Unofficial Royal Enfield Community Forum
Royal Enfield Motorcycles => Bullet Iron Barrel => Topic started by: TonyVanda on January 10, 2022, 10:11:13 pm
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G'day, I have 1987 Bullet 350. It's the SuperStar model and is a 1987 Australian delivery. It's had Hitchcock roller big end and conrod, high comp piston installed. The head has been tidied up and just about everything else has been updated. Its got the close ratio gearset and an 18 tooth sprocket on the front.
It's a great bike but I'm having a power issue with it. It loses power when under load like going up a hill. It's so annoying. It takes off ok, revs out pretty good and cruises great on the flat but as soon as there is a hill and I power on, it doesn't do anything. When I'm doing a long trip and cruising on a flat road (ideal conditions), it'll sit on 85-95 in the sweet spot. If I apply full throttle it feels like something is stopping it from getting full power.
So tuning wise, I've replaced the coil, points plate, auto advance springs, spark plug, and we've timed it using a dial guage that fits into a spark plug gadget so the timing is spot on 0.8mm before TDC. It runs a Mickarb VM24, 95 main jet (at present. Didnt make much difference between the 90 and the 95) slight larger pilot jet and the standard slide (number 2 I think). Exhaust is the standard 350 header pipe with a 500 bazooka muffler and an adapter at the join. I'm running the original airbox. The plug colour is about normal if a bit on the rich side. I measured the inlet port on the head and it's 26mm.
I've tried the Goldie open muffler and sports air filter and a range of main jets and nothing seems to work. How do I get that little bit of extra power to get me up the hill? I'm thinking it's not getting enough air at full throttle but as I said, I've tried just about everything. Any clues would be greatly appreciated.
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Could be that the gearing is just too “tall” with an 18 tooth sprocket. The standard is 16 for a 350 with a 38 rear. A 17 might be better.
My tuned 350 struggled like yours but fitting a five speed gearbox transformed it.
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Paul's right, it's way over-geared, and that's fighting against your other tuning mods. Try it on the stock 16T gearbox sprocket. Bigger gearbox sprockets only make you go faster if there's enough engine oomph to back them up. 18T would be better for a tuned 500 Bullet.
Trying to get much out of that engine without porting the cylinder head and fitting a bigger carby is a bit of a handicap too. Also, what cams are you using?
A.
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Thanks for the replies. Will source another sprocket(s). One of our fellow enthusiasts did mention that and I forget he did. Cams are original. Still doesn't answer why, under perfect conditions, it wont wind out, regardless of the front sprocket size.
If the inlet port is 26mm and a VM24 fitted, would a VM26 make any difference? Or, to feel any real difference, port the head out to 28mm. Just asking cos don't really want to go down the 'hotting up the motor' path.
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Perfect conditions don't include hills! Move to the Netherlands? Also you might be shorter, lighter and leaner than some of us pie eaters :-[, so less weight/sail area for the engine to have to deal with.
The VM24 is an economy-biased carb, at least the Indian licenced copy is. Paul W has posted elsewhere about the difference a 26mm carb made. If you don't want an Amal there are Keihin PWK26 clone kits for the 350 Bullet that are supposed to pep things up at the top end a bit. It's worth noting that when the factory in India brought out the UCE engine 350 they went from a 24mm carb (size same on both iron barrel and AVL350s) to a 29mm carb.
I'm into a 350 Redditch Bullet project at the moment which has an Indian 350 Bullet head with the inlet ported out to 28mm, with PWK28 clone on there.
(https://i.postimg.cc/7PVf1Pvv/DSCF9067.jpg)
"Hotting" up the motor IS tuning! You've already started by fitting a high-comp piston. Now let it breathe at higher rpm, as well as sorting the gearing out. Mabe some sportier cams, too?
A.
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The engine looks fantastic with the magneto, is the head a late model IB with the casting port for the PAV? Any indication of what the power output would be?
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Yes that is a late Indian IB head, the lump must have been intended for a PAV union same as the 500 AVL/Electra-X, but I think the factory just used a union on the exhaust down pipe instead. Had the IB continued in production that's probably what they would have done. That lump might get ground off before the engine goes back in the frame. I still have the Redditch original but this head came up cheap and low mileage. The SR1 mag was standard kit for '56 - '59 Bullets, it bolts straight onto the later Bullets including most Indian IBs. I was lucky enough to get a decent auto-advance to go with it, though new ones are available again - at a price.
Besides the carb and head work, there's a lightened crank and shortened alloy cylinder barrel optimised for a Meteor Minor Sports piston (it's one of Bullet Whisperer's ASBO engines), a set of Henry Price's "R" cams and needle roller conversion for the drive side mains and big-end. Power output? Don't know what that will be, but if I get the carb set-up correctly, "it shouldn't disappoint".
A.
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Ok, that all sounds good. I'll look up Pauls post about the 26mm carb.
Paul mentioned the 5speed gearbox - that sounds a bit ambitious for me but I have fitted the close ratio gearset from H's and it makes a huge difference. I have a 17T drive sprocket coming and my learned RE expert friend is coming over from Tassie at the end of the month and bringing some electronic ignitions to try out. In the meantime, I'll see what I can dig up for exhaust/carb (stuff I gave away thinking I didn't need it). Hotting up indeed... :) yeah!
Thanks all for the help. Adrian, that 350 motor looks fast just sitting there.
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Hadn't thought of that, who needs a rolling chassis after all? I might need that shopping trolley back at some stage, though. ;D
Is your mate from Tasmania called Bob, by any chance?
A.
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Yes that is a late Indian IB head, the lump must have been intended for a PAV union same as the 500 AVL/Electra-X, but I think the factory just used a union on the exhaust down pipe instead. Had the IB continued in production that's probably what they would have done. That lump might get ground off before the engine goes back in the frame. I still have the Redditch original but this head came up cheap and low mileage. The SR1 mag was standard kit for '56 - '59 Bullets, it bolts straight onto the later Bullets including most Indian IBs. I was lucky enough to get a decent auto-advance to go with it, though new ones are available again - at a price.
Besides the carb and head work, there's a lightened crank and shortened alloy cylinder barrel optimised for a Meteor Minor Sports piston (it's one of Bullet Whisperer's ASBO engines), a set of Henry Price's "R" cams and needle roller conversion for the drive side mains and big-end. Power output? Don't know what that will be, but if I get the carb set-up correctly, "it shouldn't disappoint".
A.
Wow, that is a lot of work, Adrian would you be able to share some more information about the needle roller bearings used for the drive side mains and the big end? Is it to reduce friction and rolling resistance. Does the Lucas SR1 magneto produce a much better spark compared to the IB ignition coil / TCI unit? I have never worked on a magneto IB bullet before and always have been curious about them.
The 2006 and later IB Indian models did have the PAV installed, but most people just install a bolt and block the PAV port on the cylinder head.
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The needle roller main bearing conversion is one of Mr H's for Redditch (and presumably pre-'78 Indian-built) Bullets. Later engines don't need this as the Chennai factory changed to metric crankshaft main bearings with a standard NU205 roller bearing on the timing side instead of the strange bespoke RE roller main running directly on the mainshaft.
The big-end bearing conversion is supplied by Henry Price over here with a custom crankpin running in the same size caged needle roller assembly used on the EFI and Electra-X/AVL Bullets, all supplied fitted with a new alloy con-rod.
The SR1 is because I like magnetos, as they're a self-generating spark solution which doesn't rely on batteries. This particular one still manages a reasonable spark with a resistor spark plug, so I'm guessing it's pretty healthy.
I need to post a bit more about this bike over in the vintage section and will do in due course.
The head-fitted PAVs on the 350 IBs must have been a home-market thing, I don't recall seeing one in the UK.
A.
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Ok so let it breathe - I removed the stock air filter box. Got the old pod filter out and washed it thoughly in petrol, blasted it with air then just to make sure, put it through the ultrasonic cleaner a couple of times. I fitted it and a 95 main jet and rode it about 80k's and it went better but still lacking at full throttle. Came back and fitted a 90, round the block for about 30k's and not much better. I dont have a 100 so thought I'd try the 105 and now she really goes. 100kph up the Gunamatta road. Yaay! I might see if I can define 'hotting up' to myself. Next time I pull the bike to bits, I'll investigate some of the tips youse have suggested for the top end. Thanks.
So I'm polishing and polishing the bike ready for tomorrows club ride. I notice a cable on the outside of tank on the right hand side. It's at the bottom of the tank so I havent noticed before. While I'm polishing polishing, the steering sort of flops to the left and the cable goes tight. What is it? It's the decomp cable and I was wondering why the thing would conk out when idling and the handlbars fell over to the left. Derr... Anyway, unscrew and remove the front tank bolt, lift the tank and slip the cable underneath and all good. More polishing...
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Having done quite a lot of work on my own 350 over the last three years or so, I found that opening up the exhaust made a surprising amount of difference. I had initially gas flowed the inlet side and fitted the 26mm Concentric carb but at a later date worked on the exhaust port and it was instantly noticeable once I'd put it back together.
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Thanks for the tip Paul. I'll give it some thought. After going through this exercise, I can see/feel how the engine could perform so much better. I've got the quality bottom end in it so when the top end is due for a rebuild, I'll port the head and get a better carb.
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It looks very nice, a similar colour to my own. I especially like the fuel tank 8)
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Yes the fuel tank is a unique paint job down here. The previous owner must have stuck the badges on but they look cool.
Bike went well today. Clocked up about 160ks. The 17T front sprocket should be here soon and if that is still too long legged, I'll go back to the 16T.
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I’m sure that lowering the gearing will sort out the issue. These 350s like to rev, rather than slog along like the 500 can.
I actually have an 18 tooth front sprocket on my 5 speed gearbox, but I use a 42 tooth rear wheel sprocket. This means the gearing is almost identical to a standard 350’s 16/38.
It revs well, as can be heard here: https://youtu.be/If47Pnkgfrs
Since that video was done I’ve fitted a Meteor Minor domed piston and it goes even better, but so far I’ve resisted the temptation to raise the gearing by fitting a larger front sprocket.
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Looking at the pictures of your 350 Bullet, I'm convinced that your silencer/muffler might be an issue. Regardless of what's inside the thing, the weight of it alone must be holding you back!
A.
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The silencer / muffler does looks identical to the indian market long barrel AVL Machismo silencer. Which is very restrictive and heavy.
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Yes, the 350’s exhaust needs to be one with little restriction to make the best of these engines. If I fit the long baffle in my Woodsman silencer I can feel a definite reduction in performance.
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What the old 350 Bullet was DESIGNED to run with was something like this:
(https://i.postimg.cc/JzjSbGdZ/350shortbottle.jpg) (https://postimg.cc/zyXdNXNG)
Guess what - it's still available, e.g. this.
https://www.ebay.co.uk/itm/255266263342?hash=item3b6f0e112e:g:q0QAAOSwjvdhr3Iq
You can buy the "short bottle" silencer/muffler separately, but it really need the longer exhaust pipe to match. Unlike H's 50's replica items, these still have some worthwhile baffles to keep it from being too loud.
A.
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Point taken silences can make a hell of a difference l just changed mine on the 500 it doesn’t have a blocked nose now. But in saying that carbs can play their part jet sizes needle position can have a great impact experiments can be fun and full of surprises.
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Yes I suppose my muffler is a bit of a dinosaur model. I'm spewing because i gave away the Goldie I had on it and a couple of new short bottle silencers I had with some things I sold to a dealer and I cant them back.
One of the members on the ride the other day works at the Motorcycle Accessory Supermarket and has fitted a knock off Goldie style muffler to his 350 and he says it made a noticeable difference and it's not overly loud so might look at one of those. I like the look of the scrambler style muffler too.
Stay tuned (Haha pun intended)
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I have the 50's style with the baffle in and I still doubt it will pass rego check next week. :)
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If that's a Hitchcock version, they're usually a straight-through item. The bolt-in end baffle doesn't always do a lot. The Indian short bottle types usually have something approximating to the original Redditch baffle pattern.
A.
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I finally got my new header pipe from India after 6 weeks or so. I fitted it with a shorty muffler off a 500 that one of my mates had lying around. Used a size converter I got from H's. which is way better than any of the packers I got with the muffler.
It all went together with a minimum of fuss. I havent fired the bike up yet, but I'll let you know if it makes a difference. I've yet to fit the 17 tooth sprocket and might do that today if I have time.
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I see by that club permit plate we have another Victorian on board.
Would be good to catch up for a ride, some distance from me in Ballarat though.
Nice bike, attached is a pic of mine.
Geoff.
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Hey Geoff, nice looking bike. Yes, you are a long way from me but you never know, maybe we can meet up some time. I'll be in Blackwood next week but unfortunately, wont be bringing the bike.
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Hmmm, back to tuning the Bullet after a break and doing some other stuff to it.
The head is off it, in the process of port and polish. I'll post some pics up next week as going away this weekend and also waiting on some parts. Watched Paul Henshaws port and polish vid he recently posted and I reckon I'm on the right track. There was a lot of carbon and muck on the piston and around the ports so that's being attended to. I'll fit a Mikuni VM28 as recommended by the locals who have done the same with good results.
Regards
Tv
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If there's a lot of carbon about, make sure the piston ring to land clearance is good. Enfield pistons have a habit of the crowns collapsing slightly and pinching the rings, especially the oil control ring. The more you tune and the harder you ride them, the more likely it is to happen. I'm not sure which type of piston you have but the sort where they've cut a slot right through the piston behind the oil control rings seem particularly prone to it. Worth taking the ring off and checking it rolls freely round the land without pinching.
Not unheard of for the crown to come off 500s but on the 350s it just tends to cause an increase in oil consumption and progressively poorer performance under load. I decided Indian pistons are a 15-20k mile service item on 350 bullets if you're going to ride them hard. Got a NOS Heppolite Redditch era piston in it now which doesn't have those grooves cut in it so hopefully that's the last time! I've got 5 350 pistons in a cupboard in my garage. 4 have collapsed heads of varying severity and the fifth has a valve stuck in the top of it.
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When it came to gas flowing the ports, I was surprised to find that the work on the exhaust port seemed to make as much of a difference than that on the inlet and a 26mm carb (I did the exhaust side at a later date).
I subsequently fitted an original Meteor Minor piston and that woke it up a bit more. The photo compares it with a new, unused “standard” pattern one. They are actually fitted to the same gudgeon/wrist pin for direct comparison.
Edit: My apology…I’d already posted a similar reply earlier in the thread!
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My piston is like the one on the left with the high dome. It's a Hitchcocks high compression from about 8 years ago. I've dismantled everything and giving it all a good clean up. The rings are fine and don't bind so I'll assemble as is.
Thanks for the tips. Still always interested in learning more.
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I've finished porting and polishing, noticed I see light coming in the past the exhaust valve so had to fix that. Mayb that was my power problem all along.
Reassembled the motor and in the process of fitting the new carb. Takes me ages as I come across stuff that baffles me, like the pushrod adjusting nuts. I had the logic arse about in my head so took for ever to get them right. (the little lock nut locks the top adjusting nut...). Swapped the inlet cam with an exhaust cam on recommendation so we'll see how that works.
There is always an issue. The adapter flange doesn't work with the standard inlet studs so had to make a couple of screws to fit. Because I dont have the proper equipment, I had to make 4 to get 2 good ones but they work well. I got warned the throttle cable might foul up with the petrol tank mount but I've got a bit of wiggle room so all ok. I had to scrounge through a tub of cables to find a throttle cable that fitted but I was in luck. Changed all the jetting as per instructions and might be ready to start tomorrow - finger crossed.
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Here is the setup looks before final assemble
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Just beautiful Tony , look forward to reports when running. Gotta love that bell mouth !
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From early experience with my 350, even a minor an exhaust valve seating problem will kill all the power. My engine had a very soft exhaust valve seat, so much so that the bike would close up its exhaust valve clearance every 50-100 miles or so, then it lost compression and rapidly died. I got very used to re-setting the clearance at the road side. Once set, I'd get another 100 miles at most.
I took the head to a specialist engineering company and got them to fit a new valve seat. Problem solved; the valve clearance stays as I set it now and I've done around 18,000 miles on the bike since.
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Took the Bullet out for it's first ride after the head/carb/cam update. It definitely has more power but needs some tuning. I cant set the idle mix as it just belches out black smoke so need to change the pilot jet. The main jet is a 170. I have a 160 and a 180 which I'll try but it really seems to open up at full throttle on a straight flat road. I didn't want to go too hard on its first ride. I think I should be running in gently for the first cuppla hundred K's. Did about 50 today.
I'm pleased as its a definite improvement. Looking forward to getting the tune sorted and see what I can get out of it. :)
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Went down a size on both pilot and main. Now the thing is really starting move. I reckon at least 20% more than yesterday.
Still not happy with the pilot jet (black smoke at idle and difficult to set the mixture) and I've got the next size down so will try that. Will also try the next main down. Lot's of petrol pissing out all over the place so I musta upset something during the change over. Will go through the process again tomorrow.
I've gotta find a suitable place to do plug stop (is that what you call it) trying to co-ordinate full throttle, clutch, turn engine switch off and coast to a stop without falling off is going to take some practice ;D
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If the bike gives out black smoke at lower throttle settings but runs well higher but the rev range, I’d check the float needle mechanism is seating properly, especially as you say it’s leaking fuel. Sounds like the carb is flooding.
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I took the carb off again and found I hadn't fitted the float bowl on properly. It's a bit tricky but seems ok now. Fitted the smaller pilot jet and I'm getting a bunch of main jets for tuning.
Also had to refit the petrol tap as it was weeping. I had the tank off and dismantled to get one of the rear lugs welded back on. All good now and itching to take it for a spin. The weather looks fine for tomorrow.
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I took the carb off again and found I hadn't fitted the float bowl on properly.
That would definitely cause flooding! Glad you’re sorted.
Snow here in U.K. today so no bike riding tfn.
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The float bowl issue was that the pin for the float arm hinge was sticking out and actually bent over. Totally weird as I never touched it. I'm sure it came like that but I cant be absolutely positive. Anyway, I had a pin lying around and fixed it. Lucky I didnt break anything. So I've got the assemble/disassemble/assemble thing going pretty well now. I'm down to my last pilot jet so I'll be able to make a decision on that. Still messing around with main jets and waiting for a bunch to arrive in the mail.
The power increase is really good. At half throttle the bike just keeps going. It's great. It'll pull to 100kph in 3rd gear, then shits itself when I twist to full throttle but that'll come good when I find the right jet. Dont worry, I'm not going to ride around at 100kph in 3rd gear, I just wanted to see what it would do. BTW, I have a H's close ratio gear set fitted and still got the 18t drive sprocket hence the quoted figures. Soon as the hill appears, I'm back to normal.
Looks like a fine weekend coming up so hopefully those jets turn up so I can finish the job. Thanks for your helps.
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18T sprocket on an Indian 350? :o That's higher geared than a stock 500 iron barrel (17T). The last of the Redditch G2 Bullets from 1955 with the 38T rear sprocket has 14T or 15T gearbox sprockets according to H's on-line parts books, compared to 16T for most Indian IB 350s.
Even with the carb jetted to perfection, the thing could fly through the first three gears and still run out of puff in top, unless you move somewhere nice and flat like the Netherlands! ;)
A.
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I agree, 18 teeth is pushing expectation to extremes.
My 350 has one (standard fit on its upgrade to a 5 speed gearbox), but I also fitted a 42 tooth rear sprocket, which compensates it to just about standard overall 350 gearing in top.
The engine will easily rev to valve bounce in third and get close to that in fourth. It cruises well at motorway speeds in fifth but I doubt it would would pull much taller overall gearing quite as well.
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The gearing is the next task on the Bullet list but it'll have to wait. I've got to get back to the Trailblazer and only started playing with the Bullet as a distraction. At least now I have a runner that I can ride, even if it does need a bit of pushing up the hill.
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Actually, watching Stinkwheel's video on changing his engine sprocket makes it look easy. I'll tackle it later though.
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From where I left it, three more nuts and you have the primary drivecase off. One more nut and you have the gearbox sprocket off. Usually a bit of gasket scraping to do behind the inner chaincase and possibly replacing the oil seal where the gearbox shafts come through (another three bolts).
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There's also a spacer behind the final drive sprocket that's necessary for proper gearbox operation. I found my drive sprocket nut a bit loose and this spacer chewed up, that was causing the gears to index improperly as the main shaft wasn't indexing correctly. If this spacer's not "clean", toss it and fit another. H's has all these bits.
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Thanks for the tips. If I get any more hold ups with the TB, I'll give it a go. I had in my mind that getting the clutch off was a bigger job than what it is. Thanks again.