You would be correct we are using the hole as the point for the pick upOriginally Posted by Tim Ey
L-Plate Rider
You would be correct we are using the hole as the point for the pick up
Highway Biker
Any ideas on adding a floor-port with a cylinder fed cylinder to extra feed the boost port I presume?
See it on honda mb's for instance?
Forum whore
The floor port on an MB has nothing to do with feeding the boost port.
It is just adding intake area not masked by the piston moving up and down in the intake port.
It works the same as Boyesens,but doesn't badly affect the B port duct flow like they often do.
An MB has a good cylinder boost port in that it has proper front and back walls to direct flow, not just a roof and the piston face
like many simpler designs.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
L-Plate Rider
So I was bored at lunch today and decided to make a mock-up Ryger-style stepped piston for my dead RM60 cylinder (43mm bore). Of course, it's just a display piece as all of the drawings posted so far have been garbage. It makes me curious if homemade pistons are a viable option for race engines. I normally buy forged pistons but I have a lot of this 6061 aluminum laying around. Could I possibly make my own in the lathe to try different crown shapes or will anything I make just destroy cylinders?
PS - Yes, I know the picture is blurry. My phone doesn't have adjustable focus. And yes, I know the lathe work is bad. I made it by hand. Normally I'd CNC this sort of thing.
Highway Biker
Makes sence, tnx.
Don't have the mb cyl at hand but saw pictures. Anyway, 2 points why they wouldn't work for the litlle tomos then, lol. Making an utterly detuned engine behave like something you want without changing revs seems not as easy as one might think... getting engmod to show it maybe even harder.
Fun none the less
Forum whore
Plenty of people have made their own, if you have the alloy and some machining equipment, then its worth a try....It makes me curious if homemade pistons are a viable option for race engines. I normally buy forged pistons but I have a lot of this 6061 aluminum laying around. Could I possibly make my own in the lathe to try different crown shapes or will anything I make just destroy cylinders?
Hardcore Biker
These was some discussion about two-part pistons made by makr that you may find interesting:So I was bored at lunch today and decided to make a mock-up Ryger-style stepped piston for my dead RM60 cylinder (43mm bore). Of course, it's just a display piece as all of the drawings posted so far have been garbage. It makes me curious if homemade pistons are a viable option for race engines. I normally buy forged pistons but I have a lot of this 6061 aluminum laying around. Could I possibly make my own in the lathe to try different crown shapes or will anything I make just destroy cylinders?
PS - Yes, I know the picture is blurry. My phone doesn't have adjustable focus. And yes, I know the lathe work is bad. I made it by hand. Normally I'd CNC this sort of thing.
http://www.kiwibiker.co.nz/forums/sh...tuner/page1433 #21486
He used 6061 and 2024 but suggested that 4032 may be better, this has higher silicon content and lower thermal expansion than 6061.
Hardcore Biker
if you find any tricks, please share. I'm trying the same thing with a Honda Sky moped for motorcross and I to can hardly increase the rev's (max about 8.500-9.000 rpm).Makes sence, tnx.
Making an utterly detuned engine behave like something you want without changing revs seems not as easy as one might think... getting engmod to show it maybe even harder.
Fun none the less
curently using 180/130° timings, squish area of 50%, compression of 11.7 and managed to keep the same bottom end, and better from 30km/h (haven't got a dyno, use a GPS tracker for comparisons) and gain 12km/h on top speed.
fun indeed, and very cheap
L-Plate Rider
Thanks. I read that post some time ago and completely forgot. There's so much info on this thread that it's hard to keep track. Somebody really should organize this into a book or at least make a contents page (with links).
Also, in regards to all this ignition wiring talk... I should mention that there might be some benefit in wrapping your own coils. I have friends who race electric RC cars and many of them will vary the amount of windings or the gage of the wire to perfectly fit the power output desired (while trying to prevent those little DC motors from overheating). The same goes for converting your crank rotations into electrical current. If the coils are wound more than what you require for power generation, I'd imagine you are sacrificing some hp into wasted magnetic resistance. Some time ago I added an extra pickup coil to my KX85 to power a headlight. I never had it dyno'ed but I'm pretty sure it cost my engine a fraction of hp. Probably pretty small but everything counts at the track.
Highway Biker
Gaining top speed wasn't to hard (with upping the revs ofcoarse but managable) and I think a better exhaust wil make a huge difference as wel but it's the low end I'm strugling with. There is a huge difference in running cold and warm/ hot (AC) and I'm trying to figure out how to minimize that without different cooling but by changing port timing, crancase volume, com etc. Driving away seems to be influenced the most and I can only wonder how things will be in hotter wether. It does do this stock as well but to a lesser degree.
Since my timings are pretty low, even 'tuned' 157 109 I was thinkng maybe higher timings would work giving the piston less exposure time to the heat and longer cooling from incomming mixture and perhaps upping the crankcase volume and softening the reed but engmod doesn't seem to agree, that could be my model tho. How much influence the a/f mixture has in this case I'm not sure, kind of hard carb to deal with aswell since it is the simpelesed of simpelesed dellorto sha but tunable none the less, only have to figure out how it reacts to what (airbox mostly). And only having a but dyno doesn't help things but ah well, fun and games.
I'm not sure how well these bikes would translate to oneanother btw.
Hardcore Biker
Here you go!
Hardcore Biker
For possibly the ultimate in IM-proper ports, you should get to see a late-Sixties/early-Seventies Johnson/Evinrude outboard triple of 55-60hp, maybe that company's first loop-scavenged engine: very big bore and short stroke (and short rods) with the two big transfers (the 55hp) and the equally-large boost port (the 60hp) looking like they were just scooped out of the cylinder walls; could make you barf!! But OMC sold them in huge numbers for years, even with a factory racing version.
Hardcore Biker
Here's a different approach to getting the crank's balance factor right:
http://www.accessnorton.com/balance-...st-t16773.html
Forum whore
I used to fit a piece of wire somewhere to the bike and watch in which plane it vibrates as the engine slowly climbs through the revs, but your scratch method is nice.
I may have to borrow your wife though.What do you mean by wet and dry?My motor is now balanced at 65% wet (72% dry)
Your scratch circles may be a good indication that the vibrations are equally strong in vertical and horizontal directions. But is that what we want? Horizontal vibrations are less disturbing to the rider, so you would have to go for horizontally-elongated ellipses. And then the question remains: how severely elongated?
Hardcore Biker
I should probably have said; Here's one approach to visualizing the balance factors effect on directional vibration.
I just provided the link, not my work and not my wife.
I think these cranks are oil filled in some way.
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