The life and times of my 650

[Scotchmist]

Very quick update. I managed to get a few hours in the workshop last night to make a new clock bracket. I've bolted it the old ignition mounts in the XJ yoke. It's made of 2mm stainless and is isolated from the yoke using rubber washers so I'm hoping it shouldn't suffer from metal fatigue. The hole in the centre is just there to remove a little 'visual weight'. Here are a couple of pictures. On reflection, the second one is quite odd, taken upside-down looking between my legs.

 

[Scotchmist]

Minor progress but feels like a major milestone. I've finally had the speedo drive tab welded to the left fork leg which has been holding up progress on the front end. Really annoying to encounter something that you can't do yourself. Now just the machining of the disk spacer and the caliper mounting plate left to do. Unfortunately, the lathe at the workshop I use is broken and probably won't be fixed for another couple of weeks...

 

[Scotchmist]

I've had a week off work so managed to get a bit done. Firstly I polished the reshaped XJ top yoke. It cam up a lot better than expected. Worth saying that without a Dremel it would have taken ten times as long. It's one of those tools that you can't imagine having lived without once you've got one. 

I also ended up remaking the spindle spacers as the wheel was around 1mm off centre. I got a better finish this time by using a lathe with a powered feed. 

The disk spacer is also finished. I've been worrying about making it for a while as I'm new to machining and I thought that the chance of me ruining my expensive bit of 6082 T6 billet was pretty high. It actually turned out well and by some miracle I managed to drill correctly spaced, straight holes. 

Here's the whole arrangement bolted together with the as yet uncleaned hub. 

I've started making progress on the caliper spacer which is pretty much the last piece of the puzzle. I've already been milling for an entire day and I'm nowhere near finished. Quick progress shot...

I hope to have a nice mockup shot of the whole arrangement (minus the built up wheel) on the weekend. 

I'd be keen to hear any comments particularly regarding the strength/safety of my machining as I'm new to the subject...

 

[Scotchmist]

I've now finished the caliper bracket and checked it for fitment. It took me absolutely ages to machine which I think is predominantly due to my inexperience with a milling machine. Hopefully the next item will go a bit more smoothly. I think it's probably an overkill at 13mm minimum thickness (compared to 6mm wall thickness for the fork leg caliper mounts) but it's better to be safe than sorry.

I'm also not too sure about the overall appearance. It's a little bit too industrial looking. Nonetheless, it fits well and will be fine for a while until I come up with a better solution. I think a caliper with a smaller centre-to-centre distance between mounting lugs would allow for a smaller bracket.

 

[Scotchmist]

After fixing the Dremel and briefly polishing the hub (if it looks too nice it'll make the rest of the bike look awful) I built up the wheel with an "XS Performance" flanged aluminium rim and stainless spokes from Heiden. As it's the first wheel I've built, and it's a wee bit wobbly I'll get a professional to true and tighten it before the bike goes on the road. I've also welded a few tabs to the frame to accommodate the conversion from rear disk to drum. Pictures to follow shortly.

 

[Scotchmist]

Lots of progress since I last posted. I'm aiming to get the bike back together and MOTd for summer (which would be novel).

Firsly I welded on the spring retaining lug and the throw aduster for the rear brake. That was the last bit of the disk to drum conversion that I hadnt't gotten around to.

I also modified the steering stops by welding a bit of steel onto the existing stops to match the FZR bottom yoke. I removed what was left of the steering lock and filled the hole with weld.

Here's a quick snap of the dog helping me out. 5 points if you can guess the car in the background...

I finished building the wheel which went remarkably smoothly and I finally had the chance to unite the forks and the rest bike. The forks went on beautifully. I was surprised that I hadn't missed anything having built the front end in London whilst the rest of the bike was in Taunton.

Few more things left to do. Need to finish adapting the TX650 tank for a push and twist-style cap and British-type manual taps. I also want to make a new seat with a fibreglass seatpan to suit the tank. I've prepared the bike without lights as most of the loom is a real mess. Will aim to get a "daylight MOT" i.e. an MOT without the need for lights that will be accompanied by an advisory note from the tester infroming me tha the bike has no lights.

On a final note, my brother's got an old BSA frame and while I was playing around in the garage I offered up a few parts to make a BSAmaha or YamahaBSA. Looks pretty good to me.

 

[Scotchmist]

Will add the rest of the updates soon. I've been busy!

 

[retiredgentleman]

I've now finished the caliper bracket and checked it for fitment. It took me absolutely ages to machine which I think is predominantly due to my inexperience with a milling machine. Hopefully the next item will go a bit more smoothly. I think it's probably an overkill at 13mm minimum thickness (compared to 6mm wall thickness for the fork leg caliper mounts) but it's better to be safe than sorry.

I'm also not too sure about the overall appearance. It's a little bit too industrial looking. Nonetheless, it fits well and will be fine for a while until I come up with a better solution. I think a caliper with a smaller centre-to-centre distance between mounting lugs would allow for a smaller bracket.

You do very high quality work Looks great! Yes, 13 mm minimum thickness is overkill.
When I made up adapter brackets for my Brembo calipers, I used 3/8" (about 9.6 mm)
aluminum, and find they are more than strong enough.

 

[Paulrxs650]

Nice work. Well done

 

[gggGary]

Wow what a great fizzer front end how to! Thank you!

 

[Scotchmist]

Thanks for the comments. I figured I'd go overkill on my first caliper bracket. I may end up thinning it down at some point.

 

[Scotchmist]

Continuing the updates in sequential order...

 

[Scotchmist]

Tiny bit more progress. The TX650 tank that I bought had no taps, no cap and the cap mounting lugs were held together with Araldite. I figured that gave me justification to bastardise it a little bit. I welded up the original two bolt fuel tap mounts and machined new bungs that were tapped to 1/4 BSPF. I then drilled out the bottom of the tank and welded in the bungs to take British-style manual taps. They look much better in my opinion. I then removed what was left of the filler neck and cap mount and welded in an item designed for an AJS of some description. I can now fit a push-and-twist type fuel cap.

I was intending to silver solder in the bungs and filler neck but that would have involved learning a new technique and travelling to my brother's house in Somerset to borrow the oxy-propane. In the end I got impatient and used a MIG. Probably not the idea tool for the job but I reckon it worked out fine. The welds penetrated nicely but may not be neatest in the world. I think it'll fit the overall look I'm going for - a little rough around the edges. I may end up putting a skim of filler over the welds to create a nice fillet.

 

[Scotchmist]

Nothing very exciting to report,but some progress nonetheless. After the advice I received on the forum I bought an RD350 dust cover for the headstock bearings (I couldn't seem to find one for an XS650). I can confirm that it fits fine.

I fitted a new horn and button. Quite nice to only have a single button on the bars.

I fitted new footrest mount rubbers as the old ones were crumbling and a kickstart rubber. It may be a minor part but I don't think I've ever owner a bike with an intact kickstart rubber. It really makes the bike feel complete.

After some research I ended up buying the new Hagons with adjustable damping. They are mounted upside-down to reduce unsprung weight. I'll report back on how they perform. Here's a shot of them against the worn out of Koni Dial-a-Rides. I'll probably end up rebuilding the Konis at some point for another project.

Finally here's a side shot to show how the bike is standing at the moment.

Only a few things left to do before it's ready for summer:

1. Weld on a new rear mount for the TX tank.
2. Find 1/4 bsp taps that fit in the available space between the tank and the carb tops (I've ordered a set of taps that look like they'll do the job).
3. Fit new fuel pipes and filters
4. Adjust steering stops. At the moment I get a dangerously limited turning circle. I'll just need to file down the extra section I welded to the original headstock steering stop.
5. Fit and bleed new front brake master cylinder. I fitted an 11mm master cylinder with the Yamaha 4 pot caliper but get far too much travel at the lever. I've done the calculations and a 1/2" master cylinder should give me about a 25:1 ratio which I belive is within the ideal range. I've got a spare Grimeca caliper from an Aprilia SR50 moped that I'll try out.

Finally, I've just got to persuade the MOT man that lights are an luxury and not a necessity.

 

[Scotchmist]

I'm hoping to get lots of work done over Easter as I've got a few days off. I've also booked the dreaded MOT for 26th March to give me some incentive. There are a few jobs on the list including replacing the exhausts with versions that have less kick up. Hopefully Ants will be seeing to that!

I've been learning to use Photoshop (in a very basic way) so I've adapted a photo of my bike to show my plans. Ignore the TX650 paint scheme, I got carried away.

Here's the before picture...

Here's the after picture...

I'm planning to make a seat from scratch so may also get the chance to play around with some fibreglass.

 

[zeroxs650]

Nice progress...

 

[650Skull]

73TX did have a black as well, Very rare.

 

[txxs]

73TX did have a black as well, Very rare.

Hey 650Skull,
Are sure about that?
It looks like blue on that brochure photo.

I'm not aware of any black 73 model TX650.

There were two colours; Metallic Flake Blue & Pearl Yellow Gold.
Yamaha also released accessories with optional chrome headlight shells, and chrome headlight brackets.

 

[Scotchmist]

Here are the (uninspiring) photos from last time I was in Somerset. I'm just negotiating storage space in London so I should be able to bring the bike up soon.

New rear shock washers made up in 304 stainless. Not much to look at but at least they won't rust.

New folding footrests fitted. Again, not very exciting but at least they're small and light (they were also cheap - £8 on Ebay brand new!).


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New 12.7mm master cylinder from an Aprilia SR50 moped (Grimeca). I think I'd like to try a 14mm as there still seems to be a bit too much travel at the bar for my liking. Let me know if anyone knows a usable 14mm master cylinder.


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Quick shot of the complete front end. The bike rides really nicely with the new front end. It looks to be about 15mm lower than the standard forks. They are much smoother and have far better damping.

Here's another side shot. Really, really need to replace the haggard old Custom seat. A new seat with a flatter profile would look so much nicer. New pipes are looking good (although I need to fabricate new mounting brackets.

Revisiting my to-do list...

COMPLETE

- Test TX650 tank for leaks
- Fit new taps and replace fuel hose and filters
- Fit and plumb in front brake master cylinder.
- Replace footrests
- Fit new rear shock washers
- Check over front end and threadlock as required.
- File down new steering stops
- Fit new stainless steel headers with temporary brackets
- Top up oil and add fuel.
- Ride to MOT centre and achieve a faultless MOT (accept for the advisory for not having lights).

STILL LEFT TO DO
- Weld on rear tank mount
- Clean carbs
- Change oil and fit Smedspeed spin-on filter plate

 

[Scotchmist]

Managed to do a day in the workshop on Saturday. As I’m now back in London and away from the bike I was a bit limited on what I could do. I also fancied doing some machining so decided to make one of those ‘oil coolers’ that bolt into the right hand side engine case and allow for the use of a common, pleated paper type oil filter.
I already had a spare side cover so I bought one of the filters and spent the day trying to fathom the oil circulation route of the XS. I’ve made a couple of modifications from the common types that I’ve seen online. I’ve tapered the sides to provide the maximum base size which should prevent gasket leaks whilst also limiting oil restriction around the top of the new spacer piece. I’ve also milled a little flat section into the spacer piece to sit opposite the hole where the oil feeds back into the engine. I’m hoping this should remove another potential restriction to oil circulation.

Notice the slight flat at the 6 o’clock position on the spacer piece.

I’ve tried to limit the amount that the filter protrudes but it’ll still be a fair bulge out of the engine casing.

I’d really appreciate if someone could have a look at the photos below and let me know whether there are any potential problems with my design. Obviously it’s not finished, but the last part is easy. I just need to make a protruding side cover, that can accommodate the filter and hold it in position on the new oil spigot. I plan on including a rubber washer on between the filter cover piece and the filter itself so that the filter will be held securely in place (under slight compression) whilst allowing the gasket surfaces to create a good seal accounting for slight differences in gasket thickness. Please let me know if you think this will work. Any mistakes with the lubrication system could cause some pretty expensive damage!
A big chunk of aluminium just arrived so I may get a chance to start of the oil filter cover this evening.