XR650 overheating question

We were riding yesterday in 60 degree weather and my brother-in-law's 2003 xr650 started overflowing. He has had this problem at least once before. Unfortunately he dropped the motorcycle a few weeks ago and the radiator was damaged. The dent is on the lower left side and is noticable but very small. Probably about 1/2" mashed in and maybe 1" to 2" in length. Do you think this could be the problem? We were near the end of a 20 mile ride and had been in a good bit of sand on and off for a good bit of the ride. Any help would be appreciated. Thanks.

Just a couple other things to consider:

1)Running a colder plug- i run the 8 instead of the 7.

2)Hyflow Radiators-if you do have to replace your radiators-consider going with the IMS Hyflow radiators-cheaper than OEM replacement-and 1/3rd more capacity. Superbly made and good fit.

3) Some guys have put fans over their radiators. If you are spending lots of time at very low speeds it might be an answer for you. The other 650 websites have diagrams of the fix. Essential if you are pushing it for miles over sand dunes (Dakar racers) or thru swamps (hardcore Cajun shrimp farmers), etc.

Remember the 'overflow' is - according to the idiots at Honda- NOT boil over, just 'overflow'--and according to them--its OK. The rest of us think the bikes' cooling system needs to be re-engineered!


Sorry to hijack your post krs3.

Where can I buy a radiator cheaper than OEM ?

I looked at IMS's site and same price ($200).

If its a stock bike and not uncorked then you can expect it to overheat. The stock bikes jetting is way too lean so it will pass emissions. My 650 has never overheated and most of its riding is in tight woods mountain trails. I also do dunes. Uncork the bike and your problem will be over!

My BRP was uncorked before i picked it up from the dealer. Its been ridden and raced and developed and raced again and again. It has overheated in tight desert in the summer. Its also finished the last 200 miles of the Baja 1000 with a hole in the radiator! Temps were in the 40's and 50's--so it didnt need a cooling system. Point is--your conditions will dictate overheating frequency/fix.

I am sure those in cooler climates will have far less issues with overheating. Most riding slow in hot climates will have to deal with the BRP's overheating issues.

Its been covered to death on TT, XR650R.US, Yahoo Group, etc. 'Uncorking' it properly will of course help out a bit, but many find the bike still overheats--apparently not in the mountains of Washington!

Once again, if the bike is uncorked and jetted correctly (richer), it will not overheat even at slow speeds in hot weather. The dent you mention is too small to cause a problem. My guess is that his bike is stock, not uncorked like it should be.

In any case, the overflow won't hurt it, it's considered normal by Honda, but I don't think losing fluid is a good idea even if it's "normal".

Find out if his bike is still in the stock form and if so uncork/jet it correctly. He can find all the info here in the forum.

Irondude, I noticed you have tried those IMS radiators. Like I said I dont have an overheating problem but because of sound issues in some states I would like to set the bike up with the stock silencer baffle in place. Do you think the oversized radiators would make this possible without the same overheating issues that the stock setup has? :)

Sorry Olde,

I havent ridden enough with the stock pipe and full stock baffle in to say for sure. My hunch is that the bike wont overheat with the full stock set up--that afterall is one of the reasons IMS made these available. But i cant say for sure yet as i have only got a couple months of testing into them-and this was during the winter. The engine runs cooler, for sure. I wish i had the dipstick with the temp gage...

I am very partial to riding quiet-plus the FIM/ISDE qualifier will require a 94db bike--so for sure i will be racing the BRP with the stock pipe and baffle later this year-unless someone comes up with a 94db pipe... :)

Irondude, one more question. Have you done any experimenting with the full stock exhaust and removing some or all of the inserts from the airbox and different size jets. Im really curious as to how far you can take it with the stock exhaust setup in place. You know so it will start easier and have a little more oomf and yet be stealthy.

its a good question-wish i had the answer. Not sure where the limit is-so far the standard b53e,68s, 175 has been a happy medium-but I only 'rediscoverd' the stock pipe in Jan. and am still trying stuff out-but remember i have the cut outs on the airbox cover-and a modified top end and bottom end. Let me know what you find!

The edelbrock is nice here becouse i can go from race/no suppressor to stealthy/stock pipe and externally tune the carb--all in 10 minutes! That part i have dialed in now-its a nice way to go!

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