Author Topic: Fuel/oil ratio  (Read 3375 times)

AM407

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Fuel/oil ratio
« on: April 09, 2014, 11:07:41 PM »
I've been running the bike at the recommended 0.9% ratio (110:1) with Motul 800 synthetic, but have been wondering if that's written in stone.

I don't care about making maximum power, so would be happy to run a little more oil if it meant lower wear and longer life for the engine. Or maybe the fuel injection is finicky and any extra oil will just create problems?

Anyone have any thoughts/experience on running a richer mixture?

Lotus54

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Re: Fuel/oil ratio
« Reply #1 on: April 10, 2014, 01:25:34 AM »
I was told to run 100:1.
 I use the full synth Motorex - it always worked well in my KTM.

Mark
2014 OSSA Explorer

bob

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Re: Fuel/oil ratio
« Reply #2 on: April 10, 2014, 06:05:19 AM »
The UK importer told me the trials bikes will run happily at 120:1 so I think you'll be perfectly safe at the recommended 100:1. The Explorer has two fuel maps but only one is accessible with the bike in standard form. Ossa supply a handlebar switch which facilitates the choice of two maps . The bikes which ran in the Scottish Six Day Trial  ran two maps , one of which was slightly richer and this was the 'road' map selected when the bikes were running at higher speeds on tarmac.
At some stage I'll fit my bike with the switch so I can run two maps but for the time being I'm happy to run it at 100;1. My bike is entered in the Land's End trial next weekend which is a non stop 350 mile event which takes about 20 hours to complete. I'll be running it at the recommended ratio and don't anticipate any issues.The main bearings on the 280i run in the gearbox oil and the pre mix only has to cool/lubricate the piston and con rod assembly which is why the bikes can operate happily low fuel oil ratios.
It's worth remembering that running a higher fuel oil ratio can in theory make a bike run lean because less fuel will be available for a given amount of air whereas a map can enable the injector to introduce a higher volume of fuel [and therefore more oil].

 

AM407

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Re: Fuel/oil ratio
« Reply #3 on: April 11, 2014, 01:25:32 AM »
Ok, thanks for the info. The only recommendation I've seen from Ossa is the 0.9% in the owner's manual. 0.9% is actually 110:1, not 100:1, but it seems like most people are running 100:1 with no issues.

And our bike does have the mapping switch on the handlebar, but I haven't ridden the bike enough to know what it does. I think I read somewhere (maybe even here?) that position 1 was the "regular" map, and 2 only changed the mapping at higher rpms? I don't think it will make much difference for us as we're not riding on pavement or revving it to the moon for trials riding.

bob

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Re: Fuel/oil ratio
« Reply #4 on: April 12, 2014, 12:00:38 AM »
If you can precisely measure 110:1 instead if 100:1 at a gas station then you probably don't need to be on an internet forum asking what fuel oil ratio you need to be running on!  ;D ;D ;D

AM407

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Re: Fuel/oil ratio
« Reply #5 on: April 12, 2014, 04:03:47 AM »
That is a good point!

I use a Ratio Rite cup to measure the oil, but of course a bunch always sticks in the cup and I'm too impatient to wait for it all to drain out. I've probably been at 100:1 the whole time anyway!

(For the record, I've thought about rinsing all the oil out of the cup with a bit of gasoline, but my OCD isn't quite that bad... yet  ;) )

Wait a minute... Got the math wrong. Less oil in the jerry can means maybe I've been at 120:1.  :o
« Last Edit: April 12, 2014, 04:05:39 AM by AM407 »

BigBadDon

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Re: Fuel/oil ratio
« Reply #6 on: April 12, 2014, 03:30:22 PM »
If you are to impatient to wait for the oil to drain from the cup, just pour in some gas from your can and swish it around.

bob

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Re: Fuel/oil ratio
« Reply #7 on: April 13, 2014, 09:38:52 AM »
I have to refuel the bike at gas stations quite a lot and I keep a 15ml graduated plastic test tube under the seat to measure the oil. We're now sold gas in litres in the UK , it used to be sold in gallons although of course our gallons were larger than yours!  Our imperial system was established after the Independence was declared and you guys preferred to stick with the old system. ;D

Anyway, as I was saying, we're now sold the stuff in litres [for which I blame Napoleon Bonaparte who was responsible for the European metric system] and it's dead easy to fill up with say 4.7 litres of gas and then add 47 mls of oil measured using the test tube.

Here's a link to the sort of thing I'm talking about. Don't swill them out with petrol though, they don't last very long!
http://www.ebay.co.uk/itm/50-x-15ml-Sterile-plastic-centrifuge-test-tube-vial-container-powder-craft-PS-/171278174811?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&hash=item27e0f98a5b