Big Gun CDI Unit for the XR650R


There are several CDI units which can be swapped onto the XR650R for improved performance. Big Gun makes one for around $120 called the Over Rev. Like the others it advances the timing slightly and raises the rev limiter.

Another option – and potentially cheaper is swapping an XR400R CDI into the XR650R.

There is also a Procom CDI for the XR650R.

Enlarging the Bolts on the XR650R Subframe


The subframe on the XR650R is one of the biggest weaknesses when being considered by dualsport riders. Having a lot of weight far back on the bike will eventually cause the subframe to break. There are a variety of upgrades which can be done to improve the strength of the subframe. One of those upgrades is increasing the size of the mounting bolts from 8mm to 10mm.

The stock subframe mounting bolts are 8mm with a 1.25 thread pitch. You can drill these out to 10mm and tap them. The mounting points will be significantly strong and the bolts will be less likely to become over stressed when carrying a load.

It’s not an end-all fix – it’s just one step in strengthening the rear of the bike. There is more information about this topic on the site.

Prepping a New XR650R For Riding


Any new XR650R needs to have several things done to it before hitting the trail.

  • Uncorking/rejetting – Uncorking is optional, but nice.
  • Replace the thermostat
  • flush and replace fork fluid – more about this on this site
  • drop and grease/replace all the bearings – linkage and shock bearings are generally dry from the factory
  • Check the valves, especially the left exhaust.
  • Check and tighten left footpeg bolts
  • Buy an additional clutch plate and add it when it starts to slip
  • Wrap a couple additional wraps of tape around the spark plug wire.
  • do not check oil level unless the engine has been running – make sure not to overfill
  • make sure the engine vent hose isn’t pinched

Great Honda XR650R Videos


There a LOTS and LOTS of great XR650R videos out there on Youtube, Vimeo, etc. I’ll try to post a bunch of them here. If you have a recommendation just add it to the comments and I’ll put it on the page.

Lots more to come….

Changing XR650R Stock Fork Oil


There probably aren’t too many XR650R’s running around with their stock fork oil anymore. But, if your bike still is, you should change it. The XR650R oil was known to be low quality from the factory and in some cases as been shown to cause corrosion and rust on internal components.

If you still have the stock fork fluid – drain it – flush it – replace it!

Reinstalling the XR650R Oil Dipstick


A common issue for new XR650R owners is threading the dipstick back into the frame after checking the oil level. The shape of the dipstick makes it very tricky to line up the threads properly, and many new owners will cross-thread the dipstick.

One tip is to make sure the dipstick is angled slightly towards the right side of the frame when dropping it into the frame. This will help quite a bit.

Another option is to trim and inch off of the bottom of the dipstick. This will prevent it from interfering with anything inside the frame when inserting the dipstick.

Destroyed XR650R Piston and Valves


The top end of the Honda XR650R is very robust and long living. However, if you push it too hard you can eventually hit a wall. The pictures below are from a motor that was running a stage 2 cam. This cam puts the valves VERY close to the piston when fully open. When the cam chain stretches a bit then Kablammo!

Have a Noisy XR650R?


The XR650R is a fairly smooth running motor but is known to have a variety of rattles and ticks. If your motor seems to be making a little extra noise lately the cause could be one of the below:

notes from JM-2008

Worn Cam Chain

Historically larger XR,s (old 350’s/400/500/600/650) use a ‘Morse Hy-Vo’ type cam chain.
Looks like a series of gear teeth as opposed to a conventional roller chain.
When new and in good condition they run very quiet.
As the chain wears noise emanates from the rear of the cylinder near the cam chain tensioner.
Usual sign of a worn chain is the noise will diminish as engine rev’s increase.
Strange as this may seem it is due to the chain riding up on the gear type sprockets and taking up the slack.
Suggest checking your chain is not worn and tensioner is not stuck.


(at rear of clutch basket) – If these have sagged or lost tension the clutch will be noisy at idle and low revs, the noise will usually diminish when you pull in the clutch.


Have not had one out of an XRR but suspect it’s the same as with all previous XR variants. These traditionally have a ‘spring loaded split gear drive’ to dampen drive line lash and subsequently noise when not under load.
One of the gears will be spring loaded and appear not to line up with the adjacent gear when not installed.
Should this item lose spring tension the resultant noise will be caused by clearance/back lash in the drive gears.


(item #7 on the camshaft –
Not much to do with this other than remove it.

Unless the clutch hub is notched from wear I wouldn’t bother replacing it, same applies to the balancer & decomp cam, very little to be gained throwing wads of money at the motor to find it’s still noisy!

XR650R Rear Shock Spring Rate


The stock shock spring on the Honda XR650R is rated at 9.3. Many riders will up the spring rate to 10 or 11 – but you should consult a suspension specialist to find the best spring rate for your weight and riding style.

Note sag is usually set at 100mm-110mm unladen depending on preferences.

Stock spring length is 231mm.

XR650R Oversize Front Brake – EBC – QTM – Brake King


Upgrading the stock front rotor to an oversize unit is a great upgrade for the XR650R. It provides improved stopping power and improved feel at the lever. This upgrade is great in particular for bikes running street duty, or bikes that are carrying extra gear or *ahem* a heavy rider.

There are three options.

1.) EBC Oversize Front Brake Rotor Kit

Most popular is the EBC Oversize Front Rotor. These are 280mm rotors and can be purchased with the caliper mount for under $150.

Honda XR650R EBC Oversized Rotor

2.) QTM Oversize Front Brake Rotor Kit.

The QTM unit is 270mm and comes with powder coated caliper mount and rotor mount. They are around $150 if you can still find them.

3.) Brake King Oversize Front Brake Rotor Kit

The Brake King kit is also 270mm and  is about double the price of the other units, but very high quality. It comes with a light weight wavy rotor.

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