Posts tagged Cooling System

Check Your XR650R Thermostat

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The Honda XR650R Thermostat is known to fail regularly. This isn’t a drastic issue, but will cause your engine to run under non optimum temperature conditions if not treated. It’s a good idea to check your thermostat from time to time and if it looks something like the photo below then it is time to be replaced.

Honda XR650R Thermostat

Stant Manufacturing Radiator Cap for the XR650R

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There are a few options for swapping out the Honda XR650R radiator cap. You can swap the KX500 radiator cap onto the XR650R, or you can buy the SRC Racing XR650R Radiator cap, or you can but the cap produced by Stant Manufacturing in California.

I have read great reviews of the Stant caps, they seem to be built very well. However, I am not positive of the pressure rating of their cap for the XR650R. I have read it is 1.6 Bar, but I have also read it is 1.8 Bar. If anyone knows for sure please send me the info or comment on this post.

Swapping the KX500 Radiator Cap onto the XR650R

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Many owners will swap the 1.1 Bar rated radiator cap that comes stock on the XR650R for an aftermarket unit. The goal is the prevent the radiators from boiling over as easily. It’s a somewhat debated topic in that using a higher pressure cap will increase the strain throughout the entire system. Most have positive experiences with switching radiator caps. Personally, I prefer to keep mine stock.

The 1992-1996 Kawasaki KX500 Radiator cap is 1.8 Bar and can be swapped directly onto the XR650R. The Kawasaki part number is: 49085-1059

There is also a SRC 1.6 Radiator Cap for the XR650R available new. As well as a Stant Manufacturing Radiator cap for the XR650R.

SRC High Pressure Radiator Cap for the XR650R

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Many owners will swap the 1.1 Bar rated radiator cap that comes stock on the XR650R for an aftermarket unit. The goal is the prevent the radiators from boiling over as easily. It’s a somewhat debated topic in that using a higher pressure cap will increase the strain throughout the entire system. Most have positive experiences with switching radiator caps. Personally, I prefer to keep mine stock.

The SRC (Scott Summers Racing Components) unit is rated at 1.6 Bar and is part number 1672. It looks like this:

You can also swap the radiator cap from a KX500 onto the XR650R. As well as a Stant Manufacturing Radiator cap for the XR650R.

Simple XR650R Cooling Fan Install

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The XR650R cooling system is quite adequate in most situations. However, in hot climates when riding slow steep trails, or being stuck in traffic, the BRP can get too hot and overheat. Many will try to band-aid the situation with a high pressure radiator cap (which can be read more about elsewhere on this site). But the best fix is to install a fan on the radiator attached to either a temperature controlled switch, or a manual switch on the handlebars.

A cheap route to go is using a SPAL 4″ Paddle Blade Fan built for a 12v system. This will of course require your bike to be producing 12v, so a regulator is needed, and ideally a small battery. This upgrade is optimal for bikes already dual sported. It can however be achieved with just a regulator and small capacitor.

The above mentioned fan is part number VA32-A101-62A and is similar to the fans found on a stock KTM 4 banger. The KTM fan can be used as well, but it is more expensive.

KTM Fan from all their RFS motors looks like this:

KTM Fan Installed:

With a little bending and trimming the SPAL fan can be mounted to the existing tabs on the right radiator of the XR650, then a simple handlebar switch can be installed. The fan doesn’t use much power 124 cfm @ 1.9amps but I always run a 3 amp switch to things just to but super safe. The mounting holes are 3.23″ apart, and the fan thickness is 2.36″. It can be found from vendors on eBay, or through industrial supply companies.

It can also be installed a little more gracefully with a custom bracket made up.

The fans have been confirmed to fit with the Stock gas tank, the Acerbis 6.3 gallon tank, and the IMS 4 gallon tanks. It does NOT fit with the Clarke 4.3 tank.

There are of course other fans of similar size that can work. CMP Racing out of Michigan carries a fan of similar size – though I do not have specific details on it. Looks like this:

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4Strokes .com did a Cooling fan writeup a while back that included dimensions for building a mounting plate for the fan. Here is the PDF: Honda_XR650R_Cooling_Fan_Install_With_Custom_Frame

Honda XR650R Water Pump – Parts Fiche

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Parts fiche for the Honda XR650R Seat and Side Cover.

Honda XR650R Radiators and Thermostat – Parts Fiche

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Parts fiche for the Honda XR650R Radiators and Thermostat.

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