Hitchcocks Forum

OK, so far these are just ideas I am mulling over, but I am hoping it could work out to something practical and useable. So this is the idea.....
There are now loads of surplus electric start inner and outer primary cases that are effectively useless after the starter motor and it's gears have been sent home to the scrap heap. These could surely pressed into service for mounting a supercharger in front of the engine where the electric starter motor sat. It would be fairly simple to rig up a drive similar to that which connected the starter motor, but it would not need a sprag clutch (hurrah!) then all you need to do is sort the plumbing and the carb and there we have it... one supercharged Bullet. It is a really good way to get bags more power without losing tractability. Does anyone like the sound of this.

I know there is a video entitled "Supercharged Bullet" on You Tube, but I think it is actually TURBO charged, which is a whole different ball game. I have always much preferred the feel of a supercharger, much more of a direct and 'in control' feeling.

A very interesting concept i'd certainly love to see and hear more about.
My immediate concerns would be whether the iron barrel bullet could take the extra performance but that said, I'm no engineer and I really know nothing wortwhile about super or turbo charging.

Please throw in some details and I look forward to the discussion.

Hello there HOWARD 612---- glad you took the plunge on this one....First, have a look at this }------- http://en.wikipedia.org/wiki/Supercharger --------. And have a look at this as well }------- http://www.ebay.co.uk/itm/K60-Mulitfuel ... _500wt_992 -------The second shows a Rolls-Royce Leyland K60 2-stroke diesel with it's turbocharger fitted on the front (The body having those fins. The air inlet is protected by a wooden blanking plate)...One advantage with the Bullet standard iron engine specs. is its' low compression ratio (CR) to start with..... Given the fairly robust type of big end then a mild amount of charge might be possible---equivalent to say a 9 or 10:1 piston being fitted. I think it would be quite small in size given that it will be feeding a 28 or 30mm carb---perhaps no bigger than the starter motor it replaces, maybe??.... One design problem that stares you in the face is the long air tract from the front to the inlet side of the carb......OK, let's about-turn and put the carb. on the exhaust port-----machine-out the inlet to the exhaust sizes and put the exhaust pipe exiting what used to be the inlet ?? The valves, seats etc. Another problem might be to manufacture the rotors---- unless there is a commercially available small turbocharger on the market ??

---------- As part of my "Exhausting" search---(technically that's incorrect.It relates to a turbocharger, of course !!).... I found this }-------- http://www.ebay.co.uk/itm/funny-superch ... 15278?pt=U --------. Well, it's a good incentive to make this project a reality, eh ??

-----------this might work ??}---- http://www.ecrater.co.uk/p/8503275/acur ... 5psi?gps=1 ----------

Alan R, yes, good point about the long pipe from the charger round to the carb. Would this introduce a 'time lag' making control difficult? Well I think that would only be answered by building one to try it out. good idea to reverse the flow through the head, this was the usual technique used on (Triumph?) twins where it was a simple matter to simply reverse the head and swap the cams over, not so easy on a single with the pushrods up one side. Lots of machining, building up etc required to do it with a standard Bullet head, but possibly using the right hand head from one of the twins, fitted "the wrong way round" it could be done more easily?

Two further points, the size of the unit may be a problem, but seeing as we are only going for a moderate boost a suitable unit may be possible, and the other thing, mentioned in the Wiki article, is the probable need for an intercooler, again only building one and testing it would answer this, but it could well be that this could be combined with the long pipe mentioned .....

m1ks raises the point that the bottom end would be under extra strain. I believe that the bottom end can be made very strong indeed. The standard bottom end could possibly wilt under a heavy boost, but I am envisioning this supercharged system as an extra for people who have already gone as far as they can along the 612 and hot cams route, but still require a little extra power. Obviously the 3mm compression-reducing spacer would need to be fitted in these circumstances ;-)I know that the 612 bottom end is EXTREMELY tough, my one has endured being ridden by an "enthusiastic ex-courier" (me) for three years now with no signs of strain, so I am sure that it would be up to a little boost.

Oh I wish we could do paragraphs on here. Hope that long post was not too confusing without them.

Yes that sticker is great Alan, I must get one

FWIW, there is a supercharged Bullet in Issue 3 of The Royal Enfield Fanzine. http://www.greenlane.biz

Hi HOWARD---------- You might be thinking of TURBO-LAG which occurs because a turbo. unit is not mechanically connected to the engine and so there has to be a "cause" before the "effect" can be felt.....not so with the supercharger as it is running all the time the engine is running. BUT----- that long induction tract might just act as an INTERCOOLER--have a look at this}---- http://en.wikipedia.org/wiki/Intercooler ----- I can't access that magazine article as I'm not paying for yet another publication-no matter HOW good it is---In a modern sense it will only clog up my computer memory instead of clogging up my settee, as in the old days !!!!!....... My code name is Captn. TIGHT-WAD Snr.( Fresh air is free !!!).