Julian's Scrambler build "Post 1"

[Briz]

Yes, the 89mm stroke does often need some clearancing. The first one I did many years ago was on a plunger set of cases which needed no clearancing at all. But I did use a pair of steel Norvil capscrew rods which didn't have the upper shoulder of BSA & Triumph ally rods.
This time, we're making our own rods, so we should get them to clear OK. Dont really want to weaken the cases if we dont absolutely have to.

[JulianM]

Must say that now it's all assembled with my SRM Rods, I could have got another 2mm stroke in there I think without too much probs as I have at least 2.5mm all the way round so 1.5mm between rod and case "should" be ok unless I got a hell of a lot of crank flex.  
"Next time"  

Looking forwards to visiting and poking my nose into (pinching) your ideas  

Julian

[JulianM]

Small update,

Pistons ready for instalation,  nice slight dome and due to the bore and stroke they give me 11:1  



Modified Cam followers back from Hardening, Grinding and Coating.
Can you spot what's been done?



Just fitted the followers in the barrel and gapped the rings etc,
Now to the final assembly,

Just also arrived is my Scrambler kick start, this is a longer lever that has the pivot at the bottom and flicks round forward when not in use so if I fall off I don't get collected by the kickstart "hook"

Regards,
Julian

[Greybeard]

I am so looking forward to seeing this beast running!

[bsa-bill]

Can you spot what's been done?

a little extra oil for the cam perhaps

[Briz]

Who made your pistons Julian?

[JulianM]

Hi,

Yes, cam followers Stellite coated, reground with larger rad for a little faster velve opening and ceramic coated with some fancy stuff I am assured will stay on    holes drilled for more oil aimed at hopefully the correct place.

These pistons are from Arias.
I use both Zzuhl and Arias depending on my mood.

Regards,
Julian

[JulianM]

Small update,

Clutch conversion finished!
I would not advise trying to use the FZR unit unless you like work!  It made me fight!  But I think it was worth it as the action is light and it should cope with an excess of 120hp so will laugh at my engine.



Notice that the chain and sprockets are more than 10mm in from standard,  I removed the spacer from between primary cover and crankcase and then fitted the sprockets as close in as reasonably possible. Mainly to relieve stress on the end of the crank and gearbox shaft.  I also made a modern oil seal conversion for the gearbox output shaft.

Pistons and Block went on.
Notice the special HT block studs made with rolled threads, and little ARP HT nuts.





Did it in a non orthodox way by fitting the pistons into the bores up to the pin holes, fitting the circlip on the inner side first, then fitting the pin protruding a few mm and then dropping the whole lot onto the rods,  locate the rod eye by feel and push the pins in, circlips on and drop the lot down,  took me about 15 minutes from start to finish. Luck came back after the fight with the clutch  ;o)





Top on this weekend I hope.

Regards,
Julian

[gavinoz]

Julian,

I love the look of copper & alloy, what are the two copper pipes visible over the primary case, are they oil pipes to a non standard oil tank? breather pipes?

gav

[muskrat]

Just brilliant. I've never put barrels on that way, but should be easier with light alloy jobs. Must be a pain starting the base nuts with the barrels sitting up a bit. I see the barrel skirts don't have cut outs for the rods. Are they short skirts? I luv short skirts 
Cheers

[JulianM]

Morning guys,
Thanks for looking so closely!  makes me feel like you are trully interested. 

The copper pipe is simply a breather from the timed breather port,  a copper pipe was fitted to the crankcase hole, and joined to a mating copper pipe curved over the primary (that you can see)  it then does a loop to come back down and fit into the little hole above the chain sprocket.  Breathing and dripping any oil onto the chain.  (hopefully not too much as the oil tank breather also ends above the chain)

Locating the pins was actually a 30 second job although I too was expecting to fight a little. 
Due to the ring pressure and me locking the clutch I could slide the barrels into the right position in order to fit the nuts fairly easily, and all being new I could run them down with my fingers before tightening.

Complete job from checking pistons to final tightening was miraculously less than an hour.

No cut outs for the rods due to shorter barrel skirts, only down to bottom of piston at lowest point. and bigger bores giving more clearance.
And some luck 

Hope to post more after the weekend.
Regards,
Julian

[Greybeard]

Oh yes I am interested! Can't wait for the next installment.

[JulianM]

Thanks Neil.   

J

[JulianM]

Little more work done these last few days,

Clutch fought me again, primarycover would not go on!  so now it's a 7 plate job with only about 120 bhp capacity  

Finalised the head build and fitted,  11.06:1 cr     so happy with that,  
Motocross kickstart fitted 25% loger than std,  (will eed that)
Still need to finish the rocker box etc but as that will be polished and i'm too lazy at the moment for that so I thought I would start on the exhaust.
Primaries finished and within 5mm in length of each other and tucked in very tight.  Very pleased!

 









More next Weekend hopefully,
Regards,
Julian

[MG]

Great Job, Julian! Keep those pics coming!