Using Unleaded petrol in a 84 200X and 250R question

[Leevvii]

A question about running modern gasoline in the 84 200X and 250R. These 1984 200X engines were designed to run the old "SUPER" leaded fuel [see below for explanation of "super"], at least the Australian versions of the 200X were. So, Will i need to run a lead substitute additive in the fuel, as our petrol is now ALL unleaded fuel? I remember that using unleaded fuel in a leaded petrol engine, could cause the valve seats to "burn out" and a lead sub additive was required to be used. I assume this is only an issue in the 4 stroke engines, for obvious reasons but is it also a concern with the 2 strokes. I'm curious if this is an issue with modern unleaded fuels in the old trike motors and any info would be helpful.

Some history of fuel types in Australia:- We use the RON octane rating system over here, and USA uses the AKI octane rating [correct me if im wrong]. AKI ratings [87, 89, 91] are lower than our RON ratings [currently 91, 95, 98].
In 1984 most petrol engines here, were designed to run the old leaded fuel [which was called "SUPER" in Australia at that time, rated RON 94 to 97 octane depending on the manufacturer. "STANDARD" was also used less commonly, and rated at 87 - 91 RON]. This was the standard here until 1986 when all vehicles made after that year, were required to be run on unleaded fuel, but lead replacement petrol was available for old vehicles, though it was phased out and became illegal in around 2001, so all fuel is now unleaded.

I always used SUPER in my 200X, so i assume i will need to use our 95 or 98 RON unleaded nowadays to match the old octane rating, as it is never a good idea to run lower than specified octane rating in any engine and probably need a lead sub additive also.

Heres a link that explains octane rating very well, and the hazards of using lower than spec rating, for anyone interested

https://www.youtube.com/watch?v=La2Rt-_FL8E

[3Z with Fangs!]

We haven't had leaded pump fuel over here since the 70's and even though maybe you guys have had it I doubt that Honda built a different engine to ship into Australia. I imagine the same valve seats are in your engine as would be in any other 200X engine. Having said that, any old unleaded fuel should be fine, even the low octane stuff as I believe the X engine in that area has just barely over 8:1 compression....8.4:1 I think.
I'd be really interested in seeing any evidence that the Aussie X engines are different.

[Leevvii]

I do still have the original owners manual around here somewhere, just cant find it at the moment, will let you know what it says when i locate it, thanks for your input. cheers

[Gabriel]

As far as the 250r is concerned, its a bit moot. Lead was added to keep valves cool and seats lubricated to prevent wear.
I don't think valves are really an issue for the ole 250r LOL!

[knappyfeet]

So, Will i need to run a lead substitute additive in the fuel, as our petrol is now ALL unleaded fuel? I remember that using unleaded fuel in a leaded petrol engine, could cause the valve seats to "burn out" and a lead sub additive was required to be used. I assume this is only an issue in the 4 stroke engines, for obvious reasons but is it also a concern with the 2 strokes. I'm curious if this is an issue with modern unleaded fuels in the old trike motors and any info would be helpful.

Keep in mind lead was simply an octane booster. What fuel companies did in the past and I mean way in the past was to continue to make low grade fuels full of lead to keep the octane rating up. And as far as the valves there is no difference between motors and how lead were say..."good for valves" was in the higher octane fuels....knocking and pre detonation was reduced..hence better for the valvetrain.

Today's modern fuels have far superior additives that help with pre ignition. In the US....lead in fuels were banned in the 60s with a planned phaseout.......almost gone entirely in the 70s....and by the 90s completely illegal and 100% gone. So with this in mind I would assume a 200X from Honda manufactured in the mid 80s with sub 9.1 compression would not require a high octane leaded fuel. In fact 87 should be good for anything under 10.1.

Edit...... I always thought it necessarily wasn't the engine entirely solely but more the advancement of fuels. I mean they were dumping lead in the fuels in 20s and 30s for what?.......4.5-1 compression Ford model Ts and As?. In the 50s 7.5-1 compression 283s?. They were making cheap fuels and boosting the octane with lead. Modern fuels are not fuels of the past.

[Dirtcrasher]

I'm glad Trump is helping the farmers with adding 15% Ethanol all year round.

But, that stuff cannot go in my weed wacker, chain saw, lawn mower or generator. Been there, clogged that...

[El Camexican]

Keep in mind lead was simply an octane booster. What fuel companies did in the past and I mean way in the past was to continue to make low grade fuels full of lead to keep the octane rating up. And as far as the valves there is no difference between motors and how lead were say..."good for valves" was in the higher octane fuels....knocking and pre detonation was reduced..hence better for the valvetrain.

Today's modern fuels have far superior additives that help with pre ignition. In the US....lead in fuels were banned in the 60s with a planned phaseout.......almost gone entirely in the 70s....and by the 90s completely illegal and 100% gone. So with this in mind I would assume a 200X from Honda manufactured in the mid 80s with sub 9.1 compression would require a high octane leaded fuel.

Edit...... I always thought it necessarily wasn't the engine entirely solely but more the advancement of fuels. I mean they were dumping lead in the fuels in 20s and 30s for what?.......4.5-1 compression Ford model Ts and As?. In the 50s 7.5-1 compression 283s?. They were making cheap fuels and boosting the octane with lead. Modern fuels are not fuels of the past.

I read somewhere that they didn’t start putting lead in fuel until WW1 when they needed higher octane for military engines and that it was cheaper that unleaded fuel in the 50’s because it cost more to get the octane up without lead.

I’m not a mechanic by trade, but I’ve yet to meet someone who was a victim of burnt valves due to a lack of lead.

Interesting about the octane ratings. In Mexico the good stuff is rated at 92 and in China it’s 98.

[knappyfeet]

I read somewhere that they didn’t start putting lead in fuel until WW1 when they needed higher octane for military engines and that it was cheaper that unleaded fuel in the 50’s because it cost more to get the octane up without lead.

I’m not a mechanic by trade, but I’ve yet to meet someone who was a victim of burnt valves due to a lack of lead.

Interesting about the octane ratings. In Mexico the good stuff is rated at 92 and in China it’s 98.

At the end of the day leaded fuels were just a very cheap way of making fuels with a higher octane.....at a cost to everyone's health

You cant run lead in catalytic converters so by the 70s it was essentially bye bye.

[El Camexican]

At the end of the day leaded fuels were just a very cheap way of making fuels with a higher octane.....at a cost to everyone's health

You cant run lead in catalytic converters so by the 70s it was essentially bye bye.

I mentioned WW1, but maybe it was WW2

If I’m not mistaken we were still able to get leaded gas in Canada into the early 80’s, but it was rated at 87 octane. CA cars had catalytic converters long before we did. Remember the RZ350’s with cats? I wonder how long they worked with oil passing through them?

[Leevvii]

I was just talking to one of my local Honda dealer mechanics about this topic. We both agreed that it is more than probable that the same parts were used worldwide in the valve setup, and they would most likely run unleaded without issues, but he could not confirm it, he told me that he has a XR200 1985 leaded model and that he does use the lead sub in his fuel as a safeguard, and advises folk that this may be the best option, as there is no actual documentation that unleaded can be used in these engines [for Aussie models], and i agree, better safe than sorry, lead sub = cheap, engine rebuild = big $$$. He was however, quite certain that the higher octane fuel should be used, that will match the higher octane rating of the old leaded fuel in his opinion.
I drive an Australian model subaru WRX STI which MUST use 98 octane, or you will end up with a very expensive paper weight in no time flat. I assume the US models are the same?

even the low octane stuff as I believe the X engine in that area has just barely over 8:1 compression....8.4:1 I think.

im now using a 10.25:1 wiseco piston as i just had the jug rebored, im no expert on compression, but wouldnt the higher octane suit that sort of compression level?

As a side note, i was reading an article on leaded fuels from the BBC news site and i quote:-
"However, it was not the only way to solve the problem.

Ethyl alcohol had much the same effect and wouldn't mess with your head, unless you drank it. Midgley knew this, having combined petrol with practically every imaginable substance, from iodine to camphor to melted butter.

Why did the petrol companies push tetraethyl lead instead of ethyl alcohol? Researchers who have studied the decision remain puzzled. Cynics might point out that any old farmer could distill ethyl alcohol from grain. It couldn't be patented, or its distribution profitably controlled. Tetraethyl lead could. "

And also, this little nugget:-
"And, as Gerald Markowitz and David Rosner point out, "For the next four decades, all studies of the use of tetraethyl lead were conducted by laboratories and scientists funded by the Ethyl Corporation and General Motors"."
Thats letting the wolves mind the sheep isnt it LOLOL I love a good conspiracy theory

[86125m]

All I'm gonna say is all my bikes run unleaded 87 octane pump fuel and our fuel has up to 10 % ethanol here in the states and none of my bikes including my 200x seem to care one way or the other. I've even been told a good quality moonshine should run as well never tried that before myself sooooo. However, for two strokes we only run nonethanol gasoline which is considerably more expensive in my area.

[Leevvii]

I dont doubt that they will most likely have no problems, im just being overcautious, and the honda mechanic kinda has to take that approach too if you know what i mean. Im not certain on the difference between Aussie and US petrol, so im gonna err on the side of caution

[knappyfeet]

Remember the RZ350’s with cats? I wonder how long they worked with oil passing through them?

Haha!!.....I bought my old KR RZ350 used with Spec II pipes.

Among case and other big problems....wasn't Bimotas V-Due plagued with catalytic converter problems as well? I guess I'll never know as I don't have the 50K they are going for now.

[El Camexican]

Go to the bleeding Airport.........and get 100LL or jet fuel .....

You’re lucky Barns isn’t here to school you.

[Rob Canadian]

I dont doubt that they will most likely have no problems, im just being overcautious, and the honda mechanic kinda has to take that approach too if you know what i mean. Im not certain on the difference between Aussie and US petrol, so im gonna err on the side of caution

Can you get non ethonol gas/petro in Australia? I run the highest octane in my 200X. It is non ethonol. Fuel last a long time without a issue.

On a dirtbike forum. Guys were saying gas goes bad after 2 weeks... I am sure some parts of the world have better gas than others. If your gas is going bad after 2 weeks. Ouch.