1971 BMW R75/5: Which electronic ignition system?

[krisnys]

Hi,

Someone at a local shop has told me i should convert from point to electronic ignition, and they want to sell me the Dyna III system. I'm hesitant, both because i think the Dyna III system has a steep price (almost 500 USD / 430 EUR with the Dyna green coil) and because i'm not sure it will provide any real improvements over the original ignition system - provided it's in order and set up properly.

Should i convert to electronic ignition? And if so, which system is best? The Boyer Bransden Micro digital seems trustworthy and relatively inexpensive (150 GBP), and there seems to be some advantages to the Omega-system, although it will end up costing about the same as the Dyna III system. Are there others? What would you recommend?

 

[toooldtocare]

I removed the Boyer ignition that was on my R90S and replaced it with points due to timing issues. I then sold the bike to a friend that installed a Dyna III. It did start easier, but I still like points if they are set up right. My 78 R100RS had the Dyna III on it when I bought it, but it had also been converted to dual plugs. Unless you are doing that conversation, I think I would be inclined to leave it alone.

 

[20774]

I put a Dyna III on my /7 and like it a lot. I just used the existing coils, so maybe the cost can be reduced if you consider that. The Dyna retains the advance unit mechanism...I sort of like that. Others eliminate the advance unit in favor of a built-in computer curve. This can be beneficial if the retaining threads for the advance unit have been stripped or if the bike has a tendency to ping as was the case with the early R60 series.

An electronic ignition system that can independently adjust the spark timing for each cylinder helps with smoothness. Crank mounted ignition systems are the ultimate in smoothness since it doesn't work off the camshaft.

Anton discusses the range ignition systems here - http://www.largiader.com/articles/ignition/.

Snowbum has a range of ignition discussion here - http://bmwmotorcycletech.info/Ignition.htm

 

[RPGR90s]

Hi,

Someone at a local shop has told me i should convert from point to electronic ignition, and they want to sell me the Dyna III system. I'm hesitant, both because i think the Dyna III system has a steep price (almost 500 USD / 430 EUR with the Dyna green coil) and because i'm not sure it will provide any real improvements over the original ignition system - provided it's in order and set up properly.

Should i convert to electronic ignition? And if so, which system is best? The Boyer Bransden Micro digital seems trustworthy and relatively inexpensive (150 GBP), and there seems to be some advantages to the Omega-system, although it will end up costing about the same as the Dyna III system. Are there others? What would you recommend?

Its' all up to you. Electronic Ignition does provide some benefits over the points and condenser. BUT, if it fails, you're not riding home.

Both my R90s and R75/5 have the original points and condenser. I like adjusting points, setting dwell. But I was raised in Detroit, head under the hood as a kid, working on big block V8
's!

I once installed a Dyna III in my R90s, 25 years ago and could never get it to run right, so I switched back to points and have no regrets.

 

[1074]

Dyna

You can keep the original advance curve and allow the points to last a long time with a Dyna Booster. Very easy to install and maintain. Just check the points once in a while. At last check the unit was selling for around $65, but that price may have changed.

 

[jad01]

I have used the Dyna ignition booster with good results- definitely something to consider.

You don't mention the condition of your mechanical advance unit. If it is worn out, you may consider going with a Boyer electronic ignition system, as it eliminates both the mechanical advance unit and the points. I think early units had an advance curve that wasn't optimal, but the newer ones (within the last eight years or so) have a revised advance curve that is excellent. I put one in my /7 and really like it a lot. You can check with Rocky Point Cycle for pricing.

 

[6322]

Hi,

Someone at a local shop has told me i should convert from point to electronic ignition, and they want to sell me the Dyna III system. I'm hesitant, both because i think the Dyna III system has a steep price (almost 500 USD / 430 EUR with the Dyna green coil) and because i'm not sure it will provide any real improvements over the original ignition system - provided it's in order and set up properly.

Should i convert to electronic ignition? And if so, which system is best? The Boyer Bransden Micro digital seems trustworthy and relatively inexpensive (150 GBP), and there seems to be some advantages to the Omega-system, although it will end up costing about the same as the Dyna III system. Are there others? What would you recommend?

Can't speak to the Boyer system, but I've installed at least a half dozen Dyna III's with good results. Besides retaining the original advance, being able to eliminate the cam runout by having individual adjustments for each cylinder really can smooth things out. Also as the original points degrade with use, the electronic system doesn't. Where you set it, it stays. Some folks like to mess with things, like changing points and setting timing and dwell. I like to get it right and ride. Also regarding a possible failure of the electronic system, I always carry the original system (points plate, points and condenser), and a continuity light. Good luck with your decision, and enjoy that /5.

 

[tanker4me]

A pointless conversation?

Ten years, and 100,000+ miles on 3 Airheads, a '72/5, '76/6, both with points & condenser, & a '92GSPD with stock/pointless ignition.

Last year the /6 was converted to a Boyer Bransden ignition on recomendation by a local Airhead Mechanic/Guru.

2 condensers on the /6 had failed in less than 5000 miles. I mentioned it to the "Guru", who up until then had recommended staying with points/condenser.

There was a rumor (origin unknown) that some inferior condensers (origin unknown) were in the supply system.

With about 6000 miles on it, I'm happy with the performance, & can switch back to points & condenser if needed.

I bought it from Rocky Point Cycle. They have other stuff for Airheads!

 

[cseltz]

I don't put nearly the miles on that some of you do but I did install a Dyna III when I set my '76 R75/6 up around 4 years ago and it appears to be one thing that is pretty spot on on this bike. I left the original coils and I think I paid $150 for the unit still new in the box but bought from a private seller (bought but never installed).

 

[SCBuckeye]

I had Dyna III on my R100/7 and never had an issue!

 

[ebeeby]

The 1973 R75/5 here came with Dyna ignition when it arrived in 2005. No issues.

 

[happy wanderer]

I think the guys steering you to the Dyna booster are on the right track. I've been reading of a lot of Boyer and DyanII and III ignition failures and they sound like a right PIA to diagnose whereas the Dyna booster increases your spark intensity, is very reliable and takes all the high current load off the points completely turning them into a simple low current switch that needs cam lubrication and not much else. IF the booster fails which is very very rare one wire moved back puts you back on the points and down the road you go.

 

[lmo1131]

Okay, I'm a Luddite, I admit it. Original owner of my '73 R75/5. Points & condenser the whole time, daily rider, runs like a top (except for that one time I got a set of those cheesy Chinese points). Spares are in the tool tray. YMMV.

 

[tanker4me]

I've been reading of a lot of Boyer and DyanII and III ignition failures and they sound like a right PIA

After reading that, and having had a Boyer Microdigital ignition installed on my '76 R90/6 last year, I was concerned about my choice.

The mechanic that recommended the Boyer ignition has been right on most things AirHead related. He is a local BMW AirHead/Kbrick "Guru"

Boyer has been around for a long time. I installed a Boyer on my '77 "tuned" 100 octane gas or it'd ping like crazy, Bonneville back in '79.

When I searched for Boyer ignition "failure", and variations of it, most of what I could find were references to troubleshooting. The only outright "failures" found were references to a couple of Yamaha XS650's.

New Dyna dual output coil, plug wires with NGK caps replaced the old at the same time the ignition was installed. It starts and runs better, and there hasn't been a hiccup yet! (less than 6.000 miles)

The '92 R100GSPD, '08 WR250R, and every other vehicle I have owned manufactured after '84 have EI. Just about all the electrical (ignition) bits except the EI have had to be replaced on them.

If anyone has experienced an EI failure on modern Boyer or Dyna EI, post up here.



View attachment 63390View attachment 63389

Back in '73 President Nixon saved my life!

Indirectly of course, by lowering the speed limit to 55 mph. My first car was a '55 Bug with compression in 1 cylinder.

View attachment 63373

Edit; A good chassis ground is essential for just about everything thats electrical/electronic, and the first thing to check when problems arise.

 

[20774]

I've had one Dyna III failure. I was on a trip quite a few years ago and after encountering some rain, the bike would only run on one cylinder after a gas stop. I did some troubleshooting and found that one side wasn't firing. I was an idiot and didn't bring the original points setup with me. I used the Anonymous Book (it was only the paperback at the time) and was helped greatly. I was taken to another Airhead's house where a /6 was leaning up against the wall. I was allowed to take parts I needed which got me back on the road...after my trip, I mailed the parts back and put the Dyna III back on. Fast forward a number years, I began to have more one-sided firing issues. I purchased another Dyna III which is still on the bike...plus I have another spare sitting in a box.

As near as I can tell, I think the original problem was some kind of grounding issue. The Dyna plate needs to have good contact with the engine to ensure a good ground.

BTW...I now carry the original points/condenser/plate with me on the bike!

 

[jad01]

I had a similar failure with a Dyna III (20+ years ago). Turned out that it was one of the magnetic pickups (sensors) failing.