More SV subframe stuff...

[dwilson]

My stock subframe is bent & cracked (that's the main reason I got the bike so cheap).  To buy all the aluminum I need to make the new subframe, seat and several pairs of rear sets cost me $70 (including shipping).  I already have metal working tools, no wife, no kids = lots of free time  8)
It'll be nice to save 5-10lbs but it'll save me a few hundred bucks that I can put into my suspension.  Besides I like to build stuff...

[Zac]

Yeah, I like to build stuff too.

And we also have to remember that 10 lbs makes a much bigger difference on a 55 HP MZ than it does on a 140 HP liter bike. The traction limited 1k isn't going to accelerate any faster if 10 lbs is taken off, but the power limited light weight bike will pick up a few percent in power/weight, corresponding to a little more acceleration.

We'll see, for the FUSA Thunderbike race it looks like I'll have to ADD weight to my CR500 to meet 3.8 lbs/HP.  I'll see if it makes any difference from my CCS races to the FUSA race.

-z.

[tzracer]

Seems to make a bit of difference to Ed Key, ask Mark Junge.

It is fun to do. If you have the talent, access to equipment (mill, lathe, welder, laser, band saw, shear, brake), then why not?

My subframe cost about $15 in material. I could find no source for a subframe other than the stck one. So I made one. Weighs less than 2 lbs. It is fun to look at the bike and replace steel parts with aluminum parts, especially unsprung parts such as wheel spacers.

Jason, I will be sure to put on all the steel parts for your stints in the TC races ;)

[Super Dave]

Seems to make a bit of difference to Ed Key, ask Mark Junge.

It is fun to do. If you have the talent, access to equipment (mill, lathe, welder, laser, band saw, shear, brake), then why not?

LOL, if you have fun doing it and have the stuff, do it...I agree.

Will the subframe help Ed Key, a tiny amount.  The whole package plays the biggest in the result.  And Ed is very good with sorting his suspension and riding.  

But the matter still stands that given chassis of similar quality and set up, one with a substantially different power to weight ratio will only go a little faster...a little.  Larry Denning probably weighs similar to me.  So, his R6 would have a weight vs power ratio of about 5:1.  His R1 with 30 more HP would be at about 3.9:1.  For his R6 to have a similar ratio, it would need to loose almost 120 pounds...The difference in lap times at Blackhawk was .75 of a second.  

Still got to have fun.
 ;D

[tzracer]

Really not comparing weight ratios when comparing an R1 to an R6. The R1 has more power than it can use. Compare a 300 lb R6 to a 380 lb R6. If the 300 lb R6 were .75 seconds per lap faster I would call that substantial. Weight must be an issue or why bother having weight limits in FUSA races? It is not cost savings, because if there is no real gain in less weight then why would I care if a competitor was much lighter. Does the R6 come stock with a steel subframe? 2 equal riders on equal bikes, I one is made lighter, it will have an advantage. In club level racing it is much more the rider than the equipment.

Ed Key admitted at RA that he beat Mark Junge because his bike had a better power to weight ratio, as Ed said, he out rode Mark on the straights. Mark's bike was WERA legal. For Ed it is the entire package. He has much more than just an aluminum subframe. He has removed weight where ever possible. Outside of the engine, there are not many steel parts on his bike. If a bike loses 10% of its weight, it gains at least 10% in acceleration. Removing rotating mass gives a larger boost. Then there is the issue of drag. Do race bikes really need to have seals on the wheels? What is the drag of a sealed bearing vs a shielded bearing vs a ceramic bearing?

I enjoy building bikes as much as I enjoy riding them. I used to do it for a living. Some of the changes I make are for performance gains, some to ease maintenance (such as wheel changes, I am woking on a system to keep the rear brake carrier on the swingarm, cost about $10, time about 15 to 30 minutes), and increase reliability. The thinking and building involved with improving the design is what I enjoy. I have the access to the equipment, the ability to use them, the ability to come up with the ideas, the knowledge of materials (along with the background to ask the proper questions if I need more info) to be able to do it, so why not? Riders on more stock bikes may beat me, but so what. I have accomplished all my racing goals. I retired. I came out of retirement when Rick asked me if I would help him teach riding schools. I have no secrets. I will share all the information I have gained in 20+ years of racing to help others reach their goals, regardless of whether they are my direct competitor or not, whether they are a Learning Curves graduate or not. My last crash seems to have taken the edge off, I am not sure I am the racer I was in 1999. But getting knocked out and recieving mouth to mouth may do that to a person. So I race for fun, both setting up the bike and the actual riding. Yes I still enjoy to finish well, but I am not sure how hard I am willing to push to do so.

[Super Dave]

Weight must be an issue or why bother having weight limits in FUSA races?

To have an equal playing field.  

But it really isn't.  I weigh more than Matt Wait and Eric Wood.  The only way to do it properly would be to do it with a combined rider/bike weigh in.

I one is made lighter, it will have an advantage. In club level racing it is much more the rider than the equipment.

Right on both sides.  You really have to go a long way to where it is not the rider that is the deciding factor.  And even then...

Certainly a weight advantage is an advantage, but will it result in a reasonable change in lap times?  

Ed Key admitted at RA that he beat Mark Junge because his bike had a better power to weight ratio, as Ed said, he out rode Mark on the straights.

And can Ed give blood?  I mean, does he weigh enough that the Red Cross will allow him to give blood?  Mark's about my size, so Ed might also have an extraordinary advantage on top of everything he's worked on.

I enjoy building bikes as much as I enjoy riding them... I have the access to the equipment, the ability to use them, the ability to come up with the ideas, the knowledge of materials (along with the background to ask the proper questions if I need more info) to be able to do it, so why not?...So I race for fun, both setting up the bike and the actual riding. Yes I still enjoy to finish well, but I am not sure how hard I am willing to push to do so.

I never had access to much more equipment than a drill.  Didn't have the back ground in it, myself.  Not that I wouldn't like to do more stuff.

But from my first racing career so many years ago, I learned that my work on weight savings had no discernable effect on my lap times.  Even my personal weight had no real effect.  

Lot of those clues came from working with Dale Quarterley.  And he weighed about 200#, was 6'3", and still won an AMA National and was consistently up front.

It always came back to the rider and the set up.

I'm done...
 ;D  

I blame D'Amico for getting me going...

Sounds like a lot of time and money being wasted! Go out and ride a dirt bike or cardio train, something that will actually make you faster.

[dwilson]

If I run this bike with the bare subframe and number plates but no body work will I get any hassle at tech?  I saw a couple guys riding like this but I don't remember what bikes or what classes...  
I don't see any point in having rear body work except for cosmetics and it's a pain to fix after I crash it.

[Super Dave]

Now that's a good question.

Seems like if the bike was produced with a fairing, it's supposed to have it, unless it's damaged.....?

Seat sections can be modified to accept number plates.  

I'm not sure, Don...

[tzracer]

So weight limits are needed to keep things fair but weight loss does nothing measureable in lap times?

Any difference in lap time amy be small, but adds up over time. A tenth of a second adds up over a 8 lap race. Also, it is less work to ride a lighter bike. How much does race gas affect your lap time?

I recall Vance and Hines Yamaha testing carbon fiber wheels when they first came out. Jamie James did the testing. It was a double blind test - jamie did not know ehich wheels were on the bike, magnesium or carbon fiber. jamie later admitted it was very easy to tell the difference. His lap times averaged about 1.5 s faster with the only change being the wheels. The AMA immediately banned CF wheels.

If you want weight to make a measureable difference you must go after every part that is easy to change or eliminate, especially those that can be made from aluminum. It is not really expensive, but takes some time and access to some equipment. You can actually do quite a bit with a drill, a vice, a hammer and a hacksaw. Ed Key only has a lathe and some hand tools to work with and he has done quite a bit.

[Zac]

If I run this bike with the bare subframe and number plates but no body work will I get any hassle at tech?  I saw a couple guys riding like this but I don't remember what bikes or what classes...  
I don't see any point in having rear body work except for cosmetics and it's a pain to fix after I crash it.

Nothing in the rules requires bodywork...

5.2.2 Neat and Clean. Motorcycles that are dirty or show potentially dangerous bodywork damage will not be approved.

5.2.11 Fairings must be mounted in at least three locations. The front wheel must be clearly visible from both sides except
for the portion covered by the fender. The rider must be visible from the side and above, while in a normal riding
position, and transparent material may not be used to allow for such visibility.

6.1.2C Any fairing may be used provided it is made of plastic, fiberglass or carbon fiber.

The way I read that is anything goes as long as it's not dangerous and not a dustbin.  If you have a rear subframe with no pointy parts or sharp edges, that should be legal.

-z.

[duc995@aol.com]

From personal experience if anyone was trying to be as competitive as possible with a Y2K SV, they would sell it and buy a 2003/2004 model!  I don't think a lightened rear subframe +/- a fairing is going to compare to the apparent HP increase in the new models!

[tzracer]

I guess you have never raced against Ed Key. He has 1999 SV650 SS bike that weighs in at close to 300lbs. Ed weighs about 130lb. He has no intention of updating, said the extra couple hp is not worth it.