6 speed vs. 5 speed trans

I have a 82 kz750 ltd 4 with the 5 speed trans . I have a 80 kz440 ltd twin parts bike . Just throwing it up in the air the 440 has a 6 speed trans can the 5 speed be swapped out for the 6 ? The second part of the question would it be worth it to try ? There is nothing wrong with either trans . This is just something that popped in my head .




Mike

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building now a 750/810 road racer and i bought from a memeber here a 6spd 550 cluster.

the 550 drops right in and seemingly has very few issues to resolve to make it work. see pic.

one way to check would be to go to online 440 and 550 g'box parts list and see if these have the same part numbers.

would check also in the tech specs if they have the same ratios

wouldnt be surprised if the the 440 works too

let me know if you need any measurements as my motor is still open

TG

I just got done doing some home work . It looks like that the 440 and the 550 are the same parts . I am not good with gearing would this give me 1) a lower gear ? 2) a higher gear ? or 3) an in between gear ? It would be odd to have a gear that is not stated on the cover . It would be a bones and mess some one up if they did not no about it . :evil: Next winter I will be doing a tear down for paint and polish why not a trans transplant ? :whistle:

Turbo What did you have to do to make it work ?

Thanks

Mike

kzrider.com/index.php?option=com_kunena&...ew&catid=2&id=339132

MuzzleMike wrote:

I just got done doing some home work . It looks like that the 440 and the 550 are the same parts .
Mike

How did you check they have the same parts? Just making sure you know the part numbers in the diagrams are reference numbers. The full-part number has a 4 digit extension. The first 5 or so numbers only refer to what type of part it is. Many bikes will have part numbers where the first several digits match, but the last 4 may be totally different. In the parts fiche, you have to look at teh parts list to get the full part number. If that's what you checked, then nevermind. I didn't see any matching part numbers in my quick look at 440 and 550 trans parts, but then again the 550 part numbers don't match 750 numbers either (except some of the bearings, which may be the key), so trans's can swap even if the parts have different numbers, but then it's a matter of comparing the physical parts.

Mike, Some things to consider/check.... with the exception of Honda "overdrive"5&6-speeds (which have significantly higher top gear ratios) the final drive ratios in 6th (in 6 speeds) are either the same or slightly lower than 5th (in swapable 5 speeds)& simply offer "closer ratios" thru speed/rpm band. Fine for racing applications or putting modestly powered bikes on a "par" with slightly larger/more powerful units. But for practical applications simply require more "stiring the pot". the quickest check for possible interchanges is for the bearing sizes for both ends of main axle & counter shaft. (they need be of same demension) then a quick check for shaft's length. I'm not familiar, but doubt the width of a twins cases match a 4's. it's not my intent to be a "nay sayer", but reccomend you research & evaluate possible gains before pulling the trigger. One of my "running projects" is a 1987 FZ700/FZR1000 hybrid...Neat Bike, a quick @ 60 HP gain, BUT, the 6-speed while faultless is overkill. The Best reason IMHOP to go 6 speed on a street rider would be to drop revs at cruising speed, check final ratios 1st..G

loudhvx wrote:

MuzzleMike wrote:

I just got done doing some home work . It looks like that the 440 and the 550 are the same parts .
Mike

How did you check they have the same parts? Just making sure you know the part numbers in the diagrams are reference numbers. The full-part number has a 4 digit extension. The first 5 or so numbers only refer to what type of part it is. Many bikes will have part numbers where the first several digits match, but the last 4 may be totally different. In the parts fiche, you have to look at teh parts list to get the full part number. If that's what you checked, then nevermind. I didn't see any matching part numbers in my quick look at 440 and 550 trans parts, but then again the 550 part numbers don't match 750 numbers either (except some of the bearings, which may be the key), so trans's can swap even if the parts have different numbers, but then it's a matter of comparing the physical parts.

I was looking at the bearings I thought as long as the bearings are the same and the input and output shafts line up it should be a shot. Sorry I should have been more clear on it . Like I stated both are in good shape and since I am planning to get into the 750 anyway if there would be a benefit why not try ? And the 440 is nothing but a parts bike so it will no hurt it .

Mike

I got a shops manual for the 440 online and was looking at the gearing . I would not get to much benefit with the 6 speed trans . I thing since the 5 is ok I will strip the 6 speed down before discarding the 440 so I have it just encase it is needed . I started to think while I was looking at the manual 1. No benefits and 2. as long as it is not broke do not fix it . Thanks any ways guys .

overall gearing is something you manage through the chain drive sprockets, it is related to the gearbox but you can can shorten or lenghten gearing regardless if its a 5 or 6 spd

6 speed essentailly reduces gaps, or revs drop between gears.like someone said here, really worth the while if you are going racing as 6 speeds let you match corner speed to revs better and make the most of a tuned engine with a narrow powerband.

I am currently working on the switch to 6spd, it involves some machining of the different spacers, etc. Havent finished it so there still might be surprises. Do it only if you have access to a good machine shop and know what you are doing. It's definetely not a drop in mod and a locked gearbox at 100mph is not a funny thing.