Trans engagement?

[andyb]

Got the FJ up and running and went for a ride!  News isn't good.

First gear is not usable.  It'll allow you to go forwards, but any load at all has it not engaging.  Feels like it's trying to jump into neutral, but it never makes it.  More like the gears are not close enough together.  Lots of noise and a false, dirty neutral without falling cleanly out of gear.

Ideas?  i'm a bit upset and can't really think clearly about it, so I figured I'd bounce it off the collective.  Worn first gear, bad assembly, or am I missing something reasonably obvious like having a shift fork backwards or the like?  The bike shifts through all the gears nicely, and only has a problem in first.  I just put it in second and rode a bit to check other things (the motor isn't right either, guessing cam timing issues).

Sigh.


More specifics:

It's got the later(longer) shift forks in it.  I didn't see any wear on the shift drum itself, the grooves had nice square shoulders.  Didn't see excessive wear on the shift dogs/windows on any of the gears either.

If the motor is idling, it can stay in gear and does fine.  Any gas past a crack causes it to make a grinding noise and it feels like the chain's skipping (it isn't, works in the other gears).  My current guess is that I somehow missed a shim.  Looking at the fische, it appears that the mainshaft has half of the first gear pair pressed or otherwise permanently attached, so my guess is that there's a lack of sideways force on the 1st gear on the countershaft.  Makes me think fourth isn't sliding over far enough to properly engage for whatever reason.

I don't recall pulling the trans apart at all.  Just pulled the shafts out whole and put them back into the cases when I assembled it, but I suppose there's a chance something fell apart while I had it apart and I just put things back on the shafts improperly.  Certainly never used circlip pliers or the like to take anything apart.


Also, the motor is comically gutless below 3500 revs or so, cleans up and then runs after.  Guessing cam timing is out, despite measuring things a billionty times.  I didn't go over 6k rpm or so, but I'd guess I'm making no more than 35hp or so at most.  Cam timing is my first guess?  Cams are Megacycle 268-00 "street" cams.

The motor is a stock bore with low compression wiseco pistons.  Ring gap is a touch wider than spec, 0.015 instead of 0.012" (would have to check my notes to make sure) because of intended nitrous use.  Pistons measure 0.0075" in the hole with a stock head gasket atop.  Runs smoothly enough and appears to be firing all four cylinders (head pipes are equally hot across the board).

[racerrad8]

Andy,

There is a half thrust ring on the output shaft of the trans to control bearing movement. The output side of first gear also has a different back spacing and if installed backwards with not engage the cogs. After the bearing is removed, there is a thrust washer under the bearing between the gear that easily gets misplaced as well. No special tools needed for these issues as they will just fall off when you pick them up...

Also if you install the center shift fork backward it will not allow the first gear fork to fully engage the cogs as well. All of the position markings (L, C & R) on the forks should be facing to the right (clutch side) upon assy.

So, to determine the problem, you are least going to have to pull the bottom half of the case to access the trans & shift forks.

A quick check of cam timing can be done by pulling the timing and valve covers. put the timing mark on TDC and look at the cam position. The lobes should be parallel to the valve cover gasket surface. If they are not, you are off on timing.

Keep me posted and I will offer what I can, unfortunatley sound like you are in for a little more work...

Randy - RPM

[fj1289]

Crap Andy!

I figured I had gathered so many of the FJ gremlins that everyone else should be trouble free for a while!

Good call taking a breather and thinking on it a bit.  Don't let the gremlins see you get frustrated - just makes them hungrier!

Good luck!  Sounds like you'll have to split the cases for this one.   

Chris

[andyb]

Randy may have it right with first gear being on backwards or something.  Totally possible.

Chris:  one of the reasons why I've been so slow in working on it is that when I'm frustrated, I tend to break stuff, and I get frustrated pretty easily sometimes!  Doesn't seem to have helped completely though if I'm having this sort of issue

Will it not engage the gear at all if it's backwards?  I bench tested everything and it shifted really well, and went into each gear nicely.  Is there a way to tell which way it goes on the shaft?  I suppose I'll pull it down and look at it semi-logically some.

The half-round clip thing, just locates the bearing in the cases, yes?  I definitely remember putting those back in (and wondering if I was missing one, because there was only the one rather than a pair of them on that bearing!).

Ugh.  Do not want to pull the motor out again.  Wonder how doable it is to split the cases and leave the top end intact.  Ideally leave the clutch on too, or am I making more work for myself if I do that?  Seems that the motor has to come out, the oil pan has to come off for access to split the cases, the starter and alternator are likely best pulled also.  Trying to figure out how I can get it open with a minimal amount of screwing around as I'd like to be able to do it over like two days instead of having it open for weeks.

Pretty sure the shift forks are in correctly, I distinctly remember having to look at a bunch of pictures to ensure I had them oriented properly, but anything's possible.  Guess I'll tear into it in a few days with a camera handy and post a boatload of pictures to see what I can see.

For the cam timing, that can be done in the frame, so if I was smart I'd do a compression check and see if I'm super low across the board before I get the motor out.  Hrm.

[SkyFive]

I feel your pain Andy, believe me..I do. I just finished up my engine and am ready to take it off the work bench but now I'm worried. I took my transmission completely apart to replace the bushings, bearings and thrust washers on both shafts. The only thing I can add to this conversation is that I found excessive wear on the countershaft and first gear bushing. It had worn like a ball and socket allowing the gear to wallow latterally so much so that it hit the case. I ended up replacing the countershaft and first gear cog. My engine had a hard life apparently so my problems weren't the norm. I'm thinking your center shift fork is backwards. This would be a real easy mistake to make.

[racerman_27410]

i believe the lower half of the case can be removed without even taking the engine out of the frame..... no need to mess with the top end at all.

need to remove the clutch basket  but the alt can stay in place.


BTDT hated it.

[andyb]

I bet you're right that the bottom can be done in the frame, but eww.  Too difficult to get clean access to everything on assembly for me i think.  Five more bolts and the engine's out, and I'll be able to see what I'm doing.  Laying on my back and trying to cleanly take it apart and get it together?  Probably doable for some folks, but obviously I need more practice at getting things together properly

The real issue is just putting the motor back in, it's a heavy bastage.  Ah well, it'll have to happen anyhow.

On a more positive note, it didn't leak a drop for me.  How cool is that!

[Flying Scotsman]

Lots of pictures please.
It will help me when I do mine 

[racerman_27410]

I bet you're right that the bottom can be done in the frame, but eww.  Too difficult to get clean access to everything on assembly for me i think.  Five more bolts and the engine's out, and I'll be able to see what I'm doing.  Laying on my back and trying to cleanly take it apart and get it together?  Probably doable for some folks, but obviously I need more practice at getting things together properly

The real issue is just putting the motor back in, it's a heavy bastage.  Ah well, it'll have to happen anyhow.

On a more positive note, it didn't leak a drop for me.  How cool is that!

i found it was actually easier to load the trans with the engine more upright.... you can load the gear shafts in the lower case and let the shift forks hang down from the upper case  so they engage easily as you put the two halfs together with your yamabond seal all nice and pretty.


i've never personally done the repair " in frame " but i have split a case or two and bet that it could be done if one doesnt mind a little laying down on the job (how cool is that?). If i ever have to go inside again i will probably go that route.

KOokaloo!

[SkyFive]

Andy, your problems made me second guess my cam timing so I pulled the cam cover back off to double check my work. I remembered both "dots" were in the windows on the cams but more towards the edge than in the middle, if I centered either cam the other cam was "half a tooth off". Something Randy said rang a bell, "turn the cam and not the engine  (backwards)", which makes good sense as it relates to taking up any slack on the back side of the chain. The Haynes service manual does not mention this. Anyhow, I started all over and moved the intake cam one tooth and then turned the cam backwards after installing the tensioner and the timing looks much better, the dots are not centered but they are real close. I'd rather eat a Vegamite sandwich than have to do a job twice. Thanks! Andy and Randy.
Here are the after pictures, I don't have any before, all taken at TDC (of course).


Exhaust cam centered


Intake cam off center slightly towards the rear but still in the window


Intake cam


Exhaust cam


Lobe position

[andyb]

Those adjustable cam gears?

Part of the issue is that I can't run things at stock spec if I value my valves   Didn't think I was off this badly though... Dunno, haven't done anything to it yet, figure in two weeks or so I'll have a chance to tear into it.

Trying to get a waterpump on another bike and rebuild the brake on another.  That way I'll have something to go ride for therapy if I get frustrated with working on the FJ!

[SkyFive]

Those adjustable cam gears?

No, they are stock, unslotted gears.

Unrelated but worth mentioning; I thought I would save myself some work and check my valve clearance before installing the head on the engine. I installed the cams one at a time, checked the clearance and then moved my shims around and I had a dam near perfect .006 intake and .008 exhaust clearance on all valves.  When I pulled the cam cover off the second time I remembered that I forgot to recheck the clearance after assembly so I rechecked the clearance. It's now .004 intakes and .006 exhaust, I lost .002 after assembly.

[andyb]

Got it apart, and randy is the man.

This is a picture of the countershaft being held sprocket end down, with the sliding gear slid up to engage first gear on the end.  Bearing removed so I didn't drop the damned thing.



See the lack of engagement?  First gear was on backwards.

Here's how it's supposed to look:



Notice that the dogs stick through the windows with some room to spare.


Now to clean the sealing surfaces and get the bottom back together, not looking forward to that at all!