Rebuilding Top End on Polaris Trail Boss 250!

[@alexyoung3046]

Just rebuilt mine and was wondering why and if there’s supposed to be oil in bottom end old rings were worn and had blow by should I drain it out or leave it in there or what there wasn’t a crazy amount but enough for me to be curious I’d say probably about an inch deep

[@ToyShopRestorations]

It should be pretty much dry. It’s possible the carb overflowed since the last time it ran and it dripped down the intake into the crank case. You should try to get all the standing liquid out of there. It doesn’t need to be dry but you risk hydrolocking it. If you have it together already pull the plug out and pull the motor over really fast and it’ll spray out. Do that until it quits for the most part.

[@alexyoung3046]

@@ToyShopRestorations do you know what bolt is the drain plug

[@keeganmyers7627]

I just done a top end on a trailblazer and it sounds so crisp

[@reviewtable4453]

Bro ur a hero, i jus replaced my piston head on my damn 1990 trailboss that suffered a large piston breakage, I followed ur steps and literally 5 pulls and engine fired right up.🎉 I couldn't imagine doing it without ur video. Keep up the work bro u know ur shit

[@ToyShopRestorations]

Thank you! It takes a lot of work to do these videos and I do it to try and help you guys out! I’m glad it worked and I’m glad you’re rippen again!

[@ogonbio8145]

I have a 1990 Polaris trailblazer, I was riding it full throttle and suddenly I could hear the intake sound over the exhaust sound if that makes any sense. It slowed down and died and now it’s got 60psi compression. Gunna give it a top end rebuild thanks for the video

[@growapair3880]

Awesome! Did your new piston hold up in your old bore is the machine running today? Also did you ever do a compression test after this top end rebuild was done and machine up and running? Im debating whether to get mine bored out or just change out the piston i have minor cylinder wall scuffs on my cylinder..

[@ToyShopRestorations]

Yup it’s still running! I didn’t do a compression test on it. If you only have a few scuffs I’d just hone it and do piston and rings. I was taught if you can catch your fingernail on a gouge then it needs bored or replated.

[@andrewlopez153]

After rebuild was done did you have to do anything to prime oil injection? or maybe mix first tank of gas?

[@ToyShopRestorations]

I don’t think I primed it but I don’t remember. It never hurts to run a gallon of premix in it and then go back to straight gas.

[@daviddaniels6607]

Great video! One question, do you recommend sealant on the jug gasket and head gasket and what do you use for sealant?

[@ToyShopRestorations]

No I don’t put any sealant. Just clean each surface and put new gaskets on. New gaskets are impregnated with a sealant and will liquify and stick during the first couple heat cycles.

[@RippenSXS]

Is that the first time you stuck your fingers in an exhaust port?

[@ToyShopRestorations]

Second actually…

[@cristobalmannsrosselot]

Nice video, i have a 73.5mm wiseco piston for my Trailblazer, witch sizes I should inspect before the instalation?

[@ToyShopRestorations]

I’m not sure what you’re asking 🤔 I don’t usually measure anything other than the bore to make sure the piston is correct.

[@cristobalmannsrosselot]

@@ToyShopRestorations I ask you how many inches of difference between the diameters of the cylinder and piston should I have if I use a wiseco of 73.5mm for a polaris trailblazer 250 2t, also, the minimum and maximum opening measurements of the rings.

[@ToyShopRestorations]

@@cristobalmannsrosselot ohhhh um that should be specified by the piston. The piston should have came with a little book that specified the ring end gap and might give you piston clearance. If not I’d get on wiseco’s website and see. Should be the same spec for all of their 2t pistons.

[@cristobalmannsrosselot]

@@ToyShopRestorations thanks so much

[@christopherburton4623]

Do you have any videos on the carburetor removal and install a new one?

[@ToyShopRestorations]

I have one where I’m cleaning a carb on my channel

[@stephenw5063]

Nice video! Happen to have any videos on getting the flywheel off and replacing bearings?

[@ToyShopRestorations]

Check the recoil video for the flywheel and/or the starter video. In one of those videos I had to take the flywheel off. But bearing, I didn’t have to do that on this quad so that’s a no 😅

[@cristobalmannsrosselot]

Hello, how many torque you used in the cylinder base nuts AND the cylinder head nuts?

[@ToyShopRestorations]

Head bolts 18 to 20 ftl-bs. Cylinder base 25 to 29 ft-lbs. Crankcase 6mm 72 to 92 inch-lbs. 8mm 17 to 18 ft-lbs. Hope this helps!

[@cristobalmannsrosselot]

@@ToyShopRestorations thanks!

[@ajmontgomery4564]

could i use this vid as a guide for doing a 93 350 2 stroke?

[@ToyShopRestorations]

I’m not sure. I’ve never done a 350 before. This video is pretty similar to all 2 stroke videos so I’m sure there’s a lot of similarities!

[@shawnstatz7238]

Where did you get the hoaning tool

[@ToyShopRestorations]

I bought it at napa.

[@twotiresonley8795]

I thought top end would include valves 🤔

[@ToyShopRestorations]

This is a 2 stroke. It doesn’t have valves

[@geopioneergsxr5357]

😂🤣

[@JeramieCurtin]

How long would you say it took too do this whole thing

[@ToyShopRestorations]

If I had to guess I’d say doing a top end took me probably 5 hours all said and done.

[@tylerchaney1533]

Damn, wish you would have shown how to get that damn engine mount out of there imma torch the bastard off soon lol. BTW anyone reading this the polaris manual says to use loctite 515 on both sides of base gasket...probably to make up for lack of torque spec🤣

[@ToyShopRestorations]

🤣🤣🤣 I don’t have the book so that’s great

[@tuggerman84]

yeah i specifically came to this video hoping to see somthing about that pesky motor mount. i can't get the bolt out, even with a punch.

[@tylerchaney1533]

@@tuggerman84 I suffered that same thing. It's not a bolt it's one solid peice so it can't be removed that way. Have to remove from cylinder

[@billhamby6230]

I have a 7.24 bore what size rings i need

[@ToyShopRestorations]

7.24? Stock size is 72mm

[@billhamby6230]

@@ToyShopRestorations yea stock is 72 mm but my jug is 724

[@billhamby6230]

@@ToyShopRestorations its .o4 over 72mm

[@billhamby6230]

@@ToyShopRestorations i think standered will work but not 10. Under

[@ToyShopRestorations]

@@billhamby6230 ya standard size should be fine!

[@daboituck3945]

I should've watched this before taking the whole body off.

[@ToyShopRestorations]

But now you’ll know for next time! 😂

[@kraftcraft2934]

No good didn't show torqued down head

[@ToyShopRestorations]

I didn’t? 😳 did I say what the torque was? 😅