porting cases

[FireHead]

I'd think Oringing the bottom of the jug would make setting squish just a bit tougher, though....

 

Properly designed, an o-ring should not add and thickness to a mating surface. If you were to be designing such a sealing system, you would operate under the assumption that there is metal to metal contact between the cylinders and case. The worst variation that I had wgen assembling the particular motor that I did this to was about 8 microns. You really have to pay attention to the properties of the o-ring material you are using when sizing the o-ring groove. Otherwise, like you said, your squish band will be near impossible to set accurately and because the clamping force available is less than ideal, you may get a leaky joint.

 

I never had any trouble with the motor that I did this to. Would I recommend that someone else do it: no. Is there any advantage to going this over making sure that a gasket is used properly: not really. I no longer have this motor by the way. It left in the old white bike I had. I put that motor together when I was going through dome dort of phase where I thought I was going to gain a huge amount of power from keeping the air going from the crank case to the cylinder at a fairly constant velocity approaching Mach1. If the guy that bought the engine from me ever has to to any major work to the engine, he is going to pretty much have to buy a whole new engine (yes, I explained that to him when I sold the bike). I fooled around with alot of crazy things on it, most of which did not show any increase in performance. It was alot of fun though. :geek:

[BigRed350x]

Properly designed, an o-ring should not add and thickness to a mating surface. If you were to be designing such a sealing system, you would operate under the assumption that there is metal to metal contact between the cylinders and case. The worst variation that I had wgen assembling the particular motor that I did this to was about 8 microns. You really have to pay attention to the properties of the o-ring material you are using when sizing the o-ring groove. Otherwise, like you said, your squish band will be near impossible to set accurately and because the clamping force available is less than ideal, you may get a leaky joint.

 

I never had any trouble with the motor that I did this to. Would I recommend that someone else do it: no. Is there any advantage to going this over making sure that a gasket is used properly: not really. I no longer have this motor by the way. It left in the old white bike I had. I put that motor together when I was going through dome dort of phase where I thought I was going to gain a huge amount of power from keeping the air going from the crank case to the cylinder at a fairly constant velocity approaching Mach1. If the guy that bought the engine from me ever has to to any major work to the engine, he is going to pretty much have to buy a whole new engine (yes, I explained that to him when I sold the bike). I fooled around with alot of crazy things on it, most of which did not show any increase in performance. It was alot of fun though. :geek:

 

You sound kinda like me... I've done some crazy shit to my engines before just experimenting. Some of them I loved some of them destroyed cases and cylinders and such... I figured some stuff out with the transmission that I love and still do to this day. Ruined 3 shift drums and a bunch of forks figuring it out but once I got it down its pretty easy to repeat now. I did my transmission stuff to my new yesterday and finished up this morning and took it out for a ride at KP this afternoon and noticed a world of difference in how it shifted.

 

...but yeah, I've had to scrap a few sets of cases and cylinders from messing around with ideas that I thought might give me a little edge. Some of my ideas have, some of them have taken the edge away. LOL

 

- Jared

[FireHead]

You sound kinda like me... I've done some crazy shit to my engines before just experimenting. Some of them I loved some of them destroyed cases and cylinders and such... I figured some stuff out with the transmission that I love and still do to this day. Ruined 3 shift drums and a bunch of forks figuring it out but once I got it down its pretty easy to repeat now. I did my transmission stuff to my new yesterday and finished up this morning and took it out for a ride at KP this afternoon and noticed a world of difference in how it shifted.

 

...but yeah, I've had to scrap a few sets of cases and cylinders from messing around with ideas that I thought might give me a little edge. Some of my ideas have, some of them have taken the edge away. LOL

 

- Jared

 

I haven't really gotten into making too many transmission parts yet, but I plan to at some point. My triple is taking up most of my free time the I can stand to spend desgning or machining.

 

The engine that I spoke of earlier was all stock except to the rotating assembly, crank chamber, and cylinder sleeves. I lost that engine several times on the dyno while I was figuring out how not to make cylinder sleeves. Hanging rings and aread of concentrated heat were the modes of failure that I had the most. I think I made a few sets of pistons for that engine that wound up being turds as well (some were turds by design and some were turds due to some half-ass machine work). I don't think I lost any crankshafts or rods due to their own failures with that engine if I remember correctly. The morale of the story is that I think I wound up making about 80hp out of that engine in it's final revision and it looked completely stock on the outside with the exception of the coolhead. I never could get a stock head either rechambered or machined to take removable domes to cool properly. :shrug: