well i tore down the top end of my 87 quadracer 250 i just bought,and i found something very disturbing.on the top of the cylinder,not on the sleeve,but around the topside of the jug,where it contacts the head,there are dents in it.is looks like someone before me couldnt get the head off,and used a screw driver or something similar to pry the head off,damaging the top of the jug,its in like 2-3 places,it doesnt look like it will let compression leak,but it looks like it will affect the coolant seal.they arent sharp grooves or scratches,the dents are round in shape,and there was definitely some silicone on it too,probably put on by the idiot who sold the quad to me,to keep coolant from leaking,the motor had great compression,so im guessing it wasnt leaking compression. IS THERE A WAY TO FIX THINGS LIKE THIS?,OR AM I SCREWED INTO BUYING A NEW JUG/CYLINDER

 

Try filing them FLAT,take your time you don't want to rush perfection.Just file the edge's FLAT don't try to get it all,the little pit can be sealed with head gasket sealer from the dealer.I forget the name of the stuff but it work's GREAT,it's about $8-$9 for a tube but it last's ya awhile.

 

thanks,this guy completely ripped me off,the more i tear down the more problems i find.im going all the way to splitting the cases so who knows what else i will find. one of the dents is pretty wide. it looks like the guy had some silicone in there,but it was starting to even clog up the coolant passagesbecause he used so much. at the top of the jug.will that sealer stuff not get into the coolant lines if i use it? im taking the cylinder to have them mill it down a little,that should probable help. but will that sealer be safe to use>?

 

That's pretty smart to go through the rst of the motor with a problem like that. Who know's what that yahoo may have done.

 

i showed the jug to my neighbor,who is a car mechanic,he said a machine shop would be able to remove the cylinder head studs,and mill it down a little bit.he acted like it was no problem.im thinking it will be a little harder than that.what do you guys think? thats exactly what this guy who sold me the cylinder was,definitely a yahoo............

 

Before milling the cylinder, check to see how far down in the bore the piston is at top-dead-center. If it is too close, it will smack the head when you try to start it up. The result will be a lot of work for nothing and another tear down. Plus, milling will raise your compression ratio. Maybe only slightly, but maybe enough to cause problems (depending on what gas you run and how much is milled off). Another thing to consider is the deck thickness (head gasket surface). When you mill it, you make it thinner and more prone to warpage. Most cylinders don't have very thick decks to begin with. If I were you, I would take it to a welder and see how much it would be to weld the notches. It probably won't be that much. Just make sure the surface is very clean before welding. After it is done, you can file down the beads until they are flat. Also, make sure that you check the head. If there are deep grooves in the cylinder, there are probably witness marks in the head, too.

 

I was just going to suggest the same thing. problem with milling is the compression goes upand that's very touchy with two-strokes.

 

the cylinder walls themselves are fine.is the top surface of the cylinder that connects with the head,where the coolant shaft openings are.could i j-b weld it?im sure if i took my time i could do a really slick job on it. when i first brought this home it would start up and run fine,there was silicone crap under the head with the head gasket,and it wasnt leaking air or coolant,if silicone could hold,couldnt j-b weld? my piston sleeve is perfectly intact with a fresh bore. one more queation,after having someone weld over the dents,could i have the welds milled down so itll be perfect? if forgot to mention that the dents are pretty clear of the cylinder sleave,so the jb weld would mostly be taking care of the coolant,what do you guys think

 

I use that sealer that I mentioned on my Zilla,just a little bit of the stuff goe's along way.I don't see why JB weld would'nt work to fill the screw driver pit's,just take your time and make sure it's flat when done and completely dry.You can mill the head .010 and not have it affect the performance and still use pump gas.

 

When i recently redid my top end i milled 15 thousandths off the head to bump up compression and it hasnt hadteh slightest ill effect... i run 91 octane with maxima Castor oil mix, with i think a 158 main, i did reject afterwards though. If you can get it milled and there is enough deck, it really wouldent be that hard to have a shop do. I dont know if the deck is thick enough t do so though, i had the material taken out of my head not the cyl so you have to find that out.

my .02

Mark