yzf600r swing swap should I cut 1/2" of the rear match 400

[RoadDogma]

Lowering the front will decrease trail resulting in quicker turn in (less effort at the bars). Cutting the swingarm will shorten the wheel-base, which will decrease the the bikes turning radius. (The bike should be able to make a tighter turn at a given speed/lean angle). Rear ride height adjustments are best made to give proper swingarm angle for anti-squat purposes. (Think corner exit).

I would cut the swing arm and start with OEM ride height, but that's just me.

[ragedigital]

I would cut the swing arm and start with OEM ride height, but that's just me.

You're talking racing. If you're not racing, then I would think that there is a benefit to having the rear wheel out a bit for stability.

When does the wheelbase become too short? If it is always a benefit to have a shorter wheelbase, then should the stock swingarm be shortened?

I don't know the answer, I just ask the questions, so I'm hoping someone can shed some light on the subject.

[Freestyle72]

The FZR400 stock actually has a longer wheel base than the newer R6 (about 1"). There is no optimal wheelbases. Some ZX10s have turned a better time with a LONGER swingarm. You can easily notice the swingarm length, not sure why you are claiming only Rossi would notice. There is a point of diminishing returns in that the bike will become too unstable. But this all depends on how suspension is set up etc etc.

[ragedigital]

There is no optimal wheelbases.

I'm not sure that I believe that. I have a feeling that wheelbases are a combination of several factors and that a optimal wheelbase can be found for each particular type of riding and rider.

You can easily notice the swingarm length, not sure why you are claiming only Rossi would notice.

I don't see how anyone can tell a 1/2" difference in swingarm length. You guys must ride a lot harder than me at the track. I need to try it at the next track day and see what a difference it makes.

[RoadDogma]

If you're not racing, then I would think that there is a benefit to having the rear wheel out a bit for stability.

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When does the wheelbase become too short? If it is always a benefit to have a shorter wheelbase, then should the stock swingarm be shortened?

I would say that there are too many variables at play in any given set-up for there to be a simple answer to that question. There are always trade-offs one way or the other. Intended performance goals and personal preference also enter the equation. In the end, it is a balancing act. I would venture to say that many riders would agree that Yamaha did a pretty good job of balancing the various trade-offs associated with chassis geometry in the FZR400. I've had an FZR600 and several FZR400s and I prefer the handling of the 400. Thus, I would try to maintain the OEM wheelbase. (Even for street).

As has been suggested, stability issues may arise as a result of a wheelbase that is too short. Accordingly, one could surely benefit from the additional stability afforded by a wheelbase that is longer. (If stability were lacking). I guess wheelbase can be judged as too short when it produces undesirable effects. I rode a '93 GSXR750 with a built 1100 motor, many years back. The shorter wheelbase of the 750 chassis (compared to the 1100) made it a challenge to keep the front wheel on the ground. Again, personal values would dictate whether that is undesirable or not.

[DonTZ125]

Rage, you yourself made the comment that you noticed the loss of "turn on a dime" ability with the wider rear tire, and it was to this comment that my reply was directed. If mod 'a' slows the steering, then there is a selection of possibilities to be performed as mod 'b' to restore the original performance.

You are not Rossi, as you say, yet you notice these differences on the street. How much more evident will they be to someone hustling hard around a tight set of esses on the track?

[ragedigital]

Rage, you yourself made the comment that you noticed the loss of "turn on a dime" ability with the wider rear tire, and it was to this comment that my reply was directed. If mod 'a' slows the steering, then there is a selection of possibilities to be performed as mod 'b' to restore the original performance.

That's what I'm not so sure of. I know what you're saying, but going from a 140 to a 160 is a big jump. I just don't know that you can equal those things out with raising the rearend or adjusting the forks. How much would it take? How else might it negatively affect the bike? I guess the focus should really be more on stability of the rear than anything.

You are not Rossi, as you say, yet you notice these differences on the street. How much more evident will they be to someone hustling hard around a tight set of esses on the track?

I'm more like Spies.

I would venture to say most anyone would notice a tire change out back especially one that has a significant profile change and tire width. That is something that could be addressed as well - tire profile.

Although I'm getting it dialed in more each time I hit the track, I still feel like I'm fighting my GSXR around the corners. I feel like I have to pull the bike down with everything I have. That might have more to do with tire profile than anything.

[DonTZ125]

Tire profile is important; my first year racing 125s, one of the other rookies was trying both Bridgestones and Dunlops. The rounded Dunlop gave good feedback and predictable tip-in, but the wedge-shaped Bridgestone had a very abrupt transition that scared the hell out of her! On the other hand, one of the pros swore by Bridgestone, as he was experienced enough to anticipate and deal with the faster lean.

If you find your steering is heavy, then you can quicken it by reducing the rake - either lift the rear, or drop the triples.

[ragedigital]

If you find your steering is heavy, then you can quicken it by reducing the rake - either lift the rear, or drop the triples.

This bike is already pretty tall at the stock height. The previous owner had dogbones which lowered the rear, so I switched those back to get to stock height. I already have the triples dropped about 4mm.

I've been using Michelin Pilot Race (Mediums), but since they're gone I'll be switching to something different. Time to start looking into profiles. Those Michelins stuck real well and were cheap since they were being clearanced - $200 a set shipped...

The one biggie that stinks for me is that Gateway International has been closed, so my home town track will probably be Putnam near Indy - totally different track. Gateway was flat, tight and top speed wasn't a concern - pulling out of the corners was. Putnam is a gorgeous, long track with sweeping corners and many elevation changes. It's fun, but set-up is tricky.

Here is a pic of Putnam's front stretch. It is hard to judge the first time you get out there. It dips down and so you can't see the first turn until you come up over the hill. I'm so darn slow there...

[RoadDogma]

If you find your steering is heavy, then you can quicken it by reducing the rake - either lift the rear, or drop the triples.

Smaller bikes can be more forgiving of excess ride height out back, but with larger bikes rear traction becomes an issue. Just want to remind people to pay attention to rear traction when making adjustments. It would suck to loose it coming out of a turn, because you wanted to tip-in faster.

[dru86]

Do any of you guys find the fzr400 has stuff all lean angle? On my K1 gsxr750 it would take quite a reasonable amount of lean before I would get knee down. On my fzr400 it hardly has to be tipped before "bugger me these knee sliders aren't going to last long".

I've fitted 1" higher that stock 3en1 rearsets(which are a fair amount higher that the 1wg ones). I think the issues is that the seat is so low which puts alot more bend in my knee therefore when I'm off the bike It doesn't take much to get it grounded. On the gsxr750 it felt like i was sitting on top of the bike whereas with the fzr400 it fells like I'm sitting in the bike. Thoughts?