close shave

The FCR parts from Sinceros Speed Works have come in.  These are the jets, needles, and intake bell required to convert the 39mm carb originally off of a yzf426 to work with the DRZ -- essentially the same carb as sold on the E model DRZ, and also available as at kit for $500 or so.  I spent considerably less; here's hoping it works as it should.

You can see that this carb has provision for a throttle position sensor, which I am told is not supposed to be hooked up -- makes sense, as the carb was originally from a Yamaha.  Idle wheel can be seen to the lower left; red knob is for a hot start -- very important when MX'ers crash during a race and need to kick-start the bike in a hurry while warm.  Black knob is the choke.

Like all MX throttle cables, what came with the bike is far too long.  Will leave it as-is for now, and try to track down some brass ferrules in order to make a short cable of the proper length.  Ran out of them with my earlier Venhill kit I got from the UK.

Only one cable is needed, as the return spring action of the slide is considerable.  Not sure if I should bother covering the upper hole, as I don't intend to get a lot of dirt in there!

This is where the "close shave" comes in -- the lower bolt on the float chamber misses the frame tube by 1/2 a millimeter!  The whole conversion would have been a big "fail" had my welding or the carburetor forging been microscopically different.  Result!  According to all the experts, this mod alone should be good for a couple of hp.  Just need to get the jetting right for my application and altitude.  Won't bother trying to run it till the spring, as it is below freezing regularly these days.  Fettling on this bike is done for now.

Swarf and inspiration

Atom-Jet is making me the two spacers, and so I attacked the rear subframe, cutting off about 5-6 lbs in the process.  I shoulda done a before and after weigh-in. But here's where I'm at right now.  I had some 3/4" 4130 left over, so I replaced the passenger area and luggage rack with just the cross-member seen at left.

A lot of time was spent with the angle grinder, first cutting off large chunks of metal and then grinding off the remains.  There is more that could be done, but I wanted to stop here before I went any further.  Depending on how the tank fits, I might need to adjust the angle of the subframe, or add supports to prop the seat section up a bit.

I've also been looking online for some inspiration -- some sort of neo-retro look for the bike.  Over the course of the project, my ideas will likely morph and change, but here's a neat Hawk I found while researching fuel tanks.

I can see it has a 125 GP seat on a custom subframe, and the tank was molded from foam and wood -- not clear if it is covering an aluminum tank underneath... not keen on using a fibreglass tank on a streetbike.

Speaking of tanks, I think I found something that should work with my frame.  As usual, its from a bike never imported official to North America... so I found it in Germany, sold to me by a Dutchman living there.

From a bike called a KR1S -- a 250cc 2-stroke that battled with RGV250s and RZ350s in Europe back in the 80s.  A bit rough looking, but comes with a cap and petcock, and rubber bumpers for mounting.  Hopefully it gets here in one piece and is suitable.  The original tank is too small, ugly as sin, and wouldn't work with my oil in the frame idea...

another new project

I'm addicted, I guess.  Better than crack and only slightly less expensive.  Embarking on another 'mono project -- this time, for the street.  Plan on using the DRZ/KLX engine again, as I have a bare engine for mockup purposes, and a few spares and extra hardware that I can use... as well as experience with the engine. 

As for the frame, I am starting with a Muz Skorpion frame that I got off of ebay.  The Muz was normally powered by a Yamaha 660 single, so the smaller DRZ will fit in with no problem.  I also got a subframe for the engine, but its about 10 lbs heavier than need be -- for a passenger, as well as to accomodate luggage and two exhaust pipes.  No thanks.  The angle grinder and cutting wheel will get some use.

I also found a DRZ rear swingarm for $14 -- this is the S version, so I want to find an SM for the final version -- a bit shorter, with proper streetbike axle blocks.

As for how the back end will be suspended, I'm thinking of going retro with twin rear shocks, or perhaps a single offset rear shock a la Norton rotary racer or ducati sport classic.

Allegedly a R6 front end bolts on fairly easily... I have acquired a set of 99-02 front forks (the RSU version), and a front wheel with twin discs for only $19 (the forks and triples were just over $100).

As for what the final "look" of the bike will be, I'm not 100% sure on that -- while a complete idea should be in place prior to the welding bottles being opened up, there are some mechanical things I need to develop or create, that I want to put into practice on this bike.

The first involves the oil tank.  I need a minimum of 2 L of oil for the dry sump engine.  What I would like to do is "hide" it, by incorporating it into the frame.  The DRZ400 dirtbike did this with a rectangular downtube on the stock chassis.

You can see engine mounting tabs just aft of the steering head.  The idea would be to use a 2.5" OD tube (with some jiggry-pokery to get the right volume) to mount to the front engine mount on the frame.  One would bolt to the other, and then the proper fittings would allow the hollow front engine mount tube to act as a oil tank as well.  The rad would mount to that, and etc, etc.  Of course, before I do any of that, I need to mount the forks in place, and create a "rolling chassis" -- need to get the angle of the dangle of the rear swingarm, and finally determine how long the front engine mount will be.  You can see some old 2.5" tubing in place for mock-up purposes already.

When dad delivered the frame and parts this past weekend, we also drilled out the frame engine/swingarm mount hole to 17mm -- even had a nice bolt at the right length hand I can use.  As you can see in the pic, a few spacers need to be made to center the swingarm (and ergo, the engine) in the frame.  I've got some nice aluminum alloy material to start with.

This can hopefully be an ongoing project to play with over the next few years... I'll keep everyone posted with updates as they come in.

Swingarm Swap

Started the process yesterday to switch out the steel ex swingarm for that of the versys.  Old rear swinger cam out fairly simply... and it looks like more of the parts are interchangable than originally planned, which will save me some money in the swap.  Did some comparison of part numbers on Bikebandit.com, and I already have $60+ of reusable parts, in the form of spacers, oil seals, etc.  I still need to order some items, but it will be far cheaper than I thought.

 While I was at it, I also removed the front countershaft sprocket.  I have a leftover racing chain with low miles that is slightly shorter than stock.  My hope is to shorten the gearing for racing, but go to a 13-43, rather than the stock 15-46.  The original chain had to be cut off anyway, so I went with a 520 set.  For longer tracks, I will switch to a 14-43, essentially back to stock gearing, but with the smaller sprockets overall.  Dad's bringing those in for me in a week or 2.

The bike is held up by a stand that I originally built to pass through a hollow rear axle -- this time, I just put a 3/4 inch tube through one of the hollow frame spars, and it lifts the back end up without using a rear stand.

The shock will also be sent out for a rebuild and revalve -- not sure whose weight it was set up for, and it is also weeping a bit around the seal. 

Note how much more beefy the rear swingarm is from stock -- and its still 4 lbs lighter!  Rear brake caliper hanger and caliper, along with the rear wheel spacers can be reused.

Weekend Education

Picture it -- glorious +26 degree weather in late September.  The weekend -- no work.  A new bike to break in.  Races being taped on the PVR... get out and enjoy the sunshine.  Which I certainly did, until I was about 1 mile from home after a lovely 50 mile ride (restricted to 39mph according the max revs break in according to the manual).  Me and the KLX are getting along famously.  Light, easy, fun to ride even with 20 hp, and more fun to be had when I can open it up after break in.  The supermoto tires mean that I can go through the 2 roundabouts in town without even braking, sticking my leg out with style.
On the way home Sunday, I approached the 2nd roundabout when a young kid in a Caddy pulled out in front of me -- he misjudged my speed (I wasn't/didn't need to slow down)... while he left me a bit of room I could work with, he then decided to stop dead... why, I don't know.  My brake hand reacted faster than my left foot, and down I went in a lowside with a locked front brake.  Like my roadracing crashes, things slowed down.  I saw the rear bumper approaching my head as I slid along the ground; I enjoyed the painless sensation of my Sidi boots doing their job, protecting my left foot trapped under the bike; I immediately felt pain in my hip, but the numb type I generally associated with a hard bodycheck; worst of all, I could feel my light jacket rolling up my arm towards the elbow, leaving my forearm to make corrosive contact with the pavement.  Then, silence.
I was conscious, did not hit my head, and I avoided the car.  The klx was still put-putting while lying on top of me... although I was able to reach down and hit the kill switch with my right hand.  The driver came out from his car, and a fella working on his yard also showed up.  Yard guy picked up my bike, while caddy boy claimed it wasn't his fault (was it...?).  He suggested we exchange information, but to what end?  My bike was remarkably undamaged save for a few minor scrapes.  My arm and knee were a bit of a mess, so with no information to exchange (single vehicle accident) he left.  Yard guy stayed with me to make sure I was OK, looked at my forearm to ensure that there was no bones sticking out.  I shook his hand, started up the bike, and went home for a date with the hydrogen peroxide and an old toothbrush.  Thankfully Kate was not home yet and I could howl in privacy.

The worst of it, 2 days later...


I've been riding since 1997, and this is my first street crash.  Ironically, I wasn't speeding, I was on the LEAST powerful bike I have ever ridden on the street, and I was a mile from home.  It was a day I decided against my leather jacket... my choice.  I did have a helmet on, I did avoid the other car, and I did avoid serious damage to the bike... my race-trained habit of "looking through the turn" avoided a more serious rear-end collision.  My boots saved my feet -- had I been wearing sneakers, yikes!
2 days after, I am able to put things into perspective.  This was a real wake-up call for me.  This little bike was supposed to keep me out of trouble, and while it crashes about 1000 percent better than a sportbike, it can still be somewhat dangerous.  What have I been reminded of:
1.  Never, ever, ever trust other drivers!
2.  Always wear proper protection -- where I was hurt the worst, I was the least protected.  My bottom half was covered in jeans -- still some damage but minor.  Had I had a leather jacket on, no injuries to the arm!
3.  When in doubt, chicken out (on the street, at least) -- I had been through that roundabout many times before, much faster, but there was NO traffic -- much more margin of error.
4.  My wife is a patient woman.  She made the trip to the pharmacy for more supplies on Monday.

So no repairs to the KLX -- scratches have added character to both me and the bike.  No missed work, although I am stiff and sore all over.  Again, could have been much worse!
And I got back on the horse on Monday -- rode for an hour in the warm weather again -- with a leather jacket! 
Dad, if you're reading this, don't tell mom!  If she does see it, remind her that once again, RACING is safer than riding on the street!  Keep the rubber side down, everyone!

Carb Diet

The YZ427 carb showed up.  In decent condition, but I soaked it in a product called "Seafoam" to help clean it up.  That, and some work with an old toothbrush did a good job.  Next step is to get the right jets for it -- Sinceros Speed Works to the rescue.

The wierd thing is, it looks as if this carb will fit under the tank?!  I did need to adjust the underside with a brass hammer somewhat, but it now fits fine.  Hmmm.  I also intend to pressure test the tank again to make sure my welds are holding up.

Great Weekend

Really enjoyed the last weekend of the season -- got the reffing done on Saturday with only one bad crash (rider is OK), and the hit the track on Sunday.  Was happy with how the comfort level came back -- made some good passess, picked up speed pretty quickly, and also didn't surrender spots other than to bigger bikes on the straights.  Even caught and out-dragged an SV650 -- of course, not in a race situation, but it seems that the bike has some decent speed compared to its competition, even with stock gearing.  Was a very windy day, and the fairingless bike ran well.  In fact, the mono, with its full fairing, was being tossed around quite a bit -- more likely due to its weight than anything else.  Got to the point on the mono where I wasn't even braking for turn 1 -- just pop out of the bubble, downshift once, and hold on.  Handled pretty good!  Again, some chatter and sliding through turn five on the little bike.  Not sure if that's due to the tires (the street-based 2CT michelins) or to the suspension.  Need more time to sort it out.  Did 4 sessions on the ex and 2 on the mono.

Had the bikes loaded on the trailer a few days prior -- school had started up and I was spending some long hours -- did not want to wait until Thursday night to load up, in case I was delayed...

Trailer held up OK, but I'm keeping a close eye on it -- its covered lots of miles over the past 11 years, and has hauled more than just bikes.  Might be time to get something slightly bigger -- no extra room on the deck for anything!

No shots of me "in action" that I've seen, so I can show you tire wear -- fascinating!!!  The michelin slicks were awesome!  Not sure how old the tires were, and while they were sliding a bit out of turn 9 (asphalt, not concrete), everything was controllable.  Nice wear pattern, no cold tearing despite the lack of tire warmers and the cold ambient temps.

Of course, for me to be battling at the front, I need to find 4 seconds somewhere...!  Next year!

I wondered about the bellypan in right turns -- while it did touch down, it acted as a gauge (along with my knee) as to what the suspension was doing at the back.  I need to get faster through turn 4 -- there is a bump right as you turn in that upsets the bike -- the bump carries across the entire width of the track, except for a 1' spot roughly 3' out from the inside.  On a clean lap, you go for that spot -- otherwise, you grin and bear it.  Pegs and levers were fine -- no contact.

So now its time to get the bikes ready for winter storage -- I've removed the Cool-Aid from the ex and replaced it with glycol -- gonna do the same with the mono, although its running straight water.  Winter plans include a rear swingarm swap on the ex, and a shock rebuild/revalve -- the machine is running perfectly otherwise.  I've built a stand that will hold up the rear of the bike while leaving the swingarm free to be removed.  With the mono, my 1 gal alloy tank has arrived, as well as the carburetor.  Gonna test fit the FCR, then clean it up and jet it for the DRZ.  Mounting the tank will take some work, but I've got a few ideas.  Off to get some pink foam insulation today.  As usual, stay tuned.