270° 953cc Sidecarcross engine build

That brings us to the next problem- since the gearbox bearing sits out 6.1mm further than original, the clutch primary gear did not line up with the crank gear and the whole thing sits out too far, also the shaft is shorter at the clutch end.

I had to pull apart the new billet clutch assembly and machine 6.1mm off the back of the primary gear and shorten the centre sleeve by the same amount. While the clutch assembly is apart, I will send the basket away to get hard anodised.

Primary gear before shortening:
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Primary gear shortened:
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New sleeve/Old sleeve:
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The 4 speed box only requires 2 selector forks. Removing the entire 1st gear fork allows the selector drum to over rotate, I. Could have cut the fork part off and left the round bit on the drum, but then I would have 2 neutrals (real neutral and old first gear).

The modified selector drum- allows only N-2-3-4-5
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I am going to run 8 plates in the clutch, so the centre hub had to be trimmed up a bit.
Material has been removed from the face in the centre, and a bit off the back around the outside to give clearence between the hub and the face of the basket.
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Also taken a couple of mm off the friction face of the clutch hub:
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Kick start shaft has also been modified to allow 100% engagement of kick gear onto the dummy 1st gear. Standard XS650 only engages about half way across which is fine for a stock motor, but can lead to problems with big cube engines. It causes first gear (countershaft gear) to wear unevenly, and even lead to cracks between teeth.

Quaife 1st gear damaged by kick starter- has a small crack at base of gear tooth
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Because the dummy first gear in this setup is sitting further to the right side than standard, I only had to make the kick gear slide across a little further to achieve 100% engagement.

Kick start shaft with the flange faced back to allow the gear to engage further:
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Cam chain tensioner/guide modified to fit between the jugs. I will have to get some M6 cap screws with heads reduced to 8mm to bolt this in.
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Machining the kick start shaft hole to take needle roller bearings. Made a boring tool out of an old 20mm axel to do the crank case, and for the clutch cover I welded a piece of HSS to an old kick start shaft.
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Bearings not yet pressed in to crank case and clutch cover:
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I modified an old cam sprocket to suit my new billet cam. I'll post photos of the cam when it eventually comes back from the cam grinder!!
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New cylinders 'O-ringed'- wire sits about .008" proud of the deck and bites into the copper gasket for extra good seal

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O-ring grooving tool:

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The cam chain guide from Mikes are made out of shit and the threads strip, to I fitted Helicoils for a stronger thread. Mating surface has also been filed flat, I have found in the past that they can be a bit uneven.

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Really going together nicely interested in that cam. In another thread I was researching a heiden grind sent by mistake. Supposed to have been for a 270 sidehack your part of the world. It had some valve opening and closing events unheard of on this side of the pond. Allthough the the fellow had no dial indicators he had a pretty good eye and a degree wheel.
 
It's about time I put up a few updates! I've been around the world and moved temporarily interstate so the last 12 months or so has seen very little achieved on the build.
The aim is to have it finished by the end of the year, should be easy now that I am unemployed!

Stay tuned..

Cheers
 
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Camshaft nearly finished, just need to make a new sprocket because I left my other slotted ones in a storage shed interstate..
 
New degree wheel I made using an old alternator rotor. Machined up the disc out of a scrap of 5mm plate
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I have decided to scrap the old RH pull clutch cover as seen in previous posts, instead I will make a nicer looking hydraulically actuated one.

Cutting the side out of the new cover:
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Machined up a new housing out of a piece of 25mm plate: (this pic shows the housing and clutch slave)
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Here is the clutch slave. It is drilled and tapped M8x1 for a banjo bolt.
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Before and after:
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Clutch side cover before welding, also I machined up a new oil filter cover. It's not finished yet I still need to drill some bolt holes in it and also install a pipe in the side of it for the external cooler and filter

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Dropped off my clutch housing to my mate for welding- anyone who has ever attempted to weld one of these would agree that he's done a great job, these porous oily old castings can be challenging!

I made up a jig for this job so it doesn't pull out of shape when welded- the clutch cover is bolted down onto a piece of 1/2" plate, and the new housing is bolted down square onto a machined piece of 4" pipe.

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The weld job superb. You have done a super skilled job now your self. Thanks for the update. Can hardly wait to see the beast in action. :cheers:
 
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