I purchased a non-running Trailblazer for $500 and it doesn't have much compression 30lbs. so I tore the motor out for a top end rebuild. my questions are 1. My machinist thought that newer 2 strokes had a cylinder plating and shouldn't be bored just honed, is this true or a problem for boring? 2. after all is ready for piston do I need to gap the rings on the piston or are they pre gapped? 3. is there a special tool for installing piston in head or is it just a scweeze rings and push kind of deal? 4. what are the torque specs for the head,cover,intake and exhaust bolts and what is the proper pattern for torquing the cover. Thanks for the help in advance I am so ready to ride.

 

I don't believe the cylinder has a coating, I think that is more for 4-strokes(suzuki has the nicasil plating i think). You should purchase the piston and rings first(Wiseco is your best bet) that way your mechinist can do all the measuring prior to the bore. This insures the bore to match the piston and can be double checked once the honing is done. Assembly is a piece of cake. I don't know if it has 1 or 2 piston rings but if it does stagger them. Place a call to Ritter Cycle racing and talk to Rick Ritter he will help.

 

The rebuild is very easy. You should use a ring compressor because the rings are very brittle and one little mistake can cost you another $30.00 for rings. The piston already has pins in the grooves to line the rings up in the proper position. When you do the bore job you need to think about what you want to do with the motor as far as mods go or how long you plan on keeping the bike. If you are going to mod it (most people do) Then go with the 40 over stock. If you want to keep it mostly stock but plan on keeping it for a while then go with the smaller bore this way it can be bored again in the future. It will save money in the long if you go with a smaller bore. If you go with the bigger bore, you wont be able to get it bored again if you have another problem. A bigger bore will not have a reliability problem as long as you manetain it properly. The torque of the head should be in a X motion. Im not sure off hand but it is around 30-35 ft pounds of torque. A top end rebuild should not cost more than $300 for the bore,piston, rings,wrist pin bearring,head gasket,cylinder gasket and thats about it. Sounds like you got a great deal. Good luck on the rebuild. Be patient and dont rush. Once it is all done you should have a strong ride again that will last along time with proper breakin and mantinence.

 

The Ploaris machines I have worked on had an iron liner, but no plating. You should be fine going one size over. I recommend getting the piston & rings first, and the machinist will bore it out to fit. If the machinist does his part the piston and rings should fit properly. Remember, any markings on the rings goes to the top, and any marking on the piston goes towards the exhaust, or front. Be sure to use new piston pin clips, they are cheap, and can break on occasion if re-used.
You should have rings on the piston first, then mount the piston on the rod. There are little 'pegs' in the piston groove, that MUST be lined up with the gap in the rings, or you will break the ring. Now, carefully lower the cylinder over the piston (clean everything up good, and coat the bore & piston with a very light coat of injector oil) and if you are CAREFUL, you should be able to (gently) squeeze the rings down into the groove, as you lower the cylinder over the piston. Just be sure to squeeze with gentle hand pressure, and try to close the ring gap, rather than just squeeze the ring any old way. Makes the job easier, and keeps the ring gap oriented over the 'peg'.

I strongly recommend you call Rick Ritter (his number is listed on his website at www.rittercycle.com ) if you haven't bought anything yet. For my Xplorer, he sent a piston, rings, and cylinder already machined and fitted to each other. After I got everything back together, I mailed him back the original cylinder, and he credited back me everything but his machining fee. To me, it was worth the postage to get everything fitted together. Also, he has a lot of experience with the Polaris engines, and knows all the gaskets, and what not to send along. I got everything as a 'kit', (piston, cylinder, rings, gaskets, wrist pin, wrist pin bearing, and new wrist pin clips) and after he credited me back for my old cylinder, it was right at $200 plus postage. He even included a note with a few pointers on how to put it all together. Far easier than trying to piece it all together myself, and then find out I forgot to get a gasket or something. Also, while you have him on the phone, you can talk about possibly a porting job, if you feel it might be of interest to you. As an added bonus, I tore my top end down, and put it together the same day, while I still remembered how everything fit together, instead of having a half apart engine sitting around, waiting for the cylinder to get done. I haven't dealt with him all that much, but from what I have, I cannot think of anyone I hold in higher regard when it comes to 2 cycle Polaris engines than Rick Ritter.

Just my 2 cents worth

Farmr

 

Thanks everybody. I plan on purchasing a 400ex next year so I don't want to do a whole lot to this one since I will be giving it to my girlfriend to use. I though that the wsm kit on ebay would be the way to go and maybe the stage 1 rcr kit later in time. can the wsm kit handle any mods or is it to cheap to be reliable with such a kit. I don't think I will ever do more than the kit and maybe a port job in time, any thoughts on this?

 

If you are considering a port job, I would sure do it now, while you have everything apart. If I remember right, Rick Ritter charges like $65 or so for porting. Not much to add, since you will have the cylinder off, anyway. I think whoever does the porting would be fairly close to that. Remember, every time you have your top end off, you will need to get new gaskets, and risk getting dirt in the engine. I would sure do it all at once, if that is what you want to do.
You can pipe it, jet it, change the air cleaner, or whatever, and that still won't do as much as a good porting job. It is important to have someone who knows what they are doing do the port work. A bad port job can make the powerband almost unmanagable.

Farmr