Back to the Polaris

I got an email from longtime reader Vanessa a couple weeks ago. Her Panther 303W had no spark so I sent her my procedure for cleaning points.
In a nutshell: Get a can of Caig De-oxit, open the points, squirt in some de-oxit, let it sit for a minute, pull strips of paper through until they come out clean, repeat.
Vanessa replied that she got spark bag and now has a running machine, sweet, score one for the good guys!
So yesterday I decided I'd get a snowmobile running, we really don't have any snow and theres none in the forecast (50s tomorrow...) but what the heck, maybe the snow gods need a sacrifice.

This is my '79 Polaris Cobra 340. When I first bought it there was no spark, I cleaned the points and got it running, then a couple years later put in new crank seals. This one has always been a little finicky to start if its been sitting awhile and since I didn't run it at all last year I knew it was going to be a challenge.

Right off the bat no spark on the mag side so as you can see in the picture I proceeded to clean the points which resulted in? No spark at all...

Rats.

This sled has always been sensitive to plugs and it uses B8ES which I don't seem to have in stock. I'm going to order a box of them this time...

Good and good

So the snow-quester was a washout in DC but it hit north central MA pretty good. We got our 4-6 inches of wet sloppy snow. After work Friday I rushed home and fired up the mighty Polaris Cobra. It starts kind of hard so I'm guessing it needs a little more carb work but its good enough for now. I rode around the Pantera a little to pack down the snow then got that sled uncovered and started and into the garage where I pulled the carb AGAIN. I hate doing a job over again but I clearly hadn't done a good enough job last time. This time I remembered my carb cleaning rods and rodded out every jet. I found a big chunk of schmutz in one of them which was comforting. Its a little un-nerving when you clean and don't find anything obvious. With the carb reinstalled the sled fired right up and idled perfectly.

After having such success with the carb I replaced one of the hood hold down straps, it'd broken a couple years ago and when I ordered new points for the Cobra I noticed replacement straps and ordered a set. Surprisingly the bolt holding the broken strap came right out, I thought it would fight me.

The replacement strap is very tight, with any luck it will stretch a little. Because of that and because the other side isn't broken I left it alone, I'll keep the other strap in reserve.

The oatmeal like snow we've got is not great for the Pantera, its short track wants to dig and slip on the ice under the snow, the Cobra's long track rides up better than the Cat. That said you can better your sweet whatever I'm going to get out and ride, fresh snow this late in the season is a gift I'm not going to turn down. As soon as I post this I'm going to cut the old sticky hitch off my snowmobile trailer, run to the parts store and get some bolts for the replacement I'd bought before Christmas, with that installed I'll need to figure out how to load the sleds alone which is a challenge but I think I can use the snow bank to my advantage...

Closing in on the finish

Headed out to the garage tonight all ready to pull one of the carbs and clean it within an inch of its life. I decided I'd start with the mag side and pulled the choke cable. Thats when I noticed how little slack there was in the choke cable which prompted me to remember how the choke lever had felt weird yesterday. I pulled the other cable and it seemed short too. I followed the cables back to the lever and found the back had popped off and pulled back on strangely so the choke was always half engaged. Got that re-arranged, got the cables back in place, fired the sled up and it still ran like crap. For some reason I kept it running and after maybe a minute it make a little noise and idled perfectly!

I think that yesterday in running with the choke on I'd loaded some gas into the bottom end of the engine and what I saw today was that burning off and once it did the sled running right. It was late when I started so I didn't want to run the sled too much, make a bunch of noise and piss off my neighbors but I'm pretty pleased.

Unfortunately I noticed the headlight is out, I put my trouble light on the line to the seat and it lit up so either the bulb is burnt out or disconnected. I wouldn't be surprised if its burnt out.

Anyway I decided that since the carbs don't have to come off (probably) I'd put the seat on. That was an exercise in frustration. Here's a free hint that I should have already learned from farting around with the Ski-Doo, test fit the plywood before attaching it to the seat. I didn't make the cutout at the front deep enough or wide enough. Now I need to take the seat apart again, recut the base and reattach. I'll definitely trial fit the base before I reattach the foam though!

Anyway, getting closer, nearly there!

One other note on brakes

I got chastised by the boys around the table of truth over on the Yahoo Group "Vintage-Snowmobiles" for adding DOT 4 brake fluid in my Cobra. Apparently it originally came with DOT5 and as DOT 4 and DOT 5 are not interchangeable or even compatible my using DOT 4 is bad mojo. I'm reasonably sure what came out was DOT 4 as one of the guys says DOT 5 is usually tinted.

Anyway on Saturday I picked up a bottle of DOT 5, they sure don't give that stuff away! I pulled the drain at the caliper and mopped out the master cylinder. Then I refilled with DOT 5 and left the plug out of the caliper until only purple DOT 5 ran out. Its handy that its tinted... With any luck since I only topped up with DOT 4 it won't have had time to hurt anything.

This whole incident makes me wonder if the leaking brake on my TX-L was inadvertently caused by my use of DOT 4...

Straighten out!

Dug into the steering on my '79 Polaris Cobra today, the tie rod was bent badly:

It was a bugger to get out, had to shift the engine out of the way... I bent it back straight using an old brake disc as a mandrel and my 3# hammer to finish it, got it pretty good but apparently forgot to take a picture.

Installation was no big deal and I moved on to welding up the turn stop. It'd been welded, maybe several times before and I had to grind off a lot of old weld. Then I learned what the last welder knew, its a hard spot to weld in, the engine is really in the way, this is something that should be done with the engine completely out of the sled. Anyway I got it welded back on, its such an ugly job I won't post a pic, just know that its there!

So finally all ready I took it for a shake out ride before installing the seat and found its bogging badly on the low end, won't idle good once it warms up either and when it quits won't restart unless I hold the throttle wide open. I'm guessing I didn't get one or both of the carbs clean enough when I cleaned them. Interestingly this is similar symptoms to my Pantera. I'll have to pull the carbs and do a better job this time...
I also noticed that the sled doesn't seem to shift gears, which is to say it doesn't seem like the secondary clutch is opening. That said its really hard to tell what with the short space I've got to run it in my yard and the problems with the carbs. The secondary moves, I've had it open a couple times to remove and re-install the belt. I'll lube it good and see if that helps.

Oh well, one step forward, one step back. Fortunately we're closing in on the finish!

Take a seat

The seat on my 1979 Polaris Cobra was basically trashed. The cover had pulled back from the base which is a pretty common problem, and the sled had been left outside. That had caused the foam and wooden base to get totally saturated with water. I let it sit near the woodstove for a few days which got it basically dried out but the wood base was totally ruined. So I got a sheet of 3/8" plywood (which will help me with the '70 Ski-Doo as well) and cut out a new piece. Its actually a fairly complicated shape, it needs to fit around the light assembly at the rear and then around the lip that holds it up front. Plus there need to be two holes to attach at the rear. I painted the whole thing in a thick coat of black Rustoleum which makes it look original and should protect the wood. If I get another 30 years out of it I'll be satisfied. :)

The original base was molded into the foam so getting them apart without destroying the base (which I needed for a pattern) took some doing. When done I'd cut the foam in a couple places. I glued those back together and then glued the base onto the foam to keep them from sliding apart. Finally I wrapped my new seat cover over the top and stapled it to the base.

I bought the seat cover on eBay and I'll warn you that there are 2 versions, 1 is black, one is blue. I didn't notice that until I'd bought and received the black one. The original cover was blue. At this point after I'd cut the cover to make a hole for the taillights I'm not going to spend the money to get the correct one, after all it gives me a story to tell.

Anyway, once I get the rest of the sled completely ready (which means fixing the ski that only makes right turns) I'll mount the seat, but at this point I'm so close to being done I can taste it! If we only had some snow...

Whoops!

After coming to grips with the grips I decided it was a good time to take the Cobra for a rip around the yard. I'd had a little difficulty getting it started but considering it'd never really run enough to warm the engine up properly I'm not really concerned. This would also be the first ride since freeing up the brake, on the maiden voyage the sled was dragging badly because of that brake.

So the good news is with the brake released everything feels pretty spritely. The bad news is this:

Turns out the stop which should keep the ski from getting into that position is broken. It looks as though it was broken and rewelded poorly at some time in the past. Further forcing the ski back into place has bent the tie rod so that the right side ski is perpetually turning right. I'll have to fix the stop and straighten or at least shorten that right side tie rod to fix it.

On another note the seat is nearly ready. In getting the seat foam dry I finally had to resort to ripping the plywood base off. It was soaked and badly degraded. I got another sheet of plywood (which will help me with the Olympique too), cut and painted the base. Now I'm just waiting for it to dry before I finish. I'm debating gluing the base to the seat. Not sure what to do about that.

BRAKES!

Got to spend some time in the garage the other night, one of the problems with the '79 Polaris Cobra is the lack of brakes. The brake caliper on this system has 2 pads, one the caliper pushes against another which stays still in the caliper. Polaris has long used hydraulic brakes and in this case the driven pad is hydraulically actuated and on my sled that pad was stuck.

I found that using a big screwdriver I could pry the pad back away from the disc but when I applied the brake and the pad moved back in it would be stuck against the disc again. I pried and applied and pried and applied and while it seemed like it was getting a little better I wasn't gaining much.

Realistically I knew I needed to pull the caliper and properly clean everything. Unfortunately on this sled the brake caliper is attached to the chaincase inboard of the driven clutch. The driven clutch has to come off for this to happen and the chaincase has to come apart for that. I got as far as opening the chain case and pulling the chain and top sprocket before I gave up. Fortunately with the top sprocket removed the driven clutch can turn since you're not trying to push the track which helped with freeing the pad.

Finally in desperation I carefully squirted a little PB Blaster around the edge of the pad, now when I worked it back and forth I could feel it getting looser and eventually I could apply the brake and it would release easily. With that accomplished I sprayed some brake cleaner on the pad and disc so the PB Blaster wouldn't grease the brakes and everything seems good.

Its a good feeling to make progress.

Back from the dead

This blog isn't the only thing back from the dead, today I managed to revive the '79 Polaris Cobra!

Apparently my points cleaning was good enough, this afternoon I got some fresh gas, put the exhaust back in place, drained a gallon of varnish out of the tank, primed the carbs with a squirt bottle and it fired right up. Strangely I noticed I wasn't getting any gas from the tank, a little troubleshooting later and I found:

What you're seeing in my hand is the bung that goes in the tank. To the left there should be a piece of fuel line with a brass filter and check valve. The lack of fuel line means gas could only come out of the tank when it was full.. I took a run down to the sled shop to pick up some new fuel line and the check valve. With that installed and a little more prime the sled fired up and ran nice. I ran around the yard a couple times but its very warm and our snow is like oatmeal, very slippy and hard to ride on, fortunately the long track on this sled helps with that.
After my short ride I pulled in front of the garage and gave the sled a bath, it looks a lot better with the worst of the grunge off. It needs spraying down but my hose is unusable until spring. In the spring I'll wash it again and polish/wax.

Still on the to do list:
Free up the brake
Inspect the suspension - there doesn't seem to be any suspension travel at all right now. Considering how rusty the ski shocks are I suspect the skid shock is dead.
Recover the seat - I ordered a replacement seat cover on eBay
Replace the grips - Amazon is providing Polly Grips which are the same heated grips I had on my Centurion.

All in all not a bad day. If the sled still starts tomorrow I'll consider it a major win.

Bought another!

Well friends its been several years now since the Dead Sled Wrencher has bought a new machine but here we go again, once more into the breech!

My 37th birthday is coming up and I'd decided I was due a present, I'd found a '73 Pantera online but luck was not with me and it was sold before I could get to it. Then fate took me to the New Hampshire Snowmobile Museum classifieds just minutes after the posting of a '79 Polaris Cobra 340. I contacted the seller and we made the deal.

Thats a before picture in the seller's garage. The sled hadn't been run in a year which is no big surprise as we had almost no snow last year so the carbs will of course need to be cleaned. More vexing theres no spark. This is a magneto ignition sled which means breaker points. Back years ago lack of spark on a breaker points system was why I had to get rid of my '76 TNT so I'm a bit gun shy...

Over the next two days I spent about 4 hours cleaning, cleaning, cleaning the points and managed to get spark so last night I pulled and cleaned the carbs, they were as nasty as any I've ever seen.
With that done its all ready to start I just need to go get some fresh gas and give it a try.

A few other notes, the seat cover is ruined, fortunately theres a seller on eBay who is manufacturing new covers. The grips are for a dirtbike or ATV, I plan to replace them with Poly Heaters. I had a set of those on the Centurion and although I never wired them up for heat they were comfortable grips.
Finally theres no speedo, the seller supplied one but no cable or speedo drive, again theres one on eBay. That said I'm not buying anything more until I'm sure the sled will run...