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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: DaveA on March 17, 2010, 01:12:25 PM

Title: 84 gearbox issue, not sure what it is or how to approach
Post by: DaveA on March 17, 2010, 01:12:25 PM
Hi all,

I bought my FJ just before xmas, and it's done about 700 miles since after standing for a year.  With all the little niggles ironed out from it standing for a year, another, more severe one has emerged.  It keeps jumping out of gear under load.  This may only be recently evident due to the nice weather and more confidence with the bike, but when i hit about 7k rpm in second gear it pop's straight out, and i can feel the leaver smack the top of my foot as i do it.  It's done this for the last few weeks.  On the way home tonight it jumped on second, and on third as well.  I'm starting to think that something's deteriorating and i should maybe tend to it, rather than ignore it.  What could it be? What's the best way to approach it?  Where do i get internal spare parts for gearboxes? after lot's of searching i don't seem to be able to find any.  Any info would be appreciated.
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: Dan Filetti on March 17, 2010, 01:19:12 PM
Sure sounds like the common 2nd gear worn dogs/ bent shift fork issue.  Fixing it can be done at home but it's not a small job, requires removing the motor and splitting the cases.  While you're in there, replacing the shift fork with a new beefier one, you should also consider having your gears under-cut.  Alternatively, you can pay someone to do it for $600-$1200 or so depending on the shop rate.

Sorry to be the bearer of bad news....

Dan
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: tqmx1 on March 17, 2010, 01:25:09 PM
Or just short shift 2nd. gear.
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: racerman_27410 on March 17, 2010, 01:44:14 PM
Randy @ RPM (he is a member here) can get you all the parts necessary to fix the transmission.

you have to split the case to fix it but overall its not that bad a job.... worst part is getting the engine out and back in the frame.


KOokaloo! 

Frank
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: DaveA on March 17, 2010, 01:49:59 PM
Cheers for the replies so far guy's.  I was just short shifting for the time being, but third instantly popping out on the way home did get me a bit worried :(  Do you know roughly what the parts cost and man hours would be to undertake this in my garage? (so i can weigh up the options, sell and get a better one, or undertake knowing I have a solid gearbox!)  Never tinkered with a gearbox before but am very mechanically minded, so could probably figure it out with the help of some friends.....
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: racerman_27410 on March 17, 2010, 01:56:32 PM
Quote from: DaveA on March 17, 2010, 01:49:59 PM
Cheers for the replies so far guy's.  I was just short shifting for the time being, but third instantly popping out on the way home did get me a bit worried :(  Do you know roughly what the parts cost and man hours would be to undertake this in my garage? (so i can weigh up the options, sell and get a better one, or undertake knowing I have a solid gearbox!)  Never tinkered with a gearbox before but am very mechanically minded, so could probably figure it out with the help of some friends.....


its been awhile since i did mine but IIRC the parts were about 150.00  I got a brand new 2/5 gear set and three shift forks.

my old gears were not beyond service and your may not be either... i quality machine shop can undercut the dogs/windows of the 2/5 gear set  so they will lock up and the new shift forks are much beefier than the early model originals.


if you have some help i'm gonna say about 8 hours to do the whole job

Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: Pat Conlon on March 17, 2010, 09:28:51 PM
Hey Dave, yep, happened also to me back in '86. No getting around it, ya gotta fix it.
There is a step by step write up in our files section , here's the link:
http://www.fjowners.com/index.php?topic=666.0 (http://www.fjowners.com/index.php?topic=666.0)

(topic=666, yea, how appropiate)

Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: candieandy on March 17, 2010, 10:33:01 PM
fast by gast undercut 2nd and 3rd gear and shipped the whole trans back to me for 200 bucks. they did a great job.
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: fj1289 on March 17, 2010, 11:11:13 PM
x2 on work done by Fast by Gast -- quality people and work!
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: DaveA on March 23, 2010, 01:01:36 PM
Does anyone know someone good in the UK i should ship the trans to and get it sorted? :)  Confident (ISH) in removing it, but would rather pass the problem on after that!  Would i need an engine hoist btw to pick this lump up, or is it manageable with 2 ppl lifting it out? 
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: andyb on March 23, 2010, 02:51:18 PM
Engine goes down out of the frame, not up through it.  It's heavy enough, you could do it with one person but it's far more controllable and easy with a helper.
Title: Re: 84 gearbox issue, not sure what it is or how to approach
Post by: fj1289 on March 23, 2010, 09:21:47 PM
Good discussion on engine removal from a few months ago:  http://www.fjowners.com/index.php?topic=1222.msg9147#msg9147 (http://www.fjowners.com/index.php?topic=1222.msg9147#msg9147)

I like resting the engine on a stand of sorts (stacked 2x4's etc) and either lifting the frame over it (tie down straps from ceiling joists) or dismantling the bike around it and picking up the bare frame off it.  You can also pull the head and cylinders with the engine in the frame (have to "move" the clutch line a bit) to make things lighter and easier to maneuver out of the frame.