Feels like oscillating

[alke46]

Did you change the bushings in the forks. When I read your first post I thought you were talking about your Honda. Police STs in the UK had issues with high speed wobbles.

No, did not change the bushings.

[alke46]

1.1's are pretty stiff. Did you go though the spring calculator on the Sonic website?

Yes I did, twice. But I do think I got the wrong ones and maybe should have purchased the 1.0's.

[bonanzadave]

No, did not change the bushings.

I believe its the root to my speed wobble issue.....

click vid

[alke46]

With respect to measuring sag, make sure you are measuring the sag from when there is absolutely no load on the front end (full extension) to when the bike is sitting on its wheels only with you on the bike and your feet off the ground. Takes at least 2 people if not 3 to do this properly.

Are you talking about the bike on the centerstand? That seems to be full extension in my mind.

[Ray916MN]

Are you talking about the bike on the centerstand? That seems to be full extension in my mind.

Centerstand front wheel off the ground (measure to bottom of the front tire). Using the measurement with the bike on the centerstand and front wheel on the ground is not full extension.

[mmattockx]

OK here is what I have as of now. "Laden" sag is only 3/8" on front forks.
<snip>

I think my next move is to change the spacer in the forks to create more sag.

You definitely need more sag than that. How much preload did you have when you put the springs in? I am in the process of installing Sonic springs and cartridge emulators in my 1100E and the instructions suggest 12mm (1/2") of preload as a good starting point.

Yes I did, twice. But I do think I got the wrong ones and maybe should have purchased the 1.0's.

1.1's are for pretty large riders and/or heavy bikes. I weigh 185lb without gear and got the 1.0kg/mm springs.

Are you talking about the bike on the centerstand? That seems to be full extension in my mind.

If you weight the back so that the front wheel is in the air then that is fully extended. It is convenient to measure from the bottom of the lower triple clamp to the top of the dust cover for your numbers.


Mark

[alke46]

I believe its the root to my speed wobble issue.....

click vid

I agree, there is a lot of slop in that video.

[alke46]

You definitely need more sag than that. How much preload did you have when you put the springs in? I am in the process of installing Sonic springs and cartridge emulators in my 1100E and the instructions suggest 12mm (1/2") of preload as a good starting point.




1.1's are for pretty large riders and/or heavy bikes. I weigh 185lb without gear and got the 1.0kg/mm springs.




If you weight the back so that the front wheel is in the air then that is fully extended. It is convenient to measure from the bottom of the lower triple clamp to the top of the dust cover for your numbers.


Mark

Oh to be back to 185 again. I currently weigh 200 without gear and yes my instructions called for 1/2" of preload and that is where I am.
I think I need to read up on the sag measuring so I am sure I am doing it properly.

[alke46]

Alright, let's try this again and let me know if I am doing something wrong.
As I was sitting on the bike in riding position, no center stand or side stand, I was balancing myself by holding onto the side of my truck, I had my wife put a mark on the fork tube
right at the dust boot. Then I put the bike on the center stand, using a bottle jack under the engine, I raised the front wheel just off the floor. Measuring from the previous mark
on the fork tube down to the dust boot gave me a measurement of 1.375 (1 3/8").
Does this sound like the proper way to measure sag?

[mmattockx]

Alright, let's try this again and let me know if I am doing something wrong.
As I was sitting on the bike in riding position, no center stand or side stand, I was balancing myself by holding onto the side of my truck, I had my wife put a mark on the fork tube
right at the dust boot. Then I put the bike on the center stand, using a bottle jack under the engine, I raised the front wheel just off the floor. Measuring from the previous mark
on the fork tube down to the dust boot gave me a measurement of 1.375 (1 3/8").
Does this sound like the proper way to measure sag?

That sounds pretty reasonable. The only thing I would add is to bounce the front end of the bike up and down a few times and then let it settle before measuring to help minimize stiction problems. At 1-3/8" (35mm) you are on the low side for sag. You can remove some of the 1/2" preload you put in to give a bit more sag, but I wouldn't reduce preload below 1/4". You never want the springs to come free as it can cause problems. Reducing preload will give you a 1:1 change in your sag, so at most you are going to get to around 1-5/8" (41mm) which is at the low end of what is considered good. It sounds like you do need the 1.0kg/mm spring rate instead of the 1.1's.


Mark

[alke46]

[QUOTE=mmattockx;2338535]That sounds pretty reasonable. The only thing I would add is to bounce the front end of the bike up and down a few times and then let it settle before measuring to help minimize stiction problems. At 1-3/8" (35mm) you are on the low side for sag. You can remove some of the 1/2" preload you put in to give a bit more sag, but I wouldn't reduce preload below 1/4". You never want the springs to come free as it can cause problems. Reducing preload will give you a 1:1 change in your sag, so at most you are going to get to around 1-5/8" (41mm) which is at the low end of what is considered good. It sounds like you do need the 1.0kg/mm spring rate instead of the 1.1's.


Thanks for your helpful advice and I have just sent a message to the sonic spring company. Probably will be ordering the 1.0's tomorrow.

[Ray916MN]

Now you're cooking with gas on measuring sag. You need to measure the rear too. Based on the front measurement, I really doubt that sag is the cause of your oscillation problems. Let's hear what the rear sag measures.

[BurntKittyForge]

Now you're cooking with gas on measuring sag. You need to measure the rear too. Based on the front measurement, I really doubt that sag is the cause of your oscillation problems. Let's hear what the rear sag measures.

-Maybe something with the rear suspension , sounds like damper/ rebound messed up there(?)...

-could be low air pressure in the tire(s) (sounds like), tires loose pressure this time of year from cold. Usually through the shrader valve, could be damaged/faulty as well...

-a /some wheel weights could've fallen off....

-brake caliper could be sticking...

-"brand new Shinko" LOL...(Saw one with exact tread as the old Metlers' , wish there was a speed rated one in my size though ...questionable tire though)...

-Maybe the bushing between the bearings fell out of place replacing tire/wheel mounting and is bobbing around loose inside the rim even(?)

-Oh, could have fluid inside the tire too (possible IF the tire-changer was sloppy and slopped filthy watery crap on it)...

I'm on OP's "ignore list" but stuff to consider for others reading/ my .02 is all.

Maybe it has some twinkie(S) stuck/stuffed to it.
Ever heard about the fat lady who went to the clinic with stinky rash and mold on her body and they found a very old twinkie in a fold and embarrassed she admitted it was a game of "Hide the food [in folds]" (never found/ forgotten for MONTHS, got left there!

[habsdoc]

Now that is just down right disturbing, no more reasons to eat any "twinkies" here.

[alke46]

Now you're cooking with gas on measuring sag. You need to measure the rear too. Based on the front measurement, I really doubt that sag is the cause of your oscillation problems. Let's hear what the rear sag measures.

Sure, soon as I can get some help with it.