XR650L Overheating Issue

[BRP Robbs 0]

Ok, I'm almost positive I've seen a thread about this before but for the life of me I can't seem to find anything about it.

I have a 2007 XR650L with Dave's carb mods, re-jetted, de-snorkeled, de-smog-pumped, UNI air filter, otherwise stock as far as engine and breathing goes, stock gearing, Acerbis 5.2gal tank, vented supermoto front fender, and the original Trailwing tires. I ride fairly hard on the superslab for about 20 minutes in 90-ish degree weather at 65-80mph and my XRs Only temp gauge dipstick reads 250-260. I haven't cross-check the oil temp with another thermometer yet so it could be that my gauge isn't calibrated very well, but i'm concerned about the oil's longevity at that temperature. Especially since I'm planning a desert trip soon and I suspect that slower speeds with less airflow and potentially more engine load / higher air temps will make the problem even worse. I would ideally like to keep the temps below 200 or 220 at most, so even if my gauge reads hot I doubt it's THAT far off.

I've decided to add an XR400 oil cooler, but after hours of searching online I can't seem to find a single one for sale. C&D Cycle Center quoted me $265 for the cooler only, which seems ridiculously high to me. In the meantime I guess I'll put the stock tank and wings back on and see if that helps any. I'm not looking forward to that because I really like the 250+mile range with my 5.2 tank. I think with the stocker I was only getting about 80 miles to reserve. I also plan to play with the jetting a little bit and see if that makes any difference. I can't remember what jets are in there now (I just went with what everyone seemed to be recommending for an uncorked bike with stock exhaust). Frankly, I have no idea how jetting works so I'd just be stabbing in the dark, but that's nothing new for me. At some point I will probably also look into getting bigger cooling fins welded onto the head as well. I haven't researched it yet but it sounds pretty expensive / involved / time-consuming. That one will probably wait until I decide to tear into the engine for some other reason. Also, I mentioned tires because I will soon be running more street-oriented tires for commuting, but the trailwings are smooth enough that I doubt that will make much of a difference with engine temps.

So... anybody have any advice on how in the world I can find an XR400 radiator for less, or something else that could be adapted to work without too much fabricating? Or can anyone help me find one of those old threads on the subject? Or jetting advice with emphasis on reducing engine temps? Or is there anything else that I'm not thinking of? Or do I just need to bite the bullet and drop another $265 at C&D?

[Spaugh 1]

drop the clip on your needle and see what happens.

also you didn't mention what kind of oil you use. 260F is hot for regular oil and I doubt you will get it down below 200 ever. you can buy a lot of ester based oil for 265$ and not worry about it though.

[Badfish2 0]

At 250 degrees I don't think there's a problem. Remember these are air cooled motors and will run quite a bit hotter than thier water cooled counter parts. When you shut the bike off after riding do you hear a "tink" type sound coming from the cylinder? This type of sound seemed to be the tell tale sign of the XR air cooled motor running hot (contraction of the metal). As long as you'er not pushing 275-300 deg. I think you're OK.

[BRP Robbs 0]

you can buy a lot of ester based oil for 265$

Haha, excellent point. Sometimes I get wrapped up in projects a little too much. I'll try pulling the clip, too. Thanks. I can't remember the oil I'm running exactly. I think it's TTR 4-stroke synthetic something. I started using it at Chief Gunner's suggestion, so whatever he runs (not that that helps necessarily). I think it's a pretty high-quality oil.

At 250 degrees I don't think there's a problem. Remember these are air cooled motors and will run quite a bit hotter than thier water cooled counter parts. When you shut the bike off after riding do you hear a "tink" type sound coming from the cylinder? This type of sound seemed to be the tell tale sign of the XR air cooled motor running hot (contraction of the metal). As long as you'er not pushing 275-300 deg. I think you're OK.

Really? That's definitely reassuring to hear. It seemed awfully high to me, but I guess with only 1500 miles between oil changes anyway, maybe you're right. I don't hear any tinks (from my bike, anyway. I know what you mean though). I also don't ever notice any power loss, which was a telltale sign on an old truck I used to have. That thing ate itself alive though.

Anyway, thanks for the tips, guys. Guess I'll hold off on the oil cooler and see what happens.

[PastaPilot 17]

Ok, I'm almost positive I've seen a thread about this before but for the life of me I can't seem to find anything about it.

I have a 2007 XR650L with Dave's carb mods, re-jetted, de-snorkeled, de-smog-pumped, UNI air filter, otherwise stock as far as engine and breathing goes, stock gearing, Acerbis 5.2gal tank, vented supermoto front fender, and the original Trailwing tires. I ride fairly hard on the superslab for about 20 minutes in 90-ish degree weather at 65-80mph and my XRs Only temp gauge dipstick reads 250-260. Especially since I'm planning a desert trip soon and I suspect that slower speeds with less airflow and potentially more engine load / higher air temps will make the problem even worse. I would ideally like to keep the temps below 200 or 220 at most, so even if my gauge reads hot I doubt it's THAT far off.

So... anybody have any advice on how in the world I can find an XR400 radiator for less, or something else that could be adapted to work without too much fabricating? Or can anyone help me find one of those old threads on the subject? Or jetting advice with emphasis on reducing engine temps? Or is there anything else that I'm not thinking of? Or do I just need to bite the bullet and drop another $265 at C&D?

Having been a 650L owner I can share a few thoughts with you.

One reason I never got a temp dipstick is I didn't want to know how hot it was running. It is an air cooled bike and the oil will be hotter than the water on a liquid cooled bike. Said and done.

The wings on the stock tank actually help cooling at freeway speeds. Gunner noticed this when he went from the Acerbis Veldez tanker back to the stock tank. At 90 degrees ambient temps and riding at 70+ freeways speeds you'll never have oil temps in the 200-220 zone, even with the XR400 oil cooler. The design of the bike won't allow it. Try riding to work at 50-55 and you might see temps in or close to that range. It's just an engine load to airflow ratio, at 70 the engine load is too high and the actual airflow over the engine is too low. It's an aerodynamics issue with the front tire, fender, forks, etc.

I wouldn't blow $300+ on the 400 cooler. If the engine is stock, the oil temps and longevity will be fine for your desert trip. IF you ever pull apart the engine and THEN decide to go with a big bore, high comp piston THEN look into the bigger cooling fins and a supplemental oil cooler. IF you do an oil cooler, there are a number of guys out there that have adapted other brand motorcycle or car oil and powersteering coolers to their bikes for less than $100.

[bikeslut 1]

If you want to run that fast, you may want to re-gear... i just bought 40 tooth rear for mine, but haven't installed it yet... bolts don't fit

You can jet a little richer, and that will help in the desert, and drop some temp, but you may suffer a bit with bog in the mountains

The bikes are pretty bullet-proof, but they really aren't made for the real high speed stuff... I agree with Jon on that... as far as the oil cooler, you don't need an "XR400" cooler... you need something to boost the oil capacity, and get the oil out there in the wind. The fittings are the biggest hassle, I would think.

$265 seems like a lot, but if extends the life of the motor, it may be worth it

[toddrh 0]

I would give Scott Brown a call up at Escondido cycle salvage....760-746-7467. He made be able to get you a used cooler, and/or provide some more insight to your issue.

Also, if you need to have lines made, try the hydraulic cylinder service places 1st (cheaper), then try the more custom hose builders, like Crown up in Vista, or Industrial Liquidators on Convoy.

[paulmbowers 236]

It's the tires, clearly.

[BRP Robbs 0]

Thanks guys, I really appreciate all the advice. Especially yours, FakeName. After reading your posts, I'm not so worried about doing anything too drastic right away, but I'll search around and see what I can find on the cheap. I know that the engines are designed to operate without oil coolers, etc. but having worked on large slow-speed diesels and various other things in the past I know how significant the effects of harsh environmental conditions can be on the useful life of mechanical equipment. And most of all, modifying things is fun (even though sometimes it feels like I take 2 steps back for every step forward).

[Sneeker 29]

From what I understand the XR650L is nearly the same as the XR600, just 50cc bigger.

An hour ride at 60-80 mph on a 80* day would definitely get my 600 up to ~250* on the oil temp gauge, no problem, that's what I consider operating temperature during the summer.

Nonetheless, I've been trying to dial-in my jetting to be just a tad rich to keep the engine running cooler. The easiest thing to do in this case is go up one main jet size at a time until the engine starts to blubber a tiny bit just off of acceleration, then go back and use the last main jet tried that wasn't blubbering the engine. On the 600 unscrewing the carb bowl and changing the main jet from there is way easier than pulling the carb out and changing the needle position, but sometimes it can't be avoided. I know cause I've been dealing with this for the last couple of days.

As for high temp tough oil try Shell Rotell-T 5W-40 synthetic. Works great, won't slip the clutch, and it sells at wal-mart cheeep.

Good luck

[Kevin 0]

to fix your overheating problem-purchase the oil cooler of a Honda XR400 and mount it in the same place. It mounts on the gooseneck. This is a very common fix, and fits and works perfect.