Front end conversion.

[acebars]

I'd like to apologise first, I have been searching this forum to the point of exhaustion, most threads just aren't what I'm looking for and usually end with suggestions such as use the forum search etc. There are a lot of GSXR conversions etc. but those are not the opinions I'm after.

I've bought a '73 XS650 and I'd like to upgrade the 34mm front end. A few things I'm trying to do.
-I'll be mounting a front drum (Triumph 8" I think at the moment) and getting the front spacing and axle right shouldn't be a problem done it before, so please keep this in mind.
-I'll be shaving down brackets for disc brakes etc. to make the fork lowers look older. Also don't want to be using any newer looking triple trees etc.
-I'd also like to stay away from the fork lowers being too long/tall as I'd like to sport fork gaiters.
-I don't need super sport modern bike handling, but solid handling is what I'm after.
-Ideally forks that I can mount a fork brace onto.

Given this criteria I'm looking at a pair of XS650 SE forks? Do you guys think this would be a suitable candidate for what I'm looking to do, or can you recommend something better for the job?

Likewise given the headstock is shorter on the earlier frames can you recommend a good old looking triple tree that would bolt on and do a good job?

The Enfield below has the kind of looking I'm going for with regards to the front end.

 

[gggGary]

An XS750 front end is built stronger (36mm) appearance is near identical to the XS650 fork, parts are readily available. It is bolt on to the early XS650 frames, the neck is the right length. The XS750 standard is probably the best choice. the tubes are about 1" longer The XS750 850 specials will work too if you can deal with the look of the special lower tubes. (leading axle)

 

[GreasyC]

FWIW these are the R6 forks I mentioned in your other thread mounted on a triumph. (one of Mule's builds).

except for the little blue nut at the top I don't see much difference between that and an older fork.

 

[acebars]

Thanks Greasy and Gary, does a wider diameter fork translate into a better functioning fork? Or is it not as simple as that?

Those R6 forks look huge, and I'd be worried about getting the fork gaiters and fork ears to actually fit over them, I also fear from what I've seen on other threads that the working area of the fork below the triple tree maybe a little too short.

There is something I've noticed about both the XS650 and XS750 forks that I really don't like so I'm still unsure if there isn't a better alternative, the lower part of the fork lower where the axle fits has this funny area around it (notice the R6 doesn't have this) which will detract from the look I'm going for, same goes for the 750 850 specials with the leading axle.

There is another consideration, the triple tree, first I'd have to find one that bolts on to the early frame and secondly I need one that looks old and not new or billet, I suspect the R6 one will evidently look like something off a modern bike.

 

[gggGary]

With what you are saying I think I would just stick with the 34mm forks. They have the brackets for the fender stays which scream (OK yell maybe) "old timer".

You can fab a forkbrace for the 34mm and probably do some "minton mods" type work inside them.

 

[acebars]

Gary the 34mm shocks I have don't have the look I'm after having the same funny area that the XS750 have around the axle, yep they have the fender bracket but thats about it.

The R6 area around the axle is more what I'm after.

I'm looking at my Honda CB500t 35mm forks, they are not good forks / clunkers but do fit all the criteria I'm after, so perhaps some other Honda forks might do the trick, still searching!

Just looking at GL1000s, very close to what I'm after, just missing 1 fork mount for the fender.

 

[acebars]

I think I've found a set, the TX750 forks I think they are 35mm?? They have the funny mounting area around the axle like my forks but maybe I'll just have to live with that.

 

[acebars]

Ok I think I've found the answer, Suzuki GT750 forks fit the bill exactly. They are only 1mm wider at 35mm. Do you guys think it's worth the effort to just go up by 1mm from the 34mm forks currently on?

Maybe a good setup to go with a 4ls front brake which is a consideration.

Now just to find what triple tree would be good for 35mm.

 

[jd750ace]

If I were changing the front end, I would be shopping for a 41MM set myself. The R6 and SV650 fronts come to mind. I would be going more modern than you are looking if I'm going to put the time and money into it, and the nuances of how the axle and tabs are finished would not even enter my criteria, but I'm a form follows function person. I'm not consumed by "the look" of the bike because I ride it, not look at it. Peter Egan might be able to spend winter staring at his bikes and waxing poetic about their lines, nuances, and subtleties, but I just don't have the time. Hope you find what you're after.

 

[5twins]

Those 4ls front brakes are like gold. Grab your wallet, lol. Something else to consider might be a later SR500 front end. Yamaha "retroed" them and went back to a drum. The forks are pretty near identical to the 650 35mm units.

 

[acebars]

I'm not consumed by "the look" of the bike because I ride it, not look at it.

I agree with you to a point, but I do like to have a good looking bike as well as having performance and the look comes first, not because I want to show it off but because I love the beauty of a bike, it gives me pleasure when I look and approach it. So if I had a 1950s single I'd happily put up with the old suspension given the bike looks as it should and I do believe it's often possible to have both looks and performance.

The R6 fork nuances and subtleties as you put it are actually good for what I want to do, it's the triple tree that would be work. Also I think it may be overkill in perfomance.

Those 4ls front brakes are like gold. Grab your wallet, lol. Something else to consider might be a later SR500 front end. Yamaha "retroed" them and went back to a drum. The forks are pretty near identical to the 650 35mm units.

I'd like to stay away from the SR500 and XS-1 Drums as the rubber grommets just aren't the look I'm going for.

I know the Suzuki 4LS's cost a bomb, it's rather annoying because they are overrated in performance as well being only a step better than Triumph 8" 2LS brakes.

But the problem actually comes down to the Speedometer and Tachometer, the Suzuki 4ls will mate directly with the current speedo I have.

If I buy a Triumph 8" Front Drum it means I have to also buy the rear drum to mount the correct ratio speedometer drive, then there is a replica smiths speedometer to buy and a matching digital Tachometer which costs a bomb, unless I could somehow get the Tacho 1:4 ratio to match the XS650 engines 1:5 ratio.

 

[Purplezinger]

That is one gorgeous Enfield, wow!

 

[jd750ace]

I don't think it would be overkill in performance. It's shorter travel, but it's still a damper rod type fork, so it's not a quantum leap forward. It comes from a bike that is about 50 pounds lighter than the XS, but I'll bet it's stock springs are a good bit ahead of the pogo sticks we have for stockers. The 41MM tubes are the big leap, in that they will flex less, and the captive axle arrangement makes the alignment much more stable and repeatable between the lower legs. I see where you are coming from on the triple clamp. For that reason, the SV650 standard would make a much nicer piece, being somewhat finished and already set up for risers and bars in the normal fashion. Attached is a pic of the stock first generation SV upper clamp. the lower is sand cast, and looks no better nor any worse than the stock XS part.

 

[acebars]

That is one gorgeous Enfield, wow!

They certainly are, also have a 60bhp bulletproof engine, other than the front brake that is too weak this is undeniably the best bike to have been made in the 60s and is often overlooked, I'd argue the first superbike other than the 50s Vincents.

For that reason, the SV650 standard would make a much nicer piece, being somewhat finished and already set up for risers and bars in the normal fashion. Attached is a pic of the stock first generation SV upper clamp. the lower is sand cast, and looks no better nor any worse than the stock XS part.

Thanks jd, I've been thinking maybe if I shave and round off the square edges of the upper clamp I maybe able to age it somewhat. There are other problems however such as the lack of the mounting holes for the mudguard stays I'm after. I think I'll have to stick with something from the 70s that has all of these features even if they are still only 35mm or 36mm forks.

The GT750 forks look perfect and there is only one area on the disc brake ones that needs to be ground down on the lathe. The TX750 forks seem to be good choice as well although I'm unable to ascertain if they are 35mm.

Then there are Norton Commando forks, which look visually perfect, I'm just researching their fitment and whether they function well, also these maybe pricey they are 35mm

 

[acebars]

Ok well I think I'll only be going up to 35mm whatever I do it seems, not a huge improvement, however I know that the 35mm XS650 shocks are considered a vast improvement over the stock forks the CB500t has (the bike I currently have), so something like them will be enough for me with internal improvements.

So far I'm looking at Norton Road Holders the nicest but the most expensive, TX750s and GT750 forks. All have the correct mounting areas. Was also looking at Triumph T120 forks as they are actually fairly cheap even compared to the Suzuki and Yamaha forks, damping is reported as good for the period and even better with internal changes there is lots of support also, only trouble is they don't have the exact look I'm going for and don't have the fender braces in the correct position.

Question now is, is there a bolt on triple tree that takes a 35mm fork for the early frames?

 

[acebars]

Bump, anyone know of a 35mm triple tree that will bolt on to the early frames?

 

[gggGary]

grab the 34mm triple grind out the stem and weld it into an XS650 35mm triple, done.

 

[XSLeo]

If you use a later 77 up tree from the XS650 the stem is too long for the early frames. If you have the tree for your bike it's not hard to swap your early stem into the later trees.
Some try spacers between the stem and bearings I don't like that idea much, others put the tree on a lathe and turn it down on the upper end so the top bearing goes down on the stem further.
I have a set of 37 mm forks off an XS1100 standard. These have the axle under the lowers instead of on the front, that's called a leading axle fork by the way.
The stem is the same length as the early 650's They use tapered roller bearings. The only thing I don't like about them is the bars mount right on the upper tree, no rubber mounted risers.
Leo

 

[acebars]

OK thanks both of you, I think thats something I will have to outsource, I don't have a welder.

I was actually thinking about a thick spacer to match other triple trees to the stem, is there a good reason not to do so?

 

[XSLeo]

Using a spacer under the bearings on the stem can do two things, one move the bearing up enough so it's a loose fit on the stem. Two is move the tree low enough so it won't hit the steering stops on the frame. Both can cause problems.
Leo