Turbo Seca teardown and rebuild trevails.

As some of you may have read, I have an '83 Turbo Seca that's in need of some surgery.

The motor seems to be very strong. I've played with the carbs a bit (and found out that the choke was stuck!) and it's really running smoothly now. Only 12,000 on the ticker so she should still have a lot of miles in her.

Unfortunately, all is not so well with the tranny. 2nd gear seems to be A.W.O.L. When on the center stand, I can shift into second and it runs fine. However, when I try to ride it and shift into second, it just starts making some clicking noises and doesn't want to go anywhere. My geuss is that either a fork is bent and it's not fully shifting into second or second gear is stripped.

I asked some questions over at TMIOA and it sounds like there's no way to deal with this without pulling the motor and splitting the cases. I am by no means a serious mechanic. I can hold my own with the best of the shade tree guys, but I fear this may be well over my head.

Well, I found a motor and tranny assembly on eBay for $100 so I thought what the heck. I really have nothing to loose. Worst thing that can happen is that I can't get it back together and I have several boxes of parts to sell.

So I thought I would start this thread to discuss my progress and accept any and all advice from you experts!

Tonight, I started the disasembly. Removed the seat and the tank and dug into the real stuff. I pulled the battery and it's case. Then the air box and it's parts mounted to the frame.

I pulled the front part of the pipes. The nuts are as rusty as anything I've ever seen, but they actually came out very easily. They will be replaced on re-assembly.

Now come the carbs. I loosened the screws that hold the boots on each side and assumed that the carbs would just fall out of the frame at that point. Nope. So I realized I needed to remove the throttle and choke cablse. Still nothing. Eventually, I decided to pry the back part off. Not sure of the parts name, but it's the piece that connects the carbs to the airbox. Intakes? Finally got them off and the carbs still weren't even loose! I got a screw driver under one of the front boots and as soon as I got a little leverage, they came out.

At that point, I decided to call it quits. So far so good. I've tried to label everything as well as I could and took loads of pictures. No real surprsises yet. Not that it's gone smoothly, but it's getting there.

Some initial questions. Once I get the motor out, is it hard to split the cases? I know that my motor is good and don't know the condition of the one I got on eBay. I'd like to stick with my motor and just use either the whole tranny from the other motor or maybe just parts from it depending on how it looks.

Is there anything else I should do while I'm in here. The motor seems to run great, but I doubt I'll ever get this deep into it again. Is there any reason to pull the heads? Should I check things like rings? It does smoke a little bit. Should I even think about things like rebuilding the motor?

Finally, the heads on my original engine look a little rough. Not rusted, but most of the paint is gone. I was thinking of painting the heads and then sanding the ends of the fins. I was thinking that something like grill paint would be good to use. Any pointers or suggestions?

Thanks for reading this, I know it's long and you could be spending time riding your bike. I do appreciate your time.

Greg

 

Have you got a manual?

There are case bolts holding it together from the top and bottom. Keep track of where the bolts for the cases go. There is numbers stamped on the casings, maybe take some cardboard, cut an X to push the bolts thru, and put the appropriate number beside them.

I would decide what to do with the motors once you have yours open and see what's worn, bent, or stripped.

Your pocket book should be telling you how far to take things apart. The other problem would be sourcing parts. On my XJ750RJ, I was told that standard and 1st over pistons and rings are no longer available.

If you plan on keeping the bike, it may be worth your time to strip the motor completely down and check everything out. A complete aftermarket gasket set should be available for $100ish ??

Start doing some parts search for your model and add up the cost of material for what if scenarios.

Goodluck!

 

Sound advice Nick. I hate having to split the case but if your there, check it all out. Good time to replace that pesky starter chain tensioner! Greg, I don't think you'll have any problems. You've torn into car engines haven't you? Not too much different in my book. Having the manual is the single best thing you can get to take the bloomin' motor apart. I've used my Haynes to split two motors and never had a problem with the reassembly (did the cardboard trick, only way to go). Of course I should point out that I haven't had the second motor re-installed yet (that is about a month away) but the first one was fine until the stupid tensioner when tinkle onto my transmission gears. I have had reasonable success with BikeBandit sourcing factory parts but they are by no means the only source available. There are a few links on the forum that should be helpful to you. If you would like a list, I'll send you My Favorites list. Best of luck Greg, I fancy you won't need it however.

 

I appreciate the good advice and sentiments. I was just perusing bikebandit and they have a few parts I need but I see a lot of the infamous 'Discontinued $999.99'.

I do have the manual for my normaly aspirated XJ, but not the Turbo manual. I also have the XJCDs though which seem to fill in the gaps nicely.

So, the starter chain tensioner is something I should look out for? I will definitely take a look.

Any sources for parts would be much appreciated!

One more quickie. Anyone know what any XJ engine weighs? Can 2 guys safely pull one? Can one guy in a pinch?

Greg

PS when I take this thing for the first succesful ride, I'm buying everybody the cocktail of their choice!

 

The motor is heavy for one guy, but is doable. Two guys should be no problem. If I had to guess at the weight and I'm not very good at guessing, it's around 100 to 125 lbs.

I rebuilt mine on my workbench. When I was ready to put her in I made a small platform beside the bike at frame level. I was able to pick up the engine by myself, then said holy s$^t on the way down to frame level.

Sitting on bike, chest on frame where gas tank usually is, let your arms do the work on getting the motor into or out of position.

I found out the hard way that you need to have the oil filter housing off to get the motor in or out of the frame. You also need to have the stock air box in the frame before you reinstall the motor. It gets really heavy the more times you put it in and out in one evening !!!!

 

if you can use a rattle gun to remove the big nuts [alinator/clutch hub] much easier . and you'll need 2 different size torx bits too for in the gearbox to ease splitting the cases.. avagoodgoatit

 

Progress!

The motor is out. A good friend came over and we managed to get the lump out. Fairly brutal job. Several seriously rusted buts and bolts, most of which seemed to have been rounded by a previous owner. A couple of cans of liquid wrench and a lot of hammering on vise grips and it all eventually came loose. I have to say that I'm surprised at how big this motor is. Even though I've had this bike and my other Seca for ages and spent lots of time looking at them, I'm stll surprised at the size of the motor when seperated.

Next week I get the other motor\tranny and I'll dig into the cases. Pretty scary stuff. I just pray that the turbo itself turns out to be ok.

Greg

 

I'm hoping with you Greg. The turbos I'm familiar with (VW variety) are outragous amounts of cash to fix or rebuild. I would rather put up with having to re-ring the bugger.

 

Progress! Sort of.

This weekend, I finally got down to it and cracked the cases on my Turbo motor. In some ways, it was easier than I expected and in others more difficult.

I had to remove the timing plate, the clutch, the starter, the oil pump and all the covers and it came appart easonably easily. I was pleased that I was able to get it apart without removing the heads. In fact, I didin't even remove the valve covers.

I kept pretty good notes on how it all came appart and labeled all the bolts. The only concern I have is the clutch. Lots of parts!

Here's the problem. Now that the crank case is off, I can see everything in the tranny. Unfortunately, I can't detect anything amiss! Aaargh!

The only thing I've foudn is a small piece of alluminum that was in the oil pan. It was maybe 2mm square. I have not been able to determine where it came from yet. I don't thing it was big enough to be the source of the original problem.

So, what to do now? I guess I'll crack the case on the spare motor. At least I will be able to tell of there is anything different about it.

Do any of you have any ideas for specific things to look for?

Thanks,

Greg

 

I would check out the tips of the shifter forks. By the way, check out Fox's post on the parts column, he's offering a bunch of free parts you may want to swoop on.

 

The tips of the shifter forks do look a bit worn. How does one know if they need to be replaced. I guess maybe I shoudl just replace them regardless and be done with it.

Thanks for the tip about Fox's stuff. I think he has some things I can use.

Greg

 

As you turn the clutch by hand imagine your shifting with your foot and what what happens with the gears , they [the moving ones] should engage fully.

And as 2nd was the problem pay attention to that , something has to be not right as its all mechanikal movement , you got a pic of the bit you found?

 

You're bit of aluminum cannot be part of the shifter fork since the forks are hardened steel. I would look for stripped threads - could be the aluminum thread came loose. Also for mounting tabs to have broken loose - possibly from overtightening.

Hoonz is correct, it's usually the second gear fork that goes (replaced mine last year). You can engage it and see if there is any play between the gears along the center shaft - if so they will not clear each other properly and kick you out of that gear. If in doubt, pay the $25.00 for a new fork and put it in. You don't want to find out that second gear is shot AFTER you put everything back together.

Good luck.
Rob

 

I'm sorry, missed the aluminum part. With you on this one Rob. Could also be a part off of something else altogether unrelated to the tranny (here is to hoping).

 

I have finally made some more progress and taken some decent pictures.

I figured out how to remove the shift forks. To think I spent an hour trying to find some kind of fastener before I realized how easily they slide out!

I had been concerned about wear on fork 2 but the more I look at it, I'm thinking it may not have been the problem.



Anyone know how this should look?

I am far more concerned about fork 1. It is really chewed up on one side.



I've tried to get a good look at the surface of the gears wear that fork mates and it looks ok.



I'm thinking that the gears themselves are made of harder steal than the forks. A reasonable assumption?

I've added several more pictures of the tranny to my gallery. Please take a look and let me know if you see anything else that looks amiss.

The only other concern I had was that some of the gears appear to have a notch in them. I can't tell if it's supposed to be there or not.

Does this look normal, or should these gears be replaced:



The arrows indicate where fork 1 mates.

I've been considering buying this lot on eBay. I can't determine the exact condition of the parts but it's probably better than some of what I have and the price is right.

Seca Tranny


Anyway. Thanks for all of your help as always. Your advice has been more useful than I can even suggest.

Greg

 

Once again;
from decades of 'fooling with Turbos one can get a Garret or Mitsui Turbo Rebearinged for approx $100 from most any Competent Hiway Truck repair Shop.
Only dealers and their associates charge stupid prices..for a V common part/repair.
Truckers are discerning and Frugal... follow their example.
Caveat emptor seriously applies.

 

I guess I don't understand your post Danilo. I'm not looking for a Turbo rebuild. My problems are all in the tranny and I'm doing everything myself. I'm just trying to determine what parts to replace.

Greg

 

Whoa, replace the forks! I'm wondering why you are having the clearance issues with the second fork, that wear is uncommon, too high up on the fork. I would really take a very close look at the gear cluster adjacent to the damage, looks like a bad bearing or something got loose. The gears themselves look just fine, I would look for a missing circlip or similar securing hardware. As for your FleaBay link, you can get better for less. Did you catch up with Fox? I would buy new forks unless the used ones you score are perfect. Might be cheaper and get more parts if you source a complete motor or lower end. I've pulled motors for these at $75. Shipping added up but it was ever so worth a good motor (didn't have to tear it down, just pop an' swap!).

 

Thanks Robert. I actually have a complete spare motor. I was just hoping to not have to split its cases. Looks kind of inevitable at this point. I will probably just buy new forks. They're about $35 a piece at BikeBandit.

Here's something interesting. I emailed that guy on eBay asking the condition of the forks. He hasn't responded, but the price seems to have jumped from $30 to #65. Screw that.

Given the wear on these forks, do you think that explains the behavior I was seeing. To recap, when on the center stand, I could shift into 2nd and it would run all day. However, when attempting to ride the bike, 2nd would never really engage. Just a lot of clicking sounds. As if something were slipping or the gear wasn't completely engaging.

Thanks

Greg

 

Sounds about right. I would suggest you simply swap your upper end onto the lower end (the good one anyway) and run it. I ended up doing that on my Max after I lent her to my brother and he changed the oil and put 5 quarts in. Yahoo hasn't much sense when it comes to mechanics but his heart is in the right place. If you've a complete lower end already, you should be riding by now!

 

Hmm. I hadn't considered that. Assumign the parts in the other engine are good, you think it makes more sense to use that bottom end rather than replace any parts in my existing bottom end?

I guess that's a worthwhile consideration. I might still buy new forks. I still don't see any damage in my existing bottom end other than the forks though. What would be the benefit of doing this? I'm thinking that if I get new forks, I can just put this bottom end back together. Or are you thinking that there's probably some damge that I'm not seeing?

Still loads to do before I could be riding though. I still need to get all the gaskets and a set of clutch plates and springs.

Thanks Robert,

Greg

 

This may be deemed a stupid question, but how do I check the oil in my '83 Seca Turbo? It leaks a small amount, and I want to be sure I have enough in for a ride.

Sorry for the semi-thread hijack, but this is the only current thread here that deals with Seca Turbos.

 

From the owners manual:

Place motorcycle on center stand.

Warm up the engine for several minutes.

With the engine stopped, check the oil level through the level window located at the lower part of the right side crankcase cover.

Oil level should be between the maximum and minimum marks.


Manuals are hard to come by. I highly recommend you purchase the XJ cds. There is a link to them at the top of this forum. You will likely find all the info about your bike you could want.

Welcome to the group by the way. Nice to have another Turbo guy around. I have an 83 that I'm currently rebuilding as well as an 82 that I hope to get to some day.

Best,

Greg

 

Well Greg, the swap option is a gamble since the other lower end is an unknown (I'm assuming here, correct me at will). "One in the hand is worth two in the bush" comes to mind. If you've already got this one split apart and you can guaranty that there is no other damage save your forks in the case, you would be better served to save it with new forks and run the known unit. But that is only if you can guaranty it. Otherwise, split the other case and take a peak if your adventuresome enough, you'd only need to source a few new o-rings at this point to put it all back together. Of course the thought of two motors apart in close proximity is enough to give me the willy's so I would avoid that if at all possible or you have incredibly good organization skills and no children running about to muck it all up (if that is the case, you might have weekend employment at my mess, I mean, garage). Best of luck to you, wish I was there.

 

fork knackered , probaly twisted , get a newie and check recheck how it shifts visually...good luck...

 

What kind of oil are you running in your turbos? I just found out today my bike is mighty low on oil and I definitely need to pick some up. However, I've heard of issues between the oil and the turbo on these bikes, so I'm a little hesitant to just go buy something.

 

I use Shell Rotella T, but others don't like using synthetic.

I certainly don't mind you tacking onto this thread, but you'd get more responses if you created a new one. There are several Turbo owners here who might just not be interested in this thread and therefore won't see your question.

Greg

 

man, I wish I read this thread earlier.

That shift fork looks bad to me and I would say that is your problem. I don't do a whole lot with motorcycle repair but I do work on a lot of ATV's and have seen a few tranny problems. Generally if the tranny is stuck in gear or is hard to shift then you look for a bent shift fork shaft, if the tranny shifts into a neutral inplace of a gear then look for gear problems. When it shifts into gear but doesn't move (like yours) then look at the shift fork. False neutrals and not shifting fully into gear and just poping is comonly caused by weak return springs/bad shifter arm.

So after all that I will also add that on my first trany fix I swapped two of the forks, basicaly making one act like it was worn because it was shaped differently. The trany shifted fine on the bench but when the engine was running second gear didn't work right. At the start it would click and then started to slip after a few min. ride time, then soon it would not move at all. Sounds just like yours to me.


Now for the bad news. I was packing up the trany today and thought I better double check the forks, sure enough my #1 looks almost as bad as yours. I will still check on the shipping cost for you but I would not use the #1 fork which looks like the part you need anyways.

 

Fox, thanks for the input. I think the forks are the issue as well. Not to worry about yours being worn. I intended to get new ones anyway. A bit pricey though. ABout $35 a piece at BikeBandit. Anyone know any cheaper sources?

Greg

 

The gears are fine. Mine have the same groove. Probably some extra oil clearance. I'm not convinced the forks are steel. I'll put a magnet on em and see. It would be counterintuitive to run a steel fork on a steel gear, since there would be no bearing surface.

 

Mac, what do your forks look like? Do they show the same kind of wear as mine?

Thanks,

Greg

 

No. My forks have no scoring, and there is a "finger and pad" on both sides, no circular cuts. The top and bottom look almost alike. I think somebody fudged your tranny at some point. Double check lubrication to your transmission.

 

Hi everybody another newb,
Might be a bit late for this but the grooves in the gears are for identification
of the gear blanks during the manufacturing process, nothing to worry about.Something else that might help,if you want to check individual gears for tooth wear/damage, remove the gears from the mainshaft place on a table in the sequence they came off, do the same for the countershaft what i used to do is mainshaft on the left,countershaft on the right.Pick up main 1st gear and pick up counter 1st gear ,one in each hand then mesh the gears as they would in the trans and rotate them against each other if there is any damage or excessive wear you should feel it one more thing the gears have to be very clean and you should wear cloth gloves, trust me sweat makes a great corrosive on machined/ground parts. Well hope this helps someone, great site,glad i joined
xj650 turbo

 

I'm going to be replacing my shift fork for 2nd gear as well,
and I have a question.

Which fork is used to engage 2nd gear? The shift fork marked "1"?

Theres three forks so does the first fork control 1st & 2nd, fork 2 control 3rd & 4th, fork 3 control 5th?

I rebuilt my car's tranny and the fork setup was like this (however its not sequential like a bike tranny), but i just want to be sure so I don't need to be buying unessecary parts.

 

or more specifically, which part number should I be buying to fix the 2nd gear pop-out:

 

Look at the transmission schematic, locate 2nd gear and see which fork links into it and go from there!

 

Second gear is controlled by the selector fork marked with a '2' on it. Seems almost too simple but when I replaced my second gear - I replaced the middle fork.

Keep in mind, my Yamaha OEM part for second gear looks a bit different from the pic - apparently because of a design improvement that was made. In my case, I had an old '82 shift fork replaced with the newer OEM version. The '83 may have incorporated this design change. Either way, don't be too concerned if the damaged fork and your new acquired replacement are not exact matches.

Rob

 

okay,
so i guess fork 1 just controls first gear, fork 2 is 2nd&3rd, and fork 3 is 4th&5th?

Also yeah i did notice the part numbers had been different from the OEM, so knowing about the difference in appearance is useful, thanks.

Well anyways, it makes enough sense, time to get fixin