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I am not familiar with VP 110. I am familiar C-12 though. It is an excellent fuel that is very stable at high rpm + it has a lot of lead... Just because the gas can says 110 or whatever... Doesn't mean it is 110 octane gasoline! C-12 for example is only 109 when compared to what you buy out of the pump. Like I said 110 fuel=17cc domes, 100 fuel=19cc domes. This should put you far enough away from the deto zone to be safe. There is no free ride with horsepower though! Compressions ratios w/17cc domes are going to be a lot harder on your engine than what you will see with 100 octane type compressions, plus higher compressions are much less forgiving to "mistakes". Personally, I consider 100 octane compressions a really good recreation type set-up. Some of the guys I ride with run 18cc domes with 100 octane 50/50 blended fuel without problems. I run an OEM head with the equivalent of 18.25cc domes on straught 100LL avgas, no problem. I am also very carefull with jetting, timing, fuel quality, engine temps, etc. Some of those other guys I wonder about sometimes... Probably just a matter of time for a couple of them??? Try this link http://www.dmperf.com/fuel_brands_and_octane_ratings.htm Probably more than you ever wanted to know about gasoline :geek:

What I was saying: If your running an otherwise normal 350 with typical whatever type cylinder porting, typical whatever brand tuned exhaust, etc. and 19cc head domes... and the rider dosn't weigh 400 or 500 pounds... and your not towing your broke down buddies bike with him sitting on the back of yours... or other wise doing something stupid... Then 100 octane is plenty good even a couple hundred feet above sea level at Glamis. In fact your motor will probably run noticably stonger w/19cc domes on 100 than it will on 110 since you will, in all probability, see noticably higher combuston chamber pressures on the 100. Drop a set of 17cc domes in there if you want to run 110... You'll spit less unburnt fuel out the exhaust port that way as well as get a fairly large hosepower increase to go along with it. Check it out yourself. Take a can of 110 and a can of 92, see how it runs on straight 110. Then drain the tank and blend your 110 and 92 to get the 100 and see how that works??? Report back with your findings... :biggrin: :cool:

Assuming your not running some huge bore or something and have ported, but otherwise unmolested, OEM cylinders... And using a compression ratio figuring 19cc domes rather than a gauge reading... Your totally safe with 100 octane fuel. In fact, your not anywhere near the edge... IMHO

Sounds like your running a stock head? If your not happy with sprocket changes, might consider bumping up the compression ratio?

Never mind... Was looking at the pics in the post below yours DUH! My mistake, sorry for any confusion... Europe uses a RON rating for octane, if thats the case with your fuel it would be equivalent to our 94 or 95 octane PON. Plenty good for 20cc domes even with 45 deg. air temps.

motor builder, where do you usually ride at? Ever make it down south coast?

Ahh man! Don't let all this spook you. Bottom line is that if your comfortable on your current set-up (stock stroke) with whatever type riding your doing and nothing else changes other than a +4mm crank, you will probably love it! 4mm added stroke in and of itself is not all that! It's all the other stuff that usually goes along with it (higher compression ratios, porting, carbs, pipes, etc)... It aint cheap! And don't forget rider ability (see comfort level above) that has a whole lot to do with it also... Thus my earler loop-de-loop post, because I don't have any... Found that out a couple months ago Good luck

Unless you have some other reason to suspect ring sealing problems I would pretty much disregard the low pressure gauge readings. That both cylinders blow the same kinda tells me that everything is good??? 20cc domes on 92 octane doesn't leave much room for error IMHO, so 90 octane is probably not a very good idea, again JMHO. Personally, I would take the octane booster and carb cleaner $$$ and put it toward better fuel or a set of 21cc domes. I've been using 100LL avgas off and on for 20+ years in all types of 2-stroke engines and have never had a problem I could attribute to fuel or noticed any excessive carbon build up or anything else unusual for a leaded fuel. Other than the lead deposits I am kinda at a loss as far as the avgas/carbon connection... Where did you get that info? Last I heard, the FAA doesn't have much of a sense of humor when air planes start falling out of the sky

Ahhh! The wheelie part is fun... It's the unexpected rear wheel hookups and subsequent high speed loop-de-loops that suck!

Just a heads up... Leave the edges on the neutral cog somewhat sharp (like the pic) or neutral is hard to find :cool:

IMHO, slobanshee06 pretty much nailed it... With your weight and type of riding I would probably go a little conservative on the durations. T-5's make peak horse power at apx. 8900 rpm with very little over-rev. A 190 deg. exhaust duration with an appropriate time area should work with that rpm and your weight. Higher compressions allow a little more aggressive exhaust port durations/power curves and blow down timings. But, in general, blow down timing should be in the 30-36 deg. range with the lower values for lower compressions and/or heavier riders. What octane fuel and head dome volume you planning on?

Like I said the C/F reeds were not on a Banshee motor. Fact is they were in case reed motors, Banshees don't expose the reeds to that kind of crankcase turbulance... Still, for what I am currently doing, the Boyesen's work pretty good so why bother... I also like the Chariot head shells. Only problem I have had with them is the color I wanted last time was "out of stock" ... Had to get a red one... LOL!

Yup I like the snappier throttle when the carbon fiber is new... The snap just doesn't seem to last long though. And then theres the multiple times C/F reeds have come apart on me at high rpm... Although the ones that came apart were not on a Banshee motor, just don't trust em anymore... Carbon Fiber... "Strong but not for long"...

LOL! Every time someone says "shave my head" Its WTF??? Whatever!

Yeah, you might be getting close to that cranks "estimated economic life" LOL! Only way to tell without splitting the cases is to visually inpect the big end rod bearings under magnification for pitting or scoring. Check the rod side clearance to see if the thrust washers are beyond spec. And last but not least check the top of the piston and head (especially around the intake side) under magnification for signs of a main bearing or seperator coming apart. magnification will reveal tiny little pits where the surrounding metal is pushed out and up (cratered) from a speck of hard metal hitting the aluminum.

These reeds right here http://www.boyesen.com/cwo.php?store=boyes...;product_id=171 will do you. I run them in my own bike... on edit: Per my previous post... It is better to error on the side of caution with dome volumes, if you know what I mean!

IMHO there is very little performance difference between an aftermarket dome and a similarily designed and re-cut OEM casting. Either would produce a similar compression ratio, thus similar horsepower and MSV numbers. And both will generate similar combustion chamber temps. Billet aluminum does transfer heat better than cast aluminum however. And the larger surface area of an aftermarket head shell will improve heat transfer to atmosphere. It is a relatively minimal difference though... Again JMHO If the head will be removed on a regular basis or will see high compression, aftermarket is a no brainer. If it's just going to see pump gas and cost is an issue, cutting an OEM casting might be something to consider???

Your 98 RON would be the same as 93 or 94 U.S. Just use one of the octane charts like this one http://adaracing.com/all/head-kit-yamaha-b...llet/yb350hdkit to to figure it. Near as I can tell, the closest you can get and be 98 RON safe would be 21cc. IMPO, you could probably get away 20cc domes as long as you were very careful about keeping fresh fuel in the tank.

Just a "heads up"... Gasoline octane in Europe including Great Britian uses RON whereas, in the U.S. we use PON. In short, our 87 octane gasoline is the equivalent to your 91 or 92 octane petrol. Something to keep in mind when choosing a dome volume maybe...

What he said... Shouldn't be having problems with new gaskets!

Put it on +4 and no worries... Get an aftermarket head or get your stock head milled by someone competent for an even better hit than what the timing advance will do for you.

I ended up w/the 10 deg. filters and machined about 3/32" off the bottom of the intake to angle everything down a little more.

PM sent...

I've got a mild mannered red and white 1987 that looks bone cold stock except for the T-5s and the front end up in the air all the time :ermm: None of those names sound familiar, I am pretty new around here though. I do hit Parkers fairly regular and usually unload at the first staging area in Horsefall next to the campground. I've been dabbling with Banshee motors for a while now... And since Oregon Dunes NRA is right up the road a ways... LOL! Sold my machine shop when we made the move here, kept enough stuff to motor work though. Need something to do around here when the sky starts falling in the winter Send me a private, exchange contact info or something...

LOL! I have always called it case porting... I've also heard it refferred to as case blending, case matching, case blueprinting... Then there is a thing called case tunnel porting and several other things that can be done to reduce low pressure areas and increase volume, flow and atomization while your there.