R1100GS 1999 starter not engaging properly

Hi all - this may be one for the electrical gurus.
My bike (as above) has had a very recent new battery and new starter motor. Initially the starter button was not cranking the bike and I have fixed that (corrosion in terminal blocks under front of tank) but in the process of looking at all aspects I found that the starter had shed a magnet so I fitted a new one (HC Cargo). The battery was also not doing well (3 years old) so I replaced that too with Exide AGM model from Tayna.
So now, using my CTEK charger I get the battery to full charge and when I press the starter button I just get a 'clacking' sound as though the starter pinion is not fully engaging in the flywheel. I have measured the resistance of the positive lead to the terminal on the starter and get 0 ohms and the same between the earth lead connection to the battery and the starter motor body, also 0 ohms.
If I connect a larger battery in parallel with the starter (i.e. +ve to starter motor terminal and -ve to engine block) the starter engages properly and the bike fires up as normal.
The starter on this bike has always seemed to turn the bike over relatively slowly whichever iteration of starter and battery I have been on.
I did not have this 'clacking noise' problem with any of the previous starter motors.

Any ideas what the problem might be?

Many thanks, Nick

Poor earth connection above the gearbox.
Remove clean up earth lead and casing and that should sort it.

When you changed the starter did you retain the small metal locating pin which ensures it is seated correctly? It sometimes gets jammed into the starter motor that comes out and is easily missed when you put the new one in.

Hi hops,

I think I did but I will double check. Thanks for the thought and suggestion.

Cheers, Nick

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kirby morgan said:

Poor earth connection above the gearbox.
Remove clean up earth lead and casing and that should sort it.

Click to expand...

Thanks Kirby, do you mean the earth connection under the battery housing on top of the crankcase behind the alternator? I can see it but can't see how to get it off without removing ABS unit and disconnecting a lot of electrics so I can lift up the battery box.

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Yes that's the earth lead from the battery to engine.
Had this before where I tried to use jump leads onto the battery terminals - clunk sound and no start.
Jump lead positive to battery +. Jump lead negative to a good engine ground and bike starts signifies a poor earth connection.
I normally just use the negative jump lead from battery earth to a good engine ground. If bike starts its a poor earth.
Bit of a long story but try it.....
You could run an additional earth lead to the gearbox/ engine if you can't get to the original earth connection.

Nick591 said:

Thanks Kirby, do you mean the earth connection under the battery housing on top of the crankcase behind the alternator? I can see it but can't see how to get it off without removing ABS unit and disconnecting a lot of electrics so I can lift up the battery box.

Click to expand...

Just whack a Decent jump lead from negative to the Exhaust Or top shock Bolt

If it spins over this way? Then you have a corroded earth You do not need to strip and replace the one you have Just fit an additional decent one

Just do this test with the tank lifted or removed and the seats off You just want to be sure that the starter spins easily

AS far as where to fit additional earth? Anywhere that you can run a cable to easily and get a good ground Distance from battery

Well the shorter the better but with a half decent bit of cable as far as the headstock should not be an issue

Thanks all. I will make up alternate earth and positive leads from battery to engine and starter and see what happens. If it is still the same should I suspect the new starter? I might see if I can put together an alternative starter from bits of a couple of broken ones I have. It's almost as if the spring resistance of the solenoid is too great to permit proper gear engagement, or the solenoid on the new one is binding somehow.

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Update. Cleaned all ring terminals on existing main leads and checked voltage at starter solenoid terminal (12.6v at battery 12.3v at solenoid lead from starter relay). Bench tested new starter - OK - no surprise. Starter dowel was in place. Cleaned corrosion off block bolting face for starter. With a fully charged battery it now engages properly and turns over at the same speed it always has and starts fine. Time will tell how it is if the battery is not perfect.
Thanks for all suggestions.

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Another update. Having eliminated everything else I finally decided to query with Tayna (supplier) whether the battery might be faulty since it was only 7 months since I bought it with a 12 month warranty. They agreed to take it back for testing (DHL collection at their cost). Apparently 50% of the batteries they have returned to them simply need to be charged up - so I sent it back fully charged using my CTEK 5A in AGM mode. After a few days they said 'they were in position to be able to supply a replacement unit'
This duly arrived and I fitted it today first ensuring it was fully charged.
It's like daylight after a dark night! What a difference! Even with my original starter the bike cranks much faster than it ever has in my ownership. The battery is an Exide 18Ah AGM with 250 CCA (rather than the 170 CCA of the 'BMW Enduroline' I had before. The higher CCA is the main reason I chose it.
Now I am going to refit the new starter and I may see yet more improvement.
I would recommend Tayna as a battery supplier - good prices, a wide range, fast delivery and, as I have now seen, good customer service.
It remains to be seen how long this one lasts!

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