R1 Forks, Techical Stuff I dont Understand

[Stupid Luke]

Ok I have R1 forks (5pw) everything else is still a mystery. I was half inclined to buy a set of custom yokes and be done with it. The downside is that I will still have the same offset and sterring geometry on the std bike and I want it more on it's nose like a sports bike with handlebars.


One of the major benefits, to me, of this modification is to put the bike more on R1 geometry than its current its sedate steering.

I am pretty sure this can be achieved by using R1 lower yokes and a  Gen 2 top yoke but I dont have those bits and dont really know what years etc, plus I dont want to end up with a load of bits I may or may not be able t[size=1em]o get someone more knowledgeable than me to splice together.I know Devilsyam was planning a solution with these bits but it wont happen unless 10 people commit and there is me and maybe another atm.[/size][size=1em]So today I have been chasing up some racing contacts in the Supermono mob and have found some guys that will make adjustable yoke sets, knock me up a steering stem and programme the lot into their CAD database incase anyone else wants the same done in the future. [/size][size=1em]So, what I need is a drawing or measurements of the adjusted FZS steering stem if anyone has one.[/size][size=1em]Also, the angles of rake and trail that can be achieved with the R1 lower yoke set up.[/size][size=1em]In an ideal world we will end up with a correctly specced bottom yoke that can adjust from the std offset to the most extreme R1 offset available, plus a stepped top yoke that offers the current fazer ride positon plus a variety of sportier alternatives. None of this will happen without your input as I know nothing.[/size]

[NorthWestern]

Have you considered rwu r6 forks? They go in the std yokes and you could get them setup and a trick ti ni coating for less money than fitting r1 forks.

[Stupid Luke]

Nah, I want the upside down forks and 5PW seem to be the best option as I can keep my standard brakes and wheel.


The next bit is interesting though as there are folks that have used 5PW lower yokes, 4c8 lower yokes and various other R1 lower yokes. None of them seem to know, or be willing to share, what offset or steering angle they have achieved. Then, even if they have this info they are stuck with what they have, they cant adjust anything. How without adjustable lower yokes,do we know what is optimum is?


Then we know that all the USD R1 forks are shorter than the RWU  FZS forks. There is a chart somewhere that tells us how much shorter that I have seen on here, I would be grateful if anyone has a link. Now general consensus is that this is a good thing as it puts the bike more on its nose, like a sports bike and I agree but again, what is optimum? And then what does optimum matter if you cant achieve it as the forks you bought are too short?


So if I can get someone to design a lower yokes with eccentric adjustment in the steering stem plus a stepped top yoke so that any ride height from std down to the more radical R1 settings can be achieved wouldnt that be a good thing? More so if they can make a  suitable steering stem from a drawing. Then make the fork holes oversize so they can be shimmed out to fit R1 forks but should you want to fit KTM forks in the future or use them on a different bike -not a problem.


So if anyone has a drawing of the steering stem that the american forum used I wquld be grateful.

[Falcon 269]

The thing to keep in mind here, I think, is that the rest of the Fazer's chassis isn't really a match for the kind of multi-adjustable front end that you have in mind.  I can understand why you would like to be able to optimize the configuration of an R1-based front end but is really going to be worth the cost?

My own set-up is 5PW forks in 5PW yokes (top and bottom) which have been mated to the Gen 1 steering stem.  The top yoke has weld-reinforced in the webs underneath and drilled to take the Fazer bar clamps.  It is very quick-steering, possibly too much for some, but stable at high speed.  That said, I'm considering trying fork extenders to restore a little of the front end height, which in turn will increase the head angle.

The internet has loads of info on all the offset of R1 yokes of all model years, and which ones match the FZ1/FZ8 top yoke.  I don't recall the numbers off the top of my head but Google is your friend.  Search here and on the US FZ1OA forum first.

[Stupid Luke]

You are right Mike, cost does have to be considered so I have set my budget at 400-500 quid tops.


For 450 quid I can get a set of ready made billet yokes from ebay. With no adjustability, hopefully replicating the std bike's geometry but who knows? Made primarily for the shiny chrome streetfighter crowd. This guy is just replicating his original design so perhaps we can say 100 quid for materials and 350 quid for his time and profit.


Would they be strong enough, who knows? They are probably fine for those folk that ride 50 mph upright between bike shows, bulldog bash, mayday run etc. How they would cope if you are wanging it around a corner, find a tractor in your path and have to make a quick direction change on a potholed Uk road, not so sure.


But is it really cheaper to use various Yamaha bits off ebay? Not from what I have seem: Gen 2 top yoke with risers 100 quid, lower yoke about the same, steering stem 50 quid for a stock one you have to get machined or 100 quid for a custom one. Plus getting it all fitted together. I reckon you are still in for 450 quid ish.


Also you still dont know if what you have created is strong enough. All of those bits designed for other bikes were not designed to work together so again, do we really know if they would cope in an emergency. I accept that most of us are just doing this mod for our own use and will take our own chances but I wouldnt recommend lending a modified bike to a mate or selling it without putting it back to stock.


The only way I can get adjustable yokes designed and built withing budget is to find someone that does that type of work as a hobby / sideline. Those sort of people are involved in racing and particularly in Supermono where there are few restrictions on engineering. I have a few contacts in racing and they are all pointing me to the same people. If I can get them interested enough to take the project on I reckon I can keep it within budget....I hope :eek [size=78%] [/size]

[NorthWestern]

I did mine cheaply with a 2CO R6 top yoke (£25) and a YZF 750 bottom yoke (free).  At the time they were about £40.  You can get R1 yokes for 40-50 each which just require strengthening for the top riser bolt holes.  If you want it quick then you can pay the buy it now prices but the same yokes stay on for ages so if you make a decent offer you can get them for less than advertised.


FWIW the mod list I did was very short.  2 plates welded under top yoke for bolt holes.  A single hat spacer for the top yoke and cut and rethreaded the std stem.  All very simple mods.  The YZF bottom yoke requires no modification (even the horn bolts/brake lines bolt on perfectly), lock stops etc all good and the stem seats in like it was designed for the bike where from what I Saw the R1 bottom yoke needs a roll pin and the stem not fully pressing in...


I don't recall exactly the mods I did to the stem but :



The exposed stem is 22mm which I seem to remember was achieved by cutting the stem down 12mm and putting an extra 11mm of thread on.  The headstock bearings etc are unmodified.


The spacer: (this goes in the top yoke so the stem fits nicely as the R6 uses a thicker stem).





The dims for this are: flange diam 37mm, flange depth 1.5mm, hat part diam 28mm, internal diam 23.5mm, total depth of spacer 10mm.


The offsets for the 2C0/YZF750  are 25mm (IIRC).


4XV forks, 10.0 springs.


As mentioned this lowers the front end but because the top yoke is lower than the standard one I only lost about 22mm over stock. 


Using 'period' R1/R6 top yokes fit the look of the fazer better than the more modern FZ1 IMO (and are much cheaper).


These measurements should give you all you need to replicate my particular setup.  If you use R1 yokes, FZ1, different R1 years then offsets will be different.  Different year R1 forks are different lengths etc.  My rear ride height is not standard.


You might have to faff around to get your steering lock to operate but nothing beyond the realms of a couple of files and some ingenuity.


If you want standard geom with your custom yokes then just measure what you have currently and work it out accordingly.  The forks will be sunk in the top yoke to achieve that, or use fork extenders.



Everyone's bikes will be different as they use different bits and bobs, rear ride height, tires etc  If you are wanting adjustable yokes then just go with R1 spec +- whatever you feel necessary.  I could have made 'billet' yokes as both my brother and dad make them for race bikes but what's the point really when you can do a quick 5 min mod on some £25 yokes.

[sadlonelygit]

Have you considered the rake and trail as well as the offset.
Imo the 5pw and onwards are too short for the fazer unless incredibly stiff.
There are extensions avsilable but i dont like them.
i'm going to say something contraversial here but my fazer with properly set up OE front end was as good as the R1 front end i have now. But when you throw £4-500 at your bike you need it to be better.
aesthetically they are far cooler tho.

[unfazed]

Have you considered the rake and trail as well as the offset.
Imo the 5pw and onwards are too short for the fazer unless incredibly stiff.
There are extensions avsilable but i dont like them.
i'm going to say something contraversial here but my fazer with properly set up OE front end was as good as the R1 front end i have now. But when you throw £4-500 at your bike you need it to be better.
aesthetically they are far cooler tho.

:agree

[nickodemon]

Have you considered the rake and trail as well as the offset.
Imo the 5pw and onwards are too short for the fazer unless incredibly stiff.
There are extensions avsilable but i dont like them.
i'm going to say something contraversial here but my fazer with properly set up OE front end was as good as the R1 front end i have now. But when you throw £4-500 at your bike you need it to be better.
aesthetically they are far cooler tho.

I have to say i don't agree with your thoughts on an oe front end being as good as a good R1 front end. My bike has a 2007-8 4c8 r1 front end fitted and the difference when going at a fast pace is night and day. I always thought the original front end was pretty good when set up correctly, but after fitting the r1 front end the bike handles like a very modern bike. If it only made a slight difference i would honestly say so, but it has massively improved the handling. Just my opinion..

[sadlonelygit]

and where did your bike end up :rollin

[nickodemon]

In the wrong thread :eek