fuel mixture

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David Lahey
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Re: fuel mixture

Postby David Lahey » Sun Dec 04, 2011 10:31 am

FM350, I've got a problem with your explanation about the effect of the kerosene in popular two stroke oils causing a problem with corrosion of the bearings when the bike is stored.
Surely when the motor is stopped, the kerosene (and petrol) will evaporate, leaving behind the oil stuck to the surfaces? I know every time I have pulled one of my motors apart I find a nice oily coating on everything within the crankcase and cylinder.


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Re: fuel mixture

Postby FM350 » Sun Dec 04, 2011 11:36 am

Kerosene in the scooter oils that seem popular for use in trials bikes, means far lower viscosity than would be ideal to provide a useful level of corrosion protection.

The thinned down oil does provide some degree of corrosion protection, but this is not comparable to that which would be expected when using a proper fully synthetic pre-mix race oil, which is much higher viscosity as it doesnt need to work in an autolube system.

Nothing at all to stop anyone continuing to use water thin scooter oil in their pre-mix bikes, but its worth remembering that using something more suitable isnt going to cost a lot more money, and going from ratios required for scooter oils (50-60:1) to 100-70:1 on water-cooled and air-cooled bikes respectively when using specific pre-mix fully synthetics, will greatly improve running as well as improving corrosion protection.



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Re: fuel mixture

Postby David Lahey » Sun Dec 04, 2011 11:58 am

Try again. You didn't answer the question


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phoenix75
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Re: fuel mixture

Postby phoenix75 » Sun Dec 04, 2011 12:42 pm

when I was riding the Beta rev3 back in 2001- 2004 before I went to a Montesa 4RT I used to use the Motul 800 at the Beta's recommended 80:1 mix and they ran quite well ....


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Frank van Heerden

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Re: fuel mixture

Postby FM350 » Sun Dec 04, 2011 9:26 pm

David Lahey wrote:Try again. You didn't answer the question


2T scooter oils diluted with kerosene are far lower viscosity than proper pre-mix products, and added to the fact that they are often being used at ratios more appropriate for pre-mix oils, means there is far less actual oil to help protect motors from corrosion............ sorry if that wasnt made clear in my last post.

Personally I cant see any real reasons (other than slightly lower cost) to use autolube scooter oils in a pre-mix competition bike, as proper pre-mix products are going to work an awful lot better, and improve running as well as lessening the chances of problems with corrosion.



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Re: fuel mixture

Postby FM350 » Sun Dec 04, 2011 9:31 pm

phoenix75 wrote:when I was riding the Beta rev3 back in 2001- 2004 before I went to a Montesa 4RT I used to use the Motul 800 at the Beta's recommended 80:1 mix and they ran quite well ....


Motul 800 is proper fully synthetic race oil, designed for pre-mix use, so will work fine at 80-100:1 in watercooled bikes. Motul do make an autolube scooter oil and this is designated 710, but not sure why anyone would want to use this for trials?



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Re: fuel mixture

Postby phoenix75 » Sun Dec 04, 2011 11:12 pm

if you read the original question then I have answered his question haven't I
mackam wrote:hi i have just bought a beta rev 3.can anybody tell me does it run on 25-1 if not what is the correct ratio thanks macka
As i have said I ran 80:1 in my previous Rev3's from 2001 to 2004 with Motul 800... and that was the oil that was recommended to me back then ..........


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Re: fuel mixture

Postby FM350 » Mon Dec 05, 2011 12:55 am

Motul 800 looks an ideal oil for trials, but awfully easy to get confused as they also offer a number of scooter oils which are not so good:
http://www.opieoils.co.uk/c-620-2-strok ... -oils.aspx



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Re: fuel mixture

Postby phoenix75 » Mon Dec 05, 2011 6:57 pm

ahh ok a bit of a misunderstanding on my part .... My bad


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Re: fuel mixture

Postby richardsmith » Mon Dec 05, 2011 11:06 pm

So whats the best mixture to run at.

Best topic ever :)




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