97 sx700 overheating

viperino

viperino

New member
Joined
Feb 7, 2005
Messages
174
Location
Welland, Ontario
looks like my coolant system stops pumping coolant around once i start running...i pulled the water pump cover off and the impeller is fine...even turns when i pull recoil to turn crank....made sure this was not an airlock either...i'm pretty sure it is a problem with the impeller shaft gear on the crank....has anyone out there run into this problem?

snow melting fast...

pr
 

first you need to absolutely be sure that there is NO air in the system, and that the system is holding its coolant.
 
Did you roll the sled up on its side, after you bleed it. My 97 you could blled the daylights out of, and think all was good, then roll it up on its left side, and it would drop 1 to 1.5 quarts of fluid. Don't ask how or why, I just know it did. Maxdlx
 
i had a mechanic vacuum test the coolant system for leaks and it was fine....then he vaccuumed all the air out and filled the system completely with coolant....i am 99.9% sure this is not an airlock.
..anyone aware of problems with the impeller gear on the crank shaft or impeller shaft?
 
97's didn't run a thermastat. I have heard of problems on the sxr 700 but never on the 97. I would still try and bleed it and roll it to see what you get. Maxldx
 
when you get it running, and have it warmed up feel the tunnel coolers, the rear hoses, and rear cooler to see if they are getting hot. Maxdlx
 
it seems to move coolant around when its first started up and idling as the exchangers do get warm but once i get it out on the trail i cant go any more than 1 km before the light comes on and then the coolant starts boiling....more than once it blew the hose right off the coolant return line on the top of the motor.
what do u guys suggest is a good way to bleed the line...i'll try that one more time before i tear the motor out.
pr
 
first thing i would do is roll it up on the left side and let it sit for about 5 minutes, then roll it back down and see if the coolant bottle is empty. If it is refill and try again. If it takes coolant again repeat again. Is the fluid really hot when it spews it out, or not. if it is a head gasket it would do it sitting still too. You also need to getthe rear of the sled up, take the seat off and take out the rear bleeder. I always take a squeeze bottle ( like a gear lube bottle, that has been cleaned out) with fluid in it, put the tip in the hole, and squeeze in fluid. It will force the air into the bottle, after a couple times, and have the rear system full of fluid. Give those a try. you can also run it with the rear bleeder out, and rev it up. if the pump is working it will spew fluid out. maxdlx
 
in one of the yamaha tech update manuals there is a tip what i think is happen is once the engine get warm the brass grear that on the crank that turns the water pump is slipping this happen on machine that some high miles. if you go to a yamaha dealer technical tip is in the 2000 up date book and on page 3-5 if you can't find it let me know and can fax you the page
background when engine is hot it is possible the brass water pump/oil shaft drive gear is slipping on the crank shaft. the brass gear is press fit and as the crank cools the gear tightens and operates normal. hope this helps you out
Jerry darvell@jam 21.net
 
wow originally i'm thinking headgasket, but what DARV said makes sense as well. Probably going to want to get in there and check it out.
 
it definately sounds like a headgasket..start with least expenseive and move up!
 
headgasket is definately NOT the least expensive, the gaskets are $32 bucks a piece times 3 cylinders. But you can do things to check if it is a headgasket. One symptom is that the cooling system will have much higher pressure than normal, and the overflow bottle may fill up and overflow. If you squeeze the coolant lines once it is warmed up, they make be rock hard. Another check is to open up the coolant cap (on the hose) with the engine cold, make sure it is full of antifreeze, and start it up. If bubbles are coming out, it is definately a headgasket. These checks should definately get you in the right direction.
 
Im sure it is alot cheaper to replace the water pump,or replace the brass bushing on the crank,etc... shoulda said, start with the easist, my mistake! or maybe its easier to relace the pump!, impellar seals etc.... I had a similar problem with one of my sleds...impellar burnt up..so i replaced it..it went out again...so i replaced it....did that 3 times till i figured out it was the head gasket, even though it looked good, it was sukin air in the system causing air void around the im[pellar ,which inturn melted it. If that has happened in your circumstance then you may have bad seals in your pump also...along with bad headgasket. just somthin to think about! I forgot to mention that it checked out fine when cold,,but after it warmed up it suked air.
 
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well i figured out what it was... the impeller gears were worn right down so the impeller was just spinning on the shaft..... bought a new impeller and replaced the water pump cover seal.... cost me bout $80.00...
 
the gears at the end of the shaft were still in good shape.... they looked slightly worn but looks like the impeller gears wore before causing too much damage to the shaft gears...the new impeller gears matched up really tight to the original shaft gears so im confident it will be fine....cud b wrong tho...

thanks for all the suggestions guys,

rino
:rockon:
 
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