who's going to Talladega?

I'm trying to throw gas on a fire here, Mark. Are you bringing more fuel, or water?

 

the days of f-rd bikes winning f500 at road atlanta are over!

 

Is that because you're going to take all the F-RD bikes out with exploding Kawi parts Scott?

[This message has been edited by AHRMA872 (edited 04-09-2002).]

 

Ooh, and now the Kriple jokes begin!

 

A well built F-RD is not much off the mark, a bit more bottom end of the corners than a totally built F-500, admittedly a slight notch down on HP but a bit easier to ride and a bit more reliable, and well ridden an absolute contender if F500.......




[This message has been edited by Yamaha Bob (edited 04-09-2002).]

 

Best I've heard from a F-RD bike is high 50's RWHP. Barlow's RD400's routinely dyno at 70 or more. I'd call that more than slight.

[This message has been edited by YAM#849 (edited 04-10-2002).]

 

Nothing illegal about a Barlow motor in F-RD just have to run smaller carbs (won't cut 20 hp) in AHRMA they have to run stock reed cages also. other than that it is a well ported completly legal F-RD motor (exception of the straight cut primary).. JUST WHIP OUT THE $$$CHECKBOOK$$$




[This message has been edited by Yamaha Bob (edited 04-10-2002).]

 

I would agree with Yamahopper Bob, a good F-500 bike will make in the mid-upper 60HP range, my upper 50HP RD400 is pathetically stock and has more potential in it.(see elsewhere in the BBS for my specs)I get my jollies from building and tuning my own bikes, and learn a lot in the process. Thats half the fun of vintage racing! My ethics of tuning is to seperate fact from fiction, to find out what REALLY makes power, or handling, better,not to simply do things because everyone else did that, or because it should work in "theory". I'm limited with time and money, wish I could dyno those pipes and try that porting. My development is slow at times, works for me. Why dosn't someone hire Barlow to build a 65 HP F-RD bike? Remember folks, just because you don't see it at your local track(in a grid of eight bikes on a good day)does't mean it can't be built. Long live Vintage, land of the cheap!

 

It's legal for F500, but not F-RD. Modified items include reed cages(AHRMA allows mods to the OEM part) and pistons. To find out what else, you'd have to get with HB and $$$pend.

 

Nobody's really ever asked him to make one. He thought about building a F-RD bike just to sell, but wondered if anyone really wanted that kind of HP on a skinny rimmed F-RD, so he decided to hold off and see.
His prices are about on par with most other tuners I've seen.

 

I know there are a few other mods AHRMA allows, they can relieve the reed block, harry does not modify the pistons, and there is nothing exotic in his work, it is clean beautiful shaped and redirected LARGE ports, what do the modified reeds contribute? 1 hp 2 hp? and the big carbs, 2 hp 4 hp? so 65 ish is very possible. I saw 67 hp (dyno) from an H2 (30mm) carbed RD350 in 1976. Stan Lipert and Mark Morrow have both proved that a F-RD spec bike is competitive in F-500 if you have the riding skills! The 65 Hp bike will require more maintenance and will be a bit harder on parts (pistons)… Interesting, I only started this as a comment on the complaint about running a F-500 spec bike in F-2stroke. It seems not to be the best index of the bike. Spargo was competitive in F-2stroke at the Roebling opener against Tony Smith the TZ-G master, but then again that was with the Harry Barlow motor.

(Yamahopper Bob)

 

I have raced Formula RD (Wera) and Formula 500 (AHRMA) in the past plus viewing both classes and lap times at tracks.
The Barlow magic is extactly as stated above plus the design of the carbs/reeds/porting/pistons/heads and pipes all matched together.
The best approach would be to build the Formula RD based around the flow of 28mm carbs with matched reeds/porting/pistons/head and pipes to get a strong roadrace powerband to produce the best lap times at most tracks. Based on calculations of rpm and powerband the upper 50s hp would be idea. The best Barlow engines require the 36 or 38mm carbs and opened up reeds to work with the rest of the engine to produce the powerband and hp. By replacing the carbs and reeds the rest of the parts would not matched and lose powerband and hp.

For instance, what lap times can Stan or Mark run at Putnam Park compared to Chris (1:20s) and Bob H. (1:21s) ran in the AHRMA Formula 500. A top Formula 500 will have 50+ hp available for the drive off a corner while the Formula RD hardly has 50 at max rpm. This produces mph all the way to the next corner.

Part of the question is what do you consider to be competitive? Running the top 10 or top 5 or a reasonable chance to win the race?

 

yamabob,
i agree that the f500 bikes should be able to bump to V3. ive only heard of one vrc board member comment on the change and he was in favor of not changing the rule, so two strokes could still race V3.
so to date i still havent heard from WERA why f500 two-strokes are banned from V3. does anyone know why?

 

Yea the 4-stroke guys wanted a 4 stroke only class like F-rd/F-2stroke (class envy), They did not like getting outrun by bikes that were bumping up.. Actually there is a rules conflict with the f-500 rules as V3 I believe is now limited to single disc and no factory RR frames/tranny's.

 

OK, I give up. You know more about what he's up to than I do.

Carl

 

Jim,
I completely agree with your assessment of the situation. Competitive, in my own definition, means having a good chance to win. IMO, if you take any two of the top-notch riders mentioned in this thread and put one on a fully tuned bike prepared by any of the top tuners, and put the other on a F-RD legal revision of the same thing, the resulting hp difference will make it quite difficult for the second rider to win.

Carl Anderson

 

Doubtful that anyone knows more about what HB does than you Carl.... and did not mean to call that into question.. Every little bit helps and 2 hp is 2 hp or 5 hp is 5 hp in the range of the power we are speaking 5% is significant and probably an insurmountable advantage on a good handling well built bike. It is that people make more out of issues that really don’t exist.. I cant believe the number of people asking about stuffing the cases and other crazy #$%^ tuning wives tales, I very much respect Harry’s abilities but good tuners have been making HP on these bikes for 20 years.. not much in the way of secrets left,, mostly it is the details..

And no doubt that equal riders on the differing bikes will have the stated result It has as much to do with things other than HP that are allowed in F-500 as it does the motor, Wheel/tire size and overall weight as well as additional brakes and other components such as braced or racing swingarms, lighter calipers/components and larger front ends have alot to do with it. F-500 seems to be gravitating into the battle ground of the high HP bikes, I think it is great.. but unless you take an RD all the way it seems to make more sense to run a F-RD in F-500 then it does to run a F-500 in F-2stroke.

IMHO the chances of having a winning F-RD bike that is capable of a top 3 finish in F-500 is more likely than a F-500 bike doing the same in F-2stroke.


There are the same advantages to the rules in F-2stroke over the F-500, I.E. 17 inch wheels wider than 3.0/2.5, slicks, larger brakes, water cooled motors etc, and the fact that a F-2stroke bike is legal and VERY competitive in V-5. Hey run what you want where you want..


The debate was started on getting mauled in F-2stroke on a F-500 bike

Just trying to get some more F-RD spec bikes at the races, it is a fun class with well matched bikes that can generate cheap close racing.

I think I am going to build a full on F-500 bike as I know there is an advantage…

See you at the track…


[This message has been edited by Yamaha Bob (edited 04-11-2002).]

 

Yep, I have to agree about the wives' tales, and the fact that there are no magic secrets left. Most of what Harry does is carefully observe and sift for gold amongst what Yamaha has already done over the years to the TZ's and YZ's.

Also completely agree about F-RD to F-500 being a better bump-up for most people than F-500 to F-2stroke. And by all means it's good for the sport to have riders accept the challenge in bump-up classes.

 

In the past, I'd have to agree that frd-f500 has a better chance than f500-f2strk. I think things are changing this year though. Look at the performance that Chris put in at RRR. Very competeive in f-2strk AND v5!! Dick has alluded(off the record of course) that his rd is within 5hp of Chris's rocket. Mine is running, but hasn't been sorted out, not to mention run on a dyno, but we're hoping for high 60's-low 70's hp. I think the newness of the class(4 yrs) contributed to people running bump-up rd's and non- competetive v3 bike for the most part. Only now are we starting to see dedicated f-500 bikes being built. Chris, Dick and I aren't the only ones w/ built rd's this year. The year is young and many people weren't at RRR, so sit back and enjoy the show!! We're going to have fun!!
Oh yeah, in regards to the "two equal riders, one on a frd, one on a f-500" you have to look no further than last months f-500 at RRR. I was on Lyns frd spec 400 and chris was on his f-500 400. 50 something vs 70 something. I rode my butt off for the first three laps only to watch the gap grow by a second a lap until after three laps of taking big chances w/ someone elses bike, I backed off and had to settle for second. If the two bikes are within 10% hp, a good rider might be able to pull off the win through a strategic draft. More than 10% and the faster bike tends to "walk away" down the straights.

 

Mark is quite right. It is the same in any form of racing. If you have more than 10% more power and are geared right you can really take it easy on the difficult parts of the course.

My question is why liquid cooled 2-strokes were made eligible for F-500. Kind of makes my air-cooled RD F-500 bike irrelevant.