They had a Reed Fed Cylinder on a 292 Single in the 70's. "VINTAGE 292 RACE PIPES
We have two pipes available for the popular 292 Yamaha single engine. The full race pipe is developed for modified Oval racing and delivers 70 HP at 9000 RPM with Full Race Porting, Reed Valve intake and a larger Carb. We also have a milder pipe that is turned for 7500 RPM and delivers 50-55 HP depending on Cylinder Porting. This pipe is very popular in One Lunger Sno Cross Enduro Races or for Vintage Trail Riding and Restorations."
Some good views of the 70's Yamaha 292 Reed Fed Cylinder Single apart. You can see it has better Porting than Skidoo's Singles.
Skidoo made a Prototype Rotary Valve Single (78mm x 70mm) 334.6cc, 39hp in 1969 with just a Muffler that never got put into Production. Basically, Half a 670 that came out in 1992, 23 years later and made Stock [email protected] There were Small 354 & 454 Rotary Twins released that put them in the winners circle. The 1971 Blizzard 340 Single was the Highest Production HP released Factory Single at 36hp for Skidoo. That 1969 Rotary Valve Single with a Good Tuned Pipe would have been around 58hp at Sled 7750rpms! At Ultralight 6500rpms around 45-47hp with a Tuned Pipe.
I had a chance 3 years ago to buy one of these 292 Yamaha Sleds that was For Sale close by me, whole Sled for $400. Wish now, I had went and looked at it. There is two different Yamaha 292's, a Reed Fed Cylinder, and a Piston Port Cylinder.
==================================================I was drawn to this very interesting thread as I myself am looking to make a single cylinder 2 stroke crankcase out of some 3" thick mic 6 aluminum plate(good choice?)
I presently have a 2 hotsaw build on the go. One is a 1982 YZ125 engine hotsaw I originally built 36 years ago. The other is a 1983 Honda CR250R .
The 125 stock in the motorcycle puts out over 30 hp and the Honda over 40hp.
I am building the saws both with carbon fiber and titanium grade 5 fasteners. They both will be running Mikuni 38mm SBN PWC carbs and tuned cone exhaust pipes.
I have CNC made drive sprockets made for them to drive their sawchain. They both have PVL bi directional analog ignitions.
The YZ125 has road race porting at 202° exhaust/137° transfers.
The Honda is mild at 182°/126 but will be raised to 191°/130° with 29.31blowdown. HP will be over 50 at 8K rpm.
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Yes these saws are used for speed bucking competition.==================================================
Do you run this Chainsaw as a Water-Cooled Cylinder or do you fill the Cylinder Water Jacket with something? I take it you use this in some Chainsaw competition event. I know in the 70's they used to fill Drag Race Engine Blocks with some form of I think Expoxy about halfway to Stiffen the Block. I got a 550F Reed Fed Cylinder I want to try mating to a 277 Case, or Old Skidoo Single Case. I haven't been very ambitious lately, the wife is taking me to Flordia for two weeks, now that the Snow has melted and I can get out in the Shop. Block of 6061 for a future build.
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===============================================================Yes these saws are used for speed bucking competition.
I leave the cylinder water jackets empty. We only run them WOT for less then 10 seconds so no worries about overheating, even better when running methonal fuel.
I may have to put some 1750F high heat JB Weld epoxy in the Honda CR250R water jacket when I raise the exhaust port 3mm. I have room to spare but if I do grind through into the jacket I may have a problem.
I have no idea how the JB weld will hold up. Would you suggest laying a thin sheet piece of stainless steel or copper over the hole then put the epoxy on top?
Another question I was looking into building a crankcase for a newer CR250 cylinder out of Mic 6 aluminum cast tooling plate.
I see you use 6061 plate, is there any real advantage using Mic 6 as they say it's tension free ?
I can see the 6061 would be much stronger though.
===============So after more research the cement / iron filler is not the proven choice for a cast iron liner cylinder with aluminum water jackets.
Devcon liquid aluminum 10710 will be my choice with a .500" layer of 2400F rated JB Weld extreme heat on the bottom of the water jacket directly over the exhaust port.
The trick with stiffening up the cylinder with a epoxy filler is a torque plate or the head should be torqued down before it hardens.
Good idea to torque the cylinder base down too.
Machining like boring or honing can be done after it hardens completely.
Again torque plate used when boring or honing.
There is some amazing new 2 stroke big bore cylinder technology come out of the CP Industry plant.
Big resurgence in resurrecting the 2 stroke performance line.
Yes the Devcon is lighter then the water it replaces but weight is not my concern.===============
Is there a Weight Difference in Block Fillers? I would Ceramic Coat the Piston Top, Head Combustion Chamber, Cylinder Exhaust Port, and Exhaust.
That's a good question James.Don’t want to be stupid, but could you mix aluminum powder with epoxy for use to fill the water jacket? You could use just enough epoxy to allow the mix to fetgle onto the area that you want to fill.
just a thought.
Yes I've have had good success with regular JB Weld over the years. One project is almost 40 years old and the JB is still holding strong.FWIW, regular JB Weld is OK up to 650*F.
I've used it in VW cylinder heads, repairing 'overzealous' porting and polishing.
No, not in the combustion chamber, nor the exhaust port.
============================================Yes the Devcon is lighter then the water it replaces but weight is not my concern.
From my R&D the filler needs to be similar to the material that it is filling with the same heat expansion and dispersion rates.
Coatings? I'm looking at preserving my cylinder bore and porting with Nikisel.
Millennium Industries does great doing this and that is my plans. A professional Honda engine builder from California has special piston rings for Nikisel coated cast iron cylinder liners but I haven't committed to buying yet
Second, third opinions are always nice.
I don't know alot about ceramic coatings but I do know Yamaha tried it on their YZ stroke mx race bikes years ago. But I think they discontinued that.
Wossner and Wiseco are now using a black polymer looking coating on their race pistons.
I noticed the frying pan industry has done a similar transition.
That gold ceramic coating looks just like what my new aluminum frying pans coating.
===============================That gold ceramic coating looks just like what my new aluminum frying pans coating.
Cast iron sleeves or liners can be coated with Nikisel.
Today Millennium Industries is the leader in the new application process.
They don't even have to remove the sleeve from the aluminum cylinder.
This wasn't possible 5 years ago but they got it perfected now.
Customers no longer need to resleeve their cylinders when they get to the maximum overbore.
Expensive porting work on a damaged cylinder can be kept with a light bead of weld on a scratch, light bore and a fresh coat of Nikisel.