GS1100E transmission swap upgrade into GS1000 engine?

[Chuck78]

Is it possible to swap a GS1100E or other newer transmission into a GS1000?

I know the 1100 gearboxes used more dogs to give quicker gear engagement. I'm building up a GS1000 1105cc engine and want to do everything the best I can within reason the first time, ESPECIALLY everything requiring splitting the cases.

If not, I have a race prepped but abused GS1000 transmission with a broken tooth in 2nd and very hammered dogs in another gear, as well as a stock GS1000 gearbox in the mail $30 shipped...

Is it worth having the gears back cut? The engine will be:
66mm stroker crank and 1085 pistons for 1105cc 10.4:1
Yoshimura Isle of Man .365" lift cams
79 1000 head or 1100G D-port head, rapid ray ported
Keihin CR31 smooth bore carbs
Yoshimura Series-1 GS1000 4-into-1

This is going into a Rickman CR road race chassis for now. If I race more seriously, it may go into a GS1000 frame or a Harris XR69/Magnum F1 frame or similar.

thanks,

Chuck

[GregT]

Reviews at the time said the transmissions were identical except the 1100 used a different/better heat treatment - and shifted better.

I've never had them side by side to compare. I do know a guy here blew the box in his race 1000 and swapped in an 1100 one. Never got the chance to ask if anything else had to change.

[Chuck78]

The only big red flags for me was that the clutch basket sits out so much further on the 1100E that the primary gear on the crank us outboard so much that it traded places with where 1 of the GS1000 main bearings would sit on the crank, & the 1000 clutch basket was not as deep as the 1000G/1100G/1100E clutch basket, so the shafts were likely different lengths I assume.
I might see if I can snag a cheap 1100E gearbox off eBay to compare.

I do have an 1100G engine here, so I'll have to first compare the part numbers for the gears on the parts fiches to see if the gears from the 1100G are the same as the 1100E. Then try swapping them onto the chain drive/shorter clutch basket 1000E input and output shafts.

[Chuck78]

Well I got the $30 transmission in today, & most of it looked to be in great shape aside from the dogs that interlock the sides of 3rd & 4th driven gears... the transmission with the missing tooth on 2nd drive gear also was showing even worse wear on these two!!!


Now what??? Buy a 3rd GS1000 transmission used?
I checked, & almost all gears if not all are no longer available. The GS1100E gears on the other hand were almost all still available new.

2 of the 1000E gears are exclusive to the 1000E, 1 of which is one of the damaged ones on mine. The rest 3 are shared with the 77-79 750, the remaining 3 shared with the 750 8v&16v, gt550, gt750, & RE5...
So basically to get one of the two gears that I would need, I would have to get another 1000 transmission, no other substitutes.

[Chuck78]

The GOOD news...

The good news is... at least comparing tooth counts, every gear drive & driven between the GS1000E 8V & all years of 1100E (& most gears 1150 iirc) all have the exact same tooth count between the 8v & 16v chain drive engines! There is hope. The 1100E 3rd driven gear is the only one slightly in question, as Suzuki did not list the tooth count on the parts fiches for 3rd gear driven. 3rd driven is also the only part shared between the shafty trannies and the 1100E. The drive gears are completely different design on the shafty trans.
The 1100E & 1000E both look very similar in the drawings as far as shaft designs for the drive and driven shafts. I'm crossing my fingers that the gears will swap from the 1100E gearbox shafts directly onto the 1000. I am speculating that is what is needed. I think the shafts will be different dimensions as the primary crank gear on the 1100 is further inboard. Perhaps I could be wrong on that though.

anyone have any direct experiences with this swap??? I have the cases split and parts all over my table here so I could ebay an 1100E gearbox and see, but the cheapest one is $60 ebay.And you know how ebay sellers go... "looks to be in good use able condition, sold as-is" until it arrives in my/your hands, then we see that it's not in fact all in good condition... then you or I are pretty much stuck with it!!! Always happens that way...

[Tom R]

I have what I thought was an 850 transmission, but maybe it's an 1100g transmission in my parts bin. I used the 3rd gear off of it to replace the worn one my chain drive 1100 motor - it was a direct swap with just some oiling holes drilled different if I remember right. I could get dimensions off of it if you want to compare them to your 1000. I could even send it to you if you want to pay shipping.

[Chuck78]

None of those gears will do me any good, but thanks for the offer. 3rd gear was the only one that would swap to the 1100E or possibly 1000E retrofit

[Chuck78]

So the dogs on both sets of GS1000 transmissions that I have now are back cut. Both have bad wear on the 3-4 driven gears' dogs. The one with the worse wear also has a broken tooth on 2nd's drive gear.

So I'm looking at GS1100E trannies on ebay, and there are only a few, & I can clearly see that none of them are back cut. All the dogs have clear 90 degree profiles.

The GS1000 gearboxes, however, are plentiful on ebay. The 4 that show clear enough pictures illustrate that 2 are back cut (both have similar wear on the dogs I'm having trouble with, 1 lesser, 1 worse), & 2 of them are clearly not back cut. Must've been a very common mod on these, eh? I almost thought perhaps the 77-79 1000's were factory back cut for a minute...

[Chuck78]

So my options now seem to be:

*buy $72 GS1100E transmission and send it out to be back cut

*buy the best looking of the GS1000 transmissions on ebay that is already back cut, hope that the wear I see on the edge of the dogs is useable/good enough or have APE repair

*send what I have to Big Jay at APE and see if they can hardweld and reface the 2 dogs I have that show significant rounding and hard shift abuse impact damage

Opinions?? I'm assuming an up/down undercut job would run $300+. Not sure if the worn dogs could be repaired or how much that'd run. If closer to $300, may be best to get an 1100E gearbox and mock it up to see it it fits or if it fits with the gears swapped onto the 1100E shafts.

I'm still looking to hear any further comments on if the 1100E tranny will swap into the 1000, & what is involved (swap gears to 1100E shafts?). Smoother shifting and stronger gears would be nice.

Thanks,

Chuck