[md86]

Well , I used 93 when I shoulda been using 87 for about half a year , and you shoulda seen the carbon in my head . IN fact .....

http://www.katriders.com/forums/viewtopic.php?t=16671

But then , I think that was just one contributing factor . OBVIOUSLY , that one cylinder had problems . But it's been theorised that it HAD problems because of carbon in the first place , so .... don't waste money on high-octane unless you're sure you HAVE to .

[thecynic]

Do those gas treatments really work for getting rid of excess carbon in the combustion chamber?

I mean i'm running stock exhaust/air filter/jets with 10k on the bike, but it's always useful to know down the road as i'm sure i'll bugger it up sooner or later.

[The CyberPoet]

I beleive what you're buying is leaded fuel... AvGas at 117 normally is. And it may be laden with MTBE as well (it has to be laden with some oxygenator to reach octane numbers higher than 100). Don't be surprized if your engine doesn't seen the next 1000 miles.

So are his valves and guides going to hell?

Well, you got a bunch of different factors at work.

The most damaging one in the short term would be the high concentration of oxygenators that have to be in the fuel for it to be 117 octane -- these are forms of oxygen bonded as part of the liquid which will turn back into a gas during combustion to fuel the combustion event with more air. That alone induces three big problems in this kind of quantity:
1. Jacking up the combustion chamber pressure from the introduction of the additional gas pressure when the oxygen unbinds from the liquid.
2. The combustion temp is controlled primarily as a factor of the oxygen content -- adding in a bunch more oxygen will up the combustion temps drastically (possibly even enough to melt the surface of the aluminum at these concentrations, depending on what oxygenator was used in the mix). And if any of the fuel isn't vaporizing fully when it gets into the chamber, I'd expect to see pitting on the piston face.
3. The engine's cooling system (SACS) isn't designed to deal with removing this quantity of localized heat build-up, nor with the total heat being generated. Thus I wouldn't be surprized if the oil is literally losing it's viscosity in short order from thermal breakdown... and we know where that leads.

Then you can add in all the ill effects of using leaded fuels in an engine specifically designed not to use lead fuels. It's been a long, long time since I dug into an engine that ran leaded fuel but wasn't designed to (since it's been so long since gas stations offered leaded fuels) so I don't remember all the details (aside from the obvious one about catalytic converters getting coated and not working -- but that's not an issue on a 49-state Kat). Whatever the effects would be, it would be slow, because the amount of lead in the fuel isn't all that high (don't expect overnight changes).
Oddly enough, the one time that leaded fuel would be reasonably beneficial would be during engine break-in (because the lead deposits act as a cushion on engine parts), but still only in the recommended octane ranges (no running 100+ octane in the Kat during break-in in any case!). The question there would be whether enough lead would be deposited during the first few hundred miles to actively make any difference.

Cheers,
=-= The CyberPoet

[Anonymous]

117 octane in a kat with 11:1 compression even my 16.5:1 ratio honda doesnt need that it runs just fine on 100 octane when will people learn higher octane dont do a flocking thing for ya but waste money you need compression for octane higher the compression the higher the octane all the higher octane does it burn slower yes thats right slower hence the need for higher compression the higher the compression the more bang it makes but lower octane fuels will actual ignite under higher compression too fast sometimes prior to the plug even firing so the higher grades have a higher resistance to igniton so to speak so they can be fully compressed and then the spark plug can do it job and make a very large and powerfull boom so unless you got a 15:1 compression kat motor jsut use 89 that more then enough

[loudnlow7484]

I was wondering, actually, what octane would you need to use with the Wiseco 771 kit? I believe it's 13:1.

[spiral]

Be careful of the high octane.My buddy ran "Turbo Blue" in his harley and melted the piston to the cylinder wall .To much heat for the cast pistons.I guess it could have been because it was a "Harley" .It only lasted about three or four weeks after he started using it.

[The CyberPoet]

I was wondering, actually, what octane would you need to use with the Wiseco 771 kit? I believe it's 13:1.

Super. 91 - 93 octane at sea level is what a 13:1 engine needs at torque peak (which represents maximum compression ratio at the cylinder) to avoid predetonation.
If in doubt, check with WiseCo for their advice.

Cheers,
=-= The CyberPoet

[lowster11]

Thanks for all of your replies, I've only done this 3 times and will stop now . This forum is great, do to the fact that nobody actualy called me a dumba**

[thecynic]

Thanks for all of your replies, I've only done this 3 times and will stop now . This forum is great, do to the fact that nobody actualy called me a dumba**

It's ok to melt your engine, as long as you're wearing the proper safety equipment.

[thecynic]

And I've had to come on here and shame myself with dumb questions. It's what happens when you buy something and want to know how it works. We've all been there. Hope you stick around, there are lots of cool things you can do to that bike if you're into turning a wrench and swinging the deadblow hammer.

[lowster11]

Just pulled my plugs and they are clean and new, that's a good sign!!

[illinoiskat]

One of the advantages of lead in fuel is to pad the hitting of the valves. The lead in the gas would actually soften the hit and pro long valve stem and seat life back in the day. Modern materials dont require the lead. Thats why my uncles say dont buy a car until 3 years after the catylitic converter was put in.

[The CyberPoet]

Thanks for all of your replies, I've only done this 3 times and will stop now . This forum is great, do to the fact that nobody actualy called me a dumba**

No need for us to -- you're already busy calling yourself one right now.


Live and learn.
For the record, at & below 100 octane, the lower the octane level, the more powerful the fuel is. You should be running plain old 87 standard gas here in Florida -- although a brand with more detergents in it is a good habit.

Cheers,
=-= The CyberPoet

[lowster11]

Thanks for all of your replies, I've only done this 3 times and will stop now . This forum is great, do to the fact that nobody actualy called me a dumba**

No need for us to -- you're already busy calling yourself one right now.


Live and learn.
For the record, at & below 100 octane, the lower the octane level, the more powerful the fuel is. You should be running plain old 87 standard gas here in Florida -- although a brand with more detergents in it is a good habit.

Cheers,
=-= The CyberPoet

You're funny, but I think you got it backwards, the higher the octane level, the more power the fuel is!!

[Court93kat]

Nope... he had it right. Lower octane is more powerful. Do a search on here. They have discussed it in depth at the molecular level as to why and how.

Cyber does his research.... find something to the contrary if you can. Good luck.