This sled is in the process of another rebuild. Seven years of trail riding since the first restoration has taken it's toll. The chassis has some cracks that need to be welded and it will be re-painted. The rest will need a general cleanup as well. The engine has been running great and will just get a cosmetic refinishing of the tins etc.

Here is a neat piece of history on this sled. The original customer half of the warranty registration card.

A great piece of documentation confirming that this is a "numbers matching" sled.

The CCW would not idle right. It would only idle at a speed fast enough to engage the clutch. Any lower and it would eventually die. This seemed curious to me as it had run fine at the Eagle River show in September. Swapping carburetors and using fresh gas did not help, so I tried spraying starting fluid at the PTO seal. Sure enough, the engine speed picked up slightly, indicating a bad seal.

I tore the engine down, and the PTO and mag side crank seals did not look that bad, pretty good in fact. No visible damage to them and they fit reasonably tight around the crankshaft, The center seals on the other hand were terrible. I seems as if they had shrunk, with a big gap around the crankshaft on both. Luckily I had a NOS crankshaft on the shelf, so I put that in. This time I used new Winderosa seals on the ends instead of the original NOS seals as I had done with the previous crankshaft. The Winderosa seals have a double lip instead of the single lip on the originals.

When assembling the engine I noticed the fan bearings were tight, so I replaced those. They had been replaced three years ago with bearings salvaged from a used engine, so it does not surprise me they were going bad. This time I purchased new bearings from McMaster-Carr.

Piston clearances were still .003", same as the day they first went in four years ago. More evidence that the Amsoil Saber 100:1 premix oil is doing it's job. The cylinder walls were quite dark so I honed them lightly to remove any glazing. I have read that this can be a problem with some synthetic oils.

I removed the cylinder heads and exhaust manifold from the CCW to check on piston and cylinder condition. Everything looked good. No evidence of detonation on the piston crowns, no scoring or other damage on the cylinder walls. The color is darker than I'm used to seeing though. No evidence of blow-by looking through the exhaust ports. There is minor carbon buildup on the heads and piston crowns, but I can still clearly see the markings on the pistons.

This engine ran two seasons with Klotz Techniplate oil at 40:1, then ran Amsoil Saber for two seasons at 80:1. At least judging from the condition of the cylinders, there appears to be no problem running synthetic oil at these lean mix ratios. I have read that synthetics may deposit a film on bearings and cylinder walls. This may account for the dark appearance of the cylinders and I'll have to keep an eye on this in the future.

This pinging in the CCW is driving me absolutely crazy. Here's the saga this season. I mixed up the Amsoil Saber at 80:1 and put that in the tank at the start of the season. No other changes since last year. The first three rides were great. The engine never ran better, and no detonation whatsoever. My "temperature gauge" (how hot the plug insulators are when I unscrew them with my fingers to check the plug color) told me the engine was running much cooler. Problem solved I though, but noooo. The ping came back... arrgggg! Fooling with carb mixture settings on one ride, I figured out it was running lean in the mid-range. I had been richening up the high-speed needle hoping to help the ping, but that just made the engine run doggy, and I was thinking the poor performance was from overheating. What I found was, leaning the high-speed back to a more normal setting resulted in good performance and no pinging at full throttle. The engine seemed to be running lean in the mid-range only. I dismantled the carb, cleaned it out, and reassembled. The last ride of the season it performed great again.

Turns out the pinging did come back last season. Not to the same extent as before, but after several miles of riding built up some heat in the engine, it was definitely there once again. I'm going to try Amsoil Saber 100:1 premix this season to see if that might help. I've heard nothing but good things about Amsoil products. I've discovered the local Citgo station has a pump with 110 octane leaded racing gas. As a last resort I may try some of that $3.50 per gallon go juice. The CCW burned up a set of fan bearings last season. She was overheating real bad on a long ride. The last 15 miles or so was... ride a couple of miles... shut it off for 15 minutes... ride a couple miles... etc. etc.

I'm looking forward to the Scorpion Reunion in Crosby Minnesota on February 5th. I hope the old Scorp is running good, but even if not, it should be a good time.

The mystery noise in the CCW has been (fingers crossed) vanquished! It was apparently spark knock or preignition caused by a lean fuel/air mixture after all. During the first ride this season, the noise was still there. As noted below, the knocking would go away from about 3/4 to full throttle, and was most noticeable under light throttle at low to mid-range speeds. Not typical conditions for preignition. I noticed the spark plugs were burning pretty white, indicating a lean mixture. I tried to alleviate this by richening the main needle on the Walbro. No change at all. From one turn to four turns open, no difference whatsoever. Obviously something is wrong with this carb. So I cleaned out another recently rebuilt WDA-2 I had lying around and installed it. End of problem, at least as of today. It sure feels good to hear that CCW singing again.

I've had a custom seat and backrest made by John's Upholstery in Sanborn, MN. It's made of red metalflake vinyl that is very close to the original. You really can't tell the difference unless you put the material side-by-side. Of course it's not molded like the original. John sewed in the pleats and also a Scorpion logo I designed. While it didn't turn out quite like I had hoped, it will make for a good seat I can use when riding. I'm going to save the original for show use.

I got a deal from Dennis Kutz I couldn't pass up. A full set of NOS bogey wheels. There was some corrosion on them from storage. I cleaned them up as best I could and clear coated with Glisten PC. While I had the suspension out, I repainted the weldments and springs with Por 15. The paint I had put on them during the restoration did not hold up well at all. Much of it had chipped off.

I cleaned up a set of NOS 1973 cadmium plated skis and clear coated them with Glisten PC as well. They'll be my show skis for the time being. I'll continue to use the late model black skis as my riders.

The engine woes continue. The rebuilt CCW runs fine, but after it warms up it makes a sound like pebbles being blasted at a piece of tin, or like something is rattling around inside the engine. It does not sound like the obvious detonation I experienced last year. In fact, the noise goes away under full throttle and is most pronounced under light throttle and deceleration. It seems to get louder and more frequent the hotter the engine gets. I pulled the heads and there was no damage visible at all.

I rode the sled without a helmet while sorting out some other problems. That really changed my perception of the noise, and leads me to believe it could be coming from the clutch, even though I've tried two with the same results. I've mounted a Duster clutch, but it looks like I won't have the opportunity to try it as our snow is all gone.

The original motor rebuild is complete, and it actually fired up on just a couple of pulls! In addition to those mentioned above, thanks to James Swanstrom from Brainerd, MN for the NOS Wiseco pistons and rings. The crankcase did have some shrapnel in it so it's probably a good thing I went ahead and replaced the crankshaft. Other parts replaced were points and condensers, fan belt, and cylinder cover. The cover came from the Sport Shop (Todd Yancy) in Bonduel, WI.

The cylinders for the original CCW powerplant have come back looking good from Irondog (Jerry France) in Cleo, MI bored .020 over to fit the Wiseco's.

I was very excited to locate a NOS crankshaft assembly for the CCW, including seals and bearings. It looks to be in near perfect shape. Thanks to Dale Storch of Stetsonville, WI. I was contemplating not touching the original crankcase, but with this piece in my possession, I can't help but put it in. Might as well go ahead and replace as much of the ignition as I can find also. I should have essentially a brand new engine in the Scorpion for next season. After the trouble I've had with the engine in it now, that should be one less thing to worry about.

I managed to burn a hole in the left piston while on a trail ride. Fortunately, I was within sight of the trailer when it happened. I was able to limp back on one cylinder. One of my parts engines graciously yielded a perfect cylinder and piston to replace it. After putting it back together, I went for a ride and can still hear detonation under load. About the only thing I haven't checked for a source of the trouble is a leaking crankcase seal. Time to park the sled for this season.