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R100/7 Electrical starting issue - any advice?

SCBuckeye

New member
I am very well trained in mechanics, but I also dread any electrical/electronic issues.

I used to own 2 BMW's years ago, a 1968/2 500cc & a 1975/6 900cc. Rebuilt both engines (just top end on 900) and both ran great. I sold them both about 20 years ago when I had several small children - didn't want them to grow up without a dad.

Well...now they are all grown up, and the last one, the only one with any mechanical ability just purchased a used K100, so I decided to purchase another boxer.

I recently purchased, but have not ridden yet, a 1978 R100/7. It is cold here in Ohio, but when I tried to start it, it turned over but it wouldn't start, but it did a lot of "clicking" similar to when a battery is low. From the previous owner, he said the clicking was there (he told me before I purchased) but that it didn't affect the starting. Once the engine turned over, it started.

However, the clicking bothers me. Is it just the battery? It has a "Battery minder" on it and presumably working - I've had it plugged in now for 3 days. Should I purchase a small charger and try that first?

Is it the solenoid? And even if not, how hard is it to rebuild one of those? Finally, could it be worth the time now (as I won't be riding for the next few months during winter) to go ahead and pull the starter motor and solenoid and rebuild them both?

Any pointers, instructions, videos that you might know of to help?

BTW, there are no really reliable "old-school" BMW dealers nearby to get good advice!

I recently re-joined the BMWMOA last week just to keep up. Now, that my kids are all grown up, and I have one who also has a BMW, I hope to do some enjoyment riding and maybe even make some of the BMW meets. I love the Civil War history (Southern perspective) and may try hard to make the Gettysburg meet in April.

Just an FYI, the previous owner told me the clicking has been around for some time, but he was never bothered by it, because the bike always started.

Thanks ahead of time for any help you might give.

Jim C.
jlcampbell1@juno.com - Be sure to put "BMW" in the subject line as I never open emails when I don't know their source.
 
Three possibilities come to mind, assuming the "clicking" is a relay-sounding click, and not a heavy mechanical click like the starter nose gear bouncing off the flywheel due to the starter solenoid's failing:

Dying battery (load test: measure voltage when starter is engaged -- if voltage drops below 10V during cranking, replace)

Dying starter relay (easier to replace than trying to troubleshoot)

Corrosion at the spade connections in the plug beneath the starter relay (not uncommon -- this area sees road spray).

While it could be the starter, the old heavy Bosch starters are built like tank armor, and are generally reliable (both the Bendix and the solenoid). Unless the clicking noise is a heavy metal-on-metal noise, the starter would be one of the later things to check.

ps - one way to check for the source of the click is to pull the tank, and put your finger on the starter relay shell to see whether you feel the vibration from the coil pull-in bouncing. If you feel no vibration, you can pull the starter cover and put your finger on the solenoid body to see whether the clicking is there.
 
99% of the time it's the battery.

I might be inclined to reduce this to 95% as these bikes are getting older and older.

Remember that anytime a non-direct fuel injected engine is started cold it needs both extra fuel and extra air. On Airheads there's no fast idle cam and obviously no idle control valve so the extra air comes from your hand opening the throttle a bit. Serendipitously, opening the throttle a bit decreases engine vacuum and makes the starter's job easier.
 
My son & I share a 95 R100RT that had some similar starting problems.
The problem was intermittent.
There would be a clicking, the engine turned over as if it had a weak battery .
It sounded and acted like but was not a dead battery.
It was the starter relay that worked some of the time but not all of the time.
It was easy to replace, not costly and solved the problem.

Bob
 
Once the engine turned over, it started.

This says a lot. My '77 R100RS has always been the same way, meaning, if the engine will turn over at all, it will start.

Check the voltages of the resting battery and the battery under load. Any idea how old the battery is?

Check all of your electrical connections, they can get corroded. This includes connections to the starter relay. Shine them up, lube with some dielectric lube.

Good Luck, Welcome Back, and be sure to let us know what you find!
 
Welcome back to the fold Jimmy Lee.

So much of an airhead's electrical "performance" hinges on a sound battery. If you don't actually know how old the battery is, you'd be ahead to replace it outright, IMO. The /5 models had a fatal flaw built into their starter relay/ protection circuit that imitated the sound of a low battery charge (the clickety sound is know as "the cricket") but that issue went away with the /6. That isn't to say that your starter relay might not be at fault.

BTW, this is a great book if you enjoy reading about the southern perspective of the WBS. If you enjoy reading naval history it's a win-win.

Memoirs of Service Afloat During the War Between the States

by Admiral Raphael Semmes, CSN, 1869.
Captain of the CSS Alabama.
The Blue & Grey Press
ISBN: 1-55521-177-1

588713-M.jpg
 
I don't see how you can go wrong replacing the battery (except that it will cost a hundred bucks or so). Reason I say this is that it might already be close to its 4-5 year life, so you'll be needing to replace it fairly soon anyway. And, a dodgy battery causes so many strange electrical problems that it will have you chasing symptoms all over the bike. Lots of good feedback about the new, physically smaller, but better batteries. Odyssey is one brand. Nice thing is that you can install or remove them without having to remove the carbs and air filter or separating the frame (although you will have to do it one more time to get the old one out).

Next step is to clean up the wire connections on the starter relay (especially the red one). If that (and the new battery) doesn't solve the problem, a new relay from Motorrad Elektrik is $10. Like the above post noted, easier to spend the $10 and replce than to try and troubleshoot/repair the starter relay. http://www.motoelekt.com/chassis.htm (half way down the page).

Barron
 
OK, Where's the best place to purchase a battery? WalMart?

Any suggested brand better than any other?

Any local MC shop - closest BMW shop is 30 Miles away!

Thanks,
Jim C.
 
For sure not WalMart.

You do NOT want a battery that vents through the cell caps but rather has a connection for a vent hose.

That is unless you can find an AGM.

I'd drive the 30 miles.
 
I dont even put Wally World batteries on my lawn tractor, chipper, tiller, tractor, or UTV. Let alone something I care about. If that is the type of maintenance you plan on doing with your machine then we will direct our comments that way or not even waste my time. Folks above have given some good recommendations with an origianl type battery with the side vent hose or an AGM type battery such as an Odyssy (sp?) Anyway, shortcuts on these machines are totally possible but as with anything else, in the long run, you get what you pay for in quality, service, and dependability. God bless..........Dennis
 
This is the battery that fit my /6. I think you can shop around, but the shipping is included in West Coast Batteries' price.

http://www.odysseybatteries.com/battery/pc680.htm

I've had the PC 680 for about a year and a half and am pleased with performance.

There have also been good comments about Panasonic batteries on this forum. I thought I remembered Motorrad Elektric selling the Panasonics, but I did a quick look on the site and didn't see anything.

Lots of opinions on batteries. Doesn't seem to be single, perfect solution.

Barron
 
I dont even put Wally World batteries on my lawn tractor, chipper, tiller, tractor, or UTV. Let alone something I care about. If that is the type of maintenance you plan on doing with your machine then we will direct our comments that way or not even waste my time. ......Dennis

Wow! With that kind of a comment, I'll bet you influence a lot of people!

Perhaps you shouldn't have wasted your time - or mine!

Jim C.
 
This is the battery that fit my /6. I think you can shop around, but the shipping is included in West Coast Batteries' price.

http://www.odysseybatteries.com/battery/pc680.htm

I've had the PC 680 for about a year and a half and am pleased with performance.

There have also been good comments about Panasonic batteries on this forum. I thought I remembered Motorrad Elektric selling the Panasonics, but I did a quick look on the site and didn't see anything.

Lots of opinions on batteries. Doesn't seem to be single, perfect solution.

Barron

These Panasonics and Odysseys - what is their expected life - 3 years? 5 years? 10 years? All of this will have to be considered before I shell out $180.00 for a battery!

Thanks Barron, your remarks were quite helpful. I do plan on purchasing a battery before spring. Doesn't make sense to purchase one now and not need it for 4-5 months. That is also a consideration I have to make because I don't have unlimited funds - buy expensive would make sense if I lived where I could ride 10 to 12 months a year and used the bike for necessary transportation, but up here in the frigid North (Ohio) we maybe get 5-6 months and mostly for pure enjoyment.

I also, am not a "purist" in the sense that I want everything like factory built, but I am enough of a perfectionist that I want it to run smoothly and dependably (as my old 90/6 (I wish I had it back!!) did).

I don't criticize those who want a pristine BMW, but I couldn't afford it.

Thanks so much!

Jim C.
 
These Panasonics and Odysseys - what is their expected life - 3 years? 5 years? 10 years? All of this will have to be considered before I shell out $180.00 for a battery!

The answer is yes to all but it depends!! :deal These types of batteries have been known to fall off the "battery" cliff (sorry!)...they can die without warning. Lead acid batteries tend to give a gentle warning that things are turning bad. People have gotten 1-2 years out of them...some have gotten 5 years out of them. Understand that your bike's charging system was designed for a lead acid battery. These newer batteries require a specific charging profile in order to maximize life. What's the life lost?? Hard to say, but maybe you only get 90-95% of the design life...just a guess.

I've read on this list that some people have gotten 5-6 even 9 years out of a lead acid battery. Maybe other battery types. But it takes work. You have to have an electrical system in pretty good shape...clean connections, etc. They probably make it a point to drive it more than 5-10 minutes at a time and don't spend a lot of time in city traffic. Recharging the battery after a start can take some number of miles at 60mph in order to fully replace what was used up. Plus they use a battery tender.

So there's lots of variables on battery life - charging system heath, type of driving, battery care, and probably even luck. Not all batteries are built the same.

You're best bet is to find a battery that fits, that you can afford, make sure your connections are clean, treat the battery right, and buy a battery tender (smart charger) to keep the battery topped off when not in use. It sounds like you won't be riding full time during the year...I see a battery tender in your future for sure!
 
Panasonic LC-X1228P

Jimmy Lee,

Check this one:
http://www.tnrbattery.com/lc-x1228p-12-volt-28ah-panasonic-battery/ $90 + shipping

The Panasonic 28AH with nut & bolt terminals can also be found if you search other places online. Be careful of some pages that offer "Panasonic replacement" - those are cheaper and not as well made. I've been using the Panasonic LC-X1228P battery in two airheads for over 10 years. They are giving me 6 years of solid life and then I am replacing them as a preventive maintenance item even though they are showing no sign of failure. Yes, it is true that these type of AGM battery do occasionally have a sudden failure.

The Panasonic is a good fit; just slightly smaller than the OEM wet cell battery but just a hair taller than OEM. The terminals fit to the battery cables, and don't require adapters that the Odyssey needs.
 
Much has been shared about batteries, so here's two more cents. '74 R90S, and various other airheads in the past, have always used lead acid batteries. Way back got ahold of large battery tray so a garden tractor battery fit. I get'em at the Battery Store, type U-1R, terminals reversed, just over thirty bucks. Can buy'm at wallystore, but check the cold cranking amps at 0 degrees, should be around 300amps. I'm frugal, not cheap, so I gladly pay the thirty bucks. Last one was five years old and still cranked pretty good, but there was a spring sale. It's a tight fit, each to their own meds, have a prosperous new year.
 

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Seems like batteries are almost as clear cut as oil**, which tires are the best, or maybe, whether points top an electronic ignition (lots of opinions about what right looks like)!

I used a variety of lead acid batteries over the years. I went through a period where I used Sears DieHard lawn tractor batteries (you have to slightly expand the battery carrier). My last lead acid battery was the BMW OEM brand, the name of which escapes me at the moment.

I've been living in areas where I can ride 9-10 months of the year and often (like today) get the odd ride in even during December and January when there isn't snow.

But, when it gets below 40 degrees, my bike gets hard to start. Especially if it has been sitting in a windy parking lot for 8 hours or in the unheated garage for a week or more.

Over time, I've gone through the electrics and charging, cleaned everything up, replaced some key sections of wire, and added some extra grounds. I also sent my starter to Motorrad Elektric for an overhaul. Plus, I almost always kept the bike on the Battery Tender in between rides.

In the cold weather (below 40 degrees), I was never happy with the lead acid batteries. Cranked slow and didn't seem to have much staying power. I always felt the cause of the cold weather starting challenge was because the engine wasn't cranking fast enough.

So, in the summer of 2011, after having read much discussion over several years about the "new battery technology" (and most importantly, with prices dropping), I got the PC 680. I think it has been worth the expense. I think it is better in the cold weather than the lead acid batteries ever were. Also, during the summer, when I was riding nearly every day, I found I was only putting the Battery Tender on once a week (versus every day). I don't have any graphs, or measurements to conclusively prove the PC 680 is better. Plus, there are so many variables, especially with riding style, that I don't think anyone can say one type of battery is definitively better. I'm looking forward to the reported 6-7 year life and I'm hoping not to experience the sudden total failure from an internal break. I totally understand about the cost factor. In my case, there a limited funds available for an unlimited list of upgrades. But, I was never happy with the lead acid battery, and so far, am pleased with the PC 680.

Either way, with a new-to-you bike that has some electrical mysteries, getting a fresh battery (of any type) seems like a good first step.

Cheers,

Barron

** We are making progress in the oil discussion - thanks Kurt.
 
I put an Odyssey PC-680 in my '96 Oilhead and put the exact same battery in my '81 G/S. They crank better than anything I've used before and do not require trickle charging because they don't self discharge like many lead acids do. You do need to charge them up to the correct voltage periodically and longevity would benefit from an adjustable regulator. They like a slightly higher voltage. See specs.

That said I have the Panasonic sealed lead acid battery mentioned already in my '82 RS and it still takes a charge after five years or more now. When it comes time to replace it though, it will be with an Odyssey.

I get my Odyssey batteries here http://sepbatteries.com/pc680-odyssey-battery?gclid=CInczJWW16wCFdIAQAodtmYK7A and have yet to find them cheaper elsewhere. Someone will be along shortly now and find you a cheaper one somewhere else of course!
$108 bucks, free shipping. Game on! :nyah

If you want really cheap there is one here that should work. Other guys here use these with no big complaints. Good old universal batteries: http://www.staabbattery.com/product/sla-12/UB12220-V.html
 
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