Bonneville America Forums Forums Technical Forums General Tech Dreaded Idler Gear Boss

I am an owner of a 2004 Speedmaster. Been riding it for 4 years and put 30,000 miles on it so far. I tour a lot on it far far away from home. Not once have I thought about or laid awake at night worrying about this dreaded idler boss failure. This is due to the fact that I never knew it was a problem! It's winter in Canada which makes for good times in the garage prepping the bike for the summer. Somehow I finally found out about this potential disaster of a problem reading forum posts. I was wondering how much of a problem is this? Is it one of those things that happen here and there but now has people worried to the point of not being able to sleep at night knowing that this crucial piece could fail?

I am the type of person that takes pride in making sure that the bike is as reliable as it can possibly be but also I believe the the philosophy that "if it ain't broke don't fix it!"

Seems it is mostly from backfire at start. Don't give your bike any gas when starting.

It seems to be one of those rare "ghost" problems. Most people never see'em, but the ones that HAVE are real believers! But Ian's right, the few that have had this problem have backfire problems.

I wonder if its improper starting procedures? Bad tuning? My bike has never kickbacked that I know and that seems to be when they fail.

My 2003 Speedy has over 56,000 miles on it and I have never had a kickback. That being said, I am taking my engine covers off for powder coating and while they are off I am going to go ahead and install the TTP Safe Start. For the money it seems like cheap insurance.

It's rare...but if it happens its bad.
In UK TwinPower sell a simple to fit kit which strenghtens theweak boss....its around £100 which is worth having. For peace of mind.
Al

Has anybody on here actually had the problem? Does it fail the first time it kicks back?

The first thing to ascertain is do you have the early model that is prone to this problem. PIEMAN S website can help you with that. It does happen often enough to give this serious consideration and the peace of mind it brings.

just checked....yep, early model. That TTP part is a nice part. Too bad its buried in the case. Guess I will have to pony up the money and get one. Only thing I am afraid of is that I just change the crank breather seal a year ago. I wonder if removing the cover will hurt the seal?

https://youtu.be/EUXIsralXks how it's done

After watching that video with its riveting music, how could you not want to do it?

My 2007 america backfired regularly on startup for a couple of years, and almost every time for the last year but so far everything has held together. Strangely though the battery needed to be replaced about two months ago ( 8 years old ) and it hasnt backfired since...work that out..? I have heard that latter models,if you can call 2007 a latter model, were stronger in this area, dont know for sure though.

If it always backfired at start something is wrong and the longer it stays that way the shorter the life of that engine will probably be.

My '02 with around 30K has no problems. But it starts up like a gentle puppy...

If it's a 04 I don't think you need worry to much.As far as I know it was mostly the early 05 when they were using 790 cases for the 865.Thats the story I got when mine went.

My 2002 has not had this problem.
I don't have a lot of miles on it. Never backfires on startup.

Look at the back of the left side case...where the breather exits....if its got a box with rounded off edges, you've got the later strengthened cases...if not, its the earlier one.
Al

Outside the case or on the inside ?
A pic would be great, knowing we had a corrected case would alleviate that concern.

Just under the left carb behind the high part of the primary on the top of the transmission. Outside not internal.

Here you go.

The earlier design crankcase.



The later design crankcase.

A picture is worth a thousand words. Thanks Mike !