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Fiberglass front fender, need for fork brace?

Started by Dvsrd, March 26, 2020, 12:18:57 AM

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Dvsrd

I am using a TZ replica fiberglass front fender on my RD350A, currently without any fork brace. The fork is the oem 34 mm KYB, but with RaceTech linear springs, and emulators.
I know some claim that the original fender mount bracket also works as a fork brace, although I haven't noticed much difference myself, riding the bike.
Have anyone for example measured fork twisting, with and without the stock fender installed?
Basically by locking the front wheel in position, then pulling or pushing on the handlebar end, and measuring deflection.
Or even better, having a complete, assembled fork, with triples and wheel axle, with a dummy spacer instead of the wheel hub,  all fasteners torqued to spec. Then clamp the axle/spacer securely, and use a 7/8" round bar instead of the handlebar, and again pull or hang something heavy from it, then measure deflection with and without the stock fender installed.

I am thinking, if the stock fender really doesn't do much, then adding a pound/ half a kg of unsprung weight really makes little sense.

oxford

This has my interest.  I am using the same forks and fender and have been wondering about a brace.

If deemed there should be one on there, what are the best options?

m in sc


Dvsrd

Quote from: m in sc on March 26, 2020, 01:28:08 PM
yes. make one.
That gives 2 options, either some kind of inverted U-shape, straddling the fender/ doing double duty as fender bracket, or something like the Tarozzi, clamping the fork lowers. I have a Tarozzi on my XS 650D, but they don't make them for the RD350 AFAIK.

m in sc

#4
made mine on a tubing bender



2 small flat plates on side, added a tapped plate at top to support fender:



my friend david wheeled me a fender out of titanium sheet and done

TI bolts and abs spacers:






1976RD400C

^^^  Kind of like my store bought one from 40 years ago.

20200327-101649" border="0
20200327-101705-2" border="0
'76 RD400 green  '76 RD400 red   '84 RZ350

rodneya

Fork brace from Tractech Manufacturing in Niagra

m in sc

nice. yup that type is where i got the idea.  :metal:

Im mixed about fork braces that clamp on. i have a few bikes with them, but i also have had some that distorted the fork leg -just enough- to cause a fork seal leak. 

JB Weld


teazer

Ah, the TZ replica trick.  Real TZ front fenders incorporate an aluminum brace that acts as the main mount

http://i.ebayimg.com/images/i/131538727763-0-1/s-l1000.jpg

http://www.meadspeed.com/resources/meadspeed/media-files/products/yamaha/tz250-350/front-mudguard/1976-1980/main.jpg

Try to replicate that.  Not quite as stiff as those ugly tubular designs but quite adequate.

m in sc

no, its steel, structural 3/8" tube tig welded onto the plates, not conduit.

and IMHO, not ugly at all.  :whatever:

:dawg:

JB Weld

I think it looks great. Hugh's Hand Built makes a similar brace for XS650s.

m in sc

i did set mine back quite a bit, you really cant see it unless you look for it. i agree a lot of them are just way too huge.

it son on this pic, just not hanging way out there. the longer the rod the more it will flex. i made it as short as possible. it absolutely made a big difference.



Dxrat


Djg8493

Quote from: Dxrat on March 28, 2020, 05:53:18 AM
Rswracing.com makes one for the rd350/400.

+1, I have one on my RD.
1970 R5, 1975 Rd350, 1978 GT80, 1979 KZ400, 1988 Ysr50, 1990 GSXR750, 2006 WR450 SM, 2006 R6