NLM performance pick up

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harrymuffin
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Re: NLM performance pick up

Post by harrymuffin »

I made some printed circuit boards (12+) as suggested on the Dutch site and tested a pair with coils from the MZ 250 and it worked well, but never got round to potting the boards in a suitable box and are in my electronics drawers getting knocked about. I also rewound some pickup coils which worked, but lost interest. I have only - touching my head - only had one transducer failure, it it would cut out at tick over but clear itself once the revs picked up, oh forgot, I had to rewind an ignition coil on the hybrid which has 350 transducers.
SoloFrenos
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Location: Mazarron, Spain

Re: NLM performance pick up

Post by SoloFrenos »

Well I put the old boyer system back on and she runs like a dream ( thankfully not a super dream!!). Which basically rules out plugs and ht leads (and any carb/fuel issues). So my problem is with the coils, black box or old pick up. Having spoken to Anne at SWF I must admit I'm very tempted to ditch it all and get on of their fully programmable system. However at moment just happy to have a beautifully running Moroni again ☺
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72degrees
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Re: NLM performance pick up

Post by 72degrees »

SoloFrenos wrote:Well I put the old boyer system back on and she runs like a dream ( thankfully not a super dream!!). Which basically rules out plugs and ht leads (and any carb/fuel issues). So my problem is with the coils, black box or old pick up. Having spoken to Anne at SWF I must admit I'm very tempted to ditch it all and get on of their fully programmable system. However at moment just happy to have a beautifully running Moroni again ☺
Tell me about it ;)

I spent this morning swapping NLM 'modules' between bikes. One is definitely duff. The coils are very simple devices and my experimentation suggest that with a 'module' any 4 -6 ohm coil will do the business. To be fair with the larger earthed to the frame jobbies NLM now supply (and a Mk 1 box) the project bike starts amazingly easily and idles at a speed lower than a very low thing.

How much do SWF want for their system?
SoloFrenos
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Re: NLM performance pick up

Post by SoloFrenos »

I was quoted 160€ + p&p for the unprogrammable version and 200€+ p&p for the fully programmable one. The only downside I can see (other than it running off the battery, if that bothers you that is) is the fact that you cannot adjust the two pick ups to time the cylinders individually. However that is only the same as the original system, and probably not too much of a problem with my soft tune 375 with 'M' cam. Oh just as a note, it is not a wasted spark system.
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72degrees
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Re: NLM performance pick up

Post by 72degrees »

Sounds reasonable. The programmable one might be interesting on my 'tuned' beasts. Now I have the FE bike running well I may undo all my good work by trying the NLM pickup I have again. *If* I can get it to run at all I'll report back on whether timing the cylinders independently gives a real benefit.
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72degrees
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Re: NLM performance pick up

Post by 72degrees »

Well I never. As my second NLM module is back with them (a complete mystery which may require taking the project bike to NLM on a Saturday morning, when Ollie is there, to demonstrate the conundrum of it being the only variable preventing proper running although he says it is OK when they test it ) I thought I'd try the 'performance' pickup again. It was pretty obvious that the clearance between 'rotor' and 'bobbins' was too great so I took it apart and used a dremel grinder to elongate the slots. Not very impressed with the design to be honest. The plate that allows timing adjustment for one cylinder also affects the clearance and works pretty well but the 'fixed' bobbin (though the whole back plate can rotate to adjust the timing on that one) needed easing a fair bit to get somewhere near a 2 thou air gap. I also enhanced the rather dubious soldering on the bobbins common earth lead and supplemented it with superglue and an extra layer of hot glue gun as sealant.

The rotor 'hole' needed easing to be a reasonable but not too tight (as supplied) fit on the camshaft nose. Guessed which way round to put it. Got the gaps looking 2 thou(ish) on both bobbins just by eye (though using my grandfathers hooded jewellers loupe). I had set the back plate slots in the centre so then I connected up the OEM transducers (I even remembered to hook up the correct pair of HT leads). More in hope than expectation I gave it a prod - nothing. Another more vigorous kick was rewarded with a faint splutter. Hmm, a cool afternoon so I put one starter jet of the PHBH28s on and a really lusty kick was rewarded with an engine running on two cylinders. Not terribly well though, so I had a look at the gaps and closed the rear cylinder one up another gnats cock. Much better though still not willing to idle, but it revved reasonably well once warmed up a bit. I shall now invest in a set of brass feeler gauges to finalise the gaps (might possibly need even more slotting on the 'fixed' bobbin plate) then break out the strobe.

I suspect it will definitely always need a faster kick to start than with the OEM red type 2 pickup but on the hill climber that's not such an issue as there is often a reasonably steep hill to bump start down, or willing helpers available. I think I shall keep the road 375/2C on a red pickup - or go for the SWF setup. Anyway, I'm really quite pleased with my 'fixing' - very much in the spirit of the book I am currently reading: "The Case for Working With Your Hands" by Matthew Crawford .
3potjohn
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Location: Devon

Re: NLM performance pick up

Post by 3potjohn »

Well done but...blimey what a performance. Think I shall stick with the stock components.
Papa Lazarou
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Location: Sussex

Re: NLM performance pick up

Post by Papa Lazarou »

brass feeler gauges aren't that hard to find, btw. http://uk.rs-online.com/web/p/feeler-gauges/4504326/
JonD
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Re: NLM performance pick up

Post by JonD »

Suggest you check the timing with the strobe now that you have got the bike running because I found the air gaps change every time you rotate the backplate - the fit tolerance of the plate in the casing is close to the air gap. May save you one more adjustment. I always check the air gap before starting after moving the back plate to ensure the rotor doesn't hit the bobbins. I think it is worth persevering now the bike runs. Did over 100 miles on Sunday, starts easily, very steady idle and a lot of fun to ride.
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72degrees
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Re: NLM performance pick up

Post by 72degrees »

JonD wrote:Suggest you check the timing with the strobe now that you have got the bike running because I found the air gaps change every time you rotate the backplate - the fit tolerance of the plate in the casing is close to the air gap. May save you one more adjustment. I always check the air gap before starting after moving the back plate to ensure the rotor doesn't hit the bobbins. I think it is worth persevering now the bike runs. Did over 100 miles on Sunday, starts easily, very steady idle and a lot of fun to ride.
That's a very good tip - thanks.
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72degrees
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Re: NLM performance pick up

Post by 72degrees »

Well my 'by eye' adjustment wasn't miles out, but armed with RS Components brass feeler gauges, as you might expect, I had to get the air gaps even tighter. This necessitated a bit more easing of the slots on the 'fixed' bobbin. Starting easier now, but I was wondering if such a tight clearance survives getting really hot? Then the 'rotor' is pretty small and I suppose the whole back plate expands at a similar rate as the crankcase does.

My rheumy old eyes have a problem seeing the timing marks, even with my Gunson strobe and super strong reading glasses, but it seemed pretty near spot on for the rear and a tad advanced for the front. I've tweaked the adjustable bobbin round a tiny bit and will test it again tomorrow, but inside the garage, to minimise extraneous light and keep the noise of 6000 rpm down a tad for my neighbours. This is all hooked up to OEM transducers, so for perfection I ought to wait until I rig up the NLM module again. They are sending me another one to the latest spec. so I hopefully won't have to borrow the one off the 375 again. Showing promise, but it does require a good sharp jab on the kickstart (with transducers anyway). It's all a bit fiddly though, so I'm still inclined to try a SWF system (on the road bike first).
JonD
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Re: NLM performance pick up

Post by JonD »

SoloFrenos asked if anybody had experience of the Marcus Heilig pickup. I decided to get one of them while I was having trouble setting up my NLM pickup. Marcus (MH) seems to make them in batches and you may have to wait if he doesn't have one available. To put the rest of this into context I did get the NLM pickup to work and the bike has run very well for 4 months without adjustment. It does require a faster kickstart speed compared to the old red pickup and I couldn't get it to start on the electric starter - could be my battery isn't good enough!

The MH pickup arrived last week and I fitted it to the bike. Very straight forward and I had the engine running in an hour. The engine starts on the electric starter hot and cold. For what its worth here is my comparison of the two pickups.

Construction: MH - very robust machined back plate with secure coil fixings. Coils adjustable to get correct timing. Coils don't seem to be potted so look as though they could be rewound. Resistor and diode mounted on top of coil so can be converted to a black pickup - and vice versa- instructions supplied. Only back plate and coils supplied, have to use original rotating magnet. The wiring is a bit close to the magnet so I taped it back to make sure it didn't catch on the magnet. NLM - not quite as robust construction but adequate for the job. Complete assembly of back plate and rotor supplied. Suitable for both red and black pickups without modification. Coils adjustable to get correct timing. I believe spare coils and rotors available from NLM.

Set Up: MH - very straightforward, same as replacing an original. Placing the securing screws in the middle of the slots was close to the correct timing. NLM - requires very careful setting up and close clearances to get it to work. Took me some time to get it to work but I can set it up reasonably quickly now after several earlier "practice runs".

Cost: MH - Best part of 200 euros with post and money transfer fees to the UK. NLM - about £145 with vat, etc.

Performance: I can't detect any difference in performance on the road. Engine runs smoothly and revs to the limit cleanly with a nice steady idle with either. NLM requires a higher kickstart speed.

Verdict: Happy with both but I will keep the MH pickup fitted for now for the convenience of the electric starter in case I stall the engine. I usually start the engine using the kickstarter. As they say: pay your money and take your pick.

I used Transferwise to transfer the money to Germany. Very impressed with the service - made the transfer request on Sunday evening and the funds were in the German bank account on Monday afternoon. Good exchange rate and low transfer fee of £1.59 - the banks and paypal will struggle to compete with this
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72degrees
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Re: NLM performance pick up

Post by 72degrees »

Very helpful. I'm intrigued by mention in the instructions of a 'support bearing' for the mechanical tacho drive. Neither of mine have one - with tacho drive cover taken from a 250. Should I be concerned?
harrymuffin
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Re: NLM performance pick up

Post by harrymuffin »

All the mechanical drives should have an outrigger ball bearing housed in a bracket that clamps the pickup, as the ends of the camshaft have been known to snap off. It was highlighted in the club magazine in the last century when a chap on holiday spent ages kicking or start motoring his bike and only on checking did he find that the magnet on the end of the camshaft had dropped off because of a lack of outrigger bearing.
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72degrees
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Re: NLM performance pick up

Post by 72degrees »

harrymuffin wrote:All the mechanical drives should have an outrigger ball bearing housed in a bracket that clamps the pickup, as the ends of the camshaft have been known to snap off. It was highlighted in the club magazine in the last century when a chap on holiday spent ages kicking or start motoring his bike and only on checking did he find that the magnet on the end of the camshaft had dropped off because of a lack of outrigger bearing.
Not shown in the 250 twin parts list (that all use a mechanical tacho). Did the later (than 82 in the case of one of mine) 250s? Oh well, my 375 has lasted without one for 35 years so no point worrying now, though I'm careful to check that the special nut is clamping the pickup rotor properly with washers as required after one came loose soon after first putting a 350 motor in and swapping the drive over.
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