new GS racer

[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.

[patrino]

Good ideas, everyone, thank you thank you!

I've been thinking over this a bit, I've got a few plans of attack:

1. Increase front and rear preload to raise the ride height (and hopefully add some ground clearance). I'll grab some baseline sag numbers this weekend and see what I can do to raise her up. If it was in the budget I'd have Works extend the shocks 1/2" and get some longer fork tubes from Forking by Frank, but unfortunately there's no money for it (especially after spending $400 in tires that won't work.)
2. Make or have made a new ignition cover (turns out I was grounding it too, which is worse than the pipe because there's no flex to it.) What kind of ignition are you running, GregT? I need to pull my cover and see how flat I can get the cover. Any photos you could please send?
3. Hammer some flats to the pipe. This one's a maybe at this point, we'll see. The pipe's coming off anyway so that I can change the oil, so I'll do some experimenting once it's off. I'm going to see if someone around might be willing to fabricate a new mid-pipe. My A1 go-to pipe guy (Will Jones, with Poor Bastard Cycle Works) moved to Atlanta earlier this year so I'll need to ask around.

Once I'm at the track I can also start messing with the compression damping, that'll be a trial-and-error process. Joe Signs was there this weekend, he reported a lot of squat coming out of turn nine onto the straight. I zip-tied my shocks and forks and I'm using nearly all the travel.

Kevin, I've been racing in Middleweight GP (new class), 450 Superbike, Middleweight Classic Superbike, and 650 GP Twins. Yes, mostly SVs in nearly all of those, the grids are great this year. I was able to turn a couple 1:20s after I got the tire issue sorted out, mostly 1:21s and 1:22s before then. My goal is to be in the teens by the end of the May weekend, so still work to do. I was running out of gearing once I got the tire sorted out so dropping a tooth in the back will help.

Steve, YES on the fun factor!! At the end of the day I'm really just trading a lot of money for a cheap plastic trophy, so it had better be fun!!!!

[GregT]

Our ignition is a Dyna 2000 - running inverted. The pickups are inboard of the mounting plate and the crank end rotor has been shortened to suit.
The ignition pickups are uni- directional magnetic switches so work perfectly inverted.Can't do it with a Dyna S though as you must retain the advance mechanism.
The only things coming past the end of the cases are the ignition backplate screws, so a flat plate cover, counterbored for the screw heads works well.

From what you say, I'd suspect you may have slightly too soft springs for your weight. Our front end setup is peculiar to the rider, progressive springs with enough preload it has only about 25mm sag with the rider aboard, Most of our tracks here are short and tight and he likes to trail brake deep, turn it early (backing it in often) and gas it up hard...with this setup the front pops up quickly and it weight transfers very well...ie wheelies while laying darkies...

[CivilRock]

... he likes to trail brake deep, turn it early (backing it in often) and gas it up hard...with this setup the front pops up quickly and it weight transfers very well...ie wheelies while laying darkies...

I like the way you talk.

[Charlie G]

likes to trail brake deep, turn it early (backing it in often) and gas it up hard...with this setup the front pops up quickly and it weight transfers very well...ie wheelies while laying darkies...

It sounds a bit poetic to me

[GregT]

It sounds a bit poetic to me

The guys he's done it in front of wax positively lyrical....after they've realised he's in control of what he's doing. He's scared a few though.
I've had at least one chief Marshal come and see me and ask if I can tone him down a bit. i just say he knows what he's doing and hasn't fallen off yet....

An old friend of mine had a ride on the GS and came back saying it was set up as a hooligan's machine. Too easy to wheelie in his opinion. Suits our street circuits very well though.

[sharpy]

An old friend of mine had a ride on the GS and came back saying it was set up as a hooligan's machine. Too easy to wheelie in his opinion. Suits our street circuits very well though.

They are a wheelie machine. At the Swan series in the early 80's and before rules came in gs1000 where the bike to have in the lunch time wheelie contest. Same year Dennis Neil did a whole lap of Surfers Paradise track on the rear wheel using the XL500 with the 23" front wheel. Shame the year i entered one other on a XT500 won as he was doing better wheelies than i was on my TT500 but i was 2 up. I even got the thumbs up from Jeff Sayle as he rode past on his TZ750 just before the straight and took off in the distance on the rear wheel.

[patrino]

Took some sag measurements last night, I was at ~30mm front and rear. Added some preload to both ends and am not at 20mm front and rear.

Big T found a spare points cover for me so I'm going to cut a chamfer in it today and fit a plate to cover the hole. A friend of mine who TIG welds has offered to weld the two pieces together for me, hopefully that'll help.

I'm working on tracking down a new Pirelli rear tire now. Hopefully the new Pirelli works as well as the old one.

[CivilRock]

I need to come out and see that machine. 1:20 is stinking fast on any bike let alone a 30 yr old bike.

Hero's work right here. Very impressive.

Kevin.

[patrino]

Big thanks to Big T for selling me a spare ignition cover!

Bridge City Cycles let me use their mill this afternoon; I cut a chamfer into the cover, next step is to cut a plate to weld over it. That's the plan for tomorrow. Hopefully between the chamfer and the added preload front and rear I'll stop grounding out on the RH side.



I welded up the seat pan welds that failed, too, and put Jenni's cover back on the seat. It's tougher than it was, hopefully it'll hold up.

[Charlie G]

Next time you race, how about a picture of you and the bike in the pits. We like pics.

cg