Fun Wheel Drive - The DRMX 441

I recently came across a gent selling a titled 99 dr350SE frame. We got to talking, and I found out that he had engine trouble on the freeway and decided to part the bike out and buy a dr650 instead. So I bought everything he had for $500 as soon as I could get there.
Two parts boxes, an engine and a frame, I knew I was in for a treat. Missing the front end, rear wheel, carb and instrument cluster. But I had a 99 front end already and was planning to use a trail tech setup anyways.

Apparently this is the only picture I got. It was late, and I put the frame and engine on a cargo holder mounted on my front hitch.



So I sold my 98 dr385SE to fund the new build, and so it began: The DRMXRLSEXZ 441?
It's a DR frame and engine, RMX front end, XRL tank, Street Edition. X model year. rmZ plastics.
Yeah, I know. Still working on it.

I've had a few of these bikes in the past. A 90 dirt model, 97 SE, 98 SE, and 99 dirt model. Consequently, I have a collection of spares hanging around and a decent body of experience wrenching on this model. You can see my posts over on the dr350 forum where I spend way too much time.

Back to the project:
Bike was said to be running, but noisy, when disassembled. Good starting point.

First thing I did was drain the oil. Then off came the clutch cover to check for a loose or missing shift drum bolt. All clear, it's nice and tight. I'll probably remove and loctite it anyways.

Next I took off the valve cover. Sweet! Journals and cam look good. No oil starving. The more I look, the better things look. This bike may have never left pavement!





Thought about just putting it together and assuming user error, but I wanted to do a 441 big bore anyways. So off came the head and voila! Things got hot! Definitely think I found a problem..



Piston was deforming, melting even. A piece of ring snapped off and played ping pong in the cylinder. Was embedded in the squish area still, and matched the shape of the indentations in the piston and cylinder.



This is great! I was planning on resleeving and a new big piston anyways, so it's all good news to me!

Speaking of new piston, here it is!





Update 9/5/17:
While I'm at it with pictures of new shiny things..




Update: Just about finished!

Acerbis 5.8g XRL tank swap

There's a dedicated thread on this procedure, and I chimed in the last two or three times I did it. I'm hoping to start fresh and make this a clear walk through with my measurements on behalf of posterity.
It's not as daunting as it may sound!

So, the gyst: Acerbis makes a 5.8 gallon tank for the Honda XR/L bikes. It fits the xr250, xr400, xr650L, and I believe the XR600. It's the same tank for all of them, but if you order the xr650l kit, it comes with a handy bracket that fits perfectly on our DRs.

So here's my walkthrough procedure for installation, plus notes to self.

Here's the XR650L bracket loosely installed. I hammered an m8 nut into each end to receive an m8 bolt for mounting the front arms.

Edit: a little tac weld goes a long way to make sure you don't have to worry about them.



I made a custom seat bracket before discovering that I had one on hand. I drilled a 1/4" hole in the center between the stock mounting holes, then tacked on a m6 nut on the underside of it. This will help with the rear mounting strap for the tank to get anchored down.
If you're using your stock seat/tank bracket, you may need to cut off the ears to clear the tank.



Note: there are extra holes in the bracket, because I used a piece of stamped steel I had around. Only the three holes in a row (big little big) need to be there.

Here's the tacked on nut:



I might clean it up some more, but it's out of sight and functional.

After installing the engine mount bracket loosely (I'm waiting for upper engine mount brackets in the mail), I put the SE gas tank pucks on (had a set of new on the shelf), lubed them a little, slid the tank into place on them. It was a little snug, just the way I like it. This is alignment/test fitting time. Next I put on the seat and bolted it in place.
Next I put the half moon rubber puck that came with the tank:
On top of the factory rubber tank mount on top of the frame. This ended up giving me the fit I wanted. A little shifting and wiggling to get things centered and aligned so that the seat fits and the bars have lock to lock turning with no contact anywhere.







Note that the tank might not naturally sit totally centered. Feel free to move it about and get it right where you want it(aka centered).

Now that the approximate positioning is good, I can build the mounts. I'm using 1" flat aluminum, because I have it on hand, it's light, strong, easy to work with, and shiny.

I did a ballpark measurement from mount to mount, and it looks like a 5" strap on the left and 6" on the right gives me plenty of material to have 1/2" past the holes on either side. I can always trim off more if needed. Mark them L and R if it helps, and which side is up. I have as arrow that always points up.

Edit: final measurements below.
Measure, Mark, cut, punch.

Drill the m6 hole (top) first(I marked the hole 1/2" from the end) then mount the aluminum strap on the tank, let it hang down and line it up with the engine bracket to identify where to put the lower hole. Like so (see how far off the lower hole I drilled already is? This is why top first. It's easy to mark the proper location for the bottom hole.).



Next up, remove the seat, try not to move the tank, and fab the rear tank strap.



I drilled an m6 hole centered in one end of the strap, about 12.5mm(1/2") from the end.
Also used the above pictured approach to approximate where to put the bend, then hammered the bend until it fit just about right. Next I lined up the bottom hole and marked where the upper holes go.
Center, punch, drill, debur, install.
Et voila!



Here are my measurements of the left and right fasteners. About 3" center to center for right side, 2 7/8" for left side. Add 1/2" on each side and final straps ended up being about 4" each. This is with the Acerbis rubber bumper sitting on top of the factory bumper all the way forward, the xrl bracket rotated all the way up to contact the frame, and the straps connected to the lowest mounting points on the tank (there are 3 on each side).



Update: after my first test ride, about 3.5 hrs in the saddle. Road, rocks, sand, gnarly hill climbing and general hooliganery. I decided to tear things down a little to retorque the head bolts and look things over. One of the nuts that I hammered so confidently into the Acerbis engine mount bar pulled out(left side) and the upper strap bolt on the right side had backed out and fallen out of the right side where it mounts to the tank. So if you ride hard, do it right, use washers to prevent chafing and lock washers and/or blue thread lock to keep things in place.

So I tack welded the nuts into the bar, sanded them down and reinstalled after doing my head work. They're not going anywhere now!

Supermoto conversion information here! It seems to be scattered across the interwebs, so here's a compilation that I hope will be useful to others.

I'm looking at supermoto options. Of course you can do the $1300 option of getting excel rims laced and all that(like from Procycle). No thanks.

For the early (pre cartridge forks) DR350 models, you can get a set of gs500 wheels. The axle diameters are correct.
Then you:

* Fab a relocate bracket for your front caliper, as the GS rotor is larger diameter (290mm or 320mm, iirc, depending on early or later years)
* Cut some axle spacers to put the wheel where it should be.
* Install and ride!

Many suggest getting a better caliper up front while you're at it, but you don't have to, so I consider that part of the endless "optional upgrades" list.

The rear wheel is a little more work:

* Remove 5mm from right side of gs500 hub
* Turn down the rotor to DR size (I'll update this when I find exact dimension. 220mm I believe)
* Replace bearings - the DR rear axle is 20mm, the GS rear axle is 17mm. I haven't clearly figured out what/if you need to change the sprocket carrier bearings.
* Make wheel spacers

Yes, you can install the GS (or another bigger better) caliper and fab up a fit for it. Optional upgrade.

That's it, as far as I know. Then you'll have cool 3 spoke cast 17" sumo wheels on your DR. Budget build, tons of fun.

Now if you want to do it on a later model DR350 with cartridge forks, you have a 17mm front axle diameter to deal with.

You can still do a GS front wheel, and replace the wheel bearings with 17s, bore out the bearing spacer to around 17.3mm, and run that. I'm told the spacer is very hard material.

There are other older sport bikes that come with 17mm front axles already though!

One resource for finding these is here:
http://organ-donor.org/motorcycle-data/motorcycle-front-axle-diameter/#front-axle-17

I read somewhere on the dr650 sumo forums (same 17mm front wheel) that 90-92 ninja front wheels are 17mm axle and are usable. They come with dual rotors, and are 16" though. I think I want to stick to 17", though I've seen some pics of track days with just a ninja front and street tire put on the 18" stock rear and it looked like he was having a blast. I imagine the turn in on those is unreal.

Now I see there are 3 spoke cast 17" wheels with 17mm axles on the 89-92 (confirmed) fzr1000.

So I went ahead and ordered an early 90s gs500 rear wheel with sprocket and rotor still on(which seemed like a find, as they like to part them out!), and no tire. Should be here in a few days. I'm contemplating tire choices. I really have no sumo experience, and just a little street experience. This is an experiment.

Today I pulled the trigger on a 91 Yamaha FZR1000 front wheel. 3 spoke, good Pirelli rubber on it, paint could use some touching up. If I like it, I'll probably take it to my friend's shop and powder coat the wheel set and match it to my handlebars or something. I ordered a used 320mm floating caliper from same/similar year as well. Have to source rotor bolts somewhere.

Good news: the information was accurate and the fzr1000 wheel has perfect 17mm bearings in it! I'm waiting for the disc and bolts to arrive, and contemplating my caliper relocation bracket, but we're getting closer!

My regular machine guy isn't able to take the 5mm off the rear wheel as his lathe doesn't have the clearance for more than a 15" diameter. What to do..

Sumo budget:
$70 rear wheel/rotor/sprocket
$159.99 front wheel/tire
$24.80 front 6 bolt 320mm rotor

To do:
* Machine work on rear hub (5mm off right side) * Edit - I've noticed that on some sumo conversions they take this material off the sprocket side instead, as the brake side has a lip to seat the rotor on so it's a little more work to remove the material and retain the proper mounting surface.
* Pick a tire for the rear (130/70 17 or so)
* Turn down rear rotor to match stock
* Fab a front caliper relocate bracket

I have a rear wheel bearing set ready to go into the GS wheel, but it only has 2 of the 3 bearings that I'll need, so hopefully I can pick up the 3rd at a local bearing shop.

Also, the 92 front fzr1000 rotor that I ordered doesn't fit the 91 wheel. I'm a bit perplexed at this and trying to find a solution. When this rotor arrived I had to pay extra shipping even though it was shipped in a flat rate box. Shippers take note - if you fold a side of a flat rate box - making it smaller - it is no longer flat rate but is shipped by weight. Now I have to see if I can return it or resell it and find one that actually fits.
I've lost momentum on the sumo conversion as I'm trying to find a shop that can do the work. If I could get the front wheel together at least I could play around with that on and see if I like it in the first place.

Update 8/24/17:
I contacted the seller of the front rotor that didn't fit, and we figured out that he accidentally sent me a rear rotor instead. This led to a full refund. Upon further inquiry I learned that he had a 92 fzr1000 in the shop ready to part out, and for the hassle he sold me another front wheel with both rotors for 20÷ off everything.
I now have a matching front and rear 3 spoke 17" cast wheel set and an additional 17" periwinkle (gotta love the 90s!) front wheel. Anyone looking for a front wheel for your sumo conversion lmk - wheel, decent rubber and rotor included!

Haven't figured out how to make the brake relocate bracket yet.

Suspension!

Bike came with #3 Kouba links and the stockers. I put the Koubas on (never tried them before). Bike also came with a dirt shock that looks to be in good shape. This was a pavement queen from what I've seen so far. Not for long!

So my front end came in today from a 96 RMX250. It's got some cleaning up to do, but it's all there, and has Racetech stickers on the lowers. Here's hoping I scored gold valves and tuning just right for me!

Edit: Aren't gold valves for oil dampeners? Or are those emulators.. who knows? I didn't open up the cartridge stack in the forks to see what's in there, just freshened up the oil.





These will be on hold for a bit. Going to tear them down, see what's inside, refresh the oil, maybe get new boots(probably) and seals. Nice to have them on the shelf though!

...

So I was looking in the storage area for some brackets and discovered a set of blue daystar gators new-in-box that fit the new forks! I had ordered them for a 49mm showa front end I put on my last DR, but they turned out to be too small and I didn't return them yet. Voila - they fit 45mm tubes perfectly!



(Some assembly required)

These pieces fell out of the smallest tube when I was draining the oil from the forks, but they go in under the rebound adjuster tube. Anyone know which way they go?



Edit:

Oil height is 120mm.

Short end of pieces in question go up.

I learned that the lower bearing for the steering stem is the same on both models: 30mm x 47mm x 15. Upper is different though. As my existing stem bearings were in great shape, I figured I'd reuse the lower.
Now to figure out which stem to use with the RMX forks. DR stem is the smaller one. RMX stem seems to be aluminum.



After some consideration and measuring, I've learned that the lower stem diameters match, and the lower bearings match, but the upper bearing has a larger ID, and the upper triple for the RMX has about a 5mm larger bore.
Also, the upper triple for the RMX is about 4mm thicker than the one from the DR. This means that the DR stem would possibly be too short. So to make the DR stem fit in the RMX triples, I'd have to have a 2.5mm thick bushing installed in the upper triple, and about 4mm of material removed from the top of the triple.
The benefit here is that I could use the steering lock if I used the DR stem, however I don't have the ability to do that machine work myself, so I think I'll go with the RMX stem and get an upper bearing conversion from AllBalls.
I was going to reuse the lower bearing, but after freezing the stem to shrink it, I though the bearing would slide right on. Nope. So I got a pvc pipe that was almost the right size, started pounding, and messed up the bearing race.
Oh well, add $60 to the budget for new steering stem bearings!

In retrospect, I probably should have just had the 43mm dr350 triples bored to 45mm. Plenty of material to take 1mm off.

Discovered that the old beat up race tech stickers peel off tonight. So much cleaner!

Parts and Budget:

Overall goal: <$2k

Parts:
Titled frame, engine, most parts: $500
RMX250 front end: $290
Rear wheel: $138
UFO 08 RMZ450 side panels: $41.59
Maier rear Dr350 fender: $62.96
Thumper Racing 89mm piston and gaskets: $263.90 *
MMachiningachining: bore out old sleeve, install bore & hone new sleeve, valve job, head welding and repair: $660~
Xrl Acerbis 5.8g tank: $180
Kick start components: $171.70
Battery: $26.40 Wal-Mart AGM
Galfer BOGO front and rear stainless brake lines $77 from Thumper Talk

$2400 is a good ballpark.

I've updated this list to only include build specific things. No need to include general maintenance and wear parts, such as pads, tires, oil, and stuff you'd have to put on any bike.

* You can get ~89mm piston kits from procycle.com and xrsonly.com as well. They're cheaper than Thumper Racing, but only Thumper has custom pistons that keep the stock compression ratio that I wanted.

Legend:
~ = tbd
$(price)~ = estimated/expected but not paid for yet

FWIW, if I were to do a 441 on a complete bike, I'd just send the cylinder to Thumper racing and be done for $600 + s/h. Wouldn't have to work with machine shops, multiple trips, anything else. If you have a spare cylinder then it's even easier and you would leave even less downtime.

Worked on the side plastics today. Had to remove some material from behind them and get creative.

Note: UFO 08 RMZ450 side panels



A few minutes with a Harbor Freight plastic welder and voila!



I aligned it so the upper rear hole would line up with the rubber bump that would normally be on the panel, then put some flat stock aluminum from the stock lower mount location to the RMZ panel lower mount.



And voila!



I have to work out whether I'll create my own pop in "bump" like stock or something that screws in for the upper rear mount like a Maier panel.
Also going to get a button head m8 for the center exhaust mount as that's where the most interference is right now.

I also think I should line the inside with some heat resistant material near the exhaust.

Other side was easier - didn't have to even take off as much as I did.



Have to run to hardware store to get mounting hardware, but here's me holding it in place.



Note: I don't have the battery and wiring harness installed yet, but the battery box is there and I think clearance will be fine.

Edit: clearance is not fine yet. I installed the wiring harness today, and now need to take some material off this giant extrusion around the hole:



I ordered the rear MX fender today, as I don't want to see the stock fender combined with these side panels any more than necessary. But in case you do:



Also worth note: passenger pegs won't work in stock form with these panels. A relocate bracket could fix that though.

Update: Found a way to mount the panels to the rubber bump receiver:

M6 flanged bolt sticking out with a flanged m6 nut (flange out) sitting inside the rubber and sandwiching it. Then a non flanged m6 nut to sit in the 10mm hole of the panel, and a washer and m6 nut to actually hold it on.

Picture..







Update: a newer better way to mount side panels:



The hole in the plastic is about 10mm, so I put an m6 shoulder bolt in, then a nut on that to fit in the hole, then a shoulder nut to sandwich the plastic (washer would work too), then another nut for a spacer, then a wing nut with the wings cut off. The wing nut is tapered, and fits very snug into the rubber mount. Now I can pop my side panels on and off like stock panels.

Just about Finished up my panel and plastics mounting (for now). Stuck a seat concepts seat on it as well. Just need an engine and a tank. And bars. And trail tech. And front tire. And stuff. Whatever, lookie lookie!

Subscribed.

Thanks CFH6604!

What do you think, clear desert tank or white? Ill probably go blue and white with some yellow for the overall color scheme.

- Fun Wheel Drive -

Sounds like fun. Do you have an overall budget in mind?

Good question. I'm planning on putting up prices for everything here so others have useful reference points. Looks like under $2k is good room to work with.

- Fun Wheel Drive -

The new fender should look real nice with those side panels. I think all white will be nice. But I am biased because that is the route I am going on my build. I will have my tank Thursday. Also new fork boots. White and yellow is my theme. I can't wait to see your finished bike. I am having a lot of fun doing mine right now. Also are you going to shave the tabs off of the side panels that are forward of the panels?

clear

Hadn't really thought of it, but it would clean up the look!

- Fun Wheel Drive -

White.
That tank is so big, you won't need to know the fuel level from the outside -- there will be enough lol.

True enough! I've had 2 of them with white before, so thinking of switching it up. I rarely actually fill them up as my rides are shorter and I don't want the extra weight up front.

- Fun Wheel Drive -

I like the way those side panels look, going to show this thread to my friend that bought my DR!
For those side panel top/rear mounts, you could cut those bolts down a bit and use some acorn nuts for a really nice finished look.

Yesssssss excellent idea! I'll do it and post measurements.

- Fun Wheel Drive -

Talked to the machine shop last night. He said the old cylinder sleeve is bored out, but LA sleeves was a few weeks away from having a big bore sleeve in stock(they sent him an oe size at first), so he ordered one from Thumper Racing. He'll be installing it next week, and doing a leak down test on the head to check valve condition.
Then it's assembly time!

- Fun Wheel Drive -

So I've got my 96 rmx250 forks, chucked the old yellow gators, wiped and cleaned off grime and caked dirt, drained out fork oil (which wasn't terribly gross).
A spring and two sided cone thing came out behind the compression damper rod. I don't recall seeing those in the past and am looking for a blowup to see which way they go back in.



I'm also looking for the appropriate oil height.

Edit:

- Fun Wheel Drive -

Got some great parts in the pipeline!

- Fun Wheel Drive -