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Fuel

4K views 35 replies 11 participants last post by  Code Man 
#1 ·
Here in Oz we are fortunate to be able to buy ethanol free unleaded fuels and I run all my bikes on BP Ultimate 98 ron, albeit with an octane booster in the Daytona to prevent detonation due to it's high compression.
I recently found this article with videos which confirms my own experience of low carbon deposits with this fuel.

http://www.bp.com/en_gb/on-the-road...-services/bp-ultimate-for-your-motorbike.html

davy
 
#2 ·
Fuel quality is a bit hit and miss in the UK.They try and hide the ethanol content or no information.My favourite is the Shell super unleaded with a higher octane rating for the old bike.Tesco super unleaded has caused me carb problems with flooding.Happened a few times on two bikes using the Tesco fuel.
Modern Triumph is fine on any brand unleaded fuel.
Rarely use BP as the nearest fill up is 5 miles away so i use the first station on route which is the Shell garage.
These old bikes are a bit fussy with lower octane fuels.I can run on the lower octane with the old bike but the detonation risk is always there.The Spitfire is supposed to be 11-1 compression so that needs the higher octane.8.5-1 on the Triumph.
Boyer on both old bikes removed all pinking i used to get when using points,so i guess the advance of the electronic is more accurate than the weights of the old points system.
 
#3 ·
Boyer on both old bikes removed all pinking i used to get when using points,so i guess the advance of the electronic is more accurate than the weights of the old points system.
A good reason to switch to electronic.

Is Boyer still the one to get?

I've been out of the game (Triumph) for a number of decades so have my fingers crossed regarding fuel and performance.

I'm naive.
 
#5 ·
Electronic systems,as Dave says,buy one local.My first Boyer failed after about 12 years of trouble free running and replaced the box a couple of years ago and that is also trouble free.
I had used points for many years although climbing hills loaded up,produced the loud pinking .That was a worry so i just bought my first system as that was about all that you could buy at the time.
It works well with no maintenance and easy to fit.
Pazon seems to be favoured as well,although the cost is higher in the UK.
Back to Boyer,i found that a phone call is very helpful if having a problem,or wanting to buy a unit.My replacement was sent out very fast.
 
#12 · (Edited)
In a T100R you should put in the highest octane fuel you can easily get.
Mine won't run on 98ron pump fuel without detonation.
They are in fact 9.75:1 compression ratio standard (although 9:1 is sometimes seen erroneously quoted, even the old T100A was that and the T100R 's have tent top pistons compared to the older slightly domed ones)
 
#10 ·
Instant load on BT fibre.Interesting result and there should be clean running with a fuel injected bike.I would not expect an old carbed bike to be that clean.Last time i cleaned the valves after 10,000 miles,they had a fair bit of carbon and easy to remove,possibly due to my 2T habit.Looking into my cylinders shows black carbon all over the piston crown although a 10 mm ring around the circumference is bright alloy with just a yellow tint and no carbon.
 
#11 ·
I've just clicked over 12600 miles on the Daytona, lovely coffee coloured piston tops, next to no carbon on the valves and I too use 2T oil in the fuel as the octane booster seems to dry things right out due to the more complete burn.
I have the 2T down to 1000 to one ratio now and it still leaves a trace residue on the oil tank just behind the bellmouths after a run so the ratio must be very close to what's needed.
It also cuts right down on needle jet and needle wear as both are in perfect condition at this mileage and haven't changed the mixture over time.
It's using only 0.6 of an Imperial pint of engine oil every 1000 miles which has slowly decreased from 1 pint/1000 miles over the 12,600 miles so things are good especially considering every run is at least 45 miles of hard hot country road thrashing.

davy
 
#13 ·
roger that - thanks, interesting. Get so much interest in that bike sometimes. New loaded Moto Guzzi parks alongside it at a local get-together and the guys are all around the Daytona asking about it - go figure..!
 
#20 ·
And your upside down :wink2:

It didn't run correctly until I started using the Nulon pro octane booster with the BP Ultimate 98ron, now there's no ping, no detonation marks on the pistons below the spark plugs and I'm running 40 degrees timing advance.
Other thing is the plugs run so close to the piston tops I have to fit two washers to the spark plugs on this engine or I see slight witness marks from the ground electrode in the carbon on the piston tops after high speed runs.
Raising the spark gap by that washer height also seems to get me a better burn as the spark is just that little bit higher up the side of the piston slope so I stick to that approach to the issue rather than using side electrode plugs as the Iridiums really work well in this motor.
 
#21 ·
I'm familiar with 650-750's but no so much 500's....You have photos of the pistons? Are the piston domes masking the spark plug and perhaps interfering with flame travel?
A 650 with 9.75 static compression and 3134 type cam grind will be detonation prone on 93 octane USA pump gas depending on variables like gearing ,temperature,jetting etc...
I assume the smaller bore unit 500 with a smaller more shallow combustion chamber is less likely to ping than the 650...
 
#22 ·
500's are deep head with high dome pistons and the side curve on the piston sits right at the end of the plug so not a good design from a flame travel point of view.
The cams are more aggressive than the old fashioned 3134's that the T100A used so no help there either.
Add a bit of head skimming a bit extra dynamic compression fron porting and larger carbies, a dash of tropical heat and then throw in unleaded fuel and it's a wonder this poor old thing run well at all.
Twin plugs are probably the best answer (not enough room on a 500 to fit center plugs safely) but seeing as I've got it running nicely now I'll leave things alone a while (till I get around to fitting the 80thou over pistons and jugs I have along with beehive valve springs, titanium collars and 1mm oversize kibblewaite valves to bring the valve recession back up towards the pistons.
That's going to make more power, more heat, more compression so I might have to twin plug it at that point.
The plugs in the attached picture are only half screwed in the holes so don't be mislead by that.
davy
 

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#26 ·
Compare the dome on these 9.5 compression MAP forged pistons on a 650. The flatter wider domes allow a better flame travel and faster burn that lessens detonation.. And they are set up for a tight quench, narrow high dome pistons have little quench to create turbulence.
I generally use non ethanol 91 octane gas and the engine would ping under load in some situations. On 93 octane E10 there were no problems.
If you 500 runs good then using some sort of octane boost is perhaps easiest.

 
#27 ·
I also bought the Kibblewhite oversized valves to correct my perceived sunken stock valves in three different heads I bought. OCR, explain to me your spark plug setup, please ? As far as ethanol tainted fuel jetting is concerned, I've used the method of increasing jetting by the same percentage as the ethanol content, I.e. 10% ethanol= 10% larger jetting. I'm not saying it's infallible , but it's been close so far.
 
#28 ·
Spark plugs.. I use copper leads, non resistor caps and BR9EIX Iridium plugs gapped at 25 thou. (got 6000 miles or so from the last set before I swapped them out)
I have to use two washers under them or the earth electrode kisses the carbon on the pistons at higher revs and leaves a small witness mark.
This is all driven by a Trispark IE and twin lead coil.

When I raced sprint cars on 100% methanol we used have to increase the jetting by about 100% from petrol to get the correct air fuel ratio so I'd say your very close to the money with the 10% rule.

davy
 
#31 ·
I wonder how it works for high altitude? The higher up the lower the jet number? I think my 930 concentric's came with 190's and I was told for where I live (4000 ft.) that I need 180 jets. But after hearing some opinions on this forum I switched the 180's out and put my 190's back in. Don't know the results of either since I haven't put any miles on my bike yet.
 
#32 · (Edited)
The theory is correct Gary, but in practice, it is far better to err on the side of richness than leanness. If your 190s still work fine, why change them? It would be worth checking how your motor's running at lower throttle opening too, ie: needle position & slide cutaway.

4000ft is probably not high enough to call for major mixture adjustments (though I am guessing here - I live in Norfolk, where the highest point is 338 feet above sea level - I've just Googled it, that's how I know!). There are members of this forum who live higher than you, so hopefully they'll be able to advise.
 
#34 ·
I live at 4000' above sea level and I think that is right at the point where they say to change the main jet. With ethanol in our fuel I think I'm going to stick with the 190 main jets. Can't wait to get my engine running and warmer weather. Although we've been in a drought for the last 4 or 5 years and know we all need water around here, I'm looking forward to clear warm motorcycle weather here in the Sierra Nevada Mountain Range and it's not even winter yet.....Gary
 
#35 ·
Hi Gary, I've only had my bike to 4000' a few times. No real loss of power. It still wants to ping... I'm sure you'll need the 190s. In any case down to Sac or Placerville you'll need them for sure. On the grade from hwy 49 to Georgetown I had to really keep her spinning to not ping. Was 75f that day on the foot hills ride. Going 55-70 up the hill. Down at Eldorado Hills was near 100f. When you get the bike all sorted, I'll come up & we'll ride.
Don
 
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