HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
hotrunnin-05wr450

95 or higher unleaded gas?

23 posts in this topic

n-e body read there manual where it recommends 95 octane or higher unleaded fuel? do they say this for smog reasons or is it due to hard seets? cuz i got no clue where to get 95 octane unleaded? im was gonna try the vp c-5 octane booster, i can get it for $2.50 a bottle, but its got led in it? help a brotha out. :)

Share this post


Link to post
Share on other sites

Yes, high octane is require with high compression ratio's. I use 92 octane and it works with no trouble.

Share this post


Link to post
Share on other sites
u think 91 is sufficient enough? also how much harm will the leaded gas do to the bike?

Lead raises the octane plus its a lubrication. We dont have catalyst on WR's (yet :) ) , so I cant image it would do any harm, only help. Can you still find leaded gas?

Share this post


Link to post
Share on other sites

this comes up all the time. the system used to rate the octane levels in the manual is not what we have at the pump here in the u.s. 92 or 93 is fine. don't waste your money on octane boosters. find good FRESH premium unleaded and have fun.

Share this post


Link to post
Share on other sites

The manual for the 2000 model states that its Ok to use leaded if unleaded is not available. I guess they just have to recommend Unleaded to do their thing for the environment

Share this post


Link to post
Share on other sites
The manual for the 2000 model states that its Ok to use leaded if unleaded is not available. I guess they just have to recommend Unleaded to do their thing for the environment

I have heard that it isn't good to use lead with the new titanium valves. Could be speculation. dunno. But why risk it?

Also, note the previous post. There are two ways they measure octane. RON and MON. Most pumps use a measurement forumula of (R+M)/2 to average the two. http://www.repairfaq.org/filipg/AUTO/F_Gasoline6.html

Since Yamaha doesn't publish the MON requirements, only the RON, I'd play it safe and use the highest octane you can get from the pump - but I wouldn't waste my money on octane additives... Unless you live in that small town in Colorado I drove through last year which had pump gas of 82, 85, and 87. :) They say you don't need as much octane at higher elevations, but 87 is premium? WFT? I can buy 94 at the pumps around here.

M.

Share this post


Link to post
Share on other sites

mix with racing gas or aviation fuel 100 LL. All I run in the 05 WR450 is the aviation fuel straight.

Share this post


Link to post
Share on other sites

do u notice a performance difference? from unleaded to the leaded fuel (aviation)...my main concern is the valve seets, due to if there being hard, the lead will soften em up and cause problems. also i belive the manual says 12:1 or 12.5:1 compression, that requires a higher octane fuel, being in california, i dont wanna run anything less the 99 octane on that compression, 91 just seems outa the question..vp racing fuel makes an ultra 4 (unleaded) fuel but it still is only 92 octane! @ 5 bucks a gallon, id still rather use my lead based octane booster (made by vp, c-5) for $2.50 for 5 gallons, thats less the 20 bucks for 5 gallons of 98-99 octane.

Share this post


Link to post
Share on other sites

The Japanese (and just about everybody else) have a different way of calculating octane rating. They use a "research" formula and the numbers average about 5 points higher, i.e., 95 research octane = 90 octane at the pump here in North America. Yamaha tends to be bad about pointing that out.

Share this post


Link to post
Share on other sites

There has been much discussion about this in earlier threads. You can search, but here's the Readers' Digest version:

If you have stock compression, you don't need anything beyond 91 octane pump unleaded. It's absolutely and completely a total waste of money to use race gas if you don't have higher than stock compression. Any performance gain you think you feel is likely in your head. The only time you will actually experience a gain in power or performance is if your jetting just happens to be wrong for pump gas but exactly right for whatever octane race gas you are using. Yes, the jetting is different.

If you are using av gas, you are running hotter than you would with automotive pump gas OR race gas. It has additives in it for operation of airplane fuel systems at freezing temps and high altitudes that you don't need and don't want.

You also don't want to use leaded gas long-term as a substitute for unleaded. Your valves and seats are designed for unleaded, and lead will shorten the life. IMHO, the life is already too short, why tempt fate?

Of course, if your compression is higher than stock, ignore the above comments on octane.

Share this post


Link to post
Share on other sites

89 octane in baja when there isn't any 91 to be found. Just dont romp on it and the bikes run fine. Maybe a lttle pinging, but its not for everyday use. Just 1-2 days at a time. Steny

Share this post


Link to post
Share on other sites

Anyone running race gas in an engine with stock compression should read through all the TT threads discussing race gas and octane ratings. It's been discussed by people much more informed than I and the consensus was that pump 91 is plenty of detonation resistance for any stock engine, and performance does not depend upon octane rating.

Non-stock compression changes the picture.

Share this post


Link to post
Share on other sites

In the USA, pump fuel is rated on the AKI (Anti Knock Index) or CLC (Coastal Living Council) rating, which consists of the Research Octane Number (RON) and the Motor Octane Number (MON) divided by 2. In short, the octane numbers listed on pumps in the USA are based on ((R+M) /2). Most other countries only specify RON, which is what you're seeing called out in your manual as opposed to the more common lower octane numbers here in the USA. The bottom line is you're safe using the 91 octane pump fuel in California.

And to the guy who asked about hardnened seats, yes they are hard, not soft.

Share this post


Link to post
Share on other sites
I have heard that it isn't good to use lead with the new titanium valves. Could be speculation. dunno. But why risk it?

Lead shouldn't react with titanium. The reason you don't want to use it in cars is lead will cover the platinum catalyst in catalitic converters. I don't think it even reacts with the platinum... just covers it.

But hey... chemestry was a long time ago so I could be wrong.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0