250R Head Leaking Coolant After Rebuild
#1
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i rebuilt my friends 250R top end yesterday, its an 86. new wiseco piston gaskets etc... i've assembled several motors before but when i added coolant it just starting leaking out very badly from the bottom of the head. never seen this before. i fired the motor it ran beautifully lots of compression and sounds really strong only problem is that head leak. can anyone help me out never seen this before. is there is certain torque sequence on the head nuts? i just hand tightened them all the way down then criss crossed to tighten. he has an extra head gasket left what do you sugggest?
#2
#3
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Well, if it starts and runs and has good compression it doesn't sound like it's leaking in the motor. Sounds like it's the water jacket leaking externally. My lt250r head has a screw in it, that if I removed it would leak antifreeze. Since it's the highest point of the motor I assume it's a bleeder screw or something. Is there supposed to be one in yours? Have you traced it back to the source of the water?
#4
#5
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I wouldn't put anything on the head gasket. Take the head back off and make sure both surfaces are CLEAN!! Scrape them w/ a razor blade, but be sure not to score the alumumum, then wipe them clean w/ brake cleaner (or any good solvent). Get the torque specs and sequence and try it again. Could just be a flaw in the gasket, or piece of crud on one surface.
#6
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I am assuming you used a new head gasket?
As was mentioned, take the head back off and clean the surfaces. You may need another head gasket too.
I lapped the head on both of my 250Rs prior to re-installing them (granite plate and 600 grit sand paper, using a figure 8 motion). This assured that the head was perfectly clean and flat.
Wouldn't hurt to try this with yours.
As was mentioned, take the head back off and clean the surfaces. You may need another head gasket too.
I lapped the head on both of my 250Rs prior to re-installing them (granite plate and 600 grit sand paper, using a figure 8 motion). This assured that the head was perfectly clean and flat.
Wouldn't hurt to try this with yours.
#7
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