I have decided to go with a -1/+2 gearing and a 520 conversion, I just wanted to know from you guys who have already done this, how much top end do you loose, about what rpm is 80mph at in 6th and can you feel a significant difference in low end power. Also what companies do you recomend for parts. All input is appreciated.

 

I have the Vortex sprocket with the RK Chain, and the gain down low is well worth it, as for top end i lost some but i dont usually cruise at 150 mph anyway

 

Check out this link, input f4i and your custom configuration. Looks like you give up 11.3% of top end, rev limiter kicks in at 128mph, your speedo error will approach 20%. I have this mod on my track4i. Your chain/sprocket wear and mileage will worsen. It does give you more drive. That speed is gonna cost ya!

http://www.gearingcommander.com/

 

I did a 520 with -1 in the front. The low end is tremendous in power and speed.

Pros: Low end power excellent. Can bring front end up with the twist of the wrist.

Cons: Bike runs at higher rpms, fuel mileage is lowered, top end suffers. Speedometer inaccurate. I installed a Speedohealer to correct my speedometer. But I have never topped out the high end since my conversion. So I don't know what the top speed is, I have never needed to go that fast.

The rpms with a -1 at 80 mph is approximately 7000-8000 rpms. Never really looked. Posted speed limit is 75 mph on the interstate.

Conclusion: The low end power is worth the trade, cuz I don't need to go over 100 mph. I like to zip around town.

 

Does the bike feel a lotbuzzier with this conversion? And if it is buzzier, when is itmost noticeable? Some bikes don't like it; the naked SV650 is one as italready has lowered gearing compared to itshalf clothed sibling. Thanks for feedback.

 

it's buzzier from 6K and up.

stick with 525...and -1/+2...

you don't need the insignificant benefits and cost of a 520 when you do -1/+2.

 

The conversion provides 2 benefits. Lowering the gear ratio improves acceleration. This feels very similar to riding around in 5th instead of sixth gear and you can see how that feels yourself. The bike will vibrate more at a given speed because it is running 11% higher RPM.

The second benefit comes from the reduced weight of the sprockets and chain. The chain is thinner, hence lighter, the sprockets are aluminum, also lighter. The weight difference isnt great, but it is rotating mass. Performance might improve as much as loosing a few pounds of rider weight or a few ounces of wheel weight. I've heard dyno guys say you might get around 1-2HP.

I dont think it makes much sense for a streetbike, costs almost as much as a track day, and increases your maintenance and operating costs. It was practically the last mod I did, and rated well below better gear, rider training, suspension and brake work in terms of return on investment.

 

I have an 00 F4 and I went -1/+3...whereas before the bike was very sluggish at low rpms...now it is just as quick low end as it was high end before...not quite sure top speed yet...i got an EK SRX 520 conversion kit and Renthal Sprockets...

Oh yeah...and I got a speedohealer ($100) to recalibrate the speedometer...it was off by 20%!!! (so if I was going 100mph it would say 120mph)
I got 39mpg last time I was out (country ride avg speed 50, but at times 80+)

 

I have a RK 520 -1 front on order and i'm excited about getting it. Needed to replace the chain for awhile now.

 

I just put my 520 -1/+2 on last week. There is stillsnow in Michigan. I am ready to get out on it and see the difference. I think it will be well worth it. The speedometer is 20% off? Is that common?