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October 24, 2014, 02:53:44 PM

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Author Topic: Redditch AVL gets the treatment  (Read 146 times)

Adrian II

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Redditch AVL gets the treatment
« on: October 18, 2014, 01:06:59 PM »
As my (old) project bike has been off the road for a while with a case of bad vibes, possible main bearing trouble, and since the engine is already due for a strip-down, I have finally arranged for it to take a vacation with Bullet Whisperer to get a new crank and the squish band modification. As there are some issues with the piston @ TDC and cylinder top height (probably due to using an AVL barrel on C.I. Bullet crankcases) I would rather the whole thing is done by The Man Who Knows than use a local engine shop. No disrespect to the guy up the road, but B.W. will be able to sort any valve to piston clearance issues too. 

The "new" crankshaft is from a 350 AVL Machismo, rebalanced for a 500 piston, the con-rod is fitted with an Alpha Bearings crank-pin and bearing outer sleeve and an INA needle roller bearing. This crank can't use the Electra-X style alternator or chain-cases, so I have one of these ready to go on:

http://www.electrexworld.co.uk/acatalog/STK-100.html

I will be using a set of C.I. Bullet chain-cases, stock inner and Lightning outer (same as the Sixty-5 model, but without the hole for the left-foot gear-shift). The new CDI igniton will effectively move the magneto on to the end of the crankshaft, so my lovely BT-H magneto will go onto the new project. The only downside to the new electrics is the reduced lighting output, but as this bike isn't expected to see a lot of riding in the dark, going down to a 35/35W 12V H4 headlight bulb is acceptable.  Report and pictures to follow in due course.

Regards,

A.
« Last Edit: October 18, 2014, 01:15:51 PM by Adrian II »

ace.cafe

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Re: Redditch AVL gets the treatment
« Reply #1 on: October 18, 2014, 01:34:02 PM »
Hi Adrian,
Great choice on going with Bullet Whisperer!

Sounds like an interesting project.
With the shorter AVL con-rod, you might try advancing the cam timing by 2-4 degrees, because it will breathe a couple degrees earlier in the stroke with the short rod.
Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

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Adrian II

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Re: Redditch AVL gets the treatment
« Reply #2 on: October 18, 2014, 10:02:45 PM »
Hi Tom,

it's already got an AVL con-rod. The change of crank is from 500 AVL (Electra-X) to 350 AVL, same con-rod, different drive side main-shaft. So many projects around, it's so hard to keep up!  ;D

Why the crank swap? I just need to confirm something, but I will post again on this.

Regards,

A.

ace.cafe

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Re: Redditch AVL gets the treatment
« Reply #3 on: October 18, 2014, 10:39:45 PM »
Hi Tom,

it's already got an AVL con-rod. The change of crank is from 500 AVL (Electra-X) to 350 AVL, same con-rod, different drive side main-shaft. So many projects around, it's so hard to keep up!  ;D

Why the crank swap? I just need to confirm something, but I will post again on this.

Regards,

A.
Adrian,
I think you misunderstand me.
I realize the con rod is the same.
What I"m saying is that the AVL engine with its shorter con rod will make more power with a few degrees more cam advance than the factory cam timing.
It reaches maximum piston speed at about 2 degrees earlier in the stroke than the Iron Barrel engine, so it draws its breath that much earlier. So, it doesn't really want that 112 degree lobe center. It would be happier around 109.
« Last Edit: October 18, 2014, 10:42:56 PM by ace.cafe »
Home of the ACE Fireball 535 Bullet,  Ace GP Hi-Lift Roller Rocker Head . Pistons, cams, etc. Highest performance Bullet engine mods available .  AVL mods. Redditch 700/750 Twin mods. UCE kit soon.

Please visit my new website:
http://groups.yahoo.com/neo/groups/AcePerformanceBullets/info

Bullet Whisperer

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Re: Redditch AVL gets the treatment
« Reply #4 on: October 19, 2014, 09:07:03 AM »
Another benefit of a shorter conrod is just that the piston is that much closer to the oil being flung off the crank - this is a big aid to the lubrication and cooling of the barrel and piston, but you need very good piston rings to keep things clean, as I found with my 'Short Rod' 350 Clipper racing engine.

Adrian II

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Re: Redditch AVL gets the treatment
« Reply #5 on: October 19, 2014, 02:54:37 PM »
Sorry Tom, I hadn't appreciated where you were coming from. This is something I can run past B.W. later on when we meet up.

The 500 AVL piston does use a modern three-part oil ring, though I noticed the Project bike was still putting out a lot of oil through the breather, which I took/prayed to be a sign that the rings had not finished bedding in. So that's something else on the list of things to investigate.

Regards,

A.