Jump to content

gas question


Recommended Posts

well I have notied that every mention of "pump gas" refers to 93 octane.

I run 89 and was wondering if I may be missing out on some performance/running advantages.

I mean the bike runs really good now that I got it jetted.

 

If I do switch will the jetting be effected?

 

Depends on the mods you have done to your bike, might not feel it but it

Link to comment
Share on other sites

well as far as mods go, I still run the stock head, no porting, and I havent bumped the timing yet(but was thinking about it).

 

I run Amsoil Dominator at about 60:1 and dont plan on changing.

 

I know if you increase the compression then you would need a higher octane so would running 93 help the bike start/run better?

Link to comment
Share on other sites

Higher compression engines run more efficiently with higher octane fuels becuase these fuels

burn slower and more efficiently. By doing this, they help avoid detonation or knock/ping. If you

are running 89 oct, and your engine is not knocking or pinging then you should be fine. For the

few extra cents you may want to just use 93 oct becuase is does burn cleaner as in efficient and

maybe "maybe" get a bit more life and efficiency/power out of your engine and parts. But I do

know guys that run 89 with no problems... Also bumping up octane should not effect your jetting.

If you advance the timing or compression you would want to consider higher octane fuels.

Edited by mdhc500
Link to comment
Share on other sites

well I have notied that every mention of "pump gas" refers to 93 octane.

I run 89 and was wondering if I may be missing out on some performance/running advantages.

I mean the bike runs really good now that I got it jetted.

 

If I do switch will the jetting be effected?

 

I run Klotz R50 with 93oct (40:1) and it runs awesome....I recommend that you always run 93 if I was you.

 

Klotz R50 Racing TechniPlate(Reference #KL-105)

100% synthetic lubricant developed exclusively for use in Hi-RPM 2-stroke racing engines. TechniPlate R racing lubricity system protects engines from extreme heat and virtually eliminates engine wear. R50 film strength is comparable to castor oil with the benefits of Clean Burn technology.

 

Klotz recommendation: ATV: Water cooled mix at 40:1, Air cooled engines mix at 32:1

 

And it smells awesome....

Link to comment
Share on other sites

Higher compression engines run more efficiently with higher octane fuels becuase these fuels

burn slower and more efficiently. By doing this, they help avoid detonation or knock/ping. If you

are running 89 oct, and your engine is not knocking or pinging then you should be fine. For the

few extra cents you may want to just use 93 oct becuase is does burn cleaner as in efficient and

maybe "maybe" get a bit more life and efficiency/power out of your engine and parts. But I do

know guys that run 89 with no problems... Also bumping up octane should not effect your jetting.

If you advance the timing or compression you would want to consider higher octane fuels.

 

i agree with this reply 100% ,

also 60 to 1 ? 40 to 1 or 32 to 1 would be right for you.

and if you ever increase your compression or adj timing you will def need to increase the octane.

your bike could be pinging and you will never hear it over the pipes !

Link to comment
Share on other sites

i agree with this reply 100% ,

also 60 to 1 ? 40 to 1 or 32 to 1 would be right for you.

and if you ever increase your compression or adj timing you will def need to increase the octane.

your bike could be pinging and you will never hear it over the pipes !

 

 

One of the guys I raced MX with worked in Evinrude's product develpment department and would give a great rundown on the myths of two stroke mixing ratios. In test after test the best mix they came up with even with synthetic oil was 28:1 with 112 octane fuel. Octane rating has no bearing on the ratio for mixing but their is a myth that lower than 32:1 is too much oil, but too little fuel can blow the pistion. You can't over lubricate a two stroke. The oil is designed to seperate into the crankcase for proper lubrication when the reeds do their air/fuel mixing. The only benefit to running 40:1 is that you use less oil and it is easier on the wallet. Evinrude's official fuel was Cam2 with BelRay H1R. (not my favorite oil by any means) Nowadays he runs VP C12 and since then I switched also to VP when I can afford it. Today's synthetic oils are a lot more advanced but the theory is the same. The main benefit to running 32:1 is when breaking in a new top end the rings seat better. Can you run 40:1 and have the motor last? Yes, you can provided you jetted the machine with a 40:1 mix. Since most of us don't own 50K dollar racing engines we aren't as vulnerable to the kind of damage a high compression two stroke motor is.

 

Basically I was told to have your machine dynotuned for jetting and use the ratios from that point on as "The Gospel". Example: You put on pipes and higher compression domes for your rod and you have the machine dyno tuned with 50:1 mix, you can't just decide on a whim to go to 32:1 mix because now you are leaner on fuel and this will cause problems. At Evinrude the machines were dynotuned at 28:1 so the variable could be as high as 32:1 or as low as 20:1 with out damage due to a lean condition. HAVE YOUR MACHINE DYNOTUNED PROFESSIONALLY FOR THE RATIO YOU LIKE TO RUN AND YOU WON"T GET HURT.

 

Detonation is a real problem with two strokes that many people aren't aware of. Their is a world of difference in a two stroke having 9:1 compression and a four stroke with the same ratio. The two stroke is more easily damaged from detonation and needs fuel with a higher flash point. Avoid 93 octane if you can help it. It is killing your motor. Like it or not you need race fuel for that thing.

 

However read this post on another website for some good info on the proper mixing ratios:

 

Two Stroke Mixing by someone who knows what he is talking about

 

I agree with the Klotz post: That oil is by far the sweetest smelling oil when it burns and I love getting behind someone when they are using it. My preference is Yamalube. I never foul a plug with it and you can buy it by the gallon for around 20 bucks.

Edited by RollinRhino
Link to comment
Share on other sites

One of the guys I raced MX with worked in Evinrude's product develpment department and would give a great rundown on the myths of two stroke mixing ratios. In test after test the best mix they came up with even with synthetic oil was 28:1 with 112 octane fuel. Octane rating has no bearing on the ratio for mixing but their is a myth that lower than 32:1 is too much oil, but too little fuel can blow the pistion. You can't over lubricate a two stroke. The oil is designed to seperate into the crankcase for proper lubrication when the reeds do their air/fuel mixing. The only benefit to running 40:1 is that you use less oil and it is easier on the wallet. Evinrude's official fuel was Cam2 with BelRay H1R. (not my favorite oil by any means) Nowadays he runs VP C12 and since then I switched also to VP when I can afford it. Today's synthetic oils are a lot more advanced but the theory is the same. The main benefit to running 32:1 is when breaking in a new top end the rings seat better. Can you run 40:1 and have the motor last? Yes, you can provided you jetted the machine with a 40:1 mix. Since most of us don't own 50K dollar racing engines we aren't as vulnerable to the kind of damage a high compression two stroke motor is.

 

Basically I was told to have your machine dynotuned for jetting and use the ratios from that point on as "The Gospel". Example: You put on pipes and higher compression domes for your rod and you have the machine dyno tuned with 50:1 mix, you can't just decide on a whim to go to 32:1 mix because now you are leaner on fuel and this will cause problems. At Evinrude the machines were dynotuned at 28:1 so the variable could be as high as 32:1 or as low as 20:1 with out damage due to a lean condition. HAVE YOUR MACHINE DYNOTUNED PROFESSIONALLY FOR THE RATIO YOU LIKE TO RUN AND YOU WON"T GET HURT.

 

Detonation is a real problem with two strokes that many people aren't aware of. Their is a world of difference in a two stroke having 9:1 compression and a four stroke with the same ratio. The two stroke is more easily damaged from detonation and needs fuel with a higher flash point. Avoid 93 octane if you can help it. It is killing your motor. Like it or not you need race fuel for that thing.

 

However read this post on another website for some good info on the proper mixing ratios:

 

Two Stroke Mixing by someone who knows what he is talking about

 

I agree with the Klotz post: That oil is by far the sweetest smelling oil when it burns and I love getting behind someone when they are using it. My preference is Yamalube. I never foul a plug with it and you can buy it by the gallon for around 20 bucks.

 

A good point in all this is this: If you change your pre-mix ratio you may need to adjust your jetting.

Good to point that out. I do disagree that a "stock" banshee for the most part is 100% om on 93 Oct.

I would say race fuel would be a bit of a waste. But to each his own... It cant hurt and smells good!

Link to comment
Share on other sites

thanks guys alot of good advise there.

 

I run the Amsoil at 60:1 because at 50:1 (what the bottle recomends) I was getting wet/black plugs. Since then I have rejetted at the same mix 60:1 and it runs really good.

 

I think I will try the 93 on the next tank. I am going to the Rumble On The Ridge next weekend and wanted to check this out before I went.

 

So if I bump the timing +4 will the 93 still be OK?

Link to comment
Share on other sites

thanks guys alot of good advise there.

 

I run the Amsoil at 60:1 because at 50:1 (what the bottle recomends) I was getting wet/black plugs. Since then I have rejetted at the same mix 60:1 and it runs really good.

 

I think I will try the 93 on the next tank. I am going to the Rumble On The Ridge next weekend and wanted to check this out before I went.

 

So if I bump the timing +4 will the 93 still be OK?

 

be ready for a melt down sooner or later with that ratio. might be ok for light trail riding , but if you start opening it up it will not be enough ! best of luck ,

but dont beleive everything you read on bottles.

f.u.i. --> so you know black and wet plugs are not from your ratio, its because your bike is too rich , not because your running to much oil !!

if almost everyone is using 32 to or richer why would you think 60 to 1 is ok? (thats a wead wacker ratio)

Link to comment
Share on other sites

thanks guys alot of good advise there.

 

I run the Amsoil at 60:1 because at 50:1 (what the bottle recomends) I was getting wet/black plugs. Since then I have rejetted at the same mix 60:1 and it runs really good.

 

I think I will try the 93 on the next tank. I am going to the Rumble On The Ridge next weekend and wanted to check this out before I went.

 

So if I bump the timing +4 will the 93 still be OK?

 

93 oct on +4... I'd keep an eye on it. Also I agree 60:1 even with a good synthetic oil??? I wouldnt

risk it... I personally run 32:1 and am jetted accordingly...

Link to comment
Share on other sites

ya, think I may drop it to 40:1 to be safe. I think I was miss lead by the bottle and other advice. However, I have seen a dirtbike that ran the same oil at 100:1(yes 100:1) for years. I hope I will not need to rejet again. If so anyone know where I an get Kiehin jets like RIGHT NOW?

Edited by boneyardbanshee.
Link to comment
Share on other sites

ya, think I may drop it to 40:1 to be safe. I think I was miss lead by the bottle and other advice. However, I have seen a dirtbike that ran the same oil at 100:1(yes 100:1) for years. I hope I will not need to rejet again. If so anyone know where I an get Kiehin jets like RIGHT NOW?

 

rejet and go 40 to 1 and you will be good to go ..

Link to comment
Share on other sites

ya, think I may drop it to 40:1 to be safe. I think I was miss lead by the bottle and other advice. However, I have seen a dirtbike that ran the same oil at 100:1(yes 100:1) for years. I hope I will not need to rejet again. If so anyone know where I an get Kiehin jets like RIGHT NOW?

jeff at F.A.S.T has all the jets you need

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...