There's a guy lives local to me with a race shop in town who preps rally cars incl at least one top Subaru. Next time I see him I'll ask...Originally Posted by Flettner
I was going to ask if there'd been any interest from the speedway guys.
Low personal B.M.E.P.
There's a guy lives local to me with a race shop in town who preps rally cars incl at least one top Subaru. Next time I see him I'll ask...
I was going to ask if there'd been any interest from the speedway guys.
Forum whore
Huh they might be interested, but I'm not
Muddler/Dabbler.
Great achievement on your part though, but when you look at it, the two stroke still reigns supreme from your point of view and wins hands down on the power to weight ratio!,Huh they might be interested, but I'm not
Pity about the prejudice which is still there with bikes and other road vehicles, not being helped by the bad press generated by the recent attempts at "world beaters" like Suter etc. - which don't seem to have solved many of the main problems of the two stroke!
Strokers Galore!
still basking in the glory..
would you like to replace the cam belts on that!!!! shocking..
Low personal B.M.E.P.
Seen - and worked on - worse than that. What I don't like is the use of what look like std belt tensioners. Ducati get away with a much simpler adjustment.
What size plugs are in the 2 plug heads ? If they're 10 or worse, 8mm plugs I can understand the expense going up....
Forum whore
8mm
I don't remember what the tensioner was off, not Subaru though.
Low personal B.M.E.P.
Shit, that's what ? around $350 worth of plugs....
Just as well they weren't radio suppressed ones too.
Forum whore
About, I guess.
Ta
Have you not had the pleasure of buying Yoshimura spark plugs mate? $350...each.
Forum whore
Which reminds me of the market vendor who sold little plastic bags containing apple pips.
A man stopped to ask about their purpose and the vendor explained that eating these pips would enhance the consumer's intelligence. So the customer bought a bag, containing five pips, for ten dollars.
Half an hour later he was back, shouting: "Wait a minute! Ten dollars would have bought me thirty apples; that's over a hundred pips! Whereupon the vendor replied: "See? it's already working!"
Ta
Yoshimura plugs are bike specific. They sink as close as they can to the piston crown with a flat face. Pretty good way to raise compression and stay inside the rules of any class.
Low personal B.M.E.P.
Many years ago - around 1987/88 - when we were running the alky burning GSXR1100, the local NGK agents offered us "the plugs they use on the IOM in GSXR's" Apparently the altitude changes on the IOM made it a bit hard on plugs so NGK had come up with some specials...
When they told us $160NZ each, we declined with thanks.
Plain NGK 10's worked just fine thanks. At about $4NZ each...
Hardcore Biker
Cuppla days ago, in response to Wobbly’s discussion to core reshaping on ESE, I said that not only could cores be rubbed, but also added to. Then I thought that I’d give it a fresh go with an old shell core.
So, just pre-heated up the core a little with an LPG flame, and then sprinkled a layer of new shell core sand on, softly heating up each layer by wafting the flame over til the colour became a mustard yellow and then repeating this for subsequent layers. With more heat & time it could be baked further, but this is quite adequate to achieve sufficient strength for casting. I had to build it up this way, as shell core sand is basically like dry sand, whereas CO2 sand is sticky, it could be manually built up to a desired level/shape prior to CO2 gassing.
After doing a few layers, I could easily pry these off as a single biscuit. I then roughened up the surface of the original core, even with some small undercuts, and this held on tight.
After cooling, it was easy to file and reshape as was the original core. Not the way for high production, but well adequate for development purposes.
Anorak
Tigs is for pussies
Kinky is using a feather. Perverted is using the whole chicken
Hardcore Biker
The top surface pattern for the replica Webco Yamaha 125/175 cylinder head in Renshape 472 is off the mill as of noon today. The draft angle is 1 degree, the fins are 2.25" tall, and there is a .125" radius for the gullet between the fins.
I took notes on what was happening for future reference as I sat watching it, waiting for the inevitable crash that surprisingly never arrived.I did have a near "ooops" when I had the post file modified to pick up a different toolchange coordinate, and didn't think that I only wanted it to pick up X and Y coords and not Z, as Z for a tool change is always at the Z home position. Z home's position will vary in the different world coordinate systems depending on the location of Part Zero. But I caught that in time and modified the post to give me an M25 command (go to Z home) instead of picking up the unused Z coordinate parameter (default of 0) in the "set an alternate tool change location" screen.
All in all, I'm quite pleased with how the Renshape 472 worked. You'll notice slight cusps or tool tracks in the photos but the largest of those are .001", and most are visual marks that I have trouble distinguishing with a fingertip. I will need to do some gentle scuffing with some fine Scotchbrite or similar product to blend those very small discontinuities, so I did not achieve a "hands free" pattern.
I took a lot of notes and learned some useful stuff. For example, I started at the top with a .062" step down, and then reduced that to .04" and .025" as I went to longer and less stiff end mills. At the first tool change I was very pleased with how smooth the surface was with the large step down. When I checked the next section with a smaller step down I was even more pleased with it as it was smoother (as was the final and smallest step section). But that made me want to have used the small step down all the way through! I tried redoing one fin but that was a bad idea due to the small cut (.0005" approx so probably more rubbing than cutting) and the fin being much more flexible since it was nearly cut free, so I stopped. I'll have to do a little more scuffing on that fin, though it is still only a slight change to the surface.
To avoid snapping fins as I did with the first attempt in wax I roughed the outside and the 5 inside pockets, and then largely finished the pockets (inner ends of the fins) so there would be minimal side force seen on the finish cuts. Then I did a parallel finishing operation on the tops of the fins and the corner radii, and horizontal finishing in layers from that point on. At the end I did some engraving operations to clean up some spots that were needing a small cusp removed.
I think after the blending a light coat of pattern lacquer will make any minor discontinuities invisible.
This has been a long process because I hadn't used many of the 3D machining operations (mostly I've done 2.5D projects) and had to figure out which ones to use and how to configure them. There were also spots where I had plunge/transfer speeds much too slow and speeding those up would have saved 1+ hours of "moving through air not cutting anything" time.
Now to see if I can finish and pull a rubber mold from the patterns without damaging them in the process, and then cast urethane patterns to use as the working tool.
cheers,
Michael
roughing:
roughing:
end of first .062" step down operations:
finished but no hand work:
finished but no hand work. The outside fin is the one I tried to remachine for a smaller step down and you can see the stop point half-way down that will need a bit of blending.
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