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XR's Only "Big Fin" Kit on XR650L

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So I've had a few issues with my XRL concerning heat. The valves and cam on my piggy have seen a few rebuilds over the past few months because of it. Temps normally run me in the 250 to 280 range during normal riding and upwards of there when riding slow (traffic or technical trails). This was with a properly jetted carb and an oil cooler.

I finally got sick of it and decided to try something different this time around. I searched and asked a few people and the only tried and true solution I could find was the XR's only big fin (baja) kit. It didn't really look like it would make much difference at first, but did it ever!

I don't normally do write up's on parts I've tried out, but this was totally worth the money. The only difference between my old temps and the current one's is the big fin kit. I'm running the same oil cooler in the same configuration, using the same carb/jetting. I've only put about 50miles on it so far but my engine temps have hovered around 180 while riding. :busted: (Yes thats a 1 in front of the 80). Before this my bike has never run under 200 degrees when fully warmed up.

I'll keep an eye on it, but so far this is pretty awesome. :banana:

DSC03232.jpg

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What kind of heat related issues were you seeing? The only thing that I can directly call a heat related failure is when I lost two valve seats on my 600. The head got so hot the aluminum got to annealing temperature and the interference fit on the valve seats became a loose slip fit.

From your sig it looks like you ditched the airbox and went with a pod filter right on the carb. You also say it's "properly jetted." How did you accomplish this? The only way I can think of is to run a wide band O2 sensor while on a dyno. I just don't see how the stock needle can work right on the stock carb with no airbox and still give the proper fuel air ratios.

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Yea, there's gotta be something else going on. There are soooooo many of these bikes out there with no oil cooler run all day in 90+ degree weather with ZERO problems. Funny it's just you having heat issues.

The mod looks killer anyway. Glad you are happy with it.

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maybe something from his engine being pretty built with hi comp piston and such??? from his signature

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Yea, there's gotta be something else going on. There are soooooo many of these bikes out there with no oil cooler run all day in 90+ degree weather with ZERO problems. Funny it's just you having heat issues.

The mod looks killer anyway. Glad you are happy with it.

The mods are awesome and they obviously dropped your temps.

I still have to be curious if something else is going on? Like this poster pointed out, lots of people beatin the h*ll out of these thing in very very hot weather with no problems. Mine has had no mercy shown heat wise for 18k and seems to be alright. Ive seen her get hot enough to cough and sputter a bit, but no serious problems.

What happened that makes you say it was heat failure? Curious.

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Wow, 280?! My L runs about 190-210 during all but the gnarliest riding. Never been over 250 untill after it's shut down. Might wanna make sure your jetting is on point, glad the fins brought the temp down though.:busted:

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The only time I've seen those kinds of temps was on a trail mantainence ride. It was 85-90 and I was riding in 1st,2nd and stopping every 20-100' to take signs off of trees. Then when I had the chance I'd jump on a road and get her moving and it would drop to 225-240.

Something ain't right with your jetting....and why the pod filter?

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Heat related issues were multiple cam/rocker failures. Replaced them three times this summer alone. :busted:

Piston is 10.5:1...not too bad.

Jetting was done on a dyno by a local race shop. I "trust" that they got it right, but never really re-checked the jets after I got it back. Heat problems started before I had it jetted though. The jetting was part of the "solution". :banana:

Correct on the pod filter. Bought the bike like this about six years ago and never bothered to put the airbox back on...no point really. I do like more HP.

I did beat the $hit out of it...why else would I have an L? :banana:

Some of the oiling problems I had stemmed from a partially clogged oil pump, which has also been replaced.

Either way all the little glitches (hopefully) have been fixed and with the added fin size and oil cooler hopefully she'll run for more than a month this time. :busted:

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Heat related issues were multiple cam/rocker failures. Replaced them three times this summer alone. :busted:

That indicates something wrong with the lubrication system unless oil was burned onto the head around the valves. In that case, it would be a fueling or usage problem(like not enough airflow)

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The lack of oil caused the "heat" problems. These top ends fail when they get "hot" from lack of oil not the reverse. The big fin head may be added insurance but there is no substitute for proper oiling. Even with that head if you run the cam dry it will still self destruct.

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I did one of the rebuilds with Srad600. the first one this summer and my first xr650l but not my first build. we did not pull the engine or the lines just the top end.

On this one(#3 rebuild) with new oil pump and still no flow, I found the oil supply line was pinched that was the problem the whole time. not enough oil flowing but now it flows great.

srad600, we should look at your jetting and needle to see what it is. B

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Temp Dipstick, good to have something on an aircooled bike to monitor

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How are all of you getting your temperature readings? I haven't noticed a temperature gauge anywhere on my XR650L.

I have a trailtech Vapor which gives me an oil temperature reading for anything over 100 degrees.

=srad600, we should look at your jetting and needle to see what it is. B

Yep, I'm going to put some miles on it until I get the o-ring for the Pumper. Once I get that I'll put it on and we can get together to jet that one. :banana:

Thanks for all your help so far. :busted:

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How are all of you getting your temperature readings? I haven't noticed a temperature gauge anywhere on my XR650L.

lol thats funny

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I thought about getting a temp dipstick, but then I realized that there was nothing I could do about the temps .. the bike either can survive or not. Cuz, I refuse to change my riding habits, lol. So far it's surving with just regular oil changes, lol. I don't ask it's temperature, and it doesn't tell me.

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About to do the same mods (USD, Vector, JE 10.5, #1 Cam) on my 94L. So this thread caught my eye (oil cooler search).

Daves mods done and working on the exhaust now.

Where in Ca are you guys??

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About to do the same mods (USD, Vector, JE 10.5, #1 Cam) on my 94L. So this thread caught my eye (oil cooler search).

Daves mods done and working on the exhaust now.

Where in Ca are you guys??

Good luck with the mod's. This board is a great place for information. We're in the SF Bay area, if I can help let me know. 😏

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