Hybrid project

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Gerrit
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Hybrid project

Post by Gerrit » Thu Mar 09, 2017 1:40 pm

OK boys and girls, this morning the KR-1 frame I bought was delivered so together with the various bits and pieces I bought so far I have the bare bones of a project. It won't be a concours build by any stretch of the imagination, though. I'll be asking the occasional question, here is the first; as I have one of Fred's stainless steel KR-1S exhaust brackets (I have a set of 1S spannies) I'd like to know the exact location of the locating hole in the lower rear shock linkage bracket, dimensions in mm, from the rear edge of the bracket to the centre of the hole. I assume the dimensions of the brackets are identical for 1 and 1S.

First thing to do is give the frame a thorough clean and get a set of dye check cans to check the frame for any cracks.
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James P
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Re: Hybrid project

Post by James P » Sun Mar 19, 2017 12:13 pm

Gerrit wrote:
Thu Mar 09, 2017 1:40 pm
...I'd like to know the exact location of the locating hole in the lower rear shock linkage bracket, dimensions in mm, from the rear edge of the bracket to the centre of the hole. I assume the dimensions of the brackets are identical for 1 and 1S.
Gerrit,

The measurement I used was 21mm. I'm not sure whether that part of the frame is identical for KR-1 and KR-1S, but I used a genuine KR-1S exhaust mounting bracket when fitting KR-1S exhausts to my KR-1. Everything lined up pretty well, with no need for any "adjustments".

Regards,
James

Gerrit
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Re: Hybrid project

Post by Gerrit » Sun Mar 19, 2017 5:10 pm

Thanks, James. 21 mm it is then!
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Gerrit
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Re: Hybrid project

Post by Gerrit » Mon Mar 27, 2017 1:28 pm

Had the farme blasted to bare aluminium and examined it for cracks when it was returned. No visible cracks in the lower rear engine mount area or the upper LH mount, but the RH upper mount was a different matter:

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Cause? Excessive clearance between the rubber engine mounts and the frame lugs, in this case 4 mm!!!!!

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The early triples also had problems with frames cracking because of excessive clearance between crankcase and frame, but from the 1973 model year onwards shims were installed at the factory to take up the clearance. These shims were available in several thicknesses. Clearly Kawasaki forgot the lesson!
Ideally I'd like to check the frame mounts with dye check for further cracks, but suppliers won't sell one kit of three aerosol tins, requiring a minimum sale of 12 sets- bummer!
Repairing this is a job for Nico Bakker- better start saving.........
Last edited by Gerrit on Sun Jul 08, 2018 12:51 pm, edited 2 times in total.
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Gerrit
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Re: Hybrid project

Post by Gerrit » Mon Mar 27, 2017 1:33 pm

As the frame has no log book and won't be used on the road, I removed the locating lug for the drain tube guide per KR-1 F3 kit instructions:

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Only final tidying up to do:

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Last edited by Gerrit on Sun Jul 08, 2018 12:47 pm, edited 2 times in total.
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Re: Hybrid project

Post by Gerrit » Thu Apr 06, 2017 7:31 pm

The bar in the swingarm pivot bores is a 16 mm diameter length of silver steel which I used to check bore alignment. This was OK so I can now ream the bores to 20 mm as I will be using a 1S swingarm. Pivot shaft will be a Suzuki RGV vj22 shaft as it's already been bored to reduce weight, and it's a two-stroke part (very important, this).

Image

Oh, I've removed the original subframe, by the way.
Last edited by Gerrit on Sun Jul 08, 2018 12:45 pm, edited 3 times in total.
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DougB
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Re: Hybrid project

Post by DougB » Sun Apr 09, 2017 9:04 pm

The frame clearances are a country mile out on mine too, I've got a 3mm shim in that same upper frame mount and a 2mm shim between the swingarm end and frame..

Gerrit
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Re: Hybrid project

Post by Gerrit » Sun Apr 09, 2017 9:39 pm

The clearance between swingarm inner bearing sleeve 42036-1259 and frame is 1 mm on mine, so I am looking for two 20 x 42 x 0.5 mm steel shims to take up the slack.
I hope your frame wasn't cracked, bozbridge!
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Gerrit
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Re: Hybrid project

Post by Gerrit » Sun Jul 08, 2018 12:40 pm

The steering damper attachment lug was removed by careful filing and some chisel work:

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Its new location on the RH side of the frame:

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After welding:

Image
"Mine is a long and sad tale", said the mouse.
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Gerrit
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Re: Hybrid project

Post by Gerrit » Fri Jul 20, 2018 3:44 pm

Some idiot previous owner of my frame had cut off the locating lugs for the front fairing bracket and steering stop:

Image

However, it's not all doom and gloom as I will be using ZXR400L fork yokes. After having the steering stem pressed out of the ZXR lower fork yoke I measured the included angle of the steering stops on the yoke:

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Some geometry gave the dimensions for a new steering stop which was filed from aluminium to conform to the FIM steering arc of 20 deg in each direction:

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After centralising and securely clamping down it's off to the welder:

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Back from the welder (the next day!):

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Initial checking with a KR-1S yoke, final checking and filing (if necessary) to be done when a KR steering stem has been fitted to the ZXR fork yoke:

Image
"Mine is a long and sad tale", said the mouse.
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Gerrit
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Re: Hybrid project

Post by Gerrit » Tue Aug 07, 2018 2:50 pm

To reduce weight I will be using a vj22 RGV250 style rear caliper setup, which eliminates the torque arm though does require a stopper to be welded to the swingarm. A TZ250 doesn't use a torque arm either and what's good enough for a TZ should also be good enough for a KR.
KR caliper bracket and torque arm and RGV caliper bracket:

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This means that the torque arm bracket on the frame will be redundant:

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After sawing:

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Next, filing off the remains of the bracket base and welds. Oh what fun it is to file........ NOT!

I don't have any weight figures for post-1982 TZ250s apart from the 3YL and 5KE; these are 121 and 119.5 kg with oil and petrol according to the respective service manuals, which means about 102-104 kg dry. It remains to be seen whether I can achieve this, given that TZs have magnesium goodies and are full-blown racers, but it's a figure I'll be trying to reach anyway.
Last edited by Gerrit on Fri Aug 17, 2018 4:42 pm, edited 1 time in total.
"Mine is a long and sad tale", said the mouse.
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Re: Hybrid project

Post by podman » Wed Aug 08, 2018 11:00 am

Interesting write up and pics, I wish you well with the project, I wonder how many of us are riding around with cracked frames hidden under paint n powdercoat? Very sloopy of Kawasaki that...Great to hear the legendary name of Nico Bakker is still going!

Gerrit
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Re: Hybrid project

Post by Gerrit » Thu Aug 09, 2018 3:15 pm

I was aware of possible cracking at the lower/rear engine mount thanks to this board (a gold mine of useful information!), but as far as I can ascertain I'm the first to mention a crack in a forward/upper mount. It made sense to have the frame blasted to bare metal and check it for any structural defects (especially since I have no knowledge of its history), so that's what I did.
Be assured that a suitably sized shim will be placed when eventually building the bike, also at the swingarm pivot!
"Mine is a long and sad tale", said the mouse.
"Indeed it is", said Alice, looking at the mouse's tail.

Gerrit
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Re: Hybrid project

Post by Gerrit » Fri Aug 17, 2018 4:41 pm

Torque arm bracket base removed.

Image
"Mine is a long and sad tale", said the mouse.
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Gerrit
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Re: Hybrid project

Post by Gerrit » Fri Aug 17, 2018 7:31 pm

As the KR unfortunately doesn't use the superior Injectolube system which feeds oil directly to main and big-end bearings in addition to the intake tract, the oil pump will be ditched, as will the oil pump cover and the metal surrounding the pump be cut away as much as possible to save weight.
After sawing, filing next:

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Almost finished:

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The holes for the pump and its securing bolts plus the kickstarter bore will be closed by welding when the filing is finished.
"Mine is a long and sad tale", said the mouse.
"Indeed it is", said Alice, looking at the mouse's tail.

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