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F4i shock conversion?


Off of the above posts, I ordered a 650r shock that I will install this week. I’m a big guy 6’1 and 265 and race tech shows 20.3kg spring for the rear. Not in the funds and I only ride to and from work so I figured 30 bucks and close spring rate could be worth something. I’ll let you know how it goes! Doing race techs in the front at the same time as well.
 
Fractured said:
Off of the above posts, I ordered a 650r shock that I will install this week. I’m a big guy 6’1 and 265 and race tech shows 20.3kg spring for the rear. Not in the funds and I only ride to and from work so I figured 30 bucks and close spring rate could be worth something. I’ll let you know how it goes! Doing race techs in the front at the same time as well.
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Nice! I'm interested to hear how this one feels as well. It's also cool to see we got everybody doing some experimenting with some creative solutions!
 
Do a search and see what the R3 guys are retrofitting into their bikes. If it's a drop in for the R3 it should be as well for the Fz6r?

Might open up some options for a cheap (maybe adjustable) drop in upgrade🤔

Let us know what you find!
 
I still need to get some measurements of the R3 shock, feel free to measure wire diameter and outer/inner coil diameter, then count the active coils if anyone has one off the bike. But I did measure the factory FZ6R shock. 0.512" coil diameter (maybe subtract 0.01" for powder coating), 2.172" inner diameter, ~5-6 active coils (not 100% sure how much count as active in ground flat springs when the first coil is contacting the ground end). https://eibach.com/spring-rate-calculator Plug into here and it seems that the FZ6R spring is actually somewhere over 18kg/mm. I was a bit skeptical about the Racetech listed spring rate of 9.4kg/mm, since the swap to R3 definitely didn't feel like twice the rate.

Also a note on aftermarket R3 shocks, they won't necessarily be drop-in since the lower eyelets are different. We're lucky that the factory FZ6R and R3 lower bushings are the same inner diameter, meaning you can take the solid cylindrical spacer out of the FZ6R bushing and put it in the R3 bushing (that comes with two flanged pieces that push in from either end. If an aftermarket shock comes with a spacer/bushing in the eyelet with a different diameter, you wouldn't be able to drop the FZ6R spacer in, so a custom solution would be needed.
 
Fractured said:
The 650r shock is a no go. It’s too long by about 3/4 or an inch, and the bolt holes are too small for the Yamaha hardware. Guessing I’ll do an R3 shock next!
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(Sorry for the late reply, had other things going on for a while).As is it won't fit, but with the proper spacers and technique to mount it should be ok.
Ride height will increase a bit but not so much that the centre stand won't work.
 
I went with the R3 shock after all due to unreasonable price for shipment, import fees etc. (in general) and lack of availability in my country of any shock option ( I paid ~$100 for a r3 shock and $67 of that was only additional costs, from US to where I live) and for other shocks there may be the additional cost of re-gassing it and an oil change, for shocks from older model bikes.

Mine is from a '21 model year with like 1600 miles in great condition so it should work just fine, even in harsher conditions.

I will update in God knows how many months about how it performs, when I have the chance to mount it. RN I don't have that much time and the weather is horrible where I live
 
Fractured said:
The 650r shock is a no go. It’s too long by about 3/4 or an inch, and the bolt holes are too small for the Yamaha hardware. Guessing I’ll do an R3 shock next!
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Bolts size is an easy fix... but it might work fine with a drop link.
 
Tried something... 2024 ZX10R rear shock. With some work I made it fit but at 305mm its a too long, even if used with the droplink. Stock spring is about 10kg/mm. A bit on the soft side forbmy 170lbs but the ride is so smooth compare to the 6R shock. Look like its blown up now anyway lol.

Im about 24.5 deg caster with the fork drop 1". Oh, also forgot I cut the side stand 10 years ago to fit the drop link... new stand on the way 🤣
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I love that you guys are trying different shocks to see what works. If I had known an R3 shock would bolt right in, I would have been on the R3 forum looking for a cheap, used Ohlins or K tech shock for my bike.
 
That's what the weird dudes like Marthy and I are for lol. We're down to just send it and try things out.

My E36 has a bunch of parts on it that are either one-off that I made or stuff from other BMW's that I did the digging and testing to find that they're compatible.
 
audace said:
That's what the weird dudes like Marthy and I are for lol. We're down to just send it and try things out.

My E36 has a bunch of parts on it that are either one-off that I made or stuff from other BMW's that I did the digging and testing to find that they're compatible.
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That's how the FZ6 cams project went on... LOL I did the same with the FZ09 when I go it in 2014. I had the first F09 with an exhaust and fuel controller world wide LOL I did pull the ZX10R rear shock too. One of the vendor at the time gave me a little jab about me saying is $.99 hose clamp setup was cheezy for a damper that sold for $800 or so. I came up with the ZX10R shock and Ebay was out within days LOL
 
Marthy, any suspension shops near you? You could get that shock shaft shortened to the right length for probably not too much money? I've never had it done but do know that it's a thing!
 
Little update:
I end up swaping the spring for the stiffest one I could find for the ZX10, 120N/mm or about 12.2kg/mm.

Free sag is 15mm and rider sag 40mm. I could have used a bit stiffer spring but that will do it! Cutting the drop link gave me 10mm lower fully extended, not much bur I'll take it. My front end was set at 1" up in the TT and now 1/2", remove some prefload (shims) from 35mm rider sag to 38mm now. I'll give this a run and readjust if necesary. So far the morning ride to work was smooth. Time will tell but im happy with the upgrade.
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Hi, this weekend I'm going to install the R3 shock, is the bottom (the side that bolts to the swingarm) bolt and nut both a 17mm size?
 
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