The Namesake
- Thread starter skiroule
- Start date
I can't believe how much difference it looks with just a few parts installed for "morale " purposes!
Quick question Kelly, If you need to change a belt, is it difficult? Do you have to take anything apart? Looks a lot different than modern sleds...... by the way they(modern) look different from 10 years ago too and you need tools to change them also!
skiroule
Well-known member
Kirk, the belt change is super-easy, no tools or foul language required.
mike1970 and euphoric1, I did manage to make some smoke in the shop today. Started the RTX for the first time with a tank fuel supply. Fired right up but it’s not quite time to break out the good beer.
It won’t idle below about 4500 RPMs, which would indicate that it’s pulling air from somewhere. I’d always been a little suspicious of the fact that there were Permatex remnants along the crankcase seam, like someone had tried to seal it. Question is, did they take it apart to do this or just try a superficial application because they knew they had a problem?
Tore down my “practice motor” and found out there is NO gasket between the case halves so the motor shouldn’t need much in the way of help to get a good seal. Looks like there’s a good chance it’s crank seals on the sled motor.
So….the bottom end will have to come apart. It will set the project back some and there’s probably no pony in the poop pile but there are some positives: It runs, the top end didn’t grenade so that looks OK, the clutch looks like it works as intended, and the running gear got a good run-out.
Once I get to it, the repair isn’t an insurmountable task, should be able to get it done this month if I can score some shop time. I already pulled the clutch – (one of biggest problems with crank seal replacement on these old motors).
This all begs the question, why didn’t I tear down the bottom end in the first place? I’m told that I was dropped on my head as a very small child but I doubt there’s any connection.
mike1970 and euphoric1, I did manage to make some smoke in the shop today. Started the RTX for the first time with a tank fuel supply. Fired right up but it’s not quite time to break out the good beer.
It won’t idle below about 4500 RPMs, which would indicate that it’s pulling air from somewhere. I’d always been a little suspicious of the fact that there were Permatex remnants along the crankcase seam, like someone had tried to seal it. Question is, did they take it apart to do this or just try a superficial application because they knew they had a problem?
Tore down my “practice motor” and found out there is NO gasket between the case halves so the motor shouldn’t need much in the way of help to get a good seal. Looks like there’s a good chance it’s crank seals on the sled motor.
So….the bottom end will have to come apart. It will set the project back some and there’s probably no pony in the poop pile but there are some positives: It runs, the top end didn’t grenade so that looks OK, the clutch looks like it works as intended, and the running gear got a good run-out.
Once I get to it, the repair isn’t an insurmountable task, should be able to get it done this month if I can score some shop time. I already pulled the clutch – (one of biggest problems with crank seal replacement on these old motors).
This all begs the question, why didn’t I tear down the bottom end in the first place? I’m told that I was dropped on my head as a very small child but I doubt there’s any connection.
Actually, I WAS DROPPED ON MY HEAD as a small child. And as long as we're sitting around the wood stove drinking beer, here's the story. I had tonsillitis at an early age, while being placed under with anethesia, I managed to crawl or fall off the table landing on my head. This being prior to the age of litigation, the Doctors simply put me back on the table and went to work with knife & saw. Went home the next day with a sore head and sore throat. I think they felt bad though, afterwards they gave me all the ice cream I could eat.
Now back to Skiroule and his leaking Crank Seals....
Well Kelly that's too bad on the high idle problem. You could spray the clutch side crank seal with WD-40 and see if it changes anything? I always turn the idle screws down as far as I can on Mikuni round slide carburetors. This allows the pilot system to operate correctly and doesn't create a opportunity for the main circuit to supply fuel. It also helps the choke circuit.... of which there are lots of different variations on how the choke gets set based on carburetor size.
As far a case sealer, I will use something every time, either Yamabond or similar, just a light bead and wipe off excess before mating the pieces. Torque the bolts down and let is set up for 24-48 hours.
Best of luck with the latest glitch!
As far a case sealer, I will use something every time, either Yamabond or similar, just a light bead and wipe off excess before mating the pieces. Torque the bolts down and let is set up for 24-48 hours.
Best of luck with the latest glitch!
Yamabond, 518 flange sealer or if you know a Stihl dealer near you Dirko sealant is another good crankcase sealer. has to be a good feeling knowing it runs! too bad there wasn't smellovision on this site, can see the hue of two stroke in your pic now only need the smell...love it!!
skiroule
Well-known member
Yes, I agree that this is a good starting point. In this case, the idle screw had virtually no effect. In fact, full choke wouldn't kill the engine - had to put my hand over the carb to kill it (no wiring yet to kill the ignition). There's a major air leak somewhere.
Thanks guys for the recommendations on sealers, this is the kind of info I need. I'm in uncharted waters here with the crankcase work. Yamabond seems to be way to go so I ordered some, should be here by the time I'm ready for it. Yeah, I had er' smoked up pretty good in there, really cleans out the nostrils. Have a good fire going today so when the shop is up to temp (-9 air temp up here this morning), I'll start the tear-down process. I'm half-apprehensive and half-curious about what I'm going to find.
skiroule
Well-known member
I tore into the sled motor today and got the bottom end taken apart. I’m not sure whether it created more answers or questions. Before I even split the case, I saw oil seepage behind the stator plate. It looked like it was coming from between the seal and the case and not the crank. Not right in any case (no pun intended).
Once apart, there was a lot of oil on some of the mated surfaces and between the mag side seal and the case. Some of this could have happened during disassembly but I don’t think that explains it all. The oil is most likely oil that was poured in the engine for storage but it should be staying in the engine until it is all burned off.
It also confirmed my suspicion that the gasket sealer was simply applied around the perimeter or the seam and not on the mated surfaces. Sure looks like a band-aid attempt to me.
I’m not sure what I have here but I guess all I can do is put it back together with new seals and seal the case per the recommendations from you guys and keep my fingers crossed.
For now, I’ll just clean it up and wait until the Yamabond arrives.
Once apart, there was a lot of oil on some of the mated surfaces and between the mag side seal and the case. Some of this could have happened during disassembly but I don’t think that explains it all. The oil is most likely oil that was poured in the engine for storage but it should be staying in the engine until it is all burned off.
It also confirmed my suspicion that the gasket sealer was simply applied around the perimeter or the seam and not on the mated surfaces. Sure looks like a band-aid attempt to me.
I’m not sure what I have here but I guess all I can do is put it back together with new seals and seal the case per the recommendations from you guys and keep my fingers crossed.
For now, I’ll just clean it up and wait until the Yamabond arrives.
At least you should keep some refreshments close by, alcohol is a good cleaning solution!! It removes any fingerprints.
If oil was poured into the engine, and said oil level was above the seal (or any hole where fasteners attach), it could have seeped through to the area you mentioned. Unless you find another scenario that makes logical sense, I am guessing that is what happened.
If oil was poured into the engine, and said oil level was above the seal (or any hole where fasteners attach), it could have seeped through to the area you mentioned. Unless you find another scenario that makes logical sense, I am guessing that is what happened.
skiroule, do you have a pressure/vac tester? those older engines are not difficult to block off intake and exhaust ports and put some pressure and pull some vac and check the integrity of the crankcase seal and crank seals before you just drop it back in the chassis and assume the air leak has been stopped. I have no doubt you will have taken care of leak but just to cross your t's and dot your i's since you are at this point due to a known air leak.
skiroule
Well-known member
The seepage thing on the seal may have happened but I’m thinking it shouldn’t have. It seems like the seal should have been good enough to keep the oil in the engine.
I have a mystery for you guys:
Cleaning the case today (saving the alcohol for a better purpose), I discovered brown sealant in the bolt holes of the case. The only way it could have gotten there is if it was applied to the machined surfaces around the bolt holes and oozed in, so it looks like it wasn’t just an outside surface application.
So where did it go? There was none on the machine surfaces when I separated the case. It’s like it vaporized. For fun, I tried cleaning up some of the remaining sealant with gas. It removed the sealant, no problem. It seems bad that someone would try to seal a crankcase with something that could be dissolved by gas. Is it possible that the sealant dissolved over time and possibly caused a bunch of small leaks in the seam? Especially if the case halves were originally torqued down with a layer of sealant between the halves.
The sealant looks like the old-school brown Permatex I used on stuff when I was much younger. I don’t remember ever using where it came into direct contact with fuel.
skiroule
Well-known member
I do not have one. I should put together some kind of leak-down test kit for checking these old cases. I guess the trick is to get it built and installed correctly so I have confidence in it not producing false leak readings. It’s a long shot but I’ll do some checking around town and see what I can find.
I’m thinking optimistically here so I’m moving on with making one good wiring harness out of these two while I’m waiting for the sealant to arrive.
skiroule (Kelly?): FWIW, way, way back,when I first saw just the title of this thread last year I thought you were going to be writing about a new made-in-Japan sled,
The "Namesake" (Na me sa ke): ナメサケ(Katakana) なめさけ(Hiragana). or 鮭 (Kanji) = "Salmon"!(?)
Fortunately this thread turned out to be far more interesting than that would have been!
The "Namesake" (Na me sa ke): ナメサケ(Katakana) なめさけ(Hiragana). or 鮭 (Kanji) = "Salmon"!(?)
Fortunately this thread turned out to be far more interesting than that would have been!
skiroule
Well-known member
Since I always appreciate a mildly warped sense of humor, this gave me a good laugh.skiroule (Kelly?): FWIW, way, way back,when I first saw just the title of this thread last year I thought you were going to be writing about a new made-in-Japan sled,
The "Namesake" (Na me sa ke): ナメサケ(Katakana) なめさけ(Hiragana). or 鮭 (Kanji) = "Salmon"!(?)
Fortunately this thread turned out to be far more interesting than that would have been!
Only Mr. Nash could pick up on this but now that you have, there will be many times I will look at this thread title and think: “The Nam-eh-sock-kee”. No doubt it will bring a smile each time.
I don't have a answer for you on the brown case sealer Kelly, but my guess is somebody used whatever they thought would work. I have heard that the sealants back in the day weren't always effective, heck maybe someone used plumbers sealer on it! I guess it gives a clue that someone has been inside the motor before for repairs, but it could have been 30 plus years ago.
When you're sealer arrives, the trick is to use enough to get the job done, and not have excess squeeze out INSIDE the case and just hang off the surface where it can eventually fall off into a running engine! A little is okay, just don't go overboard and make it ooze out everywhere.
When you're sealer arrives, the trick is to use enough to get the job done, and not have excess squeeze out INSIDE the case and just hang off the surface where it can eventually fall off into a running engine! A little is okay, just don't go overboard and make it ooze out everywhere.
Here you go, 1973 Namasaki.
(Actually a 1973 Honda)
Now that would be cool retrofitted with an 800cc engine. Does anyone out there actually have one of these? no wonder why Honda never ventured into the snowmobile industry...What were they thinking?