Fork spring upgrade woes

[superbig]

My right fork seal failed about 39,000 miles, so I thought it would be a good time to upgrade the front springs because of excessive front-end dive. Bought the Race Tech 1.2KG/MM springs, had a Yamaha shop do the install and rebuild of seals, along with major tuneup since valves never adjusted. Valves were hardly out-of-spec, and engine runs strong as usual, but now the front-end dive is worse than ever, and it clunks audibly at bottom of travel. I understand old fork springs were progressive, and the new are straight rate, but wow, what a disappointment. Any recommendations? I'm about 375lbs fully outfitted on bike, so it's always got a serious load on it.

 

[Bustanut joker]

Damn.. As much as I'd like to be gentle You is one big fuk! is ya ugly too? 375 ready to roll?

For shitsakes! did ya hide behind the counter at the shop and throw yer voice to a midget?

For cryin oot loud man! Them folks should have noticed ya was a little feckin mountain an suggested truck springs at least..

Seriously big fella, ya might want to get with the folks at GP suspensions.. They may be able to help.

:jester:

 

[superbig]

Damn.. As much as I'd like to be gentle You is one big fuk! is ya ugly too? 375 ready to roll?

For shitsakes! did ya hide behind the counter at the shop and throw yer voice to a midget?

For cryin oot loud man! Them folks should have noticed ya was a little feckin mountain an suggested truck springs at least..

Seriously big fella, ya might want to get with the folks at GP suspensions.. They may be able to help.

:jester:

 

[yamafitter]

My right fork seal failed about 39,000 miles, so I thought it would be a good time to upgrade the front springs because of excessive front-end dive. Bought the Race Tech 1.2KG/MM springs, had a Yamaha shop do the install and rebuild of seals, along with major tuneup since valves never adjusted. Valves were hardly out-of-spec, and engine runs strong as usual, but now the front-end dive is worse than ever, and it clunks audibly at bottom of travel. I understand old fork springs were progressive, and the new are straight rate, but wow, what a disappointment. Any recommendations? I'm about 375lbs fully outfitted on bike, so it's always got a serious load on it.

Preload is probably too soft. Check the sag on the forks by wrapping some ty-raps around the fork tubes just tight enough so they will slide on the fork and position them down against the fork tube scrapers. Now sit on the bike but don't bounce. The distance ty-rap has moved is your fork sag. Compare this number with the recommended value (unfortunately I can't remember it off the top of my head but it is listed on the forum somewhere). Adjust the preload to get there since you have the stiffest springs RaceTech has. I would also add some compression dampening to slow the diving. If it's really bad try 5 clicks up on compression and test to see if there is any improvement and dial in from there. Also be aware that you may have to add some rebound to the forks if you have to crank up the preload significantly to make things work properly. Please note - set sag first and then test. Only then start adjusting compression. Change one thing at a time and keep notes. Also note the "baseline" settings. I keep a log on both my bikes since I am old and can't even remember how old I am. :blink:

PS - this assumes two items. Racetech acually sent you the correct springs and that the fork oil level was set correctly. If either / both are wrong then there should be hell to pay.

 

[TahoeBound]

... and the new are straight rate, but wow, what a disappointment.

Well, I don't have much advice, just much sympathy. I too went with RTs recently and I feel your pain...not bottoming but ride is worse than stock IMO @ 3 times stock price. They roll over some bumps quite well, but overall I am very unhappy. Freeway ride is a joke. And I've spent ridiculous amounts of time trying to dial them in. I've checked measurements & levels 3 times and been through about every possible combination of adjustments. I'm done. I'm installing stock springs & "normal" fork oil (I find no benefit to their $30/qt US1). From info gained on this site, they do not know how to set up an FJR so their instructions are pretty well worthless. And I'm so annoyed, at one point I considered their Gold Valves, but not now.

Tahoe

 

[FJRay]

I used to be heavier than that and I got Eibach springs from GP suspension. They work great.

 

[escapefjrtist]

If you're comfortable doing it, take the top off the forks and look things over. As mentioned earlier, you could have received the wrong springs or the shop didn't assemble the forks correctly. In any event with advertised 1.2 Kg springs, the sag and ride should be improved over stock...

--G