I'm getting ready to put my Scrambler 400 back together with new piston and rings. Does anyone have any advice about doing this job, or about breakin? I just received my parts back from Hpd with the trail mod. I can't wait to see the difference!

Thanks,
Colin

 

Colin, make sure things are clean. I normally keep a seperate squeeze bottle of non-synthetic Polaris 2-stroke oil. Put a few drops down on each side of the rod, at the crankshaft. Lube the bearing on the piston end....make sure you're using a new one, cheap insurance. Also, did HPD tell you about the two additional oiling holes you can drill in the piston? If not, I'll check with them in the morning and post some pics on my website. The base gasket is installed with the silicone ring (raised white bead) facing up. Pay close attention to keeping your rings in place, and slide your well lubed cylinder down, all this after you installed the piston on the rod. Not sure what your experience level is, so forgive me if I state something you already know. Torque everything down. Once you've warmed the engine up good once, make sure to retorque those base fasteners. Also when you're refilling the coolant, make sure to back off the hose on the cylinder a bit to bleed any trapped air out of the system. Vary your engine rpm during your first outings. Never hurts to add just a bit of oil to the fuel to pre-mix things for safety.

 

Just my added two cents, but change the counter balancer oil right away too, better safe than sorry. I"m not sure what HPD recommends, but I added oil to my gas, along with the oil injection for the first tank, and don't hold it wide open for more than a sec or two, then back off, for the first tank. It also helps to have a second set of hands, one person holding the rings compressed against the piston and the second in control of the cylinder. I don't know if you did any head mods, but a brass brush, not a steel, on the head to get rid of any carbon build up.

 

Thanks for the help guys. Today I followed your tips, aside from the drilling of the holes in the piston. It started right up and seems to be running perfect. The tips helped, being that I'm not experienced. Now I have Hpd trail porting, trail head, bored .020, carb bored to 35.5 and jetted, Boyesen rad valve+reeds, pipe, k&n, and ITP .190 wheels with Holeshot tires. I can't wait to crack into the throttle being that everything is brand new except for the pipe. I hope it goes as good as I'm expecting.
Just one stupid question. Where do I check the oil for the counter balancer, and what is best to run in there?

Thanks again,
Colin

 

What clutching are you running with that? The counter balance dipstick is..... If you take the airbox off..if you are standing on the left side of the machine looking toward the right side, look down where the airbox was and to the left front way down you will see a big slotted screw head of sorts... well that is the counterbalance dipstick. I run 10w-30 in mine and I think that is what Polaris recommends.. Brands??? Whatever you want I guess, maybe someone has a fav. but I think I use valvoline.

 

The only thing I know about the clutch is it is a Aaen Roller Action Clutch with a Aaen Green Primary Spring, and a Blue Secondary Spring. What should I be running? And I don't have a manual so does anyone know how much oil I need to change the Counter Balancer?

Thanks,
Colin

 

My Scrambler calls for 3-1/4 floz. of 10w-30. Clutching sounds good, just wondering what you had since you didn't mention it.

 

Is that all it takes. It just doesn't sound like much. Changing this will be my next project.

Colin

 

Nope, doesn't take much at all. The counterbalancer is very small and so is the oil reservoir for it. Good luck.

 

I know I need to get a manual, but is there a drain plug on the bottom of the atv to change the oil? Sorry for all of the stupid questions, but any help until I get a manual would be greatly appreciated!

Thanks,
Colin