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Author Topic: Harris Scrambler gets 'S' cams  (Read 3617 times)

dampking

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Re: Harris Scrambler gets 'S' cams
« Reply #30 on: July 03, 2013, 04:34:48 PM »
Yes the VM34s will run rich if not tuned correctly (The stock needle jet is on the richer side). But once tuned, they'll do their part. Loving the carb!

You can also check BW's post on AVL500 engine mods. They are pretty solid! He did manage to hit 103mph! Maybe it doesn't offer much space for mods like the Iron Barrel ones do but 33bhp is a good figure for an AVL. One thing that scares me, is the bottom end reliability. We have a lot of AVL users in India who are swapping UCE parts, like the con-ron, barrel, head and they are running strong with those mods. Maybe need some more time for trial and error :)

For the "one sorted Royal Enfield" ;)

-Sanket
« Last Edit: July 03, 2013, 04:38:31 PM by dampking »

Bullet Whisperer

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Re: Harris Scrambler gets 'S' cams
« Reply #31 on: July 04, 2013, 08:00:20 AM »
Hi Sanket - P.M. sent to you regarding 'S' cams.
 B.W.

dampking

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Re: Harris Scrambler gets 'S' cams
« Reply #32 on: July 04, 2013, 11:17:11 AM »
Thanks Paul.

TejK

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Re: Harris Scrambler gets 'S' cams
« Reply #33 on: July 07, 2013, 05:12:00 PM »
Right Sanket. I have gone the Paul/BW way with the piston-cyl barrel mod as i was getting the engine rebuilt a few days ago. Now the bike has a higher compression and you can tell by the bump in the KS effort needed.

While i was at it had a few 1.5 mm shims added under the valve spring to increase a little spring tension. The carb was running lean with a 130 main, and even a 140 main. Now i have put a 155 main - let's see.

With the old iron cams, I did out accelerate my friends AVL with the VM34 through the gears with both bike running a 19 tooth sprocket. Only issue is that the cams are pretty noisy and there is a massive increase in the exhaust noise. Now I am unhappy with the free flow :( - need a better option now!!!!!

Paul, do the S cams also run noisy on the AVL ???

dampking

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Re: Harris Scrambler gets 'S' cams
« Reply #34 on: July 07, 2013, 06:51:59 PM »
When you got the cams installed.. did you check the valve-piston clearance?

About the noise part - maybe because of the extra lift?

Adrian

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Re: Harris Scrambler gets 'S' cams
« Reply #35 on: July 07, 2013, 08:56:18 PM »
TejK,

assuming no valve to piston clearance issues (!) the extra rattle could be due to gear gear tooth wear on the old cam wheels. The UK 500 AVLs came with adjustable valve spindles, I'm guessing the 500 Machismo did too. Might be worth checking if you haven't already done so.

Regarding exhausts, my preference would be for a free-flow down pipe with the short baffled silencer. If you think your free flow pipe is TOO free-flow a Woodsman exhaust pipe has a smaller inside diameter but nowhere near as restrictive as the factory lean burn pipe. Looks classy, too but you'd need to lose the R/H toolbox (and any pillion passenger who doesn't like burnt right legs...).

A.

TejK

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Re: Harris Scrambler gets 'S' cams
« Reply #36 on: July 08, 2013, 06:01:17 AM »
Adrian, Sanket,
I checked and double checked the valve piston clearance and there is sufficient clearance. I did this without the gasket and with some clay ( borrowed it from on of my friend's kindergarden daughter ;) ). The gasket adds about another 1mm to the height and adds similar clearance, I assume.

The noise is 100% the cam-follower noisy and on starting the bike it run very smooth and no engine mechanical noises. But, after warming up it makes the same noise as worn cams. Compression is massive and gives the right leg a massive work out to crank the engine. I'll run the engine for a few hundred kms and see as the noise seems to be subsiding in the last 30 odd kms of riding to work and back.

Since, the S cams are similar to the standard cams , do they also cause some cam noise on installation ? or is the profile more smooth and it runs quieter?


dampking

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Re: Harris Scrambler gets 'S' cams
« Reply #37 on: July 08, 2013, 06:28:38 AM »
Ahh nice! Good god lol

TejK

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Re: Harris Scrambler gets 'S' cams
« Reply #38 on: July 08, 2013, 06:48:35 AM »
Sanket,
Good God is right - Its do or die for this AVL engine for sure. And I can afford to play around with it cause I have a pristine 350cc Original engine sitting at home in case I seriously blow up this one ;) !!

Though little kids are not very happy with me swiping their precious modelling clay !! And still saving for the 34TM Flatslide. God ! When will I get the quarterly bonus !!

dampking

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Re: Harris Scrambler gets 'S' cams
« Reply #39 on: July 08, 2013, 06:59:47 AM »
Tej - The AVLs are pretty sturdy. I think they can take a lot of torture, compared to the iron barrel ones.


Bullet Whisperer

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Re: Harris Scrambler gets 'S' cams
« Reply #40 on: July 08, 2013, 08:21:03 AM »
The 'S' cams are not noisy in the AVL and they are not a 'fierce' or 'lumpy' cam - they just work very well and allow the engine to rev higher, resulting in more speed and power. I don't think shimming the valve springs is necessary - the standard [single] springs are very hard, in any case. It is just bad profiling of the standard cams that induces the valve bounce at around 5,800 rpm. The 'S' cams don't do this. I also converted the testbed machine to the double 'competition' type valve springs from Hitchcocks, these are actually a bit softer than the oem single type, but work better.
 B.W.

TejK

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Re: Harris Scrambler gets 'S' cams
« Reply #41 on: July 08, 2013, 11:09:40 AM »
Thanks BW,
That's right. I just put those in to see if those work as they were pretty worn as compared to the original CI cams. Well, am happy with the way the bike has started revving but that noise from the cams is irritating !! And it was expected but am going to run these cams as they make me smile when I open her up. Since the 'S' are very similar in shape/profile, just wanted to know if they also do the same.

I added the shims to make the valves return faster to the closed position (just a precaution as I am running the cams timed to the marks and didn't want any interference between the piston and valve at high rpm-s ).

Will run her like this for a few hundred kilometres and see how things work out. And in the meanwhile guess I better keep saving for the other bits needed till I get the kind of machine I want out of it.

Sanket,
Guess BW's reply solves the mystery. On another note - I feel Royal Enfield should seriously fire their engine design team and hire BW ! :P

Cheers !



dampking

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Re: Harris Scrambler gets 'S' cams
« Reply #42 on: July 08, 2013, 11:23:03 AM »
Nope! Paul is doing what he does best, setting new land speed records :) Check this "Pendine Landspeed racing" thread.

I don't know what to say about the RE guys in Chennai, yes they are bad at certain things but thanks to them for keeping RE alive.

TejK

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Re: Harris Scrambler gets 'S' cams
« Reply #43 on: July 08, 2013, 03:50:50 PM »
Adrian,
Will try out some of those - right now I got some glass wool from the original long Electra silencer and stuffed it in the exhaust. Sounds reasonably OK however sounds like a tin at high rpm-s. I guess the narrow header now has a strange effect with these cams and at high rpm-s the exhaust also make a screaming whistle sound - weird !! :-\

The 'high woodsman exhaust' is out of the question - my wife will not take kindly to getting burnt - it is tempting though ! ;)

Sanket,
Interesting stuff in wales - am sure it will be quite awesome ! More power to BW, I say !!

Cheers !

Buckeroo

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Re: Harris Scrambler gets 'S' cams
« Reply #44 on: August 13, 2013, 06:45:25 AM »
I'm interested in these S cams.  I have a 2008 AVL and have had up to 75, but was afraid to push it any farther.  Are there any other modifications to the engine, carb, or electrical to use S cams?  I have the stock CV carb.  My bike is pretty much stock mechanically, except that I have removed the stock air box and oil bath air cleaner.  Although more power would be nice, I am concerned about ruining the great gas mileage this bike gets.  I'm setting this bike up for long distance traveling.
This bike was stored for 3.5 years.  It had fallen on its side for awhile. I claimed it about a year and a half ago. Thus the low miles and inexperienced owner.
2008 Bullet Electra Classic 500
Classic Frame and AVL motor
Electric Start
Electronic Ignition
5 speed
CV Carb