Early 6-speed vs late 6-speed tranny differences ?

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Early 6-speed vs late 6-speed tranny differences ?

Postby smotorboy » 06 Jan 2018 01:19

Hello All,

Robert in California here, and I'm looking to use an early 6-speed from a Strada in the supercharged Morini Land speed Race Bike.

As I do not trust the 1st gear gear-pair that took the "Big Hit" during the dyno mishap a while back, I need to replace "just those parts" at the least,,,
or the entire transmission to be safe.

I've noticed some differences and a little guidance would help right now.

My original tranny is out of a K2 built in December 1985...The Strada tranny is from the 70's I guess. I can't find a stamped crankcase serial number like the K2 has,,, only the words "Moto Morini" followed by the letter "A" on the early crankcase....

The K2 2nd Gear Pair are much wider than the Strada 2nd gear set, and the 6th gear "driver" gear is wider in the K2 tranny.

Did the early bike have 2nd gear issues perhaps ?

As my supercharged motor makes 30+ lb-ft of torque at all rpms, the tranny needs to be robust so I'm thinking of mixing the gears from both trannys and use the best looking and widest pairs...

Are there issues or concerns that I should watch for ?

All advice welcome,,

Robert in California
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby norbert » 06 Jan 2018 01:26

Hi Robert,

I don´t remeber exactly the diferences, but I fear you should not mix the old with the newer gears. The forks of the old one are still made of aluminium?

norbert
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby smotorboy » 06 Jan 2018 15:03

Hi Norbert,

Forks are brass in both trannys.

Wear patterns dictate that keeping all gear pairs with their running mates is generally a good idea,,,,

I'm just concerned that Morini increased certain gears widths for a real reason that might be an issue for me on down the line...

Thanks for your input,

Robert
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby harrymuffin » 06 Jan 2018 19:18

Do you mean transmission? Over here a tranny is either a Dagenham Dustbin Transit Van (Ford) or someone who cannot make his or her mind up what sex they are.
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby smotorboy » 06 Jan 2018 20:10

Sorry about the Tranny usage for Transmission ....We here in American seem to never failed in wrecking the Queen's English in new and unexpected ways....

Maybe it all started because, like my Morini the last couple of passes down the track, the transmission couldn't figure which gear it wanted to be in...I would put it in 6th and it would jump back into 5th, over and over again all the way to the finish line....

Thanks for the clarification Harry,

Robert
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby MickeyMoto » 07 Jan 2018 08:08

I knew what you meant, Robert. Is the bike producing too much torque for the gearbox? (Nicely sidestepped!). Have you thought about a 500 gearbox? Not sure of the differences, but maybe beefier. A 5 speed box may be worth a look? Do you need six gears?

America did not mangle the language, you evolved older English in a different way! I love your use of turnpike. The use of zed / zee instead of s is not unusual, as the West Country of the Pilgrim Father's uses a lot of them... keep 'em coming, I love to see the differences.
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby smotorboy » 08 Jan 2018 14:37

Hi MickyMoto,

The jumping and difficult shifting seems to be a result of the shifting paw mechanism being out of adjustment..

I've bought a crankcase and am presently cutting holes in it to see the parts in action as per service manual.

6-speeds do help the "creep up " to get the last few mph,,,however the 5-speed is more robust for sure and would handle anything I am expecting to throw at it.

the 4 and 5th ratios are very tall and would simplify gearing for 125mph and above....

Finding a 100% complete 5-speed transmission looks to be quite a deal.....Can anyone direct me to one ????

I'm interested in finding one.

Robert in California
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby smotorboy » 09 Jan 2018 02:10

I found some drawings of the 5-speed transmission parts and the gears are wider and with larger teeth....

The output shaft has thrust bearings on both ends...

The Morini Factory Turbo 500 reportedly put out 70 hp at the transmission output sprocket and the transmission handled that.

At most, I hope to get the 350 to 50hp so a 500 tranny would not be worked hard at all....

Now, all I have to do is acquire one that is complete before the next tear-down and refurbish.

I'm going to try the Strada 6-speed I have on hand this year,,, as long as it does ok anyway

If anyone crosses path with the parts I need,,, please keep me in mind..

Robert in California
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby julianharty » 09 Jan 2018 05:56

Robert,
I don't have the gearbox parts you seek, but I do visit California for work and happen to be in Santa Clara this week (until Thursday). I'm returning at the end of February where I'll be in SF and probably the south bay area too. Perhaps I can help somehow if there are suitable parts in the UK/Europe? Where are you in CA?

Julian
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby jb666 » 09 Jan 2018 09:46

Hi Robert,
Just an extra option for you. Trawling around as you do when idle I came across this :

https://www.ebay.co.uk/itm/Moto-Morini- ... SwzRpaNQPi

I only mention it as I had a couple of heads and barrels off the seller and they were good quality and arrived quickly.

Good luck with the project!!

John.
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby Steve Brown » 09 Jan 2018 13:01

I thought I'd read on here previously that it is a bit of a challenge to replace a five speed with a six speed transmission, or vice-versa? Is that so, or is it my old and overloaded memory that needs an upgrade?
I have two 5 speed bikes and on one of them I might be tempted to swap to a six speed cluster as I have one of those lying around too. I won't be stripping them in a hurry as they are both currently quite sound but if this was an easy swap I could be tempted next winter. As I never have much to do... :roll:
All donations to the rest home for old Camels, Leicestershire.
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby smotorboy » 10 Jan 2018 03:52

Boy, You Guys are just the best,,,

Julian,,,, I'm in Orange county California city of Costa Mesa which is 45 mile south of LA....

You just might be able to help me out in the future if I get stuck for something critical and the supplier doesn't want to go to the hassle of customs and shipping to the US.

John,,, great looking transmission and it would be a same-for-same swap with my oem K2 unit. As I have already bought , cleaned, and lubed the early Strega transmission, I going to use it for the 2018 race season and see how it does.... It can always come out if necessary...

Steve Brown,,, sounds like we just might work something out when you get ready to take out one of your 5oo transmissions....Let us stay in touch...it will be after November of this year before I would have to motor apart again (assuming all goes well this summer).

A big thumbs up to you guys for all the help offered.

Robert in California

PS: I will take and post some pictures of the transmission differences this weekend for you to see
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Re: Early 6-speed vs late 6-speed tranny differences ?

Postby julianharty » 10 Jan 2018 14:50

Robert,
so roughly mid-way between SD and LA? I do visit both places and occasionally manage to catch the train between the two cities. I'll let you know when I'm next in the area, especially if I've got a weekend in town (generally SD rather than LA).

All the best with your exploits and fun


Julian
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