xpress 300 engine problems help!!!
#1
xpress 300 engine problems help!!!
I bought a 1997 xpress 300. It did not run. So I broke it down and found out it needed piston and rings. Piston was scored on the right side of it. That was the only spot that was bad. The rest of the piston looked good. So I replaced them. Put it all back together. the only way it would start is with staring fluid. But it did start up. And it ran good. but now the only way to get it started is with starting fluid. I could have it running for 20min shut it off and try to start it right back up and nothing. Starting fluid is the only way I am getting this thing started. I friend of mine told me to check the crank. So I pulled of the clutch. I the crank moves up and down. It needs new bearing. But could bad crank seal cause it to run that way too? does anyone know were to get the bearing and seals at? In a kit.
#2
Have the cylinder measure and bored out to the next correct oversize piston. Doesn't do any good on 2 strokes or for most 4 strokes as far as just throwing another standard piston and rings back in. Clearances are tight on piston to cylinder and when any kind of seizure happens,time for a top end rebuild at least.Since you checked the crank shaft and it can move up and down,time for new crank bearings and seals also... While you're down that far I'd just do it right and install a new rod kit also.http://www.ebay.com/itm/Polaris-300-2x4-4x4-1994-1995-Connecting-Rod-Kit-3082790-/400938473707?fits=Make%3APolaris%7CModel%3A300&hash=item5d59cb98eb&vxp=mtr Plus you can get the three bearings and seals on ebay. A good machine shop can install the rod kit and crank bearings along with doing the bore job..Doesn't matter whether its for a 250/300 or year model as the crank bearings are the same for all.
http://www.ebay.com/itm/1995-Polaris-Trail-Boss-300-Crank-Crankshaft-Bearings-And-Seals-Kit-ALL-*****-/281741713481?hash=item41991d6049&vxp=mtr
http://www.ebay.com/itm/1995-Polaris-Trail-Boss-300-Crank-Crankshaft-Bearings-And-Seals-Kit-ALL-*****-/281741713481?hash=item41991d6049&vxp=mtr
Last edited by old polaris tech; 07-27-2015 at 10:06 AM. Reason: crank bearings and seals
#3
The piston is 75.50mm the standard size is 74.50mm. It Is a .040" overbore. The piston I took out of it looked almost brand new. And it had tons of blow by. The kit that you showed me only have 2 bearings. I need 3 And all 3 have different part numbers. and the part number from the 95 does not match the 97. even the OEM part numbers do not match.
#4
The piston is 75.50mm the standard size is 74.50mm. It Is a .040" overbore. The piston I took out of it looked almost brand new. And it had tons of blow by. The kit that you showed me only have 2 bearings. I need 3 And all 3 have different part numbers. and the part number from the 95 does not match the 97. even the OEM part numbers do not match.
#5
#6
You have to have a bearing separator behind the inner bearing,heat the worm drive gear up thoroughly and whack the bearing separator to remove the worm gear and bearing. Worm gear has to be heated back up to slip back onto the crank shaft.. ALL ***** kits uses the same bearings for all three,same as for the 250. Plus I had discussions about this over the years with several Polaris engineers and they basically said the same thing,all three bearings can be the same! If you want to order oem bearings and feel safer about doing that,that's entirely up to you. Here's another listing for the Express 300.http://www.ebay.com/itm/All-*****-24-1084-Crankshaft-Bearing-And-Seal-Kit-Polaris-Xpress-300-1996-99-/321798637599?hash=item4aecb1881f&vxp=mtr
#7
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#8
It's got to get pretty dad gummed hot for it to move. Same for the install.Have a good punch ready in case it doesn't seat fully against the new crank bearing. I just used a hot plate at work and heated em up for a good 10 minutes are so. A bearing separator is what I used,but I suppose a good puller would work also just as long as it could get a good grip on the bearing. This is the one I had,but plenty of cheaper $19 ones (that should last a time or two)are on ebay also.http://www.ebay.com/itm/SnapOn-Bearing-Separator-2-3-8-CJ950-/121713940452?hash=item1c56b757e4&item=121713940452&vxp=mtr Plus it makes it nice if you had a 1/2 plate steel table that you could work on like at the shop,but a good work bench or concrete floor can work ok.I got tired of trying to screw em down,so I just whacked the top of the separator and job done.. On the reinstallation of the worm gear I used the hot plate or a torch,for removal I just heated the gear up with a propane torch until it was smoking hot,made for easy removal.
Last edited by old polaris tech; 07-27-2015 at 03:57 PM. Reason: heating the worm drive gear
#9
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