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_5055If yes, then can you tell me which ones are recommended for our AVLsThis?AM/2036/300 CARBURETTOR, CONCENTRIC, MK2, R/H, 36mm, 4 STROKEor this?AM/2036/301 CARBURETTOR, CONCENTRIC, MK2, L/H, 36mm, 4 STROKERegards,Sanket
SanketThose 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 !
I didn't remove anything from the motorcycle. I ate less , and lost weight.
A friend who swapped con-rod said that they do? I was assuming that he was right. But if he isn't then no other go But even with no outer race do you think UCE con-rods are better than AVLs?-Sanket
Next stage will be sourcing new UCE crank - Looks like the UCE motors use same AVL crank and con-rod with hardened outer race.
I was actually talking to Vivek and he said that UCE con-rods are slightly better so we talked about the outer race too. I will go to indiMotard and see if they got any spare UCE-Con-rod
If you have the resources, you can probably get the Hitchcock's 535 high compression piston for the AVL. More cc and higher comp as well !..........
For most affordable results, do the BW piston mod, the way he specifies it to be. It's the "best bang for the buck".However, for those with more resources....The world has changed.Just use the flat top piston, and this ACE big-valve modified chamber for improved combustion efficiency, 9.8:1 compression ratio, proper squish, better flow, and more power .
how much does a head like that run?
Interesting, who has the necessary cojones/$$$/time to take this on? If my next project goes AVL instead of Big Head I will be sorely tempted.Regards,A.
I would say that in a "full-house" AVL build as described, it would be suitable to use a TM34, or even a 35mm or 36mm carb to get all the revs that it could utilize with that stuff.
A lot depends on the way it is ported.We use the carb as the primary restriction. It is the smallest cross section in the tract, in the way we do it.Others put the primary restriction in the port, and use a larger carb.This ends up with different size carbs for the application, depending on how the builder approaches the inlet design.
This is what is going to give that elusive 40+hp figure that was alluded to when the bike was introduced. We pull more torque out of it with more flow, more compression, better combustion, increase the lift and duration to increase the rpm capacity, and push it to 7000 rpm, and you'll get your 40hp at the rear wheel, which will be around 47hp at the crank. Essentially, right about the same specs as a Norton Manx 500.
47HP , that's impressive ! . Is it just me or does the AVL head resemble the old Fury head? .
Wow, that sounds very cool ace.Do you think the AVL or UCE bottom end can handle that?
are the ace cams better than the S cams in this application? I've already made the decision to keep my avl enfield for ever, which means im definitely going to dump excess money into it in the very near future. Nothing in life would make me happier than a 40 hp custom cafe enfield.
All this with the stock Ignition timing ? or any changes to the stock TCI?
I'm sure that spending some time working on optimizing ignition timing adjustments would give best results.However, so far we have not seen problems arising from stock timing with the higher compression and our chamber mods. Perhaps it might be a little better with a few degrees retarded from stock, because of the faster burn. It would be up to the owner to experiment with it to find the best timing.The further the engine is modded away from the stock conditions, the more specialized tuning will be required. This is typical with all performance engines.B.W.'s adjustable TCI box might be a good idea, along with some offset Woodruff keys, to give plenty of timing options.
Hi TomI have heard a lot about the woodruff keys. Are these installed on the crank?
Paul - The valve springs you used were competition springs by Hitchcock. I did check them on their site and it says that they work on Iron barrels only. Any idea if any sort of modification is required? or is it just plug and play type?Regards,Sanket
Hi Sanket, From memory, I think I fitted them using the lower spring seats which came with the spring kit, but retaining the original [AVL] spring caps, even though they had no register for the inner springs as such. I relied on the outer springs to retain the inner springs at the top. Also, Hitchcocks had [at that time], two different types of competition spring - they sent both types and I remember the type I chose being able to fully compress to a shorter overall length, making going coil bound less likely. I have included the one and only photo I took of this - sorry it is of rather poor quality! B.W.
so what exactly has to be done to the head in order to fit compitition valves and springs or beehives
well what i wanted to know is if the whole Hitchcocks competition set can be made to fit with easy to no mods i can do some stuff. I feel like if its minor i can do it. Do the HC valves and springs and everything fit?
Paul, I had a doubt. I have few friends who are running their iron barrel motors on high compression pistons and cams with higher lift. They never face any sort of valve bounce and can happily rev past 5500 or 5800rpm barrier. So do you think it's the AVL head which restricts the revs ? -Sanket
So the Chennai factory might have produced the odd set of "S" cams by accident, due to manufacturing inconsistencies. Excellent! I suppose that is just about feasible as the Indian C.I. Bullet cams have broadly similar though not identical profiles.Valve bounce on stock AVL cams aside, it has always puzzled me as to why a skilled engine tuner, with a good selection of performance cams known to work in classic Bullet engines, could only find one set of cams that would really do the business, and these turn out to be a set of touring cams. There's definitely something about the 500 AVL engine that doesn't seem to want to play by the rules.I'm at a loss to understand why the head itself should be to blame, so is there perhaps some peculiarity in the rocker design that makes this engine so attuned to one particular cam profile?Still puzzled.A.
I am confused because of the same set of reasons. My friend has an AVL with UCE top end and even that one doesn't like to rev past 5500rpm or so. So I was wondering if the top end of Iron Barrels can give us more freedom? I guess it's worth the try Regards,Sanket
I thought of this because I can get an Iron Barrel head, get the performance valves and springs and do some squish band work + compression bumping and then try out performance cams for Iron Barrel, by replacing my AVL head. Not that I can do it now but maybe worth the shot later. Can always take this up as a part time project and work on it but the only doubt on my part is - will it end the valve bounce issue but I guess.. for these sorta things, we need to do it to figure out.-Sanket
This is what I have been trying to get across to people for years. You can't "hodge-podge" a motor with a bunch of old scrap yard parts and various "speed parts", and then bolt it all together without measuring anything, and then hope it will work right. It's not cooking a stew with kitchen leftovers. It's a performance engine.People wonder why all our stuff is designed to work with our other parts. And that we don't recommend using some eclectic concoction of "parts" from various disparate designers and sources who designed their "parts" while having no idea how some other unknown "parts" might interact with their "part", hoping it will somehow turn out right. It's because the engine is a system, and we understand that. So, we make systems.