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Splitting Crankcase Halves and Bolt Identification

Started by DaveBrit, March 22, 2013, 09:17:12 PM

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flips

The broken bolt  in front of the pointing finger wont help keep the drive axle bearing secure..It almost looks like there may be a washer missing in between the drive axle end collar and the 1st gear wheel too.... :scratch_one-s_head:

Cheers  :drinks:

Jeff P
Stay rubber side down.

fj11.5

aww shit, i thought it looked like a locating dowel
unless you ride bikes, I mean really ride bikes, then you just won't get it

84 Fj1100  effie , with mods
( 88 ) Fj 1200  fairly standard , + blue spots
84 Fj1100 absolutely stock standard, now more stock , fitted with Fj12 twin system , no rusted headers for this felicity jayne

Dan Filetti

In my best technical jargon:



This thinger-a-bob is worn.

Dan
Live hardy, or go home. 

Dads_FJ

Quote from: Dan Filetti on April 07, 2013, 07:56:27 AM
In my best technical jargon:



This thinger-a-bob is worn.

Dan

Dammit Dan, I could have used the 10% on fork valves!  Do I get any points for calling the thinger-a-bob dog's?
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'92 Yamaha TDM850
'80 BMW R100S/Sidecar
'81 Yamaha IT250(H)
'77 Yamaha IT175(D)
'39 BSA WM20

flips

Stay rubber side down.

racerrad8

Hmmm...

Someone is getting close, but there is a fully describable reason.

Just over nine hours left...

Keep them coming.

Randy - RPM
Randy - RPM

andyb

First gear is not on the shaft in the proper direction.  There is an inside and an outside to it, though it does look like it goes either way and it will fit either way, it will not work properly if backwards.  The dogs will not fully engage the windows, and it'll jump out of gear on anything more than a closed throttle or high idle.

It's one of those things that you can really only learn about in one way...

racerrad8

Less than 2.5 hours remaining to claim your 10% discount at RPM.

I need to know the exact reason there is a first gear issue. Several are really warm, but there is a specific reason I am looking for. (popcorn)

Randy - RPM
Randy - RPM

andyoutandabout

Surely it must be the finger preventing the two parts of the cases from sealing correctly and thus allowing the gears to jump all over the place when prodded by the selector. Removal of the finger would allow perfect crankcase mating and avoid future injury to its owner.
Easy
life without a bike is just life

racerrad8

Okay,

Well, no one technically got the reason I could see the exact explainable issue of what was wrong with the transmission. I then narrowed it down to first gear but the main visual reason was still not revealed.

On the first gear driven wheel, the one closest to DaveBrit's finger is installed 180* out. As both Frank and Andy B stated it can only be installed one way. The easiest way to make sure you have that gear install in the correct direction is the groove machined into the outer edge of the gear below the teeth.



The groove must point away from the center of the engine and if you look closely it is not there in the picture.

Dan also pointed out the "thinger-a-bob", which is the drive cog, was worn. That angled "wear" is actually the undercutting of the factory gear on the drive side and is the 3rd gear cogs, that is normal.

The broken or loose bolts in this case did not effect the transmission operation.

As I gesture of goodwill Frank and Andy B, send me your email and I will send you a 5% discount code for use on my website.

Thanks everyone for playing and DaveBrit for taking a great picture.

I think we might have to start having a monthly contest like this, what do you guys think?

Randy - RPM
Randy - RPM

Dads_FJ

"I think we might have to start having a monthly contest like this, what do you guys think?

Randy - RPM"

Even though I was wrong I had a lot of fun with it. 
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'92 Yamaha TDM850
'80 BMW R100S/Sidecar
'81 Yamaha IT250(H)
'77 Yamaha IT175(D)
'39 BSA WM20

DaveBrit

I wanted to update this thread with a couple of things I found useful during this whole exercise.  Firstly, the separating the two halves of the crankcase.  To do this I screwed in two Allen head bolts (circled in the picture) and with gentle persuasion from a pry bar being rocked up and down (B), achieved some leverage to very minutely open the seam.  With the seam open, i inserted a 2mm thick piece of wood (from an old venetian blind) to hold it open (inserted where arrow A is pointing and behind the pry bar).  I then repeated this exercise every night after work for a few days working down the seam until with a very satisfying sigh the whole thing came apart (yes, i know, plenty of time on my hands).



The other thing I found useful was when I reinstalling the carbs it is very difficult to get an even amount of pressure across the four carbs for them to seat evenly into the rubber intake manifolds. To get the even pressure, I wrapped a block of wood that was just long enough to fit over all four carb intakes with a towel and then used my Toyota's scissor jack braced against the rear tank mounting location to appply gentle but even pressure to the carbs which pushed them in perfectly (when I say gentle pressure I mean tightening the jack with thumb and finger only).  See picture below.  The other pain was getting the air filter box back in its place.  This was greatly aided by undoing the seat frame on both sides at the bolt circled which allows the whole frame to hinge backwards (put some card/towel where it will pinch on the lower part of the frame to avoid scratching).  This gave me about another 3 - 4cm of wiggle room which was just enough to get the air filter box back into its place.



And the finished article looks like this:


racerrad8

Quote from: DaveBrit on January 20, 2014, 09:02:38 PM


Dave,

I just want o reaffirm that this picture is for "demonstration" purposes only as all of the case bolts appear to be in place in the photo above.

Randy - RPM
Randy - RPM

DaveBrit

Excellent point Randy. This was a staged photo during rebuild to show how I did it. As Randy says, remove all the case bolts before trying this!