Winter motorcycle project; DR650

[Greg]

I love my DR650, but it's needing some serious attention... and Winter is the perfect time to tear it down. I have 2 major projects and a few minor changes.

Big Project #1- Better front suspension. The factory DR650 forks are a non-adjustable damper rod design, very old tech that isn't easy to make them work any better. My bike has been upgraded with the heaviest front springs available for the DR, plus an aftermarket fork brace, to help tighten things up. The suspension is OK on the pavement and it works (not well) on mild dirt roads. If you push the bike hard at speed or ride some rough terrain, it's easy to bottom out the forks, and they usually hit HARD. I hate that feeling, it's not a good one.

My plan is to swap on a set of 47mm Showa forks from a 2006 Suzuki RMZ450. These are true motorcross forks with adjustable compression and rebound. This swap has been done before and it's a huge improvement over the factory DR650 forks. Here's one guys writeup-
http://hawkeye.ualr.edu/~ltjones/showa-install/rmzforkinstall.html

I picked up a set of RMZ forks and RMZ triple clamps from Ebay, as well and the other needed parts. I'll document the upgrade with all the needed parts later.

This should make a huge difference in how capable the DR is, especially at speed and in nasty terrain. I'm really excited for the improvement, once the front is taken care of, we will see how bad the rear shock works. At this point, the factory front suspension is so bad, it's hard to tell how poorly the rear shocks works.

Since the controls will be apart for the fork swap, I'm thinking hard about upgrading to the Highway Dirt Bikes handguards. I've had a few problems with my current hand guards coming loose mid-ride and the HDB guards will take care of that issue, as well as make a huge strength increase and offer some neat upgrades as well.


Big Project #2- Engine rebuild / MORE POWER! It's time to upgrade! I wanted to do this down the road, but soon sounds better! a 725cc big bore kit from ProCycle! Combined with one of their custom grind camshafts, the big bore will crank up the horsepower from a measly 36 HP stock, to close to 50 HP! Not bad for a super simple, air cooled Suzuki!


The other small projects include...

Swapping out the aftermarket gear shifter for a stock one, purchased off Ebay. The aftermarket shifter is a good deal shorter than the stocker, making it hard to shift with riding boots on.

I'm going to chop and re-weld the stock foot pegs to lower them 1 3/4" to open up the cockpit. The DR650 is pretty compact and has a low seat height, great for shorter riders but I'm 6' 4". I've dealt with it, but since the bike will be down, I might as well re-work the ergonomics.

I need to rework the rear blinkers and tail light. I moved the stock blinkers so they mounted to the plastic brake light housing, but several thousand miles later, the brake light housing is breaking and the signal's have taken a beating after vibrating on the rear rack.


So that's what I have on my plate this winter... the fork swap is the first project and hopefully I will post up some parts pics soon.

 

[Caleb]

I look forward to seeing how you like those forks and that big bore kit. Those forks are the exact same thing as what's on my 2006 CRF. (47mm dual chamber Showa)

 

[Spork]

This ought to be interesting :greg:

 

[Rot Box]

Sounds like a lot of fun Have you considered using a steering damper? Scotts can help you adapt one to your new setup and they are well worth every penny.

You may want to look into a port and polish as well as a larger carb (depending on what came stock on your bike you may get away with just boring the carb) to complement the increase in displacement. I would also run an aftermarket external oil cooler as more power = more heat. It will feel like a rocket when you are done that's for sure. Be sure to take some pics while your in there!

 

[Greg]

I look forward to seeing how you like those forks and that big bore kit. Those forks are the exact same thing as what's on my 2006 CRF. (47mm dual chamber Showa)

I think the forks will be a huge improvement over the factory DR parts, there is some debate about how well forks built for a lighter MX bike will work on a heavy dual sport, but the general consensus is that the stiffer MX springs work well with the weight. Personally, I think the big 47mm Showa's will be improvement over the 43mm damper rod forks, no matter what.

The big bore kit will be fun, I like the torque the DR650 makes but it really signs off on the top end. The camshaft and big bore kit, with the increased compression ratio, should really wake things up!

This ought to be interesting :greg:

My thoughts exactly! I think it's good to upgrade the suspension along with the engine, hopefully they'll balance each other out. I ride my little DR pretty hard and I'm really looking forward to these upgrades and the increased ability of the DR.

I just hope I don't get myself into too much trouble riding the modified bike next year...

Sounds like a lot of fun Have you considered using a steering damper? Scotts can help you adapt one to your new setup and they are well worth every penny.

You may want to look into a port and polish as well as a larger carb (depending on what came stock on your bike you may get away with just boring the carb) to complement the increase in displacement. I would also run an aftermarket external oil cooler as more power = more heat. It will feel like a rocket when you are done that's for sure. Be sure to take some pics while your in there!

I've never ridden with a steering damper and I'm not sure that I need one... am I really missing something? If I get headshake, I either handle it, or speed up... or slow down.

The DR650 head is pretty restrictive, so any improvement would be great. At the least I plan on port matching the cylinder head, clean up any flashings inside the ports, than having a 3 angle valve job done. If I can find someone that will do a port & polish that's decently priced, I may consider it.

The stock carb is a Mikuni BST40, which is sufficient enough as is to provide enough air and fuel to the bigger engine. When I first got this bike, I pulled the carb apart to re-jet it and since I was in there, I did all the carb mods I could to make more power. It runs well, but in the future (after I recover from this round of mods) I do want to swap on Mikuni TM40 Pumper Carb. As the bike is now, I really have to work for a wheelie... I'm hoping a pumper carb, with the engine mods, will create a DR that pulls the front end off the ground with ease.

The DR has a factory oil cooler that is quite sufficient, the company that makes the 725cc big bore kit claims that the DR runs cool enough that increased engine temps aren't a problem.

More info here- http://www.procycle.us/info/questions/dr650/engine.html#725_kit_quest

The best quote regarding the DR and engine heat from that link- "The DR650 is very good at shedding heat. When we're running one on the dyno we have to run the fan on the low setting and turn it off between runs in order to keep things up to full operating temperature."

No worries, there will be plenty of pics...

 

[Greg]

The main components of the RMZ fork swap...

I picked up the forks, triple clamps, rim/tire/disc brake and axle shaft all separate from each other, thru Ebay. Putting them together was fun.

The steering head bearings are interchangeable between the RMZ and DR, so bolting the RMZ forks onto the DR is a simple operation. Its the rest of the project that gets interesting. The DR caliper will bolt onto the RMZ fork, making it one less part to buy.

 

[Rot Box]

I've never ridden with a steering damper and I'm not sure that I need one... am I really missing something? If I get headshake, I either handle it, or speed up... or slow down.


The DR has a factory oil cooler that is quite sufficient, the company that makes the 725cc big bore kit claims that the DR runs cool enough that increased engine temps aren't a problem.

You are missing out and thats good to hear. I installed 440 kits on a couple XR/TRX400's back in the day and they produced a lot more power than stock, but man did they run hot when worked hard This build is going to be sweet! Can't wait for more

 

[Rot Box]

I'm still dumbfounded as to why Suzuki held onto the damping rod forks that long. There is no doubt that the new RMZ forks are going to be the best mod ever especially with the riding you do. I'll bet you instantly notice how much more rigid they are too :greg:

I might hit you up about your fuel tank dimensions once you get going on your motor work--I'm thinking I can make one work on my ATK--hmmmm

 

[Greg]

You are missing out and thats good to hear. I installed 440 kits on a couple XR/TRX400's back in the day and they produced a lot more power than stock, but man did they run hot when worked hard This build is going to be sweet! Can't wait for more

I'm planning on installing a TrailTech Vapor with the fork swap and will be able to monitor engine temps with the addition of that. It will be interesting to see wherethe engine temps will end up with the big bore kit. More, coming up next!

I'm still dumbfounded as to why Suzuki held onto the damping rod forks that long. There is no doubt that the new RMZ forks are going to be the best mod ever especially with the riding you do. I'll bet you instantly notice how much more rigid they are too :greg:

I might hit you up about your fuel tank dimensions once you get going on your motor work--I'm thinking I can make one work on my ATK--hmmmm

$$$, IMO. They're cheap to build and I think Suzuki figures the DR650 isn't going to see that much action. If Suzuki put RMZ suspension from the factory and bumped the engine up to 50 HP, with a pumper carb, I bet they'd sell 2-3x more of them.

Keep me posted on when you need the dimensions! The DR IMS 4.9 gallon tank might be easier to fit.

 

[Greg]

Here's progress... I don't have all the parts I needed, but I had enough to get started. So I started tearing the bike apart...

The RMZ forks next to the DR front end.-

The controls, before the RMZ fork swap.-

All gone!

Side by side comparison, RMZ forks on the right.

RMZ forks on the DR650! The steering bearings are the same between the RMZ and the DR, making the fork swap nearly a bolt-on mod. Now that the fork is in place, the real fun starts.

With the RMZ forks on and me waiting on parts before I can button this up, I went ahead with bolting on the front fender and fork guards.

 

[Jared]

Greg, it's great to see you tackling your "Dream DR650" projects this winter.

I do foresee one big problem though... how will the rest of us keep up with this 725cc monster?

Jared

 

[Greg]

I'm currently waiting on the DRZ400SM headlight brackets, that slide onto the fork tubes between the upper and lower triple clamp. I ordered from a local Suzuki shop over a week ago and haven't heard anything about my order... hopefully they show up this weekend. I can't really move any further forward at this point, since I'd have to take it all apart to put the headlight brackets on.

The forks are getting into the tank pretty hard when turned. I may have to take a heat gun to the tank and try to mold the tank further inward around the fork legs. If I don't do that, I won't have much of a turning radius.

I also ordered my Highway Dirt Bikes handguards, along with a new set of high bend Woods bars that HDB will have threaded for their guards. I upgraded to their Ultimate Handguards, which are made for bikes that are 400+ pounds. I think the DR650 with a 8 gallon tank qualifies... Here's the Ultimate handguards- http://www.highwaydirtbikes.com/HDB...efeature&sid=6r506320616ox7cpre50s772msk1e807

I opted to include their fold-out mirrors, so those factory monsters will go away. I also added on their TrailTech Vapor billet dash protector from ProCycle.

 

[Greg]

Greg, it's great to see you tackling your "Dream DR650" projects this winter.

I do foresee one big problem though... how will the rest of us keep up with this 725cc monster?

Jared

You'll do fine... I will still be riding a pig of a bike, it's just going to be loads more fun for me, that's for sure.

 

[Greg]

Just learned that ProCycle has a prototype a 780cc big bore kit they're putting together for the DR650, in addition to the 725cc they currently offer. :freak: :greg:

I'm curious how well that thing will cool and how much more $$$ it will run verses the 725cc kit. Also curious what that will do for HP and torque... this could push the bike well over 55+ horse power.

My Highway Dirt Bike guards and bars will be here Monday and the DRZ SM headlight brackets should arrive either today or Monday. I'm hoping for today, so I can button up the triple clamps.

 

[Rot Box]

Just learned that ProCycle has a prototype a 780cc big bore kit they're putting together for the DR650

Holy smokes! I'll bet the torque output on that is insane! By the seat of the pants dyno I'll bet hp nearly doubles--seriously :greg:

 

[I Lean]

Any worries about a prototype kit being all it's cracked up to be, versus a proven one?

 

[Greg]

Holy smokes! I'll bet the torque output on that is insane! By the seat of the pants dyno I'll bet hp nearly doubles--seriously :greg:

It will be interesting to see numbers, I think the head will seriously limit air flow at the top end. Good thing there's a big valve head mod option in the works. :greg:

Any worries about a prototype kit being all it's cracked up to be, versus a proven one?

Plenty of worries since it's yet to be tested, honestly I'll probably just run with the 725cc kit since it's been proven many times over. The 780cc is just plain badass and has me dreaming of the possibilities. The owner of ProCycle won't release the 780cc kit until it's been thoroughly tested of course.

 

[Dominic]

Cool project man. My Dad just did a 705cc kit on his 2008 KLR 650. He was very pleased with the extra power. I am sure a 725cc or 780cc will be really really nice.

 

[turbohaulic]

X2 on the steering damper. I rode Rot Box's and really love how you can hit a rock pile and not eat it or bust 90 and no death wobble. Deff worth the money IMO. Looks like it's going to be a great project. I'm plannin to tear mine down this winter to rebuild pretty much all of it too.

 

[Greg]

I've had the bike put together as a roller for a couple weeks now, but between waiting for parts and the recent holiday, I haven't made a ton of progress. I finally got some of the parts I needed and went back to work.

I ended up using the RMZ upper triple clamp, with a pair of 2" Rox risers, then the Highway Dirt Bikes handguards and their threaded Protaper Woods High bend bars.

I've also decided to make some major electrical/switch changes, that I'm hoping won't bite me in the ass in the future. I've decided to get rid of the key switch, and if I can make it work, I will instead be using a series of push-button switches, from Highway Dirt Bikes. There will be 4 switches and only by turning on a certain combination of those switches, will the bike be able to start. At least that's the plan....

In addition to all that, I'm adding a TrailTech Vapor and will gain a Tachometer, engine temperature gauge and many other nice features. The Vapor will be mounted in a Highway Dirt Bikes billet mount. Hopefully the Vapor will hold up over time to the water and dirt it will be subject to.

There's plenty of wiring to be done... and I hate wiring. It's a little more effort than I wanted to get into, but I think it will make a clean, neat setup once it's done.

Here's how it's progressed...

First thing I had to do was to build some stops for the forks, since the DR forks has larger stops built into the triple clamp and the RMZ has short ones. I used some extra parts I had from some hand guard clamps, drilled and tapped the holes and bolted them to the frame.

I put the tank on, the Rox risers and bolted on my old handlebars to test fit the new forks. The forks ended up hitting the fuel tank just before hitting the new steering stops, so I took a heat gun to the tank, hoping to re-form the plastic tank around the forks. Unfortunately, all that happened was that the plastic blistered and didn't re-form very well. I'm just going to have to run it as is, it should be fine and I'm not worried about it.

While I was fitting the tank & forks, my order from Highway Dirt Bikes arrived, as did the TrailTech Vapor that came from ProCycle. The handguards from Highway Dirtbikes are phenomenally well made, they are honestly some of the finest motorcycle parts I have ever seen, Paul is amazing with his machining skills! They are a bit spendy, but are far better than any other handguard option out there and are obviously built to last.

My wife is great... she was OK with letting me bring the DR into the house to work on the tedious assembly ahead. Wiring the switches and the Vapor will be difficult, it will be nice to be inside.