Fresh motor with only 3 race weekends on it. Every time I go out I was noticing the over flow kept filling with water. Bike isn't overheating (it is running 20 degrees hotter then my last motor though. About 190 degrees while racing). It was bad enough this round that the over flow filled completely and starting chucking water down the side of the bike and in my belly pan. When I shut the bike off it will suck the water back into the radiator. Tried a new cap but same results. No mixing of oil and water at all. Motor runs fine. Any ideas?
Do a leak down with radiator cap off. If it is bubbling water in radiator you have a combustion chamber leaking.
Is the radiator fill neck bent up? Sounds like a bad cap but if you replaced the cap, then maybe the radiator is the problem. Leakdown is the way to go but if the head gasket is leaking, sometimes you can see bubbles inside the radiator while the bike is running. Is it a high compression big bore? If so, did you stud the top end?
Since the water is being sucked back in, I'd think the rad and cap are sealing properly. +1 to leakdown as the next step. Id add a strip of tape to my radiator if the water temp was at 190F. Any lower would require even more tape.
Motor is high compression stock bore and it is studded with all new suzuki factory gaskets. Only 3 weekends on the motor and again it's running fine and no mixing fluids. As long as I'm moving it stays under 200 but if i stop it quickly will jump up to 210+. It's just blowing water into the over flow every race. My last motor it would push alittle bit in and the. Suck it bavk out but this one is over flowing and just spewing fluid everywhere.
You might consider replacing it with a new one. It’s lived in an unfriendly environment, ~14yrs. It might be starting to stick. You’re running Water Wetter or Engine Ice or something other than straight water?
Ya running water wetter. Radiator looks clean. Some messed up fins but nothing crazy. Hasnt been a problem.
My original thought was maybe it’s boiling the coolant away from the cooling jacket walls? As others mentioned, I think I’d perform a leak down. If there’s a head gasket issue, you’ll definitely see bubbles at the filler neck. If no bubbles and it were me, I’d pull apart the entire cooling system. Replace the thermostat with a new OEM piece. The radiator cap needs to be a new OEM or Stant part (the offshore aftermarket stuff is garbage). Check the water pump impeller for degradation. Check inside the radiator core for debris/blockage from the new engine. Ensure you have no soft hoses collapsing, while at high rpm. I prefer an organization-approved coolant, for assured boiling point and their surfactants. If you removed the cooling fan, I’d put it back on. They really don’t weigh all that much and are effective in keeping temps in check, even on the cool down lap. If after all this you still have issues, I really don’t have any other ideas. I have a stock, 1st Gen SV streetbike. It has a new water pump, OEM thermostat, OEM radiator cap, AS3 hose and clamp kits, OEM fan, and Engine Ice. Even in FL traffic, the cooling fan hardly ever kicks on. No. I’m not running the crap out of it. But, I can sit through light after light, without the fan kicking on.
Start the bike and feel both the inlet and outlet of the radiator, you may have a clogged radiator. I had that happen to me! Easy way to check is to run a garden hose on one end and see how the flow is coming out. If its clogged you can unclog it, I fixed mine.
In the garage i have done that with no problems. The real issue is sitting still it's totslly fine. Even with me reving the piss out of it. Issue only happens when on track. Thats the hardest part. I can't duplicate what happens other then being out there.
Sounds like the radiator is clogged up, but just enough to allow flow for idle. I had the same exact issue! Even when I ran a garden hose through it the flow on the other end of the radiator didnt match the garden hoses pressure. Remember these bikes sit, not ridden for awhile lime other minerals builds up inside of the radiator clogging the tiny holes. Especially when you run water as coolant.
drain the coolant and run distilled water for a few heat cycles. Tends to pull the contaminants out of the system (lime, scale, etc). A few weekends with distilled water usually helps.
