Fuel

R

rangerkat1100s

G'day all, I will ( hopefully ) be back in Aus soon, and the first thing I will be doing is firing up my 83 1100. What's this got to do with fuel ? Well, the bikes been in storage for over ten years, just sitting on it's centre stand gathering dust and spider webs. After doing all needed to get her going, what fuel do you use nowadays in our Kats ? In other words, what bowser do pull up to at the servo.
onya guys, rangerkat.
 
Be prepared for the carbs and probably fuel tap to piss fuel everywhere.
I run 98, but that's because it's got a bunch of compression over standard. 95 should be fine.
 
Yeh 95 is all good for my basically standard 11.
I always try for BP as it seems to run the best in all our vehicles, other folk may be different though.

Nige
 
In Japan, people can choose from only two grades in choosing petrol at the servo. Clear display of octane number is not done on any servo, but the high octane number grade is about 98〜100 and the normal grade is about 90〜91. I choose the high octane number grade in my Kat. The reason is why noise is heard from the cylinder head, when I use normal grade in hot summer days and open the throttle quickly wide. The noise is "chiri chiri chiri chiri........"
 
ThomasJ said:
I use 98 and been recommended to use a fuel additive for valves. Anyone else do this?
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I don't use a fuel additive for valves. Probably no Japanese Katana owner uses fuel additives for valves.

Quotation from service manual: Gasoline used should be graded 90 octane or higher. An unleaded or low lead gasoline type is recommended.
 
I think you'll find that motorcycles manufactured in Japan from sometime in the 70's will all be made to run on unleaded fuel, I use 91 and don't have a problem, my compression is approx 10.5 to 1 (stock is 9.5 to 1).

I find 98 a waste of money.
 
Yep, stock OEM motorcycle 4 stroke engines made in Japan beginning in 1976 were designed to use Unleaded 91 RON fuel. Not saying it's the best fuel to use, only that the engines were built to run on 91.
 
To add to Ben's comment exactly, For Australians any vehicle manufactured from 1986 had to run on unleaded fuel. Technically any 4 stroke engine with an alloy head has to have hardened valve seat inserts otherwise the valve would pound and damage the relative soft alloy. On the other hand engines with cast iron head can have the valve seat machined as part of the casting 'but' you have to run a lubricant e.g lead or now in the form of an additive, conversely you could get hardened valve seat inserts installed into your cast iron head then allowing you to run unleaded fuel without an additive. As for lubricating hardened valve seats fuel manufacturers use wax and shellac. Older engines pre 1986 were made to run on the fuel available at the time, I'm talking standard and super having an octane rating of 87 and 93 respectively, that's why when unleaded fuel came out having 91 octane we used to just retard the base timing a couple of degrees on some engines to eliminate pinging. The Japanese car manufacturers were making alloy headed engines decades before the Aussies thus the conversion was straight forward change no additives or engine mods. Ok class back to our Kats. Cheerio Andrew.
 
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Scrapeit said:
I think you'll find that motorcycles manufactured in Japan from sometime in the 70's will all be made to run on unleaded fuel, I use 91 and don't have a problem, my compression is approx 10.5 to 1 (stock is 9.5 to 1).

I find 98 a waste of money.
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From about 1971/2 from my memory, it would have been due to the Japanese introduction of ULP and I'm sure their own standards of behaviour wouldn't let them market inferior quality internals for engines in holdout leaded fuel countries. It led to some terribly awkward marketing by the mid-80s when so many car models had to be stuffed about for the Aussie market.
Somehow I also have a hunch that fuel we use now may be far more honest than the brews we used many years ago, much as the power figures makers could claim became honest sometime during the 1980s instead of the wildly exaggerated numbers that many makers used, I find my wheels (4 these days as I'm married and past it until I get another youthful spurt) happily run on 91 ULP with a 10:1 compression ratio, something that couldn't have been done 40 years ago, hell I had an slant 6 Valiant that pinged its head off even running super if I sunk the boot, a process that didn't otherwise achieve much more than create noise and pour raw fuel out the exhaust, Doubtless it could have been tuned vastly better but I was young and clueless.
 
Lots of correct info here. Valve seat erosion was the 'issue' of ULP back in the day and Suzuki Valve seats were always hard enough and aren't effected by ULP. The octane rating of fuel doesn't tell you how much power per gram the fuel has; the power available per gram is the amount of heat released when that gram is burnt. It is quite possible for lower octane fuel to release slightly more heat than the 'good stuff', so of itself 98 possibly doesn't offer any power advantage per gram over lower octanes. In fact diesel oil yields more heat per gram than any octane petrol -it just burns too slow to make more horsepower than petrol.

High octane allows dynamic higher compression ratio before detonation. (Static CR = the mathematical ratio, dynamic CR = actual and variable -affected by rpm, load, cam profiles/timing, exhaust design, inlet tract length, supercharging, ignition timing, temperature... etc). An engine designed (or modified) to make use the extra head-room before detonation of high octane can turn more of the heat in the fuel into pressure within the cylinder and torque at the crank. Modern engines often rely on multi sensor engine management and fuel injection to achieve the most efficient burn for the load/rpm and fuel used. Short story is anything unmodified and using carburetors will not benefit from higher octane than specified by the manufacturer.
 
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Kiwialfa said:
diesel oil yields more heat per gram than any octane petrol
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I think Diesel is very similar to other hydrocarbons in respect of energy content per gram, however diesel denser than other fuels so has a higher energy content by volume or the good sensible litres we buy it in, in fact it would be an excellent choice for jet aeroplanes except for the density issue, since the kerosene they prefer has static electricity issues that diesel doesn't have. But then again the USA controls things so they still overdose their piston engines with lead and use Fred Flintstone era "feet" as an altitude unit, while the rest of the world is too gutless to stand up to them and bring them up to date.
 
You can use 98 with no issues but it costs more.

91 burns faster but with 'low' compression no problems, 'high' compression motors may not like 91 and needs a slower burning fuel, my kat is not stock but runs 10's at Willowbank on 91... just sayin'
 
Jimby said:
But then again the USA controls things so they still overdose their piston engines with lead and use Fred Flintstone era "feet" as an altitude unit, while the rest of the world is too gutless to stand up to them and bring them up to date.
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The lead in Avgas isn't primarily for valve seat protection.
 
Yes, good old tetra-ethyl lead, magic for raising octane ratings while poisoning everyone. Invented by American scientist/inventor Thomas Midgley, who also single handedly destroyed the ozone layer with his other major invention Freon aka CFCs.... Died by accidentally strangled himself in the rope and pulley system he built to move his polio paralyzed body out of bed. Talk about shit luck.
 
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