TOPIC:

to start the topic off, what do you run in your bike? what has ran crappy in your bike and what has ran good

be sure you have your cc's and compression listed or in your sig.

my compression on my 1170 should be 10.25:1 even though my pistons look like (see pic) is it possible i could run half and half leaded 100 octane to help the valve seats and other parts?


Post edited by: themachine, at: 2007/06/26 21:39

Post edited by: themachine, at: 2007/06/26 21:39

Post edited by: themachine, at: 2007/06/26 21:41

I'm lost, in this day and age where do you find leaded gas to begin with???
Ride safe

They sell lead additive in a can.

91 should be more than adequate dependng on actual numbers from compression test.your motor has hardened valve seats so lead additives shouldnt be needed;)

en.wikipedia.org/wiki/Tetra-ethyl_lead

as a rule with iron headed water cooled motors you'll need about 10 points of octane for each point of compression, ei; 9 to 1 will need around 90 octane, 10.25 about 100, this will vary with the type of head and cooling. Water cooled aluminum heads can get by with about 1 more point of compession. Air cooled hemi heads (KZ heads) would be about as poor as it gets, (sorry but true) and that's why the newer bikes and cars use the "pentroof" head, more compact and the flatter the combustion chamber and the flatter the piston top the less octane per points of compression, henc the newer motors can run 11:1 on 91 octane, and our old motors with a high piston domes can't. Most motors can take some detonation and survive, but if you start to break the centers out of your spark plugs or blow head gaskets it's time to lower the compession or run higher octane gas, as you'll be breaking upper ring lands soon. Forged pistons will take more abuse but will eventually break too. Be sure to get rid of any sharp edges or carbon build ups in the combustion chamber as they create hot spots and will start detonation. nothin to it!

I put another base gasket (total of .050") on mine to lower the compression so that I can run pump gas without a booster. (have used 104+ in the past with some luck)

Post edited by: Z1R rider, at: 2007/06/27 17:47

I had a discussion with a mechanic not too long ago regarding some of this and was curious about some of it.

According to my owner's manual (the one that comes under the seat) unleaded 87 octane is supposed to be what to use.

The engine pings sometimes, although I have de-advanced it five degrees.

It's stock at 9.5 compression.

The mechanic told me fuel today is not as high octane, even though the pump says the same number.

What should a compression reading show on an otherwise good 650 motor?

Not trying to redirect the thread.

Just trying to find out about proper fuel.

As far as i know japanese manufactures have a stelite coating on the surface of the valves so you do not need to run a lead additive, and you should be able to run super unleaded of a good quality without any problems!
Thats my two cents worth

did you bore the stock 998 sleeves to 1170 or use some 1089 sleeves or ???

how thick are the sleeve walls now?

Post edited by: Duck, at: 2007/06/27 19:39

dont use the lead or octane additives, they dont stay suspended in the fuel, and you could have a major failure

I think we have some aviation members here who could verify this, but can't you get 100 octane low-lead at a local airstrip. That's what the piston planes use.

Wirewulf wrote:

I think we have some aviation members here who could verify this, but can't you get 100 octane low-lead at a local airstrip. That's what the piston planes use.

differant rating system