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XR650L is overheating

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I need some opinions on this.  I bought this bike a few months ago and according to the aftermarket vapor gauge it gets over 300 degrees if it sits very long at all idleing.  I thought it was running too lean but I don't think that is it.  I believe it actually has a XR600 carb on it.  I know that some people do this as an upgrade mod.  I put the richest jets available for it and its still overheating. I've checked the valve clearance and its at spec.  I wonder what else could be causing this?  I also wonder if the gauge is working right.  Its sensor is in the oil feed line.  Please see the picture.  It was about 70 deg outside when I checked it.  The gauge was reading around 300 deg while using an infrared temp gun we checked the center right side of the head and it was about 250.  I'm not sure how accurate the temp gun is.  We took another reading after turning off the engine for 5 minutes.  it was reading 320 on the gauge and 285 using the temp gun in the same spot.  I know that air cooled bikes run hotter than water cooled, but this seems too hot to me. 

 

 

Did the previous owner install this thing correctly?  I'm trying to figure out if this is really a problem and what is going on.  The picture shows where the temperature sensor is mounted.  Any help is appreciated.

20130926_202634.jpg

Edited by shanman2001

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Oil temps are going to read MUCH hotter than water temps. 275 to 300 seems to be the high end of normal for oil temp on these bikes. Don't think you have anything to worry about. 

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I believe it actually has a XR600 carb on it.

But you're not sure? What bike do you have?

 

I know that some people do this as an upgrade mod.  I put the richest jets available for it and its still overheating.

What jets exactly? Jet sizes for the Keihin PD go high enough to make an RFVC, Which I assume you have, not even run, so I doubt you have the richest ones available.

 

I've checked the valve clearance and its at spec.  I wonder what else could be causing this?  I also wonder if the gauge is working right.  Its sensor is in the oil feed line.  Please see the picture.  It was about 70 deg outside when I checked it.  The gauge was reading around 300 deg while using an infrared temp gun we checked the center right side of the head and it was about 250.  I'm not sure how accurate the temp gun is.  We took another reading after turning off the engine for 5 minutes.  it was reading 320 on the gauge and 285 using the temp gun in the same spot.  I know that air cooled bikes run hotter than water cooled, but this seems too hot to me.

When are you getting these elevated readings? At standstill? What are the temps when your speed is sustained between about 30 and 50mph?

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The bike is a XR650L, but the carb doesnt match what the manual shows for this model.  It actually looks like the carb off of the XR600.  I believe the previous owner was moding it with a different carb for more performance.  If I remember right, I installed a 168 for one jet and a 68 for the other jet.  I know that the dealership told me that at least one of those jets was the biggest available for the carb.  I had another forum post on here previously and someone thought it was a carb from a XR600 after posting a picture of it.  So I'm pretty sure it is.  It does also have a K&N replacement air filter on it also.

 

As for the other question about the temperatures, I havent even rode it outside of my sub-division yet.  The headlight and turn signals dont work right now, and I havent trusted that it isnt over heating so I havent taken it out anywhere.  So I 've only had it up to like 30 MPH for short periods of time and most of the time slower than that or sitting still.

 

Do you think that the sensor for the aftermarket temp gauge is not supposed to be mounted where it is?

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Okay, I found the pictures and you do have an XR600 carburetor, hence the "PD" one the side. 650R carbs have "PE."

If I remember right, I installed a 168 for one jet and a 68 for the other jet.  I know that the dealership told me that at least one of those jets was the biggest available for the carb.  I had another forum post on here previously and someone thought it was a carb from a XR600 after posting a picture of it.  So I'm pretty sure it is.  It does also have a K&N replacement air filter on it also.

Those may be the highest jet numbers that Honda provides official part numbers for, but they are certainly not the highest numbers that Keihin provides for that carburetor. For example, I have a 170 main in my bike now and a 70 pilot on the shelf, both genuine Keihin parts.

I don't know what power improvements have been made to your bike, but it's doubtful that 68/168 jetting in the XR600 carb is at all lean or causing high temps.

 

and I havent trusted that it isnt over heating so I havent taken it out anywhere.  So I 've only had it up to like 30 MPH for short periods of time and most of the time slower than that or sitting still.

RFVC engines tend to run coolest between about 40 and 60mph. The "wind wings" on a 650L's tank that many people remove (or wipe off in a crash) actually do improve cooling at moderate and elevated speeds. They understandably get hot when there is no cooling air moving over the fins and engine.

 

Do you think that the sensor for the aftermarket temp gauge is not supposed to be mounted where it is?

I think it's fine where it is; you're just going to get different readings in different locations. Under the oil line fitting is going read partly oil temp and partly cylinder head temp (CHT). Under the spark plug would be mostly indicative CHT only, which tends be higher than oil temp.

Also, why does your bajo bolt look like a regular metric grade 8.8 hardware store bolt? It's a little concerning.

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I`ve never seen a vapour read correct oil temp on that line yet,,it has heat coming from the combustion chamber elevating the reading,,,a temp dipstick if calibrated,,,is a more accurate in my opinion.........

 

I seriously doubt if you actually ride the bike that it would overheat,sitting still though,,it`ll get seriously hot,,it is an air cooled engine,,it needs airflow..

 

B

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Okay, I found the pictures and you do have an XR600 carburetor, hence the "PD" one the side. 650R carbs have "PE."

Those may be the highest jet numbers that Honda provides official part numbers for, but they are certainly not the highest numbers that Keihin provides for that carburetor. For example, I have a 170 main in my bike now and a 70 pilot on the shelf, both genuine Keihin parts.

I don't know what power improvements have been made to your bike, but it's doubtful that 68/168 jetting in the XR600 carb is at all lean or causing high temps.

 

RFVC engines tend to run coolest between about 40 and 60mph. The "wind wings" on a 650L's tank that many people remove (or wipe off in a crash) actually do improve cooling at moderate and elevated speeds. They understandably get hot when there is no cooling air moving over the fins and engine.

 

I think it's fine where it is; you're just going to get different readings in different locations. Under the oil line fitting is going read partly oil temp and partly cylinder head temp (CHT). Under the spark plug would be mostly indicative CHT only, which tends be higher than oil temp.

Also, why does your bajo bolt look like a regular metric grade 8.8 hardware store bolt? It's a little concerning.

 

 

Holy moly, I too would make sure that bolt holding the banjo fitting is in fact the correct hollow one and not a generic solid bolt blocking all the oil flow to the head.

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Ehh.  Not good.  This looks like a regular bolt to me.  I really want to punch the previous owner in the throat.   This might explain the overheating.  Hopefully it hasnt done much damage.  I have only riden it around the neighborhood.  The previous owner was a real dumb@ss I assume.  I really appreciate you guys catching this.  I hope they werent trying to coverup something else by using this bolt.  Ugh!!!!!

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Holy heck,,can we assume that the odd bolt actually has a hole in it to allow oil flow to the head..It should be hollow internally with a small hole drilled through the side of it. If it's just a solid bolt then the damage will be kinda extensive..I suppose if the centers been drilled and a smallish hole drilled through the side you may be lucky depending on how the small hole aligned with the top fitting..If she's solid you really just have to shake your head in disbelief..surely no one could be that dense.. :thumbsdn:..Possibly it was the p/os attempt at more oil delivery to the head,,must have read about it here.. :lol: ,,just appears he got it slightly wrong..

 

Not really a laughing matter,,just couldn't help myself.. :naughty:

Edited by Horri

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There is no hole!!!!!! I am fffffing pissed!  Luckily it hasnt been rode much since I got it, just around my sub-division.  But not sure what happened before that!!!! 

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There is no hole!!!!!! I am fffffing pissed!  Luckily it hasnt been rode much since I got it, just around my sub-division.  But not sure what happened before that!!!! 

Check the other one as well...The one at the other end of the oil line.

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That is a new one to me. There should be a sticky for things to look for on used bikes, even the unbelievable.

 

Demotivational-Redneck-mechanics.jpg

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Explains some of the heat, oil takes some heat away along with lubricating cam shaft. You now need to remove head cover and inspect for damage, cheap insurance at this point.

 

"HJ"      :cheers:

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I bought this oil cooler (have not installed yet)

http://suttoncycleworks.com/oilCooler.html  I live in Phoenix so any extra cooling is welcome. Plus there is a thread around on the forum somewhere where a member did an incredible amount of oil testing and found any oil choice was pretty well spent by 500 miles, but after adding an oil cooler 2000 miles was more like it.

 

Another pitfall to look for, the braided part of the oil line that goes into the bottom of the frame can get twisted during the install (this is the same line that has a metal screen behind it that needs cleaning from time to time). If that line is twisted it will greatly reduce the oil flow. Happened to me and I a complete tear down, new pistol, reamed out cylinder - it was a mess and expensive.

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not sure if I want to look at any possible damage.  It gives me deniablity if I decide to sell it.  I hate to do that, but it will still be in a lot better shape than when I got it, if I do decide to go that route.   I might replace the bolts and change the oil then ride it some.  It has an oil cooler on it.  Of course, that didnt help the top end in this situation.  I have no idea how much it was ridden after this dumb-ass-ery was performed.  It may not have been that much.  I think that is why they sold it because they didnt know what they were doing and couldnt get it running right.  Somehow the engine is pretty quiet.  I did get a free set of cams with it when I bought it though.

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mmm..Not something I'd be doing,,just not kosher or fair dinkum if you like..Can you somehow get a video with some sound of the thing sitting there at idle and then your giving it a few revs..We may be able to tell if it sounds gone from that as long as the gorilla who did it hasn't stuffed some bananas in the head cover area to quieten the thing down.. :mad:

 

Free set of Cams aye,,you may need them yet..Should be no "mights" about replacing that top bolt and the bottom if it's the same..Any more than ten minutes running like it is and the head area will be toast.,,I'm kinda astounded the thing isn't rattling like a rattling nancy already tbh..

 

Once you replace those suspect bolts or bolt you'd start it then crack that top bolt open a little immediately with a spanner to make sure oils getting to that point..Soon as you see oil running down the side of the engine you know it's at least reaching that point..retighten the bolt..Each of those bolts should have a copper washer beneath the bolt head and fitting and the fitting and engine head..They stop oil leakage,,ie ,,crush washers..

Edited by Horri

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Holy heck,,can we assume that the odd bolt actually has a hole in it to allow oil flow to the head..It should be hollow internally with a small hole drilled through the side of it. If it's just a solid bolt then the damage will be kinda extensive..I suppose if the centers been drilled and a smallish hole drilled through the side you may be lucky depending on how the small hole aligned with the top fitting..If she's solid you really just have to shake your head in disbelief..surely no one could be that dense.. :thumbsdn:..Possibly it was the p/os attempt at more oil delivery to the head,,must have read about it here.. :lol: ,,just appears he got it slightly wrong..

 

Not really a laughing matter,,just couldn't help myself.. :naughty:

 

Didn't shanman say he bought his bike from a guy in New Zealand at a really good price?  Only ridden on Sunday's by a little old lady.

Edited by Go Big Red

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not sure if I want to look at any possible damage.  It gives me deniablity if I decide to sell it.  I hate to do that, but it will still be in a lot better shape than when I got it, if I do decide to go that route.   I might replace the bolts and change the oil then ride it some.  It has an oil cooler on it.  Of course, that didnt help the top end in this situation.  I have no idea how much it was ridden after this dumb-ass-ery was performed.  It may not have been that much.  I think that is why they sold it because they didnt know what they were doing and couldnt get it running right.  Somehow the engine is pretty quiet.  I did get a free set of cams with it when I bought it though.

Excuse my rant... But, I hope you arent suggesting pawning a bike with KNOWN damage off on an unsuspecting buyer... You sell it to someone else knowing full well that the top end is likely bruised (or worse) and you are no better than the dickweed who pawned it off on you. The jerk who I bought my bike from had hidden a few surprises for me.  I intentionally avoided his neighborhood for a good long while... Knowing my sometimes toasty temper (Irish... can't help it)... It wasn't worth going to jail over.

I couldn't have sold it to someone else though... Being able to look at myself in the mirror is worth more than a thousand bucks. The upside is that it caused me to turn every nut and bolt on the bike. I know what I have now.

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