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How strange, all mine, top and bottom on these BS38s are all M5 x0.8

Interesting. All my parts lists show 70-79 BS38 have 4mm bowl screws.
Yours seem to have a history. Maybe some overtightening.
Might want to check the carb bodies for warpage at those threaded corners.

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277 pamco with dynatek mini coils. I've found its best to have it in a particular place in the firing cycle, you get a feel for it after a few kick backs :) but when you find it I can gently push down prob past 50% of the kick distance and then it's just a little kick to the bottom and it fires surprisingly easy

I've been wondering about this. Same story with my old panhead. Would get better kickstart results on one cylinder versus the other. Had to feel for the long vs short kick throw to know which one to stomp on.

Imagine a viewport in the topside of the left points cover, that would let you see a painted edgemark on the pamco rotor, telling you it's a go to kick...
 
Yes, perhaps these carbs are "one over" already:laugh:

Everything appears straight and the diaphragms hold when you place your finger over the vacuum port.

Yep, getting the kick routine right on the rephase will take a little practice I think. Perhaps a little sensor and an LED on the instrument cluster to say GO :D
 
ha ha ha ...just realised I bought your scissy bar last night :D

i hope to god its going to fit :doh: Its the right pattern according to 5twins but your donor is 77 whilst mine is a 79 special. fixing spacings on mine are 10.25" perhaps you'd check your spacings before posting out if its not too late:thumbsup:

You've made a great start paul I can't believe I didn't notice this thread before now.
I'll be following progress of your project with much interest .
Johnny
 
Hi Peanut,

You know what, I thought you had as I saw your posts last night but it had already been bought, as I was going to reply and say I had one. Sorry, it's already off to the post office. I hope it works for you. Its the one on the pic in the second picture, which looks the same as the one you need from your post as 5twins says.

Thanks Johnny - just getting the shopping list from Heiden at the moment:yikes:
 
thanks paul I'm sure it will be fine thanks for the quick posting.I think I should have bid on that gorgeous tank as well.:wink2:
Heiden ........mmm ...I'm trying to avoid their site at the moment . My shopping list is gurt :D
 
Well the crank is now off to be rephased and my order from Heiden tuning is placed. Hopefully it won't take long to arrive. Today, I wanted to get the Helicoil into the cylinder head to sort out the stripped threads. I wanted to make sure that I got the angle into the head spot on, so I put the head on a flat bed, threaded some straight bar into the plug hole and measured the angle from the flat bed. Then popped the head on the milling machine and canted the mill head to the correct angle then drilled the plug hole out, tapped it and threaded in the Helicoil. Pretty quick and simple. The result is very good



I want to make this bike have a hydraulic clutch. Looking around the appears to be two ways of accomplishing this. The first using a slave cylinder effectively in place of the cable and actuating on the clutch worm mechanism. The second uses a slave cylinder directly bolted to the case, acting directly on the clutch push rod. I favour the second method for two reasons. One, it looks better in my opinion. Two, it acts directly onto push rod, rather than through a worm mechanism.

A couple of others on this forum have written about this. I believe it was Osteoderm and Ipytatto. They used an Aprillia slave cylinder and modified the piston retaining part. I had a Rotax slave cylinder, which appeared to be very similar





I cut the "legs" off the piston retainer



Then machined it down my a millimetre or so to fit into the existing clutch adjustment aperture





It's then simple to transfer the bolt centres onto the casing



Then drill, tap and bolt on



This setup means the actuating surface on the push rod is further out than using the stock cable clutch. A brief measurement comparing the original to the hydraulic, shows around 45mm difference, so it looks like a redesigned, longer push rod is required. Once I get the engine builds ill be able to work out the lengths more exactly.
 
Thanks for that TwoMany - some evening reading for me:laugh:
As another note, the 12.4mm length Helicoils are just long enough. Any longer inserts I would say will project into the chamber
 
A little more done today. I fitted the Derby cover to the clutch case as I want the engine to be unbranded. It fits very well and should look in keeping once it's polished up



I then got cracking with the Yamaha R1 2014 yokes. The R1 stem knocks out in the usual way being held in by a wire clip. To keep the bearings dimensions, I wanted to re use the XS stem. Unfortunately, the difference in stem is only 1mm, so I had to machine a very thin bush to allow the XS stem to be an interference fit in the R1 yoke. Furthermore, the R1 bottom yoke is around twice the width of the stock XS bottom yoke. So, to ensure that stem had the correct height, machine a threaded slug, which I welded into the bottom of the XS stem. I could then press the XS stem into the R1 yoke and press it through so I could get the correct stem height. In doing this, the stem was around 35mm into the yoke. So, I machine off 35mm of the old R1 yoke and pressed that in behind the XS stem. Now flush with the bottom of the yoke, a bolt into the slug in the XS stem, secures the whole stem







In order to seat the top yoke from the R1, I had to machine a simple collet to take up the difference in top yoke apertures.





I've deliberately left it high, so, once it's in the frame , I can machine down the stem and lower the height of the collet accordingly
 
While I am waiting for the frame, crank etc, I'm just pottering with little bits and pieces. Today I machined a blank for the tacho drive as it won't be required




I also stripped out a hub from an old XV535 front I had. Someone has painted it all black but beneath the paint, it's in good condition. One problem was that x2 disc bolts had sheared off in the hub.



So, popped the hub on the mill and drilled out the offending items, running a tap through to take out any remnants. All sorted.

 
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Hey, Paul. Not sure if you want to pursue this, but I've been researching "full complement needle roller bearings" in 14mm and 9/16" ID, to fit into my left cover's shiftshaft boss, to offload the sideloads from short shift linkage arms. I know others have done this, just haven't found out what bearings they've fitted.

Found a UK supplier of the 14mm bearing, but the 20mm OD is kinda pushing the limits of the boss's wall thickness.

http://simplybearings.co.uk/shop/Be...th+Two+Open+Ends+14x20x12mm/product_info.html

It'd be nice to find one in 18mm OD.

Also found a similar 9/16" bearing, with a smaller 3/4" OD. Better support in the cover boss, but would have 0.011" slop clearance with the shiftshaft.
 
Hey TwoMany, I thought about doing the very same thing on the Cafe build I did. I'm sure it was you that mentioned it in that thread too actually. I remember I looked at it but, I never went any further, for the exact same reason you mention above - I couldn't find a bearing any less than a 20mm OD

I'll do a little searching tonight and see what I find. It's something I would like to do, as that shaft does need something to help it, I think it would also smooth the shifts too.
 
Yep, I came across those. As you say though, my concern is the 0.011" or 0.29mm additional clearance with the shaft.

I'm going to order some and see just how they work out
 
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