'77 Cases Will Not Fit Back Together

[Suzuki_Don]

For those of you that have had the cases apart on the GS motors I could use some advice.

I did a trial fit last night to see how difficult it was going to be to fit the upper and lower crankcase halves together. I fitted both of the transmission shafts with their respective gear and shifters forks, etc. to the upper case half (I did not fit the crankshaft). I then fitted the lower case half. It went on OK till the halves were about a 1/4" apart and then I met stiff resistance. It was going to take a lot of force to get it down, so I pulled the lower case off.

I then did another trial fit with the transmission shafts and gears removed. I struck the same problem. The rear dowel seemed to be going on OK, but the front dowel didn't seem to want to go in the corresponding hole for it. I was able to hammer the front of the lower case down (forcing the dowel into the hole) till the case flanges met OK (Don't worry I didn't hammer the aluminium case, I used a block of wood resting on the case and struck that). I had difficulty removing the lower case and had to use the "jacking bolts" to get the case off.

I took a measurement of the dowel (13mm) and the hole (13.04mm). I thought the hole might have closed in over the years, but my 13mm drill fitted in there and turned OK.

Sorry for being so long winded, but wanted my situation fully explained.

My questions for those that have fitted cases back together before.

Is it normal for it to be this tough to get the cases pulled down for the flanges to meet?

Is what I did originally OK and even though things seem tight pull the cases together using the 8mm bolts?

Or should I reem the dowel hole out a bit and could this cause any misalignment when the cases come together?

 

[gearhead13]

My cases were tight on the dowels as well, a couple taps and it went down ok. I wouldnt use the bolts to force it down could bugger something.
I just made sure it shifted ok and the crank turned ok before putting the bolts in. Are your dowels out of round, or covered with the suzuki bond (glue) stuff they used? Even my bearings were stuck together when i took mine apart. My dowels were a bit rusty, and I cleaned a LOT of sealer off the case mating areas, actually used a dremel with a sanding disc to get it off.
I used enough threebond on mine that I dont think it'll ever come back apart

 

[Suzuki_Don]

Thanks. I don't think my dowels are out of round, but I will check with the vernier tonight when I get home.

 

[Nessism]

I went though this exact same thing yesterday; the dowels and case half's corrode and often times don't fit smoothly together. On my engine I removed the dowels and used emery paper on them to smooth out the surface. Smooth out the holes in the cases as well as necessary. The dowels should fit easily into the hole in the case using hand effort.

Another couple of things worth doing before you actually assemble the engine are to clean all the threads with a tap, and clean the case screws and lubricate the threads with oil. Having the screws laid out in order really speeds along the assemble operation; always a good idea since you want to get everything assembled before the case sealer sets up.

Good luck and good job about trial fitting the cases together before applying the sealer.

 

[trippivot]

you have missed something- they should fit like mates.

hope you did not distort them from riding abuse before and or during the removal/ disassembling process.

get a straight edge and start checking for flat surfaces and twisting evidence- you might have a big problem

 

[Suzuki_Don]

I went though this exact same thing yesterday; the dowels and case half's corrode and often times don't fit smoothly together. On my engine I removed the dowels and used emery paper on them to smooth out the surface. Smooth out the holes in the cases as well as necessary. The dowels should fit easily into the hole in the case using hand effort.

Another couple of things worth doing before you actually assemble the engine are to clean all the threads with a tap, and clean the case screws and lubricate the threads with oil. Having the screws laid out in order really speeds along the assemble operation; always a good idea since you want to get everything assembled before the case sealer sets up.

Good luck and good job about trial fitting the cases together before applying the sealer.

Ed did you have any trouble removing the dowels, any tips. I grabbed mine with the vice grips but they did not want to move, so I did not persist as I was wary of damaging them with too much pressure.

Some other good tips there as well, I will make sure I get them done before reassembly as well.

I've made a list of the essentials to do before putting the cases together, i.e. fit new camchain over crankshaft, oil "O" ring between cases, lower cam chain guide.

Ed when the transmission shafts and crankshaft are fitted to the upper crankcase half is the sealant applied to the lower crankcase half before it is offered up to the upper half. You don't apply it to both halves do you, and if you were to apply it to the upper half the bearings, seals, etc. from the transmission shafts and crankshaft would get in the way. Right. Advice please. This is a first for me.

 

[Suzuki_Don]

you have missed something- they should fit like mates.

hope you did not distort them from riding abuse before and or during the removal/ disassembling process.

get a straight edge and start checking for flat surfaces and twisting evidence- you might have a big problem

I hope you are wrong. I will try and remove the dowels and clean them up a bit for a better fit. Also check surfaces with a straight edge for distortion.

As I said I hope you're wrong, Mind you I had a bit of trouble getting the cases apart. The jacking bolts were used to good effect for the removal. So maybe it's not surprising that it is a bit difficult going back together.

Thanks

 

[Nessism]

Hi Don,

According to the factory manual on the 1000, the sealer is applied to the bottom crankcase half. I used a small brush and spread the sealer as thin as possible. Sealer is only used on the horizontal surfaces, stay off the round areas were the bearings fit.

Regarding those pesky dowels, if they won’t come out easily you can wrench them out anyway and buy new ones, or try to clean them up while they are in place using emery cloth or a small file. Sandpaper rolled into a tube can be used in the case to clean out the bore as well.

Good luck.

 

[Suzuki_Don]

you have missed something- they should fit like mates.

hope you did not distort them from riding abuse before and or during the removal/ disassembling process.

get a straight edge and start checking for flat surfaces and twisting evidence- you might have a big problem

Hi Don,

According to the factory manual on the 1000, the sealer is applied to the bottom crankcase half. I used a small brush and spread the sealer as thin as possible. Sealer is only used on the horizontal surfaces, stay off the round areas were the bearings fit.

Regarding those pesky dowels, if they won?t come out easily you can wrench them out anyway and buy new ones, or try to clean them up while they are in place using emery cloth or a small file. Sandpaper rolled into a tube can be used in the case to clean out the bore as well.

Good luck.

Thanks Ed,

Just a bit of cleaning up of the crankshaft mains (two of them are a bit notchy) could be a bit of grit in there. Will need to wash them out with kero till they run smoothly. Then I will get ready to put the cases together. Also I need to paint the upper case and bake it before I finally fit them together.