Large Spine Frame XS650 / Egli / Rau / Cafe Racer

I found some old covers off the donor bike, the engine was in multiple baskets. My god those were in bad shape, Gaskets were as hard as aluminum and difficult to remove, but before I could get to the gaskets, they were covered in something black, crispy and maybe .05 - .1 thick in some spots. What happened that poor old motor! :eek: They are cleaned and ready to help locate the CAM. Thanks for all the help so far!
 
One step forward, two steps back...

Regarding CAM position, I found some additional info on this website - it's in German, but very nice photos.

http://www.cco-classicracing.de/motorradumbau/xs650-motor/xs650-motor-instandsetzung/

After viewing this - I decided I'd follow along put together this simple clamping tool.
1/2" threaded rod. Left and right spacers are same height and have been turned down to sit on the bearing inner race.
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After fitting this and loosening the bolts, it was eas to shift the cam side to side, but decided I could get a better view of placement by removing the rocker cover.

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5.28mm is my target dimension on either side for center placement.
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One step forward.

While torquing everything back up... I stripped out the very last screw.
Two steps backward.
On the upside, I'm getting very familiar with this engine.
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Engine top end torn down again, getting really good at this.
Looking the hole bits and pieces of aluminum are seen, this is what I got out.

The hole is blind and not very deep, so I ground down the top of my helicoil tap so that I could get enough actual helicoil thread engagement. Improvise on a bottoming tap.

Helicoil inserted successfully, repair done. Now - on hold for fresh gaskets.

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There's no groove in the big bore jugs for an oring.
Who's jugs are those?
653CM3?
That Chinese for CC's?;)
 
This is a 750... (JE 750 Pistons verified) and I know there were no o-rings there when I originally took it apart and I don't see any grooves, so... No O-rings...

But, I am curious about the head origin. Below is a pic of other tooling markings on it. I don't believe it is aftermarket.

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I suspect it was an original Yamaha piece.

Engines and Cases that I have in my garage:​
Peterhansel Eng (THIS ENGINE)​
447-011xxx​
653cm3​
73-74 TX650A
spare parts (black) Eng:​
5V4-006xxx​
653cm3​
82-83 XS
Eng used in Jig:​
2FO-003xxx​
653cc​
78 XS
XS650 VIN: Steering head donor​
2F0-117xxx​
653cc​
77-78 XS-SE

This makes me think the head on the TX motor, might be a newer XS one. In the heads marked 653cc, there are no other markings (at least on the same location as the pic above).

The 5V4 engine is somewhat assembled, but I can see there are some markings in the same location as the picture above.

makes me think the older ones are marked "CC" and the newer one says "CM3".

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When I bought this engine, the seller threw in a parts engine and an empty engine with, head, etc to use for frame JIG. Perfect.

Then, I had to buy another XS650 parts/basket case bike dirt cheap for the steering head paperwork - ahem.

As a result, I have 4 engines in the garage (only one is complete).
 
That particular cylinder in pic post#306 appears to me to have provision for an o-ring:shrug:
 
Comparing the 2FO-003xxx head - Oring Groove to the location on the 447-011xxx (Peterhansel) head:

2FO-003xxx head:
Almost 3mm deep O-ring groove and wide enough the gauge fits in it easily. This could fit an O-ring.
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447-011xxx the 750 (big bore?!?): maybe .3mm deep and not wide enough to fit the gauge. Comparing these, looks difficult to fit an O-ring.
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While cleaning up and preparing to re-assembly - I noticed the front cam chain guide is missing some material.
:rolleyes: Another new part ordered. This engine (before my teardown for the 277 conversion) should have had less than ~100 miles on it... How delicate are these?! Or maybe this is an old part...?

Question: Using the original head - when converting to 750cc, are new sleeves used or typically just bored out?

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Still waiting for a couple of parts to arrive. On the issue of Cam Covers...

I scanned the Mule cover, reverse engineered it and created my own design. One that I could hopefully create on a rotary table, with as few set ups as possible.
Blue cover, dark background is the scan.
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Imported to Solidworks (white background).
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The new design.
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Solidworks mock up on a Rotary table... (With a 3" chuck.)
And - I had to order a 4" 3 jaw chuck. My Mini lathe won't hold the 3" stock material - and having a 4" chuck around that I could bolt to the rotary table or the lathe could have it's benefits.
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With the 4" chuck, I should be able to machine the bottom side, holding the material on the outside. Create the Pocket and lip. Drill the three M6 holes. Flip it, create the chamfered surface, mill the three edges and counter-bore the three M6 holes.

(I do not have any dividers, so machining the edge will be "visual". Maybe mark it up with some Dykem ink.)

Thoughts and suggestions appreciated.
 
Nothing ever goes as planned.

I had the Cam Covers quoted at one of my favorite quick turn suppliers. I didn't think this was going to be in the budget, but... Just sharing:

With a 3 day lead time: $734 for the Pair.
With a 3 week lead time: $278 for the pair.

Either way - ouch. A local shop could probably do better, but most shops just don't want to deal in supper low volume, with no promise of greater volumes to come.

So - going to do this myself.

To get these Cam shaft covers fabricated, running parallel paths, I was hoping to get an old (primitive, low budget, Mill/drill) CNC up and running again after 10 + years of hand cranking --AND-- as back up - planning to make manually if necessary. (The CNC with servo motors is fully capable of functioning by hand crank and I have a very small lathe.)

Anyone familiar with USB to Parallel port interfaces for CNC machines? I bought a UC100 interface and updated to Mach 4 software - Dead in the water. The USB to Parallel (dongle?) isn't giving a blue light (which means it's installed correctly and communicating). No matter what I do. If anyone has experience with this - It'd be great to hear about it.

Ok, so putting the CNC on hold, got the new 4" replacement chuck for the lathe just need to bolt it on. Material for the new parts and drawing in hand, ready to go to work. Sliced off two pieces from the stock.
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Nothing ever goes as planned. New chuck bolt pattern is too large and won't fit the lathe. Not to be defeated - just design an adapter and fabricate - how difficult could that be. It's Saturday morning, around 8am.
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Adapter designed, drawing and a scrap piece of aluminum in hand, ready to go.

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On the mill... That was the easy part. Making a rectangular plate round was far harder than expected. Got the 4" chuck mounted to the lathe - 24 hours of work later. Cam cover "material" is squared up and ready to be made into parts.
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I'm exhausted. Sunday late afternoon around 4:30pm.
 
Cam cover development ran into some Lathe limitations that I wasn't aware of. Which caused a slight redesign to the covers. The original design had a nice conical surface, with about a .75" (x 45°) chamfer. But my lathe could only produce about a .4" chamfer. This left the covers with far too much material, in other words - very heavy.
Lathe set up:
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Old design, new design:
New design is much more manufacturable (in my garage - without the CNC running); and lighter weight.
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Tomorrow: clean the garage and prep the engine for reassembly. Finally getting back to the engine!
 
"But my lathe could only produce about a .4" chamfer"
Why was that? Only 0.4" / 10 mm travel on the compound slide???
Actual travel - when parallel with the bed is about 25mm/1inch (I haven't actually measured it). But at 45° angle - half of that, then - at the angle and distance it tends to crash / interference between the handle and the compound slide base - so I can't get even the full travel. I feel I am just at the limits of size for this mini lathe. It's too bad because I really preferred the original design. But - the new design is lighter weight.
 
Starting the assembly of the top end today. Didn't get far I ran in to the brand new head-base gasket problem. The Larger corner holes, are on the wrong corners.

Options:
  • Complain and get new ones sent out from the supplier.
  • Cut out the offending material, as carefully as I can.
  • Flip the gasket upside down, so the print is facing the engine case.
  • Re-use the old gasket (which was only assembled and full compressed, engine never ran yet).
Sage advice? What would you all do?

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