Pulled Warrior topend, lots of ?s

[fishx65]

New member here with lots of questions. I've had an 87 Warrior for about 10 years that I use for trail riding and hunting. It's in pretty good shape and I take really good care of it. I had the topend done when I first purchased this machine. This summer I started getting a little low speed knocking and it would smoke a little at startup so I just pulled the topend to check things out. Had a leaky base gasket anyway. Piston and bore look really nice but I'm gonna have them measured. Not so sure what to do about the valves. So, here are my questions:
1. What would cause the startup smoke? (Bad valve oil seal?)
2. Exhaust port is pretty carboned up so I've been scrapeing and wire brushing the best I can. Is there a better way to remove carbon from the port?
3. The head and cylinder were painted black from the factory but now most of the paint is gone. Can I have them sandblasted? Should I even bother repainting them? Engine paint or exhaust paint? I do want it to look good.
4. Think it's a waste of money to have a complete valve job done with new springs and valves?
5. Think the low speed knock was Piston slap? Would it show on the piston?

Any tips and things I should get done while I have this thing apart would be great. The bottom end seems pretty solid so I think I should be good to go after this topend job. Machine has run perfect ever since I got it and was the same when I pulled the topend.

Thanks, FishX

 

[jasonp]

New member here with lots of questions. I've had an 87 Warrior for about 10 years that I use for trail riding and hunting. It's in pretty good shape and I take really good care of it. I had the topend done when I first purchased this machine. This summer I started getting a little low speed knocking and it would smoke a little at startup so I just pulled the topend to check things out. Had a leaky base gasket anyway. Piston and bore look really nice but I'm gonna have them measured. Not so sure what to do about the valves. So, here are my questions:
1. What would cause the startup smoke? (Bad valve oil seal?)
2. Exhaust port is pretty carboned up so I've been scrapeing and wire brushing the best I can. Is there a better way to remove carbon from the port?
3. The head and cylinder were painted black from the factory but now most of the paint is gone. Can I have them sandblasted? Should I even bother repainting them? Engine paint or exhaust paint? I do want it to look good.
4. Think it's a waste of money to have a complete valve job done with new springs and valves?
5. Think the low speed knock was Piston slap? Would it show on the piston?

Any tips and things I should get done while I have this thing apart would be great. The bottom end seems pretty solid so I think I should be good to go after this topend job. Machine has run perfect ever since I got it and was the same when I pulled the topend.

Thanks, FishX

1. Could be bad valve seal, rings/cylinder or worn con rod bearing.
2. It is the exhaust port so I wouldn't worry to much about it. You can buy some carbon cleaner that they actually inject into the engine while running. Just put some on there and wipe it off after a couple mins.
3. Beed blast or sand. Then high temp paint.
4. You should be able to go to the machine shop with the head and see what it needs as far as a head rebuild costs and if it even needs to be done or what parts need to be replaced. I think it would be worth it while you have it appart.
5. Yes if you know what to look for. Opon start up it is usally worst until the piston skirt expands and takes up the tolerance. I heard worn timing chains and bad adjusters sound like piston slap.
I personally if you got it all appart do a little upgrading while in your in there.

 

[fishx65]

Thanks Jason. I found a place that will blast the head and cylinder for 30 bucks. Sounds like they turn out so nice I may just want to clearcoat it. I'm gonna drop it off at a reputable shop and have them check to see if it needs a valve job. They are also gonna check the valve springs for me. Even though the piston and cylinder look good, I think what I heard was piston slap. I just read that you can really hear piston slap at low speed under a little acceleration. Probably worth doing piston and rings while I've got it apart. I just want to make sure I do everything while I've got it apart. Not sure what you mean by a little upgrading but I'm open for suggestions. I do some trail riding in the summer but use it mostly for scouting and hunting so I don't really need more power although, it would be nice. After doing some trail riding on a Raptor 660 last summer, the old Warrior isn't even fun on the trails. I satisfy my need for speed on the snowmobile!

 

[jasonp]

Thanks Jason. I found a place that will blast the head and cylinder for 30 bucks. Sounds like they turn out so nice I may just want to clearcoat it. I'm gonna drop it off at a reputable shop and have them check to see if it needs a valve job. They are also gonna check the valve springs for me. Even though the piston and cylinder look good, I think what I heard was piston slap. I just read that you can really hear piston slap at low speed under a little acceleration. Probably worth doing piston and rings while I've got it apart. I just want to make sure I do everything while I've got it apart. Not sure what you mean by a little upgrading but I'm open for suggestions. I do some trail riding in the summer but use it mostly for scouting and hunting so I don't really need more power although, it would be nice. After doing some trail riding on a Raptor 660 last summer, the old Warrior isn't even fun on the trails. I satisfy my need for speed on the snowmobile!

Like a higher compression piston and a little bigger cam.. the stock stuff is about just as much as aftermartket, if you were to go about replacing them. I would have them hone and put new rings in for sure. I would play around with the gasket thickness as well just for fun to raise the compression a little and give you a little more torque.
If you clear the head make sure it is high temp stuff otherwise it will just flake off.
Yeah piston slap you can hear more so when cold and changing engine speeds quickly. But if that is the case I would guess it is something more so like a timing chain just because if the bore was that far out you would be getting a lot of smoke out of the exhaust and blow by.

 

[fishx65]

I would do the thinner gasket mod. I did this to my sled and could actually tell the difference. Am I looking for a thinner head or base gasket? Do you know who makes and part number? I gotta pickup a topend kit anyway.