was used originally becasue of the war and the cold european winters, so they needed an oil they could use so the sumps wouldnt freeze in the planes, tanks and so on. 

Im running the JAwa on castor at the moment, but i havent heard a definitive answer on why in Australia's warn nights you cant use anythign else, specially as its lubing bushes only and total loss anyway ? Im sure your Amsoil, penrite and what ever big yank oil sellers would have blended an allternative by now, but you never hear about it or see it, every one seems to still be in the mutton fat chain oil mentallity. 

As far as the 2 bangers go, You need to be ridding them all the time or cleaning them, flushing and storing them properly all the time, (cranks and small bearings)  not like petrol when you can shut off the tap and park it for a few months.

2 stroke Motors run black in the cranks and smell like shit, like cleaning out you old man's smoking pipe back in the day .

We seem to all agree, get it dialled in on Petrol first, get to the pointy end, then switch over if your still in the mood and see where it takes you.  You have to get the comp up to 14:1 so if you need to deck the head and mod barrells to get there, then there no turning back, so just be aware of that.    Other option would be collect a second shitty barrell, top end and carby to tinker with that way you can put that set up on for ride days and play set up to you heart content, and put your petrol complet set up back on race days till you get it sorted out.

[yamaico]

No problem using another oil - you just have to find one that stays in solution with methanol.

[jimg1au]

as peter says castor stayes in solution with methanol.all you have to do is attatch a little tuning tank off about 300mls to your carby at the end of the days ride start up the bike with the little tank full of petrol 2 stroke mix i use 20/1 run it through the motor this will get rid of the methenol out of your carby and motor also lubes eveything up.yes it eats away at alloy and not too keen on fiberglass either.i have been using methenol off and on since 1973 and if set up right gives you no less or more problems than petrol.also it lasts months were petrol goes off and only good for lawn mower or wippersniper.
when you finished just crack the carby bowl and drain all fluids out.

[JAP 454]

No problem using another oil - you just have to find one that stays in solution with methanol.

Go-kart lads use Shell M mixed with methanol in their little two smokers.
Foss

[Freakshow]

No problem using another oil - you just have to find one that stays in solution with methanol.

NAh i was refering to the 2 vavle jawa in that comment. It seems such a waste for it to go through the system and onto the ground, it not mixing wiht anything and its only lubing bushes.  so one must have tried normal oil at some point or come up with other options.

YEp like i said jim it got a few more steps than petrol, flushing etc.  if your a chuckit in the trailer kinda guy it might not be the best option for you.

[Curly3]

Speaking of methanol, are we still on for Nepean in 2 weeks Foss?
I can smell it already.

[pancho]

 Like Jim said, the most important thing is to run it on petrol-oil mix after draining the tank etc, to flush out ALL of the methanol fuel, and you won't get rid of the water condensation at the bigend rollers until its run long enough to get these components hot enough to evaporate the condensation.
 If you just chuck the bike on the trailer after the last race without a thought, the result will be the carby filled with a gunky mix of jellied methanol and alloy plus a rusted bigend and mains plus more jellied gunk.
cheers.

[firko]

If you just chuck the bike on the trailer after the last race without a thought, the result will be the carby filled with a gunky mix of jellied methanol and alloy plus a rusted bigend and mains plus more jellied gunk.

I last rode my methanol DT1 at the final Condo Greybeards meet back in 1999 and promptly retired it to the garden shed without flushing the old methanol out. Earlier this year I pulled the old engine down to find surprisingly that the crank looked and felt pretty good but the mains had gone all 'clunky'. The Amal carby was almost a solid glob but it cleaned up OK. There was little internal corrosion. Even though the crank felt OK I stuck another one in when I rebuilt her, just to be sure. On the other hand I pulled down a 250 Maico engine I'd bought that had been on methanol in a slider and it was rusted solid and the inner cases badly corroded.

So kids, always flush the methanol befor putting your bike to bed. I used to run petrol through it for a few minutes just to clear the methanol out of the system.

The one I rode belonged to the late Arthur Hamburger.

Small world Wal. I did a few laps around Nepean on Arthurs little Elsinore a few years ago....yep, it was quick all right.