93 Vmax with 93 FZR1000 Front Forks Questions

[Ramalama]

I have some suspension setup questions about my Vmax that I need some help with. First off, it's a 93 Vmax with USD fork conversion, sport bike wheels off of a gsxr, works connection rear shocks, and a Fischer Millenium swingarm. The front forks are from a 91-93 fzr1000 and it has MEK triple clamps and a hyperpro steering stabilizer. I bought it with all of this on it already about a year ago and love it, but I want to improve on the handling some. I think that the guy I bought it from put all this stuff on the bike but never took the time to dial it all in because it handles like a chopper in corners and the front end just feels terrible. If I hit a bump while cornering with any type of lean angle and speed it gives the whole bike a nice unsettling shake from front to back. Now to my questions. I'm getting ready to pull the front forks and I'm trying to figure out how to calculate the spring rate for the front forks and I'm not sure where to start since they aren't really for this bike. Also, if anyone has any opinions on the RaceTech gold valves I'd be glad to hear them. I'm generally looking for any advice or previous experience on how to set this bike up to handle better. If there is any other info that would help out in figuring this out, I'll do my best to give it to you, and there are more specifics about the bike in my garage.

edit - Any ideas on what weight fork oil to use would be good too

 

[Fire-medic]

Well a '93 FZR1000 weighs ~490 lb. w/gas & a VMax is ~624 lb. so the fork springs are set up for something 27% less heavy than the VMax. That alone can seriously affect the handling. If you look on the forum for other threads on USD forks, you will see this is a commonly-mentioned concern. To have the correct handling from the bike you would need to correct this.

I do not believe the forks you have are cartridge. Being a participant on the FZR1000 forum and owning my own conventional fork FZR1000 for 23 years, owners report that the later model FZR1000's USD forks offer no real advantage over the conventional forks. The 'eye-candy' aspect of USD forks is there of course. Members report a well-fettled conventional fork can out-perform the stock USD fork. Add the excess weight which you are asking the USD fork to manage, and it isn't unexpected that your bike is not confidence-inspiring.

Height of oil (volume) in the tube is important as is weight. W/o checking my FZR1000 factory manual, my conventional fork as I recollect uses 10W oil. A common mod is to go to a 15 wt. oil if you want firmer handling or are a heavier rider.

 

[wildweasel_pt]

Guys

The weight of oil can seriously hinder the behavior of the bike, take in consideration that the valves may not be able to cope with that thicker oil and the oil weight is mostly a factor for the rebound and not the compression, it just allows to settle more quietly instead of bouncing around when hitting a bump (happens when you increase compression for added weight and let the rebound be untouched). The thicker oil allows for smother cycle considering the valves are able to deal with it (R1 KYB forks should not use more than 10W). Another thing to take in consideration is the rake of the VMAX compared to the FZR. They are not the same. When i got my forks i tried to calculate the new spring load for the extra weight of the vmax and racetech calculator was giving me a 1,2 kgs spring (the toughest they have) and i found it awkward. What i didn't recall is that the calculator was considering R1 forks on a R1! not on a vmax, and the different rake is an important deal. I installed them on my bike and changed nothing besides extending forks internals by 40mm, and the only thing im gonna do now is replace the oil for 10W to smooth out the cycle. All the other settings will be done on a trial error basis so i can get that cherry spot... Another thing that may impact the reaction is the span between forks on corners associated with fat tires up front (No one cares because its a minor issue but it may cause bad suspension issues still...)

Check this thread so you can grow your knowledge on suspension a bit more...

http://www.r1-forum.com/forums/showthread.php?t=252234

 

[satariel666]

Guys

The weight of oil can seriously hinder the behavior of the bike, take in consideration that the valves may not be able to cope with that thicker oil and the oil weight is mostly a factor for the rebound and not the compression, it just allows to settle more quietly instead of bouncing around when hitting a bump (happens when you increase compression for added weight and let the rebound be untouched). The thicker oil allows for smother cycle considering the valves are able to deal with it (R1 KYB forks should not use more than 10W). Another thing to take in consideration is the rake of the VMAX compared to the FZR. They are not the same. When i got my forks i tried to calculate the new spring load for the extra weight of the vmax and racetech calculator was giving me a 1,2 kgs spring (the toughest they have) and i found it awkward. What i didn't recall is that the calculator was considering R1 forks on a R1! not on a vmax, and the different rake is an important deal. I installed them on my bike and changed nothing besides extending forks internals by 40mm, and the only thing im gonna do now is replace the oil for 10W to smooth out the cycle. All the other settings will be done on a trial error basis so i can get that cherry spot... Another thing that may impact the reaction is the span between forks on corners associated with fat tires up front (No one cares because its a minor issue but it may cause bad suspension issues still...)

Check this thread so you can grow your knowledge on suspension a bit more...

http://www.r1-forum.com/forums/showthread.php?t=252234

I have 1,2kg springs if you want to try but I will not recommend that.
I will recommed 0,9 even...If you will change the oil weight then you need to revalve your pistons...I think.

DanQ is on this forum.

 

[wildweasel_pt]

I have 1,2kg springs if you want to try but I will not recommend that.
I will recommed 0,9 even...If you will change the oil weight then you need to revalve your pistons...I think.

DanQ is on this forum.

Yes i do agree with you Prez, i think we already talked about this in the past if im not mistaken... The revalve is only needed if the oil is not suitable for the valves like i said on previous post. At least i talked about that with Dan and he agrees... Suspension is a sketchy subject...

 

[WIKDMAX]

I'm going to chime in here although it's been a few years so I may not be exactly correct. I had this fork set up on my 86, primarily because it was a direct bolt on. It worked extremely well and the handling was improved over stock. The springs were upgraded with the heaviest ones Race Tech had available at the time which wasn't exactly what was needed for the weight of the bike and rider but wasn't that far off either. Again it's been roughly 15 years since I did the upgrade. I also remember calling Race Tech with the application and they provided me with the valving and what weight of their oil to use.
This was using all the components off the 1993 FZR, no upgrades to the triple clamps and no steering stabilizer. Just new head bearings and upgrading the internals. Made a huge difference in the handling and no problems that I can recall. That front end was still on the bike when I traded it in for a Warrior at a Yamaha shop in Blue Ridge GA. The Sales manager ended up buying it from the dealership and called me so I could mail him all the information I had on the different modifications.

 

[Ramalama]

Well a '93 FZR1000 weighs ~490 lb. w/gas & a VMax is ~624 lb. so the fork springs are set up for something 27% less heavy than the VMax. That alone can seriously affect the handling. If you look on the forum for other threads on USD forks, you will see this is a commonly-mentioned concern. To have the correct handling from the bike you would need to correct this.

I do not believe the forks you have are cartridge. Being a participant on the FZR1000 forum and owning my own conventional fork FZR1000 for 23 years, owners report that the later model FZR1000's USD forks offer no real advantage over the conventional forks. The 'eye-candy' aspect of USD forks is there of course. Members report a well-fettled conventional fork can out-perform the stock USD fork. Add the excess weight which you are asking the USD fork to manage, and it isn't unexpected that your bike is not confidence-inspiring.

Height of oil (volume) in the tube is important as is weight. W/o checking my FZR1000 factory manual, my conventional fork as I recollect uses 10W oil. A common mod is to go to a 15 wt. oil if you want firmer handling or are a heavier rider.

Well....The good news is that none of this is going to hurt my feelings because I was already figuring this would be the case. I found factory manual for the 93 FZR that has a bit of info but not much.

Guys

The weight of oil can seriously hinder the behavior of the bike, take in consideration that the valves may not be able to cope with that thicker oil and the oil weight is mostly a factor for the rebound and not the compression, it just allows to settle more quietly instead of bouncing around when hitting a bump (happens when you increase compression for added weight and let the rebound be untouched). The thicker oil allows for smother cycle considering the valves are able to deal with it (R1 KYB forks should not use more than 10W). Another thing to take in consideration is the rake of the VMAX compared to the FZR. They are not the same. When i got my forks i tried to calculate the new spring load for the extra weight of the vmax and racetech calculator was giving me a 1,2 kgs spring (the toughest they have) and i found it awkward. What i didn't recall is that the calculator was considering R1 forks on a R1! not on a vmax, and the different rake is an important deal. I installed them on my bike and changed nothing besides extending forks internals by 40mm, and the only thing im gonna do now is replace the oil for 10W to smooth out the cycle. All the other settings will be done on a trial error basis so i can get that cherry spot... Another thing that may impact the reaction is the span between forks on corners associated with fat tires up front (No one cares because its a minor issue but it may cause bad suspension issues still...)

Check this thread so you can grow your knowledge on suspension a bit more...

http://www.r1-forum.com/forums/showthread.php?t=252234

Thanks for the link. I will be checking it out. I've done a lot of work on motocross suspension, but not really any with street bikes so this should be interesting. I think what is going to make this a challenge is the fact that these forks don't really have comp and rebound adjustments, they only have a spring preload adjuster

I'm going to chime in here although it's been a few years so I may not be exactly correct. I had this fork set up on my 86, primarily because it was a direct bolt on. It worked extremely well and the handling was improved over stock. The springs were upgraded with the heaviest ones Race Tech had available at the time which wasn't exactly what was needed for the weight of the bike and rider but wasn't that far off either. Again it's been roughly 15 years since I did the upgrade. I also remember calling Race Tech with the application and they provided me with the valving and what weight of their oil to use.
This was using all the components off the 1993 FZR, no upgrades to the triple clamps and no steering stabilizer. Just new head bearings and upgrading the internals. Made a huge difference in the handling and no problems that I can recall. That front end was still on the bike when I traded it in for a Warrior at a Yamaha shop in Blue Ridge GA. The Sales manager ended up buying it from the dealership and called me so I could mail him all the information I had on the different modifications.

WIKDMAX, I'm already on the same route that you took with RaceTech. I've used them for most of my past and present motocross bikes and have always been very pleased with them. I'll probably revalve and change my springs out depending on what RaceTech has to say.

Unfortunately, I'm going to have to put this whole operation on hold for a bit though. I was out riding this past Monday and the clutch gave up. Baaahhhhhhh!!!! Time to purchase the spring conversion, some new plates, and I think I'm going to make one of the see through clutch covers while it's apart FUN FUN FUN

 

[DanQuin]

Have you been able to get anywhere with this?

If I could offer my opinion I would suggest not changing one damping rod suspension for another. Regardless of being inverted cartridge, internally they are essentially the same as your stock Vmax forks. So for either case you'd be looking at some form of valve emulation and springs. And then only a preload adjustment (air or mechanical). Between that and about a 3 inch difference between the FZR and the Vmax forks, you'd be making a very significant change to rake, and more importantly stability granting trail.

A good set of springs and emulators, with some fine tuning to your oil level/weight and you'd get very good performance out of the Vmax forks, in my opinion.

Sorry for the uber late bump :wink2:

 

[Fire-medic]

"Regardless of being inverted cartridge..." DanQuin's comment.

As I mentioned previously, the forks are conventional damping-rod USD forks and are not cartridge. Here is a diagram of the 1993 FZR1000 forks:

http://www.ronayersmotorcycles.com/fiche_section_detail.asp?section=20864&category=Motorcycles&make=YAMAHA&year=1993&fveh=532

I am waiting on my Race Tech springs and already have RICOR Intiminators to go in my late-model 1993+ forks. I have a full front end from a 1989-1990 FZR1000 I was thinking of putting onto my 1987 FZR1000, but for now I think I will keep the FZR stock. I had also thought of putting the '89/90 front end onto the VMax, but have decided to keep the parts in storage for now as I decided to replace the smaller 1992 stock forks w/the later forks (done), the RICOR's (got 'em) and the heavier-rate Race Tech springs (expecting them today). My plan was to try and make the F & R '89/90 front & rear FZR1000 wheels fit my VMax. My machinist will do the rear wheel conversion any time I want, all it costs is $.

I did use the FZR1000 100 mm spacing/mounting Sumitomo 2 pair opposed piston front calipers on my VMax front end, only needed the 298 mm late-model rotors to make them work, it was a big improvement over the stock single opposed-piston calipers of my 1992. I have some R1 blue spots I haven't bothered to mount because I like the FZR calipers.

 

[DanQuin]

"Regardless of being inverted cartridge..." DanQuin's comment.

As I mentioned previously, the forks are conventional damping-rod USD forks and are not cartridge. Here is a diagram of the 1993 FZR1000 forks:

http://www.ronayersmotorcycles.com/fiche_section_detail.asp?section=20864&category=Motorcycles&make=YAMAHA&year=1993&fveh=532

I am waiting on my Race Tech springs and already have RICOR Intiminators to go in my late-model 1993+ forks. I have a full front end from a 1989-1990 FZR1000 I was thinking of putting onto my 1987 FZR1000, but for now I think I will keep the FZR stock. I had also thought of putting the '89/90 front end onto the VMax, but have decided to keep the parts in storage for now as I decided to replace the smaller 1992 stock forks w/the later forks (done), the RICOR's (got 'em) and the heavier-rate Race Tech springs (expecting them today). My plan was to try and make the F & R '89/90 front & rear FZR1000 wheels fit my VMax. My machinist will do the rear wheel conversion any time I want, all it costs is $.

I did use the FZR1000 100 mm spacing/mounting Sumitomo 2 pair opposed piston front calipers on my VMax front end, only needed the 298 mm late-model rotors to make them work, it was a big improvement over the stock single opposed-piston calipers of my 1992. I have some R1 blue spots I haven't bothered to mount because I like the FZR calipers.

I am terribly sorry for the inconvenience. I should have said USD or upside down. But I did go on to say that internally they are the same (damping rod forks).

 

[Rollie]

I echo the opines of others suggesting USD forks with Race Tech springs ( I weighed 215 lbs. & got .95kg springs & gold emulators , 10w fork oil ) and Works Street Tracker or Progressives better grade rear shocks , notched & braced swingarm. That rear swingarm you have should help a lot as well regarding stability . With that said , I would also suggest frame braces for the less than stable VMax frame , to give added stability .

 

[Fire-medic]

Sorry, I am not pointing fingers at anyone, I am only saying it isn't a cartridge system. If you are taking offense, I apologize.

Unless you got a super deal on a FZR/YZF USD fork there is no real advantage to one which is properly set up and of conventional design. Feedback to that effect is in the forum entries I mentioned before. Some people just want 'the look.' Shorter suspension costs you cornering & ground clearance.

 

[DanQuin]

Sorry, I am not pointing fingers at anyone, I am only saying it isn't a cartridge system. If you are taking offense. I apologize.

Unless you got a super deal on a FZR/YZF USD fork there is no real advantatoolbar one which is properly set up and of conventional design. Feedback to that effect is in the forum entries I mentioned before. Some people just want 'the look.' Shorter suspension costs you cornering & ground clearance.

No offense taken at all. I really should have stated USD, because they are not cartridge.

And I agree 100% on not swapping for the FZR forks. I might be inclined to consider YZF 750 or R1 forks, but all of them would cause significant lowering.

A well tuned emulator/spring/oil swap would be the best thing, in my opinion. But I tune/build mostly sportbike/racebike forks.