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Xlt 600 seized please help

10K views 19 replies 5 participants last post by  polar800 
#1 ·
All, just found this forum and love it already. My brother's xlt 600 is seized at present. Another fellow needed towing out and apparently after a number of miles the xlt quit. They unhooked and tried it again (not good) and after 30 yards was done. My question is can some one advise me as to procedure to 'unseize' the engine for repair. We wish to disassemble then ship parts in for rebuilding. Cannot afford the shop time to dicky do with this. Any and all advice greatly appreciated. Wantin' to go up here in cold white Alberta Canada.  Today it is -30 Cel with 3 ft of snow in the west country begging for tracks. Cheers, Voltar....
 
#2 ·
Be very careful doing this as you can twist the crankshaft out of timing very easily. Drain the antifreeze from the engine, Pull the head cover assembly and then take the individual heads off. Look into cylinders to see which one is stuck.  Use wd-40 or some two stroke oil and pour a little on top of each piston and let it sit for a few minutes.You could have more than one piston stuck. Try grabbing the clutch and turn it counterclockwise,rock it back and forth a little bit each time. If it does not want to go do not beat on the piston or force the clutch to move. Hopefully this will free up the engine. Try this andif it does free it up do not go ahead and remove the cylinders yet as you need to check the crank for trueness before you remove the cylinder. You can call me @ 260-637-7953 if you need assistance
 
#3 ·
Thank you for the help. My brother started to strip her down last nite and updated me that he can turn it by hand on the clutch so stripping this down should be okay. Do you check crank runout withthe cylinders on to maintain crankcase rigidity? I presume we need to check that before teardown? Will advise him to hang tuff until we know more about that engine. Again thank you for the help and for giving me your ph number. When I see/know more will call. Voltar.
 
#4 ·
Crankshaft Indexing
Polaris crankshafts are pressed together or "indexed" so the connecting rod journal center lines are 1 80" (twins) or 120" (triples) apart from each other.
It is sometimes necessary to check multi-cylinder crank- shafts to verify that one cylinder has not been forced out of position relative to the other cylinder or cylinders. Causes for out-of-index crankshafts include but are not not limited to:
Hydrolock from water or fuel;
Impact to drive clutch from foreign object or acci-
dent;
Abrupt piston or other mechanical failure;
Engine lock-up due to drive belt failure;
Following is a method of checking:

Disconnect battery ground cable and all spark plug high tension leads; ground high tension leads to engine. Dis- connect lanyard from engine stop switch before proceed- ing with the following steps.
1 . Securely fasten a degree wheel on the flywheel or PTO end of crankshaft. Use a
large degree wheel for more accuracy, and
make sure it is mounted concentrically with the crankshaft center line.
2.  Sharpen a coat hanger or section of welding rod and anchor it to a convenient spot. Point the sharpened end at the outer perimeter of the degree wheel.
3.  Install a dial indicator into the magneto end
cylinder spark plug hole (front) (#l). (The ignition timing is referenced by the magneto
end.)
4.  Rotate the engine to bring the piston to top dead center (TDC) on the cylinder with the indicator installed.
5.  Locate TDC as accurately as possible by
finding the center of the point where there is no
piston movement. "Zero" the dial indicator at
this point. Continue to rotate the crankshaft in the normal direction of rotation until the dial indicator reads . 1 00" (2.54mm) after top dead center (ATDC).
IMPORTANT. Do not allow the crankshaft to move from this position.
 
#5 ·
Crankshaft Indexing (Continued)
6.  Bend the pointer or move the degree wheel until the pointer aligns with the 180 or 120' mark on the degree wheel.
7.  With the pointer aligned, make sure the degree wheel and pointer are secured and will not move out of position. Re-check accuracy of this location by repeating steps 4. and 5. . The pointer should align with the 180 or 1200 mark when the dial indicator reads. 1 00" (2.54mm) ATDC.
IMPORTANT- Do not move the degree wheel or pointer after the initial setting on the mag end cylinder - simply read the wheel and dial indicator.
8
Remove the dial indicator and install in cylinder #2 or center cylinder. Repeat steps 4. and 5. Note the degree wheel indication when the dial indicator reads.100"ATDC. ltshouldbel8Oorl2Oo:)t2")fromcylinder#l. Repeat procedure on PTO cylinder (#3) where applicable. Cylinder #3 should also be 120":)i- 2") from cylinder #1.
Symptoms of an out of index crankshaft can include:
Difficulty calibrating carburetor (repetitive plug fouling on one cylinder with no other cause);
0    Unexplained piston failure on one cylinder (i.e. severe detonation, broken ring lands, piston holing); 0    Excessive vibration of engine, backfiring, etc.;
0    Rough idle, poor top speed.
 
#6 ·
Polar, thank you for the info. Will do this for him. I have the dial indicator from my street bike points ignition days so it will have the spark plug adapters required. I hate to mention what I ride over here but here goes.....:) zr700 AC but then again you guys may be more 'objective' than the cat guys. Are they, were they any good as an engine? Cheers. Volter...
 
#7 ·
600 XLT is a good engine. No known issues. I think I remember seeing somewhere where they were figuring there were more of them built than any other single model by ANY manf. There are a ton of them still on the trails everywhere you look.
 
#8 ·
Thank you all for the help. It turns out that the main bearings have pooched and the top end is fine. So now a crank job is required. Good to hear that the 600 is a good engine, I know it will smoke my zr700 in the hills for sure. Take care all and happy sleddin', Voltar
 
#9 ·
Plugged oil filter or broken throttle cable? Man. tell him not to put that thing back together till he figures out why those bearings let go.

AL
 
#11 ·
Hmmm,
Crank problems with the piston ported 600 (XLT) is news to me. I've never seen one. EVERY blown crank I've seen have ALL been the case ported (XCR) engines.

AL
 
#13 ·
Michahicks: Very odd that you have never seen a crank failure on the Monoblock engine. Ever since it was produced the cranks were issue. 95/96 especially were suspect. XLT/XCR were the monoblocks and the XCR SP(after 1995) was the case reed motor. They changed the monblock case and bearings in 1997 and went to a crank oiler on the PTO end to try and avoid the problems. The case Reed (Ported?
) engines generally had great crankshafts, but any crankshaft is prone to failure at some point
 
#14 ·
Very common problem with this sled. My buddy has a 97 xlt and last season with like 1500 miles on it she locked up. It was the bearing on the pto side. Top half of the motor was fine. Had it back together for just over $400.00. Made an adjustment to give it a little more oil. It has about 3500 miles on it now with no other problems
 
#15 ·
What adjustment is made to give it more oil? I'm about to go and buy a 95 XCR 600, and I'd like to get any work that it may need done over the summer.

Just how common is this? Is it a milage thing, or is it a question of alot of faultly motors?
 
#16 ·
Newfiebullet: It is a issue with engineering. Some(XCR or XLT) sleds went thousands of miles with no problems. Some went 300 miles. Make sure that your oil pump settings are on the rich side. The best cure is to split the case and drill the oil drain hole bigger in the top half of the case. These were great sleds in there day. If you leave it alone, and do not pipe it, you probably won't have any problems, but when you spin the rpm up on the engine the failures become more common. If you are going to run this "hard" then I reccomend that you split the case and modify the oil hole. I can help you if you need it, call me @ 260-637-7953 or email me back @ perfmoto@comcast.net
 
#17 ·
Hey thanks for the offer of help Polar800.
The Machine I'm looking at has got pretty low miles, and looks like it's been babied.
I do tend to run my sleds pretty hard, but I don't race much.
If I can find a good deal on on set of pipes I'll probably get them, but if not I'm sure I'll still be happy.
 
#18 ·
Polar, thanks for the help. it was the PTO bearings and the guy my bro has working over the crank believes only the PTO bearings to be bad. Is there a reliable way to test the mains before he runs this thing? I have access to a lathe for a runout test if that helps. Am interested in the size of that hole that you recommend as well. Thank you again. Voltar...
 
#19 ·
Voltar: If you put the crank in between lathe centers make sure that the centers are seated properly. Just because the crank shows true between lathe centers does not mean it is good on index. Go back to my previous post and check it for index first, and then true in between centers. I am attaching photo's for the hole in the case. Drill it the same size as the other ones in the other bearing journals.
 
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