Double the troublezz. AMA style Racecrafters Z1000 and Moriwaki Z1R Turbo.

[r3sc]

Cheers Rob. I live in Sheffield and that’s who I use and I have used for many years.

Mostly, the service is great but they do sometimes lose bits. I’ve just had two full bikes worth of everything that was zinc including spokes and nipples etc and they lost the large centre stand shaft from one bike.

They are good and I’ll still use them but it does sometimes set me back!

[zed1015]

Cylinder head complete with external oil feed connections installed ready for fitting.
Stainless valves in with bronze guides, new viton stem seals, HD valve springs and 1mm spring seat shims to regain the correct spring pressure after sinking the valves and tipping the stems.
I've sidelined the Titanium retainers i was going to use because i was didn't know if they would be strong enough after trimming which i know the stock steel ones are.
The stainless valves along with the stock trimmed retainers are lighter anyway so still an improvement.

Nearly every camcap bolt and thread in the head was in some way damaged or badly helicoiled so to rescue them they all had to be drilled as deep as possible without breaking out the bottom of the holes.
This got me around 7mm extra depth and allowed the fitting of some nice, long 20mm helicoils and the use of these 50mm ht flange bolts which take advantage of all of the extra depth and actually gets more thread engagement to spread the load than the originals.
They are pretty much identical and as strong as the genuine Kaw bolts but miles cheaper at 28p each rather than the £3.74 each a kwak dealer will prise from your wallet.

Once that was sorted i could finish off by bench shimming the Kent competition cams.
I've gone for around 0.18mm on the inlets and 0.20mm on the exhausts to start and have got all the inlets in the shim range of 285mm to 295mm and the exhausts a little thicker at 295mm to 305mm which leaves plenty of room for any initial settlement and future adjustment

Also in readiness for plonking the head on i managed to complete the modified Z650 tensioner and solid idler sprockets with the correct hard to find INA needle roller bearings and new genuine idler axles..
The bearings are the same high spec as the originals which have an additional roller compared to the cheaper ones commonly found on ebay and at the bearing suppliers.

[zed1015]

Cylinder head on and torqued down.
Kent Competition cams in with APE slotted sprockets, sat in new genuine cam shells and the carb inlet adaptor plates mounted and fitted with new genuine J manifolds all blended and matched to the ports.

Crank was set at true tdc with the cam bolts eyballed in the middle of the sprocket slots and 1 + 4 lobes pointing at each other for the initial assembly.
As well as the lobe center timing specs of 110 degrees Kent also supplies lift figures at TDC overlap for quick and easy timing of the their cams which is 2.65mm inlet and 2.60mm exhaust for these KAW16's.
Ideally you need the exact valve clearances for this to be accurate or adjust the discrepancy from the lift figures which is what i've done for now but i'm going to go back and double check it with the lobe center method which although more complicated and time consuming it's very accurate no matter what the clearances are.

Itching to get the bike up on its feet now that the bulk of the motor is done and the wheels are complete with their spindles so got the top yoke finished , polished and the bars bolted on ready to take the forks .

Then cobbled up this tool from bits out of the scrap bin and a 30mm nut welded on

Which slips in the top of the stanction and allows a socket and bar to be used to unscrew the stanction from the axle casting once a ton of heat has been applied to soften the permanent loctite on the grub screw and stanction threads.

All dismantled and i can now blast the ally lowers ready for paint without having to mask off the stanctions or risk etching the chrome.

Which didn't take long to do and are now hanging to dry overnight before giving them a bake tomorrow.

And then breakout the marigolds and drain cleaner ready to give the alloy sliders a shiney makeover by stripping off the faded gold anodising before treating the whole lot to a rebuild with new bushes, seals and fresh oil.

[zed1015]

Looking like a bike again.
Anodising stripped, sliders polished, forks rebuilt and wheels fitted.

Bit more clearance around the bike now to get the cam timing finished off and start tackling all the other little jobs to get the motor sealed up.

[r3sc]

It’s looking good Rob! Will it be on the road for springtime?

[zed1015]

That's what i'm pushing for.
Still loads more parts to make and mods to do as well as paint and covering the seat though.

[zed1015]

Got the cam timing finished off and dialled in so tackled a little job today that i'd kept putting off because there was good chance it may not work out.
I'd bought this Electrex race alt for the turbo build which allows the use of a starter motor and decided i wanted to use it on the Racecrafters if my plan works out (and if it does i'll get another one for the turbo).
Unfortunately they only do a version with a rotor that fits the later MK2 and J/GPZ large taper keyless cranks which is fine for the MK2 item in the turbo but not for the early 900 crank which i'm using in the Racecrafters that also has a woodruff key.

I had the idea that i may be able to extract the key slotted steel hub from a duff 900 rotor and devise something that will take the electrex rotor and original starter clutch to convert it for use with the small taper crank .

I started by using a worn rotor that had rattled its core loose.

PICT0362.JPG (208.4 KiB) Viewed 155482 times

And used the end web from a damaged small taper 1000 crank clocked up in the lathe to mount it.

PICT0360.JPG (227.91 KiB) Viewed 155482 times

Which enabled me to machine off enough unwanted material until i could expose the magnetic core and remove it.

Once the magnet was removed it just needed the remaining cast aluminium that encased it machining off so i could see if there was enough left of it to work with.

Luckily the gamble paid off and there was just enough meat left on the irregular shaped steel hub to allow it to be squared it up straight and leave plenty of wall thickness to the internal taper and key slot.

This left a 26mm diameter shaft that needed enlarging to 36mm with the addition of a tight fitting steel sleeve.

Which was fitted courtesy of a few tons of force in the hydraulic press so no chance of anything moving at high rpms.

And then once clocked back up in the lathe was turned down to the correct size.

Job done for now and very pleased that it went more or less as planned and is begining to resemble the Electrex rotor mount on the right.

Fits like a glove.

I've left the original hub full length for now and the rotor is sitting around 10 to 15mm further out than where it will end up as i need to correctly align the rotor and windings for maximum output when it comes to the final fit
( Which is more than Electrex manage to do with them ).
I'm also hoping i can retain some if not all of the internal threads for the extractor bolt once i've worked out how much clearance there is to the outer case and if there's any scope to gain a little more if needed .

[r3sc]

Nice tidy machining work there. Has it clocked true when fitted to the motor?

[zed1015]

Nice tidy machining work there. Has it clocked true when fitted to the motor?

Yes! Just the same as the crank nose i jigged it on in the lathe.
The stock rotors are never that accurate .

[chrisNI]

Brilliant work Rob!!!

[zed1015]

Now that the rotor hub has had all the cast aluminium removed it's diameter is a few mill too small to accurately center the starter clutch so i've had to come up with this steel spacer cup to make up the difference.

It's a very snug fit and is securely sandwiched between the hub and clutch when the three bolts are fitted.

And once test fitted i've also managed to do some measuring and retain the extractor threads which just needed 2 millimeters trimming off the end .

For the retaining nut to just clear the inside of the alternator case.

With no gasket fitted.

The next job is to work out how far inboard the rotor needs to sit for it to centralise its magnetic field to the windings .

The only fly in the ointment is that the hole in the rotor is just over 6mm smaller than the 26mm portion of the hub that contains the extractor threads and is preventing it from sliding on any further.

I didn't plan on modifying the rotor and i really don't want to loose the extractor threads but one or the other will have to give when the time comes.

Depending on how far the rotor needs moving and if there's enough clearance between the back of the windings and the starter clutch it may be possibly devise an alternative extractor mounting that uses three extended bolts for the starter clutch or something similar. .

[Al]

I made a three bolt extractor for mine but as you know i have the std. fully flanged hub from the original kit. If it wernt for the fact that weld is so hard to drill and tap, i'd suggest building up the three stubs between the mounting 'arms' and machining back, then drill and tap. I would not have wanted to use an extractor thread in the front of the rotor (if it had one) last winter when mine got properly 'stuck on' but was glad of being able to 'pull' from the back of the hub flange to extract it and maybe spread it a little in the process. Pulling at the front would be a bit like removing a rubber glove by pinching at the finger tip!!!!! That said; i guess you wont be torquing to the same degree as the J motors are.
It goes without saying that the standar hub flange also give the opportunity to fashion a holder (peg spanner) to stop it rotating whilst tightening / un-doing which again; i could not have got it off without. It still took me about three days with all these things!! What made it worse was i couldnt release the 'push fit' magnet sleeve whilst this was happening. Note to self; do not over tighten the centre bolt.

AL
I meant to ask if there is any residual magnetism in the hub from the old rotor, it having been in close proximity with strong magnets for such a long time??

[zed1015]

I meant to ask if there is any residual magnetism in the hub from the old rotor, it having been in close proximity with strong magnets for such a long time??

There's no magnetism at all, even the complete rotors are not magnetic at the internal taper.
The hexagonal "star" surrounding the core in one of the previous pics is aluminium so there's a good separation with no direct contact between the magnet and the steel.

I just measured the distance to the back of the windings and there's no chance of using longer bolts with enough thread protruding to get a nut on so it's either remove the extractor threads or open up the hole in the rotor so it slips over.

The problem with opening the hole is that the rotor relies on friction from the thin flange being sandwiched by the rotor bolt to prevent it slipping and with only 18 ft/lb on the 8mm rotor bolt and the reduced flange area around the bored out hole it's unlikely to stay put.
I will probably then have drill the face of the hub to take a hardened location pin with a corresponding hole in the rotor flange to prevent it spinning and then a cupped washer to slip over the protruding extractor thread portion to clamp it all together when the rotor bolt is tightened.

The more i look at it i think it's more likely that the extractor threads will have to go so that the rotor can simply slip on un-modified but still have a locating dowel to lock it in place and then come up with an extractor that bolts to hub somehow.

There's enough meat and width on those "stubs" to get three m6 holes tapped like the Electrex rotor has but i'll put them closer to the center.

[Al]

With only 18 ft/lbs and a keyway broached in that original hub there should be zero chance of the hub getting taper lock on the crank nose. That should make the extracter threads redundant and a basic three (long bolt) puller like mine tapped into inboard holes on the flange more than adequate i would have thought. If the hub doesnt spread when tightened, there should be no possibility of it expanding into the magnet sleeve and pinching it internally which should mean it is never more than hand tight to remove it. A knock pin or roll pin, drilled into the end sounds like a good way to ensure its always driven.
AL

[zed1015]

The postie delivered this piece of 50mm dia Acetal bar yesterday so set about working out the rotor and winding alignment measurments this morning.

Started by machining the outer so the windings just slip on.

And then bored the inner to take the rotor which has left a wafer thin shadow of its former self.

This takes up the small 0.46mm running clearance and allows the magnetic rotor to slide in square but prevents it canting over and sticking to the windings .

Which then enables the rotor to float freely and centralise the magnetic field.

So that i can measure from the face of the cover to the inner face of the rotor which is 63.60mm once the 25mm width of the steel rule was subtracted..

A measure from the face of the wide portion of the rotor hub to the engine case came up with exactly 65mm and accounting for the 0.5mm gasket means that there's just 0.9mm i need to skim off the hub for perfect alignment at the next workshop session..

Out of curiostity i set up the rotor on the turbos large taper crank which this alt is originally for and now knowing the distance of the rotor in the case i could work out how accurate this kit is if it's just bolted on as intended.

No big surprise now knowing electrex's attention to detail and accuracy from the previous alt i fitted to the alloy cafe ( which was 6mm out and killed the battery ) that this one is a good 4mm and a bit out of line inboard and would require a spacer under the rotor to achieve maximum output so something certainly worth checking before fitting one.