Hitchcocks Forum

Hello all. I'm considering upping my indian iron barrel 500 to 535. I see our hosts stock the necessary parts to replace the barrel and piston with a 535 option. I'm familiar with rebuilding car engines but never opened an enfield up before. What other parts should I be looking to replace?

Thanks in advance.

Andy

Hi Andy. I'll dip my toe in the water first. I would be considering how many miles the engine has done. A bigger barrel and piston can only put more stress on the bottom end, so maybe new mains/big end may be required. If you are wanting a bit more performance, the 535 kit will help, but for any real benefit, the engine needs to breathe better. So, a ported head and larger carb would be needed. Then you may wish to change the cams also.......It all comes down to money! Good luck. Allan.

hi Andy ,i aggree with what Allan says european bearings nice free breathing exhaust get ready to splash the cash Mr H,s way atb paul

Start with a strong bottom end then work your way back to the top

Hi the cast iron barrel can be bored to 535 no problems mine is out to 20 thou oversize with a 8.5 acralite piston on std bottom end bad news is you have to run 98 fuel, im on 19 tooth gearbox spkt and 26degrees btdc timing on boyer [done at half throttle with strobe 140 main jet and 27.5 pilot. im back on std head as my ported head has pulled a rocker cover stud but will still pull to just over 130kph no worries and will stand getting belted down the motorway i dont go down the roller btm end road just make sure the oil pumps are lapped in would replace main bearings most bearing services have them and the 2 seals. spend the money you save on a close ratio gear set150 quid i think makes a big difference only about 1 hours work to fit, also run 6 heavy springs in clutch no slip. have a go enfields are like a big lawnmower engine even the crank can be split with 4 nuts and bolts pop the old bush out clean out the sludge trap new sealing screw you only need someone with a lathe to true the assy up, more you do more you save.

I have a 1995 bullet with the 535cc Accralite/Omega piston and a heavy ported head with alloy rocker bearings , race valve springs and bronze guides an extra large exhaust valve , high lift performance cams and a big 32mm Mk2 Concentric carb and about everything to get my 40 bhp engine to run sweet with free flow exhaust pipe but !!! I still have the stock big end with bonded seal for it's oil feed and a very well lapped pump and it seems to be able to take the power .
My next step is a race RE15 big end for my 612cc plan as I already fitted the close ratio kit with all new bearings ready for it , beefy cam followers were fitted for the high lift cams with ajustable spindles and electronic ignition .
I'm doing it in stages and the motor really kicks power now that comes in with a big surge at 3,000 rpm , I'm very happy as it ticks over as well, Hitchcocks parts are great and last much longer with 1,000 mile oil and filter changes ( dont forget to get the magnet ), you seem to be on the right path to a strong engine ..keep going and you will have a really hot motor , well worth the money when you get a 45bhp motor Fury replica that can do 100mph without blowing up .

I have read this posting with a great deal of interest, remember I do not have an Enfield, and out of curiosity just how much will the 535 conversion, plus the other parts required to make the bike fly, actually cost. I see Scotty says his will do a tad over 81mph, in real imperial measurements, after what appears to be a capacity increase of some 7%. So I am guessing that it can only have provided an additional 4 or 5mph. Of course with the right combination of capacity, compression ratio, cam and gearing the increased torque generated will make for a higher cruising speed and more grunt. So in real terms how much does all of that cost?

It's me again. Sorry but I forgot to add that of course a 7% increase in capacity will not give the same increase in power due to total inefficiency of the ICE. Thus it will not give a 7% increase in speed or torque. After all let's be clear a 7% increase in speed is only an additional 7mph for every 100mph of original top speed. When carrying out these extensive mods has/does anybody follow thw real tuners creed and dyno the engine at the start to give a base value, and then make each mod individually and dyno at each stage until you get to the full conversion? Curiosity is a killer you see.

Mike, the costs are huge and the gains not massive.... Phil put yours on a dyno before making these statements, we put a 612 on a dyno a few months ago, a frightening 28 hp which is not bad when you realize the original Bullet puts out 18hp not the blurb the factory claimed. The Speed Dog Racing 612 is pushing close to 50 hp now but the dollars spent on it would fund my retirement

40 bhp? 45bhp? 50 bhp? I have seen [on a very good day] 45.95 bhp fromn our 500 Bullet which has won a few races and done 110.5 mph on Pendine Sands.
I used to pluck figures out of the air when asked how much power our bikes had, but quickly realised that just because we had very high compression, lumpy cams and a huge GP carb [which incidentally will give a slow, steady tickover and easy starting], as well as a 'Big Head' etc only gave 33 bhp on the dyno, made me realize that you cannot assume that just because you bolt on a few chosen parts, you will end up with a very fast motorbike.
More often than not, our 350 can show about 32 bhp and the 500 around 42 bhp at the rear wheel, best ever 37 and 45.95 bhp respectively. I would say to anyone wanting more power, go for it, buy and / or modify certain bits, but, while you may give your machine a boost, try not to anticipate huge increases in bhp, because a trip to the dyno might disappoint you. Cheers, Paul.