[AVL Power!]

----UPDATED---


Hi Guys!!

I was going through ACE Fireball videos and other articles and was wondering if there is any way to boost AVL 500's performance. I mean something similar, since I don't have that much technical knowledge so I thought of asking you all RE Gurus


Thanks in Advance

-San

[Bullet Whisperer]

Here is a 'cut and paste' of some info I keep handy when people ask about tuning the AVL:
 I tried many different cams, the 'S' type were the only ones to give a free revving engine.
 The Hitchcocks kit is loosely based on a machine they asked me to 'see what I could do with'. I shortened the cylinder barrel by 2mm from the bottom, also the bottom of the liner, or it fouls the flywheels. I machined 2mm off the outside edge of the piston crown, to keep the squish area stock, leaving the central 64mm diameter untouched to raise compression from 8.5:1 to 9.2:1. The steel insert in the exhaust port was opened up by 2mm diameter, the edges of the valve heads were chamfered for a little more clearence over the piston on the overlap. 'Classic Bullet' competition double valve springs were fitted, as were Redditch 'S' cams, timed to the marks. Out of all the cams I tried, these were the only ones I could exceed 6,000 rpm with - nearly 7,000 rpm being recorded.
 For ignition I had a custom made CDI box with an extra 4 degrees retarded to prevent kickback and give better idling, but also 4 degrees more advance at high engine speeds.
 A 36 mm Amal MK II with 290 main jet was fitted using a Honda CB 500 T [1977 model] inlet manifold. The stud holes of the manifold had to be enlarged a little to fit over the AVL head studs.
 With a 'Goldie' silencer, I saw 32 bhp at the rear wheel. With a very noisy exhaust I had 33.5 bhp and 103 mph top speed in top gear on the road, it pulled 95 mph in 4th gear, approaching 7,000 rpm, changing to top and laying flat on the tank gave the 103 mph top speed in two directions. The cycle parts were all standard, even the handlebar mirrors were stilll fitted.
 To fit the cams mentioned, you have to lose the exhaust valve lifter, with the shortened cylinder barrel, the standard pushrods will still reach despite the cam followers sitting lower than before. I should still have the valve timing figures somewhere, but as stated S type cams were fitted, timed to the marks
The pickup for the ignition is fixed by two dowels around the bolt holes. I filed off the dowels and slotted the bolt holes whilst experimenting, this will give an adjustment range of about 4 degrees at best
 Hope this helps,
 B.W.

[AVL Power!]

I guess I will need a specialist for this type of work. Here in india, I don't know many who can do this type of work, so I think I won't risk it because mechanics with less amount of knowledge on this might kill my bike's engine. Also, using a 535 on my AVL will help in any way? the high compression 535 Bore Kit I mean.

Also, at moment I can't afford a 36mm MK II. So if I use 32mm Flat Slide (TM32 I mean), will it help much?

Also, about the cams! I don't know from where I can get the "Redditch 'S' cams" but using other performance cams will help in this case?

-San

[Bullet Whisperer]

Hi San,
 The Redditch 'S' cams were the most important single item where a boost in performance is concearned. I tested about half a dozen different cam types and only put the 'S' cams in at the end, as I had tried everything else to hand with no luck and they were lying around, so I put them in. They transformed it all completely. I had a small batch of 'S' profile cams made and sold every set, but have not had enough interest to warrant ordering another batch, also they were quite expensive to obtain in small numbers. I doubt if any other cams will help much, but you could try. Also, any 'better than standard' carb should help a bit.
 B.W.

[AVL Power!]

Thanks again! For now, I will try for a TM32. Have a Keihin, a friend was using it but he gave it to me but I think I will save up and go for the TM32. 19T Sprocket and maybe some stuff from Hitchcocks.

Stuff like ELECTRA (X) - TCI UNIT - I think that works with any AVL since mine is 500 too.

[Ice]

 Here is a link to an article on a mod for the UCAL carb that will help a bit as will a low air filter and low restriction silencer. of course adding either of both of the those will require a change in the carbs jetting.

http://www.indiancarsbikes.in/automotive-technology/crisp-punch-ported-throttle-slide-cv-carb-9399/

http://www.indiancarsbikes.in/automotive-technology/crisp-punch-ported-throttle-slide-cv-carb-9399/

[AVL Power!]

I was going through the Amal Carbs listen in Hitchcock site. I found a series of carbs which are 36mm.

Are you talking about these?

http://www.hitchcocksmotorcycles.com/amal_carburettors/complete/mk2_concentric#part_5055

If yes, then can you tell me which ones are recommended for our AVLs

This?

AM/2036/300    CARBURETTOR, CONCENTRIC, MK2, R/H, 36mm, 4 STROKE

or this?

AM/2036/301    CARBURETTOR, CONCENTRIC, MK2, L/H, 36mm, 4 STROKE


Regards,
Sanket

[GreenRE]

I was going through the Amal Carbs listen in Hitchcock site. I found a series of carbs which are 36mm.

Are you talking about these?

http://www.hitchcocksmotorcycles.com/amal_carburettors/complete/mk2_concentric#part_5055

If yes, then can you tell me which ones are recommended for our AVLs

This?

AM/2036/300    CARBURETTOR, CONCENTRIC, MK2, R/H, 36mm, 4 STROKE

or this?

AM/2036/301    CARBURETTOR, CONCENTRIC, MK2, L/H, 36mm, 4 STROKE


Regards,
Sanket

Sanket

Those carbs will only help with wide open throttle, and in fact you will most likely end up losing low end torque. If you go through ACE's postings he has explains this better than I ever can i.e. it has too large of an intake port. The large intake port does not flow well at low rpm's...and the high rpm's will hurt the bottom end unless you beef it up...Free flowing air filter and exhaust will work well..the 30 mm flat slide has a big fan following here in the US too...Now for a radical idea: If you can find a head from the 350 cc AVL engine which will hopefully have a smaller intake port....that just might be the ticket...

Good luck !

[AVL Power!]

Sanket

Those carbs will only help with wide open throttle, and in fact you will most likely end up losing low end torque. If you go through ACE's postings he has explains this better than I ever can i.e. it has too large of an intake port. The large intake port does not flow well at low rpm's...and the high rpm's will hurt the bottom end unless you beef it up...Free flowing air filter and exhaust will work well..the 30 mm flat slide has a big fan following here in the US too...Now for a radical idea: If you can find a head from the 350 cc AVL engine which will hopefully have a smaller intake port....that just might be the ticket...

Good luck !

Thanks for the info

[Ice]

Me, I would modify in stages or levels.

 The first level would be the mods my friend Bill Harris did in evolving his ElextraX  based scrambler. This level of modification gives gives the best bang for the buck IMHO.  After this level, the costs for additional gains go up steep and fast .
(Reducing weight helps liven thing up as well.)



 The low restriction air filter and exhaust let more air in and spent gasses out.
Note the silencer location; the exhaust note is devoid of high frequency sounds with only the pleasant low frequency Thump-Thump-Thump- ThAaaUuuuummp,( 1st gear)
Thaaauuump, ( 2nd gear) Thuuuuump delivered from the tail pipe  

 The UCAL CV 29 was an alright carb but the 30mm flat slide gave him vastly improved throttle response at all revs and helps make more hp's

 *About the 30mm PKW that Bill is using on his Scrambler and my son is using on his Iron Barrel. The throat is oval, not round. It is 28mm diameter on the bottom portion tapering to 30mm on the upper portion. This gives good manifold vacuum for good fuel atomization and inlet tract velocity and cylinder fill at all revs.*

 Along with those mods would be an ignition system mod to make sure as much fuel air as possible was being being turned into power and for for fuel economy.
 On an Euro/US spec ElectraX's a performance TCI would be in order. On domestic Indian market AVL's with a "delco" ( a.k.a. distributor in the US)  I would go with a Power Arc ignition.

 Assuming all is assembled properly jetted and tuned correctly, as Bills Bullet is, there will be no problem pulling away from and out running stock Bullets. Fuel economy would be that same or slightly improved except when running hard and fast, then it will dip while making and using the extra HP's of course.

 Bills Scrambler also has the factory 18 tooth counter shaft sprocket while my Iron Barrel has the 17 tooth sprocket and a lessened restriction exhaust. You would think that my Bullet should accelerate quicker than his but Oh no it does not. His Bullet is both quicker to accelerate to a higher safe cruising speed and has a faster final top speed.

 Me,I would enjoy the easy starting, steady tick over mild increase in performance and all around Bullet goodness of that set up while saving for the next level; Big bore kit and cams.

 This is where the experience of those AVL owners who have gone big bore is needed.

[AVL Power!]

Now that's one NEAT bike!

[Bullet Whisperer]

Sanket

Those carbs will only help with wide open throttle, and in fact you will most likely end up losing low end torque. If you go through ACE's postings he has explains this better than I ever can i.e. it has too large of an intake port. The large intake port does not flow well at low rpm's...and the high rpm's will hurt the bottom end unless you beef it up...Free flowing air filter and exhaust will work well..the 30 mm flat slide has a big fan following here in the US too...Now for a radical idea: If you can find a head from the 350 cc AVL engine which will hopefully have a smaller intake port....that just might be the ticket...

Good luck !

TThere are left and right versions of the Amals, I fitted a right for decent access to the adjuster screws. The machine I tuned had shedloads of torque with the big carb, beating the standard setup from idle to flat out.
 A big carb on an engine set up for one will give good performance throughout the rev range., with no flat spots.
 B.W.

[AVL Power!]

So I am assuming that using any other racing cam for electra X will not give results good as yours. Also, using the setup that you had in your bike, will it effect the bike in any negative way? I mean churning out so much horses from the AVL will lead to any kind of engine seizure?

Well.. I am really inspired by what you did on an AVL and will surely try my level best to get there. OFC! Its an awesome feeling! Its really nice to push a single 500 till such extents. I think in few months I will be able to get the 36mm carb, tho I will use a 33mm CV carb for most of my rides. It's decent and also saves money

For certain occasions, I believe the Amal 36mm will be really good. In India its really hard to drive through regular traffic, it just gets annoying. So I will have 2 carb options open for me and when I am all set to do the modifications you have mentioned, I will let you know, maybe I will require some more help from your end regarding the "engine compression" part. I have a friend who blew up a dozen of 535 Cast Iron pistons for too much compression. It literally scares me.!

Thanks a ton for all the information once again

Regards,

Sanket

[basanti]

Here is my 2008 AVL Machismo which I've been working on little  by little by little over the years. Used to be regular here until I got banned for no reason. I think it had to do something with our Indian servers. Anyway, I found out I can login again so here is an update. So far these are the mods done:


535cc JE forged piston running at 9.1:1 compression ratio
Mikuni TM36 carburetor
Bullet Whisperer's "S" cams
Anthony's dry clutch plates running in our own belt drive primary
Upgraded TCI ignition box with more retard and advance (BW)
Battery eliminator from Hitchcock's
Electronic Tachometer
Head ported to match the 36 carb
Combustion chamber reshaped
Crank lightened
Rockers lightened
Chassis reinforced here and there
CNC Triple tree and fork brace out billet 6061 T6 aluminum made by your truly
Tapered roller bearings in the head and swing arm pivot.
Tuned inlet velocity stack made by yours truly out of billet aluminum
Tuned header with megaphone exhaust
Steel braided front brake line with EBC HH brake pads
35mm Tommaselli adjustable clip-ons and quick throttle
18" alloy rims
T19 front sprocket
Oil cooler from Pulsar 220
And way too much time researching, fabricating and getting the work done!!!!

The bike is a pussycat in traffic (yes I do ride it to work in Mumbai traffic also) with full on torque right off idle and pulling hard all the way to 6700 rpm.  It is proper scary doing  second gear power wheelies without me trying to. Super fun to ride!!! I've taken it to the track in Chennai twice and although the engine was proper fun, need to work  on handling/suspension.

You want some info on modding the AVL? Here is some of my experience:

I've tried the 30mm, 32mm, 34mm and 36mm flatslides on my bike. IMHO, for a stock head, the Mikuni TM32 was much stronger every where than the 30mm PKW slide I got from CMW. The TM36 was super strong in the mid to higher rpms but below 2200 rpm it was a little bit weaker than the 32, but still very ridable in traffic). That was before I ported the head to match the 36mm cab and modded the combustion chamber. Then the 36 was super strong right off idle all the way till the engine exploded heh heh heh, just kidding. Here is the article I came across on the head job which I carried out and can post pics if anyone is interested. Everything else being equal, This made a huge difference in torque.

victorylibrary.com/mopar/chamber-tech-c.htm

I've tried a bunch of cams and BW's "S" cams made all the difference in the world. They make the engine run smooth and full on torque all the way from idle till the 6700rpm (in 4th gear) I've dared to pulled the engine to. Stock cast iron cams perform way better than the AVL cams. Hitchcock's Performance cams for the AVL were a waste of money. After I get the engine back together again, I'm gonna borrow a friend's  Magnum cams and see what the difference is. The Magnum cams have 0.5mm higher lift than the "S" cams, apart from a few degrees difference in timing figures.

To answer your question if the engine is reliable for all this modification? The answer is no. I've had to rebuild the big end at 12k km then again at 22k km and then again at 24k km. Of course riding the bike hard to see its performance and being a work in progress with sometimes too much advance or sometimes too lean carburation etc could also have contributed to an already very iffy situation. The last time was totally my fault cuz I asked my mechanic to make an outer race for the big end roller bearing (like what H sells and claims is the problem with AVL big end failures). He obviously didn't do a decent job and after 2k kms its failed again. Another issue with revving the AVL so high is the front and rear of the piston gets scored a lot. I'm guessing its because of the shorter con rod this engine comes with? So I'm going to rebuild the engine with the big end roller bearing and forged con rod for the cast iron engine in my AVL. The con rod is 14.5mm longer, so we're going to have to deal with that. But the bottom line is the material from the factory is utter sh*t and needs to be replaced. Lesson learnt: you want a quality machine, you have to get the quality parts.

Then you have issues with the clutch....  Dear God, I'm going to stop now.

[AVL Power!]

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