Well I have been on a lonnnng vacation from riding the Raptor since I have been focusing on my car and recently started wondering about this.

I know that the opinion on the Sparks timing advance is that basically there are minimal benefits from running it on a stock or modded machine. Now here comes my question. I know that in theory added timing=added power, but only to a certian point where the engine isn't getting any knock. Well what if with the timing advance key in the Raptor you run a higher octane fuel to reduce the chance of knock, would there be any added benefit to the key if you ran it along with say 100 octane gas?

I ask this because I had been riding my Raptor around with 91 octane in it and then added in some of my Torco race fuel that I use in my car which should have bumped it up to somewhere in the 100 octane range and I swear the thing felt much stronger. Now I guess it could have been all mental but who knows. Just wondering.

Mods to the machine are just GYTR carbon fiber exhaust, Dynojet kit, no lid, Sparks timing advance key and Barnett Clutch.

Tim

 

Well then whether you advance the timing 5 degrees or 10 degrees your saying octane wouldn't matter at all? So for that matter you could advance the timing 20 degrees and get the same results as if you advanced it 5?

I guess what I'm asking is when does there become an adverse effect to advancing timing, and what is that effect? Because it must not be knock if octane makes no difference.

Sorry if the questions are dumb, its just I'm coming from the mentality of a vehicle with automatic knock senseors and computer controlled timing.

Tim

 

You can put so much timing into an engine that it won't start. On an adjustable advance, you can run retarded at low speeds (like starting) then advance quickly. You don't have this option with fixed stock ignitions which have narrow advance curves. Basically, as long as you keep it from spark knocking by adding octane, you can advance it until it kills the engine. However, here are my thoughts on it:

Large single cylinder engine takes a while to thoroughly burn the fuel charge and higher octane burns slower (the reason you can run more timing), so you will want more timing. However, this is in the perfect world. As you add weight (if the bike isn't lightened or you are a big boy like me), you want to figure in some retard in the timing. Remember, at the exact time you make peak power, you want to slowly start retarding. Doing this will give a flat spot in the curve and actually extend the powerband. This advice will only work with adjustable timing. With the key, you are still limited by the stock advance curve.

I personally don't like the idea of mixing pump and race fuel. They have a tendancey to seperate, plus you aren't sure of the exact ocatane. I loved the 110 Torco when I ran it, but I have switched to B32 now.

I will be ordering the banshee Dyna ignition next week, and I will let everyone know how it works. I have been happy so far with their technical assistance.

 

How can gas seperate? Oil and Water, yes. Gas is all pretrolum and it will mix. Two stroke oil and gas don't seperate.

Could you clarify?

Thanks

Smitty

 

When I built my original 250x with a big bore at 10.5:1, I was planning on running 93 octane pump. When spark knock was detected, I mixed half and half with 108 Turbo Blue. Fired the bike up and it ran great. The next day I started it again and it ran poorly at first, but finally lined out. When I got back to the shop, I noticed the jug of gas had seperated with the turbo blue on top. I have heard of others having this problem (always with Turbo blue now that I think of it), so I just won't chance it.

 

<< Two stroke oil and gas don't seperate. >>




yes they do, if you let them sit they seperate. every time i grab my can to fill up i shake it. have you ever took your float bowl off after you quad sat all winter?

 

CT330

Honestly I don't have that much experance with two strokes. My buds Banshee goes though it to fast to notice. LOL I guess if you left it long enough it would. HHHMMMMM something to check out.

ALky,

You noticed this only with Turbo Blue fuel? Mu understanding of Gas is it's all hydrocarbons and they should mix and stay mixed in a homoganus (sp) state. What do they add to it that would cause this?

Learn something everyday.

Smitty

 

I really don't know what causes it, but I have seen it happen.