For quite some time my bike has been having trouble starting (turning over) when the bike was hot. It has continuously been getting worse. At one point I thought it was the battery so I bought a new battery. I even got a more powerful one than listed in the book. There are two Yuasa batteries that fit the bike. The one listed in the book is the YTX16-BS, which is 14 Ahr, 230 CCA. The other is a YTX20CH-BS, 18 Ahr 270 CCA. Much better. They go for the same price, so there is no reason to use the weaker one. This newer, stronger battery helped, but the condition continued to deteriorate. Finally, I had to bump start the bike every time I got gas. This was unacceptable.
I knew this was a known problem. The question was, can useful information be found on the internet? Sure, amongst a bunch of baloney. If a bike is turning over slowly, there are a few things that it could be. There could be a problem getting power to the starter, the starter could be faulty, or the engine could be causing increased load when hot. My thoughts are that all of these are probable, since the bike is used a lot in New England winters. The key was finding the major cause, and fixing the minor ones in the process.
From everything I could find on the Mis-Information net, the original starter motor for my bike is Triumph Part Number: T1310060, the actual manufacturer/part number: Denso/428000-5540. Both these sets of numbers are listed on the side of the starter. This part has been superseded by Triumph Part Number: T1311112, the actual manufacturer/part number: Denso/428000-5542.
All indications are that the original model was poorly designed. The brushes wear fast, and also tend to clog up the commutator on the rotor. This means that the starter will wear out or become a poor performer fairly early in its life.
The on-line parts dealers currently specify the Triumph Part Number: T1311112 for $402. Talking to the dealer, the part number is T1316677, which looks like a new part. It is also $150 more expensive at $554. AND back ordered. So, I could have what was the correct part a few months ago for $402, or I can wait an unknown number of weeks (probably a lot of weeks) for a potentially improved part and pay an extra $150. I chose to get the earlier part.
The process for gaining access to, and removing the starter is quite involved, requiring removal of the fuel tank, air box, battery, fuel rails and more. This is easy, but time consuming. I looked into removing it without taking apart too much. There is a way to do this, but there is very little room and rather difficult. Since I had to do some long overdue service anyway, I decided not to try the shortcut. Bit, if anyone wants to try, there is a page showing how to do this here:
Removing and disassembling the starter showed that the inside was a mess. The brushes were gone, the commutator was clogged:
The Brushes were worn to the wire, and at an angle. I am amazed it worked for this long.
The Commutator on the armature. Also in pretty bad shape. I am not sure why the unit would look this bad, nor how it worked for this long.
It took me 4 days to get the starter from the dealer, not bad. This was the $400 starter, not the new starter made out of unobtanium.
All in all, I wish I had replaced this starter a year or more ago. Mine lasted longer than most of the failures I am hearing about, but then I probably have more miles on my bike than most, and tend to put up with "quirks" longer than most.
After replacement, the bike sounded like the starter was supercharged. I had not realized just how bad it had gotten.
There is lots of information on various repair parts, methods of repair and replacement on the following site:
The starter tucked away behind the engine.
You cannot see it here. It is behind the gold shock reservoir.
The green blob is the starter motor
pic pilfered from the mis-information net.
All this stuff had to be taken outo to get at it. Even then it was not easy.
The starter, with the part number shown.