Race chassis

[F5 Dave]

Athena are the other choice people seem to go for. My 496 Cheetah kit with PVs crank etc was circa $5k a decade ago. Pre kids of course. The Cheetah Cubs are cheaper option. There is the Serval which is similar but not so biased on drag racing which is what these quad guys in 'murcia seem obsessed with.

[el chupacabra]

What did you end up doing for your exhausts?
I think I’m in it about 4K including the bike . . . So far

[F5 Dave]

I had a forum mate in souf affrika hydraulic some headers and send pipes in kit form. Actually he did 2 headers, the 2nd set were made into the VJ21 RZ 421. Actually I think his engine was level so he must have made new rear mounts. . . . getting back to chassis for a small moment.

[el chupacabra]

Decided to go ahead and re-do the engine mounts after looking at how every other Banshee swap had the engine sitting pretty much level so i made up a frame jig during the week. It'll probably come in handy for a few of my other projects I've got coming up.

[Frits Overmars]

Just stumbled across this Feet-First discourse.
http://www.oesten-creasey.eu/hightec...fNM3-qaqI1p2QI
Feeling fairly positive about FF-twowheelers myself, I agree with about 50% of the contents.
In other words: food for thought.

[F5 Dave]

As I lie here in bed in the approximate position propped up a bit I can't think of anything more unnatural than lining up a corner and deciding to roll into it. Can't move any weight and unlike luge tracks, race tracks are severely banked on every corner. Long wheelbase and you'd have to lean further to achieve the same effect, again with minimal weight redistribution.

[mr bucketracer]

Decided to go ahead and re-do the engine mounts after looking at how every other Banshee swap had the engine sitting pretty much level so i made up a frame jig during the week. It'll probably come in handy for a few of my other projects I've got coming up.

nice . Should go well . May need to steping the fork angle a bit

[Michael Moore]

Frits, there's more of Royce's (and other FF enthusiasts) writing and photos at

http://www.bikeweb.com/

Dave, NSU was planning to use the short (compared to the LSR bikes) Baumm road race FF on fast/open tracks and the conventional GP racers on tight stuff, in a "horses for courses" concept. But they pulled out of GP racing before doing more than testing.



I think FFs have a lot to offer in certain cases. Rossi etc are probably not going to want them in the high-end road race case because that (to me) is so specialized it hardly qualifies as a regular motorcycle activity (much like watching Bau defy physics on a trials bike). For a public roads bike they have a lot to offer, and I suspect that if they help a rider to feel more confident (as has been reported by owners of Gurney Alligators and some of the few track FFs) they might actually help slow/low fear threshold racers like me go a bit faster in club racing. I was going to build a track FF to address some ergo issues I have (stiff neck that makes it hard to look around corners with clip-ons, hands that go numb from pressure) but I'm now a former racer so that project has lost a lot of what little momentum it had.

Some FF proponents are very much in "evangelist" mode and I think there are some claims made for them that seem unlikely to hold up. But on the other hand there seems to be a lot of riders of conventional HF bikes with very closed minds who won't consider anything that doesn't look like what everyone has been riding for the last century+. A Gurney owner told me he likes to park his bike at a gathering spot and hang around to listen to the (often uninformed) comments. When he finds a likely suspect who pontificates on "must be crap, can't work" he'll offer them the keys for a quick test ride. He said he never had anyone come back who hadn't changed their opinion.

cheers,
Michael

[el chupacabra]

What is the usual process for changing the steering head angle in this situation on an RGV?

[Frits Overmars]

What is the usual process for changing the steering head angle in this situation on an RGV?

Heading for a brick wall might help...

[jato]

What is the usual process for changing the steering head angle in this situation on an RGV?

I'm not sure what others do but the last one i did i set up the chassis on a fairly large milling machine and machined away the old headstock leaving an accurate void at the new angle. you have to go 8 or so mm bigger diameter for the new headstock - depending on how much change of angle you are going for. being ali i'd be inclined to finish the last mm or so of the bearing seats after you've welded the new head stock in. if you don't have a pet machinist send me a pm if you like

[F5 Dave]

Lot of work and an RGV is probably fine for a track day bike as is.

[el chupacabra]

sounds like a lot of hassle. Probably almost as much hassle to make a steel tube chassis from scratch.

[TZ350]

I'm not sure what others do but the last one i did i set up the chassis on a fairly large milling machine and machined away the old headstock leaving an accurate void at the new angle.

I did something similar but just used a good hole cutter in a mill drill.

Left an old bearing in the new alloy housing so it would hold its shape when it was welded. Pretty crude but it worked.

[Michael Moore]

Kosman Racing here in NorCal had a fixture that mounted on the table of a Bridgeport mill to hold frames (typically KZ1000) to have the steering heads cut out. They used a hole saw on a custom arbor. Since the hole saw was not deep enough to do the entire cut at once they'd stop now and then and trim out the sections that were free of the main frame. The new larger OD steering heads would be both reangled as well as moved over onto the center line (it sounds like there was often a bit off lateral offset from the factory).

My Cagiva Allazurra was easier to do. Since the swing arm was mounted off the engine I was able to remove the original motor mounts from the frame, reposition it with a steeper rake angle, and then make new (boxed sheet metal) motor mounts. I also removed some of the original bracing tubes and added new ones that did a better job of triangulating the structure, and moved the engine forward in the frame too:



cheers,
Michael