XR650R's grunt vs...

How much more power does the XR650R have than a YZ426F? I am just curious.

Just about 224cc's worth - I'm serious

the 650R has a different kind of power, not that revving high strung power, but more just really violent snap off the bottom that doesnt quit until the revs get really high. Very wide powerband and it will keep pulling to very low revs. But its also easy to putt around on if you can get over trying to roost your buddies. Its very tame if you dont use your right hand or have a case of limp wrist :D:)

How much more power does the XR650R have than a YZ426F? I am just curious.

The numbers I have written down are as follows, but your mileage may vary depending on various factors. The stock XR650R right off the showroom floor is unimpressive. The numbers I listed for the XR650R are based on an ‘Uncorked” XR650R, which simply means the bike has the stock exhaust tip drilled out, the intake manifold restrictor removed, the air box restrictors removed and proper jetting. The XR650R is sold as an off road bike (not a race bike) that has to meet certain emission standards unlike the YZF, which is a full bred race bike right off the show room floor. The XR680R numbers are from installing a 680 piston, pumper carb, HRC or aftermarket cam, performance header & exhaust canister, but it’s possible to take these numbers even higher with further changes. As you can see, the XR650R make its power way down low compared to the YZF and it has heaps more torque, but it also weighs more too. Don’t plan to be a MX superstar on this bike, but it’s a great dual sporter, a great fun / play / trail bike for the west coat and it loves high speeds. You can easily get past 100+ MPH with this bike and it won’t be out of breath and it’s very reliable for what it is.

2000 YZ426F 45.3 HP @ 9,000 RPM

2000 XR650R 48 HP @ 5,500 RPM

2000 XR680R 64 HP @ 7,500 RPM

2000 YZ420F 31.2 lb/ft @ 6,800 RPM

2000 XR650R 42 lb/ft @ 6,500 RPM

2000 XR680R 50 lb/ft @ 6,000 RPM

In regards to various bike weights, the May 2000 issue of Dirt Rider weighed the following bikes full of fuel, oil and ready to ride. Here's what they printed as honest full wet weights.

Honda XR650R = 302 lbs

Suzuki DRZ400E = 295 lbs

KTM520 E/XC = 272 lbs

Husaberg FE600E = 285 lbs

Honda XR400R = 278 lbs

Yamaha WR400F = 276 lbs

Kawasaki KLX300 = 271 lbs

Here are the ready to ride full wet weights for some more bikes, but I got these figures from owners who posted in the Yamaha & Suzuki TT forums that weighed their bikes filled with oil, gas and ready to ride.

2003 WR250 = 253 lbs

2001 WR426 = 265 lbs

2001 YZ426F = 266.8 lbs

2003 WR450 = 269 lbs

Here’s the power to weight ratios based on the above info.

HP / Weight

XR650R 48 HP / 302 lbs = 0.1589

YZ426F 45 HP / 267 lbs = 0.1685

XR680R 64 HP / 302 lbs = 0.2119

Torque / Weight

YZ426F 31.2 lb/ft / 267 lbs = 0.1168

XR650R 42 lb/ft / 302 lbs = 0.1390

XR680R 50 lb/ft / 302 lbs = 0.1656

well, I owned an '00 YZ426 for about a year, then sold it and bought an '00 XR650R which I then uncorked/jetted.

Based on ride impression, and not dyno numbers, I can honestly say the YZ "feels" faster, due to it's super wide powerband and high revving engine. But of course, the YZ is not "really" faster than a 650R. I clocked my YZ with a gps to a top speed of 94.6mph, and later, my 650R to 100.2mph. So therefore the 650R is "faster" in that respect.

As far as acceleration, both bikes are super strong, but in different ways. The XR accelerates best right off the bottom and into the lower midrange you can actually feel a very slight hit, but then it tapers off fast. The YZ is ok on the low end, but builds really quick into the midrange and then pulls like crazy all the way to the rev limiter.

It would be interesting to drag race these two bikes, I think it would be really close.

Oh yeah I forgot to mention, I also have a '97 CR500 which can smoke the crap out of either of the above bikes with no problem haha. But it's a two smoke, which sux really

QADSAN, great info, thanks for the numbers, I want the 680 kit even worse now. Any advise on doing it? I have a spare cylinder to get punched. Do they sleeve it? Recomend Hot Cam stage 1 or 2? Anything else? Where would you send it? WHere wouldn't you send it? (haha) Thanks for any help.

I want the 680 kit even worse now. Any advise on doing it?

I just have a simple XR650R, stage 1 HotCam, Edelbrock carb and some other goodies and I too would like to upgrade to the 680 kit, but I'm torn between doing that and waiting for the CRF450X to come out and keep both bikes. I've thought about doing the brunt of the install myself, but its super critical to get porting done right to match the other components if you want to maximize the results and a good engine builder could assure a fully functional package where the components work in harmony to deliver the best possible results.

As far as the cylinder goes, it's simply sleeved. LA Sleeve Co doesn't offer a sleeve kit for the XR650R (they do for the XR650L), but I think Q&E does among other companies.

I've ridden Rob Barnum's XR680R and it was incredible compared to mine. In fact, I think he was running 15/45 gearing and mine was running 13/48 and his bike easily outpulled my bike in any gear at any time :) Other people that have ridden my bike thought mine ran pretty strong, but Rob's the man when it comes to building 'reliable' performance on these bikes.

I may have forgotten some of the details, but I think Rob builds the XR680R with his own custom cam grind (I think its similar to the HotCam stage 2), larger valves, heavier valve springs, Edelbrock pumper carb that's specially prepped & bored even larger, high compression piston that still runs on pump gas, his own custom porting, his own exhaust header & cannister that he makes, different ignition mapping which also bypasses the rev limiter, lighter flywheel, carillo rod, etc. Rob's bike spins up quickly and makes tons of power everywhere and just flat out hauls ass compared to my bike!

If you're in SoCal, then you can drive to Rob's shop near Victorville CA and he can get you setup from anything mild to wild depending on how far you want to take it. Rob just got back into Racing again after taking a bit of a brake and took first place overall with Baja Rudy here on TT in the Code/Record 275 in Mexico with a substantial lead. This last week in Mexico he had a 10 minute lead over 2nd place until he punctured his rear tire and 2nd place finally caught him 7 miles from the finish line, but he would have taken that race too if he didn't have tire problems. Rob's a great guy to deal with. He's a highly experienced racer, engine builder, suspension tuner, very down to earth and always willing to help out.

He can set you up with as much or as little as you need if you want to pursue the 680 kit. Rob's also a ThumperTalk partner and ThumperTalk's engine expert who built the ThumperTalk race bike. Rob's company link www.barnumspro.com is on the front page of TT, but his web site was partially updated a while back and hasn't been completely functional since then, but they hope to have it working in the next month or two from what I was told.

You can contact Rob Barnum at:

Barnums Pro Product

2525 Marco Road

Phelan CA. 92371

(760) 868-8097



do you have any of the same numbers for the lowly XR650L?



do you have any of the same numbers for the lowly XR650L?

Sorry, I don't have any of those details for the XR650L, but I think the engine is very similar to the XR600R and you could probably dig up stats on that engine from googling around and find what you're after.

Qadsan, how is reliability on these engines and transmissions when you start moding. Any issues on overheating? I would like to do some eventually but I don't know how the bike would do for the type riding I do (some slow trails). Was the stage 1 hot cam easy to do?

From talking to Rob Barnum and others, the reliability is excellent up to about 60 HP or so and the bottom end can take it. I honestly don't know about overheating issues for all types of riding with this kind of setup because the few people I know that have gone the distance of installing the 680 kit are extremely fast and simply don't ride slow or leisurely like me :) I also like to ride fast at times, but I mainly ride with family and friends and usually spend most of my time in 3rd gear on trails as opposed to 5th WOT like some guys. I don't have any overheating issues with my bike even if I'm crawling in 1st gear during the summer time when its 100F outside.

The stage 1 HotCam is an easy install if you're fairly mechanicaly inclined. The bike comes apart pretty quick and before you know it you've got the valve cover off with the cam in plain view. In short, you'll get the bike to TDC, then loosen the cam chain tensioner, remove the cam chain & wire it up so it won't fall down, then remove the stock cam and remove the cam retainer plate from the stock cam or buy a new one and install it on the new cam while carefully torquing the cam sprocket bolts (they strip easy so be careful). There will be a pin with a spring in the head that actuated the auto decompressor mechanism on the stock cam and you'll need to remove it just to be safe. Then install the new HotCam, put the cam chain back on while making sure the bike is still at TDC and aligning the marks on the cam sprocket to the head. Make sure the valve cover is cleaned off since it was glued on and then apply Yamabond or Hondabond or Threebond 1104 (all the same product made by Threebond) to the valve cover and its mating surface and torque things down per spec. After getting everyting together, you'll have to break in the new cam, so be prepared to take your bike for a healthy ride or break it in while standing still without a load, but be preapred to have fans running full blast into the radiators to keep the bike cool. Afterwards, change the oil and filter just to be safe. I've probably left a thing or three out, but that's the basics.

I was a bit dissapointed with the stage 1 HotCam and expected more from it, but I still think it was worth the $99 I paid. As with most aftermarket cams, you won't be able to install the auto decompressor from the stock cam, so you loose that function, but that's not a big deal to me since I thought my auto decompressor was acting up anyway. From talking to HotCams, they told me their performance gains were based on a completely stock bike and that they didn't design this cam with an uncorked bike in mind.

Here's an interesting clip from an article about how the Honda Off-Road team builds Baja bikes and Johnny Campell gives his input.



An HRC Power-Up Kit (available through all Honda Dealers, Part Number 06130-NLB-010) is the star of this show, but many times the team will elect to use only a portion of the kit . The kit’s heavy-duty clutch springs, cam chain (plus corresponding sprockets and tensioner), high-performance cam and appropriate jetting (as well as additional breather holes in the airbox cover—though the stock filter and backfire screen are retained) are used for all events. The kit also includes specs for an exhaust system, and Pro Circuit’s full T4 system complies and is used by the team.

When conditions demand more power, Campbell employs the kit’s high-compression piston as well as minor porting of the head to help bring out the optimum power characteristics for specific racing applications. Unless the high-compression piston is used, however, the team runs stock porting.

“We really like the way the engine runs using the stock piston and stock compression,” says Campbell. “We can run that motor for tens of thousands of miles, no problem.” And with 15/47 gearing, compared to the stock 14/48, Campbell’s Baja bike will nudge 115 mph.

“It’s a pretty simple engine package,” he points out. No balanced cranks, no shot-peened gears or other tricks are necessary. “The bike’s proven itself over and over,” says Campbell. “The bottom end was built for more than 70 horsepower , and we’ve never been able to get that much out of our bikes,” he laughs. (Campbell admits to getting 60+ horsepower out of the full-kit motors.)


Thanks again for the info, man are we on the same page. I am looking forward to the 450X as well. I had one of those blue bikes and LOVED it, shouldn't have sold it but thats hind sight. I think the 450X could be my answer to what I miss about the 426 and in my favorite color as well. I am a power freak however and those numbers you posted have me thinking. Decisions decisions.....

Thanks qadsan. If I mod the engine it will be down the road a bit. $100 for the doesn't sound bad and seems like an easy install. I'm really looking forward to getting the Edelbrock and that will do it for spending money for me for awhile.

So Qadsan - if you had it to do over would you go with the stage 2 cam?


Your post steered me away from the Stage 1 cam, so I have the same question as Dutch.

So Qadsan - if you had it to do over would you go with the stage 2 cam?

If I had to do it over again, I'd still stick with the stage 1 cam for my riding needs unless I was going to do further mods that included porting, larger header, different exhaust canister, etc. I was after an increase in the mid range without losing anything on the bottom end and that's what I got. While the stage 2 cam will deliver more power on top, it will likely sacrifice some low end power to achieve that and you'll also likely have to compliment the stage 2 cam with a larger exhaust header + canister and possibly have the head ported to get the most from it. To get some of the low end back, you'll likely have to raise the compression by running a different piston and the costs start to add up quickly. The HotCams guy here on TT can give you more actual details as opposed to me speculating about the stage 2 cam, but you can't always have your cake and eat it to when it comes to bolting on aftermarket parts, especially cams.

Installing an aftermarket cam into a bike doesn’t always a guarantee the performance gain you might be after. Some bikes will benefit more from aftermarket cams than others and I'm sure emission regulations `sometimes' has something to do with this because a cam that offers one level of performance to meet emission requirements may not necessarily offer the best performance, but there's not always a great deal of hidden performance in aftermarket cams, unless you're targeting something specific performance wise. The bike manufacturers have gone to great lengths to provide an engine with specs that will hopefully meet most people's needs while offering a certain level of reliability, but not everyone uses their bike for the same purpose or rides at the same level or rides in the same environments, which is why some people have different needs & wants than others.

I don't believe you can always have your cake and eat it with just a cam swap because you may have to live with some kind of trade off such as gaining more top end power at the expense of losing something off the bottom, etc, but not always. It really depends on your application as to what you want to achieve. If you want to race flat track, then you'll likely want to achieve something different than a bike built for MX, which again would be different for GNCC or desert racing, etc. To get there, you `might' have to make some type of trade off whether it's less performance somewhere else in the curve or perhaps the tradeoff is that you'll have to spend more money for head work or a new exhaust system or higher compression to minimize or prevent a loss in performance somewhere else in the curve while gaining even more performance elsewhere.

Some people swear by flow bench numbers as proof that their ported heads flow better than their competitors, but you can't simply look at airflow numbers from a flow bench because you can have two heads of the same type that flow the same numbers, yet produce significantly different results. Airflow isn't everything; otherwise we'd choose the longest duration cam possible, but we all know there's a finite limit to how long the valves can be open before performance suffers since the valves have to work in concert with other engine components and the same thing applies to the cylinder head. It's not the amount of air flow that's most important, but rather the air speed, port cross section, port volume, port shape, and the relationship between the size of the throat and the valve seat, etc. If these things aren't taken into consideration for a given cam, then simply pumping large volumes of air through the head may do nothing for performance and quite possibly hinder it. It's all about the package and how everything works in concert when trying to achieve specific results.

You also can't rely 100% on today's trick engine building software no matter how good it is, because there's more to the story than meets the eye and that's where experience comes into play on top of the science because the software won't know if a short turn radius is properly shaped or whether the flow is turbulent at critical valve lifts or whether the flame speed is fast enough, etc. It's a complex issue that requires lots of understanding and experience to achieve specific results and the cam specs are just as vital.

I simply don’t know ‘exactly’ what the stage 2 HotCam will offer with various bike configurations, (uncorked, or uncorked with side panel open, or uncorked with porting & side panel open, high comp piston, etc) but I think it would be important to know the details of what you’ll get with the way your bike is configured if you want the outcome to meet specific needs, otherwise you’re just guessing or taking a chance. There’s nothing wrong with that either if you don’t mind taking a little risk as it could pay off nicely, but from what I could tell, the stage 2 HotCam wasn’t going to achieve the results I was looking for unless I was prepared to spend more money and I just didn’t want to put anymore money into the engine with the CRF450X coming out.

The bottom line is that a good engine builder will know what works and what doesn't to achieve specific results for a given application. At some point you're going to have to either trust an engine builder’s advice or figure it out for yourself while possibly taking some lumps along the way or just take a chance and see what happens. Some builders are better than others and nobody knows it all, so do plenty of research before plunking down your money or take a chance and see what happens. Hopefully, somebody else here as installed a stage 2 HotCam and can offer before and after dyno charts as opposed to a seat of the pants opinion to show how things changed with their bike config and from there you can make a better decision.

:):D :D

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