Pros and Cons to Flipping Rear Swingarm Eccentrics

Hey KZR,

Ive read that one of the easiest and cheapest (read FREE lol) mods on these early ZX750's is to flip the rear swing arm eccentrics 180 degrees to gain some ride height and reduce trail (pretty sure that is what it said), but I really haven't seen a detailed explanation of why you should or should not. Was hoping that someone with more knowledge than myself could chime in on what the benefits are as well as what any potential drawbacks would be? I am 5'10" tall and about 180 lbs and my riding style is mostly in the mountains and canyons with some highway driving, not sure if that makes any difference on why I should or should not flip the eccentrics but figured more info is better.

Thanks,
Brett

your essentially raising the rear ride height, which may bring the front fork rake back a degree or two.
seems like it wouldn't be noticeable to me :whistle: ,but maybe others are more perceptive

i don't believe there to be a "downside".just a personal preference that will only matter to you.


that's my .02 fwiw,
leon

Thanks Leon appreciate your thoughts and that makes sense

- Brett

Do it, then carefully road test it...you'll might enjoy the look and feel of a raised rear end and notice a faster turn in on steering, you may also get a little less stable at illegal speeds. It is really about how you like the stance of the bike and how it fits you.

I reversed mine onto a plank of wood 1 inch thick and so on... you can notice the slight difference in weight distribution just sitting on it and turning the bars.

Technical issues are chain clearance - not usually an issue unless the frame is braced - I goofed up here on mine.

There are also some chain run / angle of chain from horizontal across the axle/SA pivot engineering considerations, but on both my 550 and 750 I have done it with good results. I am 6"4 so seat height isn't an issue...also they look and steer so much cooler in a slightly hunched over stance. imo

if you are determined to lift it the back but keep the frame geometry closer to factory the you could lift the forks and dump the clip ons with a handler bar coversion for another 15mm or soi...

It is really about how you like the stance of the bike and how it fits you.

edit,,, it is about feel and handling from the 'revised' frame geometry and weight distribution, but in my experience altering the castor and trail by raisng the back works for me,

On my r1 without a faring, even 70mph is tiring on a long run so 100mph plus handling isn't an issue for me.

A couple years back, I junked the air-ride shocks for a set of Progressive's, after finding a barely used set (with springs) while scouting ebay. Forty bucks later...
I now had 12.5" (one inch shorter) shocks on my bike, and could finally set my feet flat on the ground.
The immediate effect was dramatic, and the change has significantly improved my riding confidence. The bike feels more comfortable and responsive, like a whole new ride.

WAIT! {Rookie alert}

What is this you speak of and how do I do it?

Tyrell Corp wrote: Do it, then carefully road test it...you'll might enjoy the look and feel of a raised rear end and notice a faster turn in on steering, you may also get a little less stable at illegal speeds. It is really about how you like the stance of the bike and how it fits you.

I reversed mine onto a plank of wood 1 inch thick and so on... you can notice the slight difference in weight distribution just sitting on it and turning the bars.

Technical issues are chain clearance - not usually an issue unless the frame is braced - I goofed up here on mine.

There are also some chain run / angle of chain from horizontal across the axle/SA pivot engineering considerations, but on both my 550 and 750 I have done it with good results. I am 6"4 so seat height isn't an issue...also they look and steer so much cooler in a slightly hunched over stance. imo

if you are determined to lift it the back but keep the frame geometry closer to factory the you could lift the forks and dump the clip ons with a handler bar coversion for another 15mm or soi...

Thank you Tyrell, this type of info combined with Leon's was spot on for what I was looking for, thank you!! In terms of high speed twitchy-ness I am less concerned about that as this bike will never see a track and rarely see anything in the triple digits. I feel it would be the height of foolishness for me to take a 30 year old bike to those speeds consistently without having done a full frame up rest and knowing that every single nut and bolt and component is solid since I don't want some 30 year old component or piece to fail at the absolute worst time and turn me into human jello splattered over the pavement. In rare cases sure I will see those speeds but that is the exception not the rule. The seat height is the only thing I am marginally concerned about and that is because plain and simple I am short and the shrimp of my family. I am 5'9.5" on my tallest tippy toe day, with my SIDI Vertigo boots on I crack 5'10" at least. Currently my feet sit flat on the ground when I am on the bike, so long as after flipping the eccentrics I can still get my feet flat or at least darned close to it I should have any issues but testing it out will be the difference.

As for the physical task of flipping them, is it truly just as straightforward as loosening the pinch bolts on each side and sticking a steel rod into one of the eccentric openings and rotating it 180* from where they are currently at, then testing and adjust chain tension and deflection again?

Thanks,
Brett

daveo wrote: A couple years back, I junked the air-ride shocks for a set of Progressive's, after finding a barely used set (with springs) while scouting ebay. Forty bucks later...
I now had 12.5" (one inch shorter) shocks on my bike, and could finally set my feet flat on the ground.
The immediate effect was dramatic, and the change has significantly improved my riding confidence. The bike feels more comfortable and responsive, like a whole new ride.

Glad to hear and yeah being able to get your feet flat completely changes your confidence when you are on the bike, at least thats how I have felt in my very limited experience. In my case with the air assist rear uni-track mono shock thats not easy to change, but it is something to look at down the road when I magically have money leaking out of my ears haha (those replacement ones are SUPER pricey).

Brett

GPzMOD750 wrote: WAIT! {Rookie alert}

What is this you speak of and how do I do it?

Hey there GPzMOD,

I stumbled across this a month or so back, super helpful and lists the eccentric flip in here too, give it a looksie...

members.tripod.com/gpz_rider/technical/FAQ2000.htm

Brett

Looks like my bike doesn't have this, Damnit! I'd like to raise my back end a little, longer shocks I guess

Irish-Kawi wrote: As for the physical task of flipping them, is it truly just as straightforward as loosening the pinch bolts on each side and sticking a steel rod into one of the eccentric openings and rotating it 180* from where they are currently at, then testing and adjust chain tension and deflection again?

Thanks,
Brett

yes


leon