Forks pre-load problems - Triumph675.Net Forums
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post #1 of 70 Old 07-28-12, 13:26 Thread Starter
Ricardo_
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Forks pre-load problems

guys, I was measuring my SAG today and some weird thing is happening on my front end (rear is fine).

Forks free SAG = 122mm
Rider SAG = 105mm (5 marks showing)

120 - 105 = 15.
Too stiff.

Then I start to work with my forks preload and I was like "wtf" when I've got 8 marks showing and 100mm rider sag. I can't reach more then 20mm of SAG.

What the hell is happening?
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post #2 of 70 Old 07-28-12, 14:24
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Are you sure you are measuring correctly? Where did you get the 120mm from? Free sag is only the bikes weight. That measurement would be equal to or less than the measurement with the forks topped out.

Measure the inner fork tube from where it enters the lower casting to the bottom of the dust seal with forks fully topped out. Place a zip tie on the tube and slide it up against the dust seal. Get on the bike and assume riding position geared up. Do not bounce the suspension while you do this. Now get off the bike and measure from the same lower point to the TOP of the zip tie. That is your race sag.

If you cannot get enough sag using the adjusters then you need lower rate springs.

2012 Daytona 675
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post #3 of 70 Old 07-28-12, 14:33
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If your running stock springs, something is very wrong. Is this the first time adjusting preload on this bike? How long sense you rebuilt them? I remember another thread of yours with front end problems, sounds like a good time to open them up.
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post #4 of 70 Old 07-28-12, 15:30
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Quote:
Originally Posted by rikke View Post
guys, I was measuring my SAG today and some weird thing is happening on my front end (rear is fine).

Forks free SAG = 122mm
Rider SAG = 105mm (5 marks showing)

120 - 105 = 15.
Too stiff.

Then I start to work with my forks preload and I was like "wtf" when I've got 8 marks showing and 100mm rider sag. I can't reach more then 20mm of SAG.

What the hell is happening?
If I understand your posting correctly... Your springs are to stiff for your weight, get some lighter racetech springs, or other brand... the lightest springs you will find is .85 from racetech, they are a little linger then the stock springs so you will need to cut your preload spacer down to compensate. However, if you are racing, I wouldn't think you would really want to go any lighter... I am only 160 fully geared up... and I use the stock .90 springs... But it also would depend on how hard of braking you are doing.
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post #5 of 70 Old 07-28-12, 16:26
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Has the bike been down?

Make sure the triple clamps, forks, and axle are not in a bind then recheck.

06 675 Track Bike
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post #6 of 70 Old 07-28-12, 18:24 Thread Starter
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Yes i did this cobalt.

Yes, stock springs and first time setting sag.
Never rebuild them, only fluid change.

Yes, the bike has been down.
I loosened lower triple clamp because i thought the forks were twisted, but they didnt.

And i have 8mm from the cap to the top triple camp.
Manual asks for 4mm.

Last edited by Ricardo_; 07-28-12 at 18:33.
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post #7 of 70 Old 07-29-12, 08:23
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What year is your bike?

I have a 2006 model and I recently had the front end sorted by Darren at MCT. Darren advised me that the standard fork springs are too hard as standard. This was backed up by my lack of confidence in the front end when hard on the brakes on track.

When he measured the spring weight they were 10.5 items!!! These were the heaviest he had measured out of a Daytona and are far too heavy even for track work, unless you weigh a hell of a lot. He fitted 9.5 springs and now all is good with the front end, it made a massive improvement.

So I'd get them out and have their weight measured, as it seems that there is a lot or variance in spring weight, certainly in the earlier bikes.


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post #8 of 70 Old 07-29-12, 08:51 Thread Starter
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my bike is 2007.

so 20mm SAG is the maximum I cant get because of those heavy stock springs? damn...

Last edited by Ricardo_; 07-29-12 at 09:02.
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post #9 of 70 Old 07-29-12, 22:21
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Quote:
Originally Posted by Cobalt135 View Post
Are you sure you are measuring correctly? Where did you get the 120mm from? Free sag is only the bikes weight. That measurement would be equal to or less than the measurement with the forks topped out.

Measure the inner fork tube from where it enters the lower casting to the bottom of the dust seal with forks fully topped out. Place a zip tie on the tube and slide it up against the dust seal. Get on the bike and assume riding position geared up. Do not bounce the suspension while you do this. Now get off the bike and measure from the same lower point to the TOP of the zip tie. That is your race sag.

If you cannot get enough sag using the adjusters then you need lower rate springs.
I've never seen anyone measure sag that way. It's always to the ground. The way you are measuring it will result in less sag because of the angle of the forks.
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post #10 of 70 Old 07-29-12, 22:22
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Quote:
Originally Posted by rikke View Post
my bike is 2007.

so 20mm SAG is the maximum I cant get because of those heavy stock springs? damn...
How much do you weigh?
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