new GS racer

[Rob S.]

Makes sense

Makes sense

Starting to make sense. I do very little leaning, as I'm just getting back on after a 24-year hiatus.

But I do love taking the heel of my boot and kicking it into first. Damn! I rode four days ago (NYC), and I'm jonesing for more.

1100EZ Vance & Hines, K&N

 

[GregT]

Impressive - but I'd point out your ankle is one down, three up from the midline...

All your points are valid but it's still down to personal preference really.

 

[gs58]

P.S. I prefer because GP for two reasons:

1. it's easier for me to get positive gear engagement with a push down, than a pull up. At the track, when a bad upshift can cost you a race, that's important.
2. it's easier for me to upshift when you're heeled over in a corner (and can't get your foot underneath the shifter if you're not running GP). This doesn't happen often but when it does it's nice to be able to upshift at a large lean. (Like GregT noted, this is less an issue nowadays.)

But at the end of the day yes, it's personal preference, whatever you're comfortable with is the way to go. I still run standard shift on my street bikes.

I have considered using the GP pattern but have seen several examples of bent valves due to over revving when natural instinct takes over. You do not want to be shifting from third to second when you are look for fourth and are hard on the gas. There are so few corners where it is an advantage (especially with the GS spread of power) that the risk/reward ratio does not warrant it (for me).

 

[CivilRock]

Sorry for the hijack Patrick.

If anyone wants to continue discussions about GO Shift, I urge you to go to the thread I started last summer on the subject, and do post your solutions there. This thread is about a sweet GS road racer. http://www.thegsresources.com/_forum/showthread.php?t=212785

 

[patrino]

Got the seat finished and put my numbers on.

Had hoped to make it out to the dragstrip last saturday for shakedowns but they canceled due to rain. I have plans to make it up this Wednesday, the weather is supposed to be better.

In the meanwhile I ran the bike around the block. The brakes are TERRIBLE - very wooden. I think it's a master-to-slave cylinder mismatch. I'm trying to track down the piston sizes of the calipers, but a review of the m/c ratio chart available at Vintage Brake makes me think the master cylinder the bike came with (3/4" / 19mm) is way too big.

I was all set to head down into the basement to find an old Brembo m/c I have (14mm or so) when some internet research made me realize the m/c that's on there is an AP Racing adjustable. It looks like I can adjust the lever down to an effective 16mm bore size. Next time I'm down at the shop I'll give it a whirl. If it improves but still isn't good enough I'll have to fit a new m/c with a smaller bore.

In the meanwhile, if anyone has an EX500 shop manual in their garage, I'd appreciate the caliper piston diameters, please!

 

[CivilRock]

** GP shift**

Patrick. If it's dry Wednesday night, I'll totally race you at the PIR street rips. Shoot me an email if you're going.

I need to fabricate a chain guard for my bike, and it looks like you might too. Seems like a silly requirement, but they stopped me last time. That my my helmet wasn't SNELL 2010. (It was Snell 2005). They gave me a warning on the chainguard, but I had to borrow a helmet to pass tech.

Kevin.

 

[CivilRock]

Wednesday looks like the only dry day this week.
Kevin

 

[GregT]

Ex500 is 14mm, hook out that old Brembo....

 

[patrino]

Located a couple used master cylinders, going to do some experimentation over the weekend.

Shoot. My helmet is 2010 Snell but no chainguard. I'll see if I can kluge something together for tomorrow.

And yes, GP shift.

 

[patrino]

I swapped out a 14mm master cylinder, it was a big improvement over the AP Racing one, but it's still not as good as I'd like. I roughed out the numbers yesterday, I'm at a ~18:1 slave/master ratio. I've got a line on a 12mm m/c, I think that'll do the trick.

That said, I could live with the 14mm if I had to.

Drag races were canceled last night, so I just ran it around the shop a few times. Still no leaks, which is good. The CRs pop a bit at ~1/8-1/4 throttle, I'll futz with that this weekend and try to get it tuned out.

 

[gs58]

Your bike is looking great Patrino. I look forward to seeing some results. When determining a master cylinder it's not just the size of the master cylinder that counts - the location of the pivot point of the brake lever can also change the feeling and effectiveness of your brakes. Not all 14mm (or 12) master cylinders will be the same.

 

[GregT]

Your bike is looking great Patrino. I look forward to seeing some results. When determining a master cylinder it's not just the size of the master cylinder that counts - the location of the pivot point of the brake lever can also change the feeling and effectiveness of your brakes. Not all 14mm (or 12) master cylinders will be the same.

Very true...believe it or not, the best we've found is actually a GS450 14mm master. Better leverage than anything else we've tried.

 

[patrino]

Found an inexpensive 1/2" m/c from a friend who's a bike breaker, and put it on last night. It's a bit too far in the other direction: much more lever travel than I'd like.

GS85 and GregT, thanks for the tips. Pivot length for both the 1/2" and 14mm m/cs were about the same, so most of the braking feel difference seems to be attributable to the bore size difference. I'll probably run the 14mm one for the first weekend, but I'd still like to try a 15mm or 5/8" unit to see how they feel.

Anyway, working through all these master cylinder swaps and experimenting now gives me a much clearer picture on what piston / master cylinder ratios really mean "at the lever". That alone was worth it. I'm only down a couple pints of DOT 4 and $20 (and a six-pack) for the 1/2" master cylinder!

 

[patrino]

Traded my buddy the 1/2" m/c for a 5/8" (16mm) master cylinder, that's the ticket for me!

All set to go now, bike is plugged into the battery charger, ready to load up on Thursday night.

 

[MK3Brent]

Good luck. Keep it stick side down.

 

[patrino]

Thanks MK3Brent!

Wow ... great weekend. Some of the headlines:

1. Brakes worked great

2. Bike pulls like a freight train - revs out well, carburates great, etc. A ton of fun to ride.

3. It burns a LOT of oil. Given that I can't afford to rebuild the motor until the season's over, I'm going to live with it for now and hope it doesn't get worse.

4. Bike handles very well.

5. Bike is VERY sensitive to tires. For some reason it doesn't like Bridgestones at all (I tried two different tires, the H-pattern supermoto race tire and a full medium-compound race slick) and it developed a bad high-speed weave. I tried to work around the problem (different steering damper settings, checked steering head bearings and swingarm pivot, moving my weight around the bike, ride height, and more), but couldn't get rid of it. I ended up putting the four-year-old Pirelli DOT tire on and taking 2nd place in 450 Superbike (and set my fastest-ever lap time in the process). The weave disappeared. Our Bridgestone rep is great, I like Bridgestone tires (I run them on my 250 race bike and my RC51 because they work so well) but for some reason they don't take to the GS. I'm going to do some sleuthing, I'm guessing it has something to do with sidewall / carcass construction. The difference between the two blew my mind - if you'd have blindfolded me and had me ride them back to back I would've said that they were completely different machines.

6. Pipe grounds often and hard. I struggled with that all weekend, and had to take some unorthodox lines and manage my braking so I wouldn't lever a tire off the ground. (I scraped a lot but only levered once, the front came off the ground for an instant going into turn eight, I recovered but it wasn't fun.) You can see in the photos where it's hitting - up front and in back. I don't know what I'm going to do here. I'm thinking about having a new midpipe made, or else maybe just taking a hammer to it to flatten it out. I'm open to suggestions if anyone has them.

More info later, I'm going to service the bike this weekend. Any questions ask away. Hopefully this is the start to a great 2014 season!

Patrick

Our pits.

Buggy number plate, after three days on the track.

You can see where the pipe is grounding out by the torn heat wrap. I ended up removing it from that section and adding additional hose clamps.

New trophies for this year. Janice Logan is the class sponsor.

 

[steve murdoch]

Congrats on the results but from the sounds of it the fun factor was the best part.
Would a longer rear shock be of any value for your clearance issues or would it upset the handling too much?

 

[CivilRock]

My guess is that the tires have different profiles. Just a guess, but I've experienced wildly different handling because of the shape of the tire. Rounded vs pointy mostly.

What kind of bikes are you racing in 450SB? Sv650?
What was your best lap time?

Love the pics, the stories, and the race report.
Thanks for posting.

Kevin.

 

[Sandy]

Any chance on upping the preload or spring rate on the suspension a bit to reduce it squatting in the corners too much? Might give you a little more clearance on the pipe or would that screw up your suspension setup too much? That and the hammer might do wonders.

 

[GregT]

Looking at what you've got, I'd reckon there's very little more to come in raising the rear. The pipe on the other hand has plenty of room to tuck in better. Roadrace pipes should be tailored to the bike they go on for maximum clearance.
Ours tucks in quite a bit tighter and I run a solid flat ignition cover abt 10mm thick...and he's decked that a couple of times.