Another Cafe Build [Finished]

[Case100]

Update from end of 2023:
Bike is largely finished.
As of today the only remaining visible items are finding a rear fender solution I like.
Non-visible includes swapping to stiffer fork springs, and swapping to a set of coated K75 pistons and K1100 crankshaft.



You're joining well into this project. I am just now deciding to share some of the work.

I'll begin with a couple photos and quick summary of the state of things;

Up Next:

• New valve shims. 7 of 8 were running very tight.
• New boots are going on the wheels and will return tomorrow.
• Fit up the license plate bracket and install license plate light after rear wheel is in
• Fit tachometer
• Install stainless lines below steering manifold
• Replace defunct radiator fan with spal unit
• Crappy vinyl wrap will be replaced with proper paint once the mechanicals are finished

Just completed:

• Swapped clips-ons to those with a rise. Needed some more clearance for poor steering lock angle. Improve ergonomics considerably as well
• Repaint of rear wheel.
• Drive shaft and clutch splines inspect/lubricated
• Transmission, swing arm and final drive cleaned and painted
• Final drive seal replaced
• Oil pan removed, cleaned and resealed - I am chasing a leak, hoping it is not higher up on the sump. Or at the very least just the sight glass. TBD

Current state of things:


Before the most recent round of work:

[Laitch]

Welcome Case!
Bring on the photos!

[Case100]

Ah that’s a bit anti-climatic. Fixed with a new host for the pictures.

[Laitch]

Please post using one of Motobrick's methods because several interesting posts in a number of subject threads dropped the photos posted from offsite hosts when such accounts were neglected. That is a frustrating outcome for those of us who use the site for help and research.

[Case100]

Good to know the forum can host images, I’ll do that in the future, thanks!

[Case100]

Today all of the valve shims went in. A couple ended up just a thou on the loose side, but I am happy with the grouping and tightening by the 0.05mm increment would move them tighter than I'd like compared to the others.

To complete the job, I made my own valve lifting tool, it's cut from untreated 4130. It did the job well, and is a bit less hard than the buckets which has prevented any unwanted marking/burring. I found it was very nice to have a solid handle to manipulate to wiggle things around while dropping a shim into place. I made extras of these that I would like to sell for $15 to anybody looking to avoid spending on the expensive BMW prying tool, but wanted a proper tool to get this work done.

Not pictured are the wheels reinstalled. More to come.

Overview with my tool in place



A couple pictures of the  fit - very happy with this. Accessible from either side.

[Case100]

I installed the main stainless lines up front yesterday, always seems fiddly to get these brakes bled nicely. The lever feel is nice with the stainless lines at least.

Topped up all the other fluids and took it for a spin. Definitely some poor behavior coming off idle. I think the throttle bodies need a bit of synchronizing, and I'm quite certain an injector was acting up. Some fresh fuel and seat time has cleaned up the on-throttle behavior. Throttle bodies and verifying the idle will be the next steps for running performance.

Still to go:

• Fit up the license plate bracket and install license plate light
• Fit tachometer
• Replace defunct radiator fan with spal unit
• Paint tank and tail

The radiator has some damage from stones etc it looks like. I've straightened a few mostly just for cosmetics. I would like to find a decent radiator guard, and I definitely need to find some mirrors for it. In keeping with my overall theme of trying to leave things in a sort of OEM+ state, I may just use regular short mirrors.

[Case100]

Tinkering with the bar placement. Raising the front of the tank makes it difficult to get clearance, so I've opted to change to these riser clip on bars. I want the triple tree to remain open for how I have incorporated the ignition, and I will cover the other handlebar mount with a roundel when it arrives.

To get the bars swept back slightly further, I have swapped the clamping bolt to a low profile head. The few mm helps a lot. Things are feeling quite natural in the riding position now. I still need to reduce the size of the upper headlight clamp to clear the low corner of the tank, but otherwise I am able to hit the original steering limit which is nice for moving around the garage and at low speed.

I have also found a suitable trim to my liking to place on the weld bead of the tank after paint. I am surprised how far it goes to help make it feel "finished" I am still torn in that regard whether or not I want to run a small front fender. I will probably pick one up and paint it to match and decide after actually seeing it.

Some time was spent getting the throttle bodies synced up. Things feel much better coming off of idle and rapidly closing the throttle as well.


Current state of the front, showing bars and a couple small pieces of trim on the tank which is just wrapped in vinyl for the time being.

[Case100]

Spending quite a bit of time getting ready to paint - all of it focused on the tank currently. Think my paint stripper may have been old, it was a bit of a chore to get the tank stripped - but it's done now.
There are a couple dents on the right side that I have filled, as well as smoothing out the rear of the tank so that the weld seam is less prominent.
Additionally I filled the sharp edge from the tank shell to the welded base for the gas cap. On the RT it's obvious that gas likes to sit in this crease and has damaged the paint, I'm hoping to prevent that from happening here.

Radiator fan has arrived, which also makes it a good time to drain the coolant as it will need to be replaced, and I'll remove the radiator while I am fiddling with things. I think I will go the route of splitting the original housing and using it to mount the new fan as some others have done. If not, I will design a couple brackets to mount it.


Sanding and priming to get the surface ready:

[Case100]

Paint is complete - quite the experience.. but I am pleased with it for never having used an HVLP system before. The color is BMW's "Sparkling Graphite Metallic"

While the tank was off for paint I removed and repainted the fuel rail as well. Did a couple rounds of vinegar in the radiator to clean it up and flushed it out.
The spal radiator fan is now wired and confirmed working, so cooling is all taken care of - save for fitting an overflow bottle. I will tuck it in front of the air box. I have flipped the filler neck around so that the overflow line faces forward, and will route the line stealthily down the frame to the tank.

I ended up purchasing an R9T front fender - in my opinion the wide fit of the fender looks much better than the skinny aftermarket options I have seen. I will design a couple brackets to adapt it to the mounts on the K100 forks. Although I have liked the naked appearance for quite a while, I think it looks much more complete/intentional with the fender. It's a good match for my build.

I have stiffer springs (not progressive) for the fork as well, which should round out the suspension and ideally help keep the dive on braking in check.

I'm down to just a few remaining items before I will call it complete for the year.

[Case100]

Well, I've been enjoying riding the bike and not posting. Most recent update here:





I have had a dash panel made, which houses the tach/speedo nicely and otherwise "closes up" the front end from seeing most of the controls run behind the headlight.
I've also designed some new brackets to mount the headlight, removing the fork tube clamps. I much prefer the cleanliness of this solution.
A pair of horns are now mounted in front of the airbox, rounding out all the usual controls/equipment you would expect to have.
The r9t fender is mounted with some custom brackets as well.

At this point my list from my original post is complete. I do have a set of K75 pistons that I had sent out for ceramic and friction coatings, as well as a K1100 crankshaft that I will install after they are balanced as a set.

[Laitch]

Thanks for the update. Would you give us an cost estimate of pistons and the work being done on them? Is some of it quid pro quo or is it all out of pocket? I have a feeling it will be attractive to some of the owners here of the K100 2V.