98 SRX exchanger problem??

ejcamaro

ejcamaro

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My friend has a 98 SRX 700 that seems to be overheating on the railroad grades. This is not at full throttle, but at 1/2 to 3/4 throttle for long periods. The sled keeps building up ice on the front heat exchanger and when I feel it it seems not as hot as the others under the floorboards (they are so hot you can't touch them for more than a second). Is it possible that only that exchanger could not be getting as much coolant? On the twisty trails it gets pretty warm, but not to the point of the light coming on. Could it have crank issues? The sled did get over 300 miles this last weekend without breaking down???? Kevin at Port Yamaha didn't think he could look that sled up anymore to see if the crank had been fixed. What do you guys think?
 
If the motor had good power during those 300 miles, then it's not likely that the crank is out of phase. If the clutch does not have a wobble to it at an idle, and the motor runs smooth, then I would say that the crank is good. Your overheating could be a waterpump issue. Or low on coolant. If I remember back then, I think that the dealers put 3 punch marks either on the end of the crank on the pto side or by the serial number by the recoil. Any other takers here? Is the motor running too lean? Check the hyfax for abnormal wear-tight track?
 
Coolant is full. I adjusted/cleaned the powervalves as they were stuck before this trip and only opening half way(he just bought the sled). I haven't gotten into the carbs yet and wondered about it running lean, but thought it would've melted down before the coolant got that hot??????? It seems to have good power. All I have to compare it to is my ported SRX and the 98 is not as snappy but pulls pretty hard. Track is good, we put a viper skid in it and adjusted accordingly. The sled only shows 1800 miles but I know that isn't right, it must have lost the speedo side bearing and snapped the key at one point in its life. Anyone else?????????
 
Waterpump circulates coolant through motor and all of the heat exchangers. Have you purged the cooling system of all air pockets? How about a bad thermostat?
 
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The steaming hot exchangers would mean that the thermostat works and is flowing, right? Same with air bubbles, if there was an airlock I wouldn't think the exchangers would get that hot. Although the front exchanger doesn't seem that hot. Is it possible that the front exchanger has air in it but the rest are flowing?
Thanks for the help Bluehammer, its got me stumped though. Anyone else think it could be running lean?
 
i would try a thermostat, my riding friend, who is also a yamaha tech carries a thermostat with him all the time. claims it's a problem that could arise anytime. he changes mine each year. we both ride 700 srx's
 
Take the thermostat out and see if it makes a difference. The front heat exchanger will have coolant flowing through it even though it could have air in it. Coolant will flow with a bad pump because the heat of the coolant just by itself will cause the coolant to circulate. Pull off one of the main coolant lines and see how much flow you have when it's running, then you will know. You might also get some air out of the systerm. I would say either a pump or an air pocket.
 
That makes some sense. I'll pull a hose off this weekend and see whats crackin. I would try putting my thermostat off the 01 on it but there is no snow to really check it. How much flow should it have (i.e. how far should it shoot coolant?).
 
Not very far. Like a garden hose with no sprayer on it and turned on low. You can do it without the thermostat and use a cold motor. If you get a dribble, then it probably is the pump impeller.
 
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