Trying a different rad cap
Posted April 19, 2006 - 04:39 AM
Says 16 pounds on cap, hoping that's higher than stock cap.
Posted April 19, 2006 - 06:26 AM
Posted April 19, 2006 - 07:33 AM
I agree. First figure out why it's overheating. If it's just slow technical terrain, try different coolant. Straight distilled water transfers heat better than anti-freeze (i.e. Prestone, Zerex, etc.). Water wetter or other surfacant helps to increase that heat transfer. I only use just enough anti-freeze to achieve my desired freeze protection. In the summer you don't need any, just remember to change it before it gets cold. If that doesn't work (and assuming you don't have an underlying problem) Evans NPG-R is a waterless coolant that has something like a 400 degree boiling point. That will definitely stay in your rads, but it's expensive at about $30 per gallon for the NPG-R and another $30 for the required flush. You won't need any pressure cap if you use that because it doesn't need the higher boil temps provided by the pressurized system.
There is a reason the stock cap is rated where it is. I don't think I would be messin' with that!
Posted April 19, 2006 - 08:12 AM
Posted April 19, 2006 - 08:47 AM
Posted April 19, 2006 - 10:15 AM
When I had my old KLX650R, it also would get hot and spit coolant in certain situations. I was told a higher-pressure cap (got one for a 2001 KX65), would help. Installed it - never had trouble with ovrheating again.
If stock is ~15, the 16-pound cap I installed may not be enough:
Posted April 19, 2006 - 11:37 AM
I have run every coolant combo except the EVANS NPGR, and I will try that sooner or later, but every one of them has boiled over in certain conditions. To date my best luck has been with Engine Ice but I hear the EVANS out performs the Engine Ice
My 2 cents worth is to run the stock cap with the overflow resevoir in place.
Posted April 19, 2006 - 12:12 PM
I find the WR's run hot, but mine seemed to get hotter with age (unlike most things). It's probably a combination of things like the rad cap spring weakening, old coolant, slightly bent rad, all adding up.
Do you remember your bike boiling over as much when it was new? I don't think mine did.
Posted April 19, 2006 - 12:26 PM
I'll check the exhaust pipe to radiator clearance, good suggestion. Bike doesn't overheat anymore now than when new, just according to riding circumstances.
Posted April 19, 2006 - 01:16 PM
It's happened to me a few times. With or without the reservoir doesn't really make much difference except you don't actually loose the coolant with the reservoir but the engine gets just as hot. Run with it on my dual sport and run naked on the sticker bike.
Posted April 19, 2006 - 02:30 PM
You can notice if thats the problem pretty easy as your coolant will be dirty and foamy.
anti freeze not only does what has been mentioned, lubrication, anti corrosion, and freeze protection, but also increases the boiling point of the fluid. The pressure from the cap also increases the boiling point of the coolant.
Your pump also needs to be doing its job. If your impeller or volute is damaged at all you wont have the circulation needed.
Posted April 24, 2006 - 05:58 AM
"You CAN make a higher pressure cap!
(Yep! I'm giving away a BIG secret that we found out in 1994!)
1. Buy a "Stant" brand, #11233 cap. It has a BROWN spring in it that is just shy of 1'/25.4mm diameter. Actual measurement was .965"/24.46mm on the one that I'm measuring right now. It's the only "Stant" radiator cap spring that is brown AND ~1"/25.4mm diameter (if you forget the STANT part number and have to measure every Stant cap on the rack). It's almost always in stock in automotive supply stores.
2. Take the STANT cap. Get pliers, diagonal cutters, needle nose and attack the STANT cap. You WILL be amazed at how some parts can be designed to be assembled quickly and easily and are nearly impossible to have accidentally come apart.
Anyway - get the brown spring out.
3. Take your stock cap. Now take the brown spring and spread the "tail" of the spring by hand, just enough to work it around the spring retainer on the stock cap. You'll have to lever the end tail over the cup to avoid damaging the rubber gasket. Presto - 21 to 25 psi cap - just like all them car guys use!"