UK Cafe Racer Build Thread

[Paulrxs650]

So, plenty of things arrived this week. Not least a nice set of R1 USD's and also a couple of spoked rims. Tring to find XS650 rims in the UK is nigh on impossible. However, there are a plentiful supply of Yamaha XV535 rims, which use the same hub

As I was making a start on the front end this weekend, I need to pop one of the wheels in the back so it had some support. So, I knocked out the original bearings and popped some in with 20mm ID to accomodate the wider rear axle and slid it into position. Ill be doing the Omars conversion on the back end, so for now this will do.

Onto the front end. I stripped the USD forks out the yokes and put them to one side. The R1 stem is shorter than the Xs's so I had to swap them over. They both are press fit, however the XS's is welded on the underside of the bottom yoke. I ground the weld down and gave it a good whack with a 4lb hammer and a 1" bar and it drifted neatly out

The R1 stem contains a surprise for the unassuming. It has to be knocked out from the top as there is a split ring preventing it from being knocked from the bottom. A little heat on the yokes, and again drifted straight out.

The R1 stem and the XS's only measured 0.10mm difference at their bases. This meant that the XS stem was not a tight fit in the R1 yokes So for 0.10mm I wasnt planning on machining it all out for a sleeve. I decided to heat the XS stem and measure again - perfect. So, measuring the inside of the stem I machined a steel slug 0.10mm oversize. Put that in the freezeer for an hour. Then heated the stem back up and knocked the slug in. The slug expanded, the stem contracted and settled at the exact outside diameter at the base All that was left to do was to drift it into the R1 bottom yoke - perfect!

I drifted out the old ball bearing races and knocked in some nice new tapered head bearings

Dropping the bearings on the stem and offering the yokes up to the headstock showed that the bearing was sat to low on the stem and the yoke caught on the bottom of the head stock. So, using one of the old bearing caps, I machine it down to 1/8" and tapped that down to the base, then knocked the bearing down to meet. Now the yokes can clear the headstock

Fitting the top yoke, requires a bushing to be machined, so I machined one out of some alluminium stock. I tapered it to meet the top nut and give a better finish.

Heres the front end mocked up

As I was on, I also decided to de-tab the yokes and dress up all those ugly casting marks too

 

[Johnt3]

Wow! As usual,nice work Paul. Really clean install. Your lucky to have that lathe to spin up those parts when you need them.

 

[Paulrxs650]

Hi John, Thanks for the comments
Hopefully might be helpful for someone else doing the same thing.
Its worth its weight in gold. So much more is achievable with it

 

[Johnt3]

I'm sure it will be Paul.

 

[Paulrxs650]

Thanks John.
Thanks to Airwolfie for pointing out the USDs on eBay

 

[Airwolfie]

Thanks John.
Thanks to Airwolfie for pointing out the USDs on eBay

Glad I could help bud!! Looks really good, almost exactly like mine!!!!

 

[Airwolfie]

What are your plans for steering stops BTW? I see you nipped off those lumps on the lower yoke, I was going to use them somehow.......

 

[Paulrxs650]

Yeah, lopped them off. Once I get the tank on I'll work out the stops. I'll just machine some bobbins, drill and tap the yoke and that should be it.

 

[Airwolfie]

I just though of that lol!!! Sounds like a plan, as the ones on there are a bit awkwardly placed, but I am going to get my mate to just weld a plate smack in the middle of the tab at the bottom of the neck, I think that should work too.

 

[InnesMotors]

awww spoked rims look so much better than the others nice one dude

 

[Paulrxs650]

Hi Airwolfie, I did think of that too, but I wasnt comfortable with that kind heat on the headstock. Probably overthinking it a bit, hence going for the stops on the yoke

Thanks InnesMotors, yes, totally agree. Thats why the original Mags are in the corner now Its a bit of a faff especially with the disc on the rear spoked rims but I think its worth it in the end

 

[Paulrxs650]

Well winter is here - woke this morning to thick frost - brrr!
So, what better way than to spend a pissy wet cold day than in the shed! This week I took delivery of a fantastic tank and seat unit, along with some very nice CNC machine clip on bars and wheel bearings, frame rubbers etc etc.

So, I started on the tank first. I wanted to get that set up right so the flat line I want flows through the bike,

Fairly straight forward - I cut away and ground off the bracketry from the neck brace and left the gussets and neck stay in place (ill use them later to mount my coil). Once that was clear, I took some 1 1/4" flat bar and put kinks in either side to raise the tank 1/4" to clear the top rail and tacked it on. As there was a gap between the bar and the neck stay, I made a small gusset to fill it. Then did a few pasess with the MIG and put in a nice fillet weld.

Ill work out the back of the tank fixings tomorrow (it will involve a rubber band )

Onto the rear end. The seat unit is probably not designed to support a lot of weight, so I fabricated 3 x cross members and rubber mounts. I also tidied up and boxed in the sections to the rear of the strut mounts. Tomorrow, I will fabricate a lightweight frame to a) give some support to the rear and carry lights etc but b) to take a small cradle to carry the battery.

Popped the clip ons on and had a sit on - feels like an R1

 

[Johnt3]

Wow Paul, that's looking good man! Fine work man. Going together way too fast though, what will you do the rest of winter?

 

[Paulrxs650]

Ha ha - spend it in Egypt

Yeah the big bits always make it look as though its going together quick, then you get bogged down on the little stuff which takes days.

Still got to work out the rear wheel conversion and the front brakes

 

[Johnt3]

Oh, I see! I know what your talking about Paul,it seemed like it took no time to get to the big items and looking like a runner, but then you get to the "real" work!
Glad you got some time with your bike build.

 

[Airwolfie]

Looking good Paul!!

 

[Paulrxs650]

Thanks Airwolfie.
Hey John, yeah I'm trying to shoe horn a such time in this week as I can, as after that I'm out of the country

 

[Paulrxs650]

So, today a little more done. I made a plate and fitted it beneath the "arse" area of the seat to take the electronics, reg rec, fuses etc.

Once that was in, I made a small L shape bracket and machined some little bobbins to hook my rubber tank strap to.

Once that was done, I set about manufacturing a rear sub frame to give some support to the rear end but also hold a small battery under the hump. As there was no specific datum, most of it was guesswork and trial and error. Once it was there or there abouts, I could measure up from specific parts of the bike to check for true and weld up.

And as it stands this evening

 

[Johnt3]

Nice work Paul! The tank strap mount is right on man.
Your line from the tank and rear cowling is spot on my friend.

 

[Sub xs650]

What's left lol yr allmost done looks good