Hitchcocks Forum

I recently posted the following to Britbike forum and despite many views I got no replies at all. So I am posting it hear where the real experts are.

"My iron barrel 500 has been running like a hairy goat for ages and I was sure the problem was with the carby. A friend lent me his complete Mikcarb as his bike is identical to mine, stock standard except we each have POD filters. First thing I noticed was his needle is shorter than mine. Mine is 54mm and his is 46mm. I put his needle in and now I am riding a different bike. So I cut mine down to 46mm and rounded off the end. It runs ok but not as well as with his needle. Hitchcocks tell me the needle is exactly 50mm long so we have ordered 2. Has anyone else had experience with wrong needles. The other night, riding with my bodgied 46mm needle I tried full throttle only to find it jammed open and I had to ride to a street light (to fix it) by shutting the kill switch on and off. Had to laugh but! Turns out my shortened needle popped out of the needle jet, fell to the side and jammed the slide up. Another bodgie up got me home. Now waiting for Mr H to send my new one."

Hitchcocks have been very helpful with the info about the needle length and also they confirmed that the distance from the bottom of the needle to the lowest (richest) slot is approx. 46mm. Has anyone else ever heard of different length needles for the Mikcarb? Also before someone says it, I know cutting my needle down would not be too good as the taper was in the wrong place. What I should have done is cut 5mm from the top and. with the clip in the lowest slot packed washers under it to make it 46mm from the bottom. Another question: When I get my new needle and set the jetting as per Hitchcocks recommendations what slot do you suggest to start with. I am using a PO needle jet, 27.5 pilot and 3 slide. My main is a 120 as I have not yet got a 117.5 but I will probably change to that.

Hi I would try middle position first, 27.5 pilot worked well for me stopped bike stalling when cold. Hope your ign timing is spot on, 120 main should work ok with pod but I think main only comes on 3/4 throttle.you quite often find the port in the head is smaller than carby size and needs opening up one of my heads was 26mm from new bit of careful file work fixed it.if you go to mikunioz.com on the net they have a free download tuning manual, the micarb is a local version of mikuni. Best of luck.

Having read Creaky45's two solitary posts on BritBike I can understand the lack of interest by the community.

Throw away the cut down needle, you have destroyed it. You have removed a big chunk of the taper that controls fuel metering. Shortening it from the top is also a really dumb idea as the taper is in effect over a specific length of the needle.

Hey Beeza, Please explain what you mean by lack of interest. Which 2 posts? and, Tim, I am not being a smart alec (dumb idea you say) I was just after some serious information. I have been working on motors for over 50 years and I fully realize a carby is a precision piece of equipment not to be messed with by amateurs. However I am relatively new to Enfields. My carby was stock standard and original or so I believed. Mr H. informed me there IS only one needle for the PO or P2 needle jet for my bike and mine was WRONG. Tell me if you used a 41.5 mm needle in my carby it would pop out of the jet at full throttle like mine did, wouldn't it? I was suspecting poor quality control in manufacture of my Indian made bike, that's all and I was wondering if anyone else had had the problem. And bodging up my needle was only a quick fix to get the bike running. I am not using it till I get the right needle which can take 2 weeks delivery to Australia. I read the Hitchcocks forum a lot and have been wanting to join and ask a few questions but .......not so sure now

Hi Creaky gave you a bum steer email is [email protected] tel is 07 47712677. Postage internal aust is a lot cheaper than uk and they sell genuine parts as mikuni agents.

Hi Creaky,
I got good results by spinning a needle from a MK1 Concentric in the lathe [a drill would have done] and slimming it down a little with emery, before fitting it to my 500's Mikcarb. It took two attempts to get it right, but it has run fine since. It needed richening up slightly in the low and mid range and I couldn't wait for the post, as I was on a roll, so careful bodging can work. As already mentioned and you already know, the overall length is important, for safety as much as anything, but I am probably just an idiot who should be ignored ...

Scotty, No I gave you a bum steer. I am using a Mikcarb, not a Mikuni. I spoke to Mikunioz last week as I was going to buy a VM32. I had almost given up on my Mikcarb when I discovered the needle length problem. I am sure the Mikuni needles won't be the same but I will ring them again tomorrow to double check. My needle from Mr H should arrive this week anyway. And, Bullet Whisperer, don't let Tim NZ know you are making your own parts. But isn't that what it's all about. Good on yer. I have not got a lathe or I would have had a go. But to get the taper just right you would need a correct one to copy off surely. You must have used a lot of trial and error to get yours right. My problem was that the last thing I suspected was an incorrect needle and I have been farting around with jets and timing etc for years and everyone else's bikes ran better than mine. I even had an oxygen sensor connected for a while and it was no help. I'm sure I am on to it now and will keep you posted.

My new needle arrived but it did not solve my problems. It has a thicker taper than the other making it leaner so when I installed it using Hitchcocks specs (P0, 27.5 and slide 3) even with the needle in the richest slot it would not run from idle to half throttle. Kept spitting back. After every combination of my jets and needle position the best I could get was P2, 27.5 and richest slot. A 30 pilot did not help. It still floundered a bit on acceleration from quarter throttle so I fitted a washer about the thickness of half a slot under the needle clip and it is greatly improved. Maybe that's the best I will get. Three quarter to full throttle seems fine even though I don't have a 117.5 main jet yet. It has a 120 in it. I'm thinking my POD filter is too un-restrictive, more so than the S and B recommended by Mr H. and my POD makes it too lean. So, at present I have the standard slide (3- the only one I own)a 27.5 pilot, P2 needle jet with the clip in my new position 6 and a 120 main and it's going well enough I think. Also to lift the needle higher like I did I had to drill a hole through the round block that the cable connects to or it would not sit right down. I could have cut a bit off the top of the needle I guess.

Creaky, what part of oz are you in , I, m west of sydney.