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Discussion Starter #1
After riding my ST1300 for years and getting injured and older I purchased an AN650 for local two up riding with my wife.

Compared to the ST1300 the burgman suspension is very inadequate. Over the last two months, I've read everything I can find on improving it.

Seems like the easiest/cheapest thing is to start with increasing the ride height with a spring spacer.
Anyway, I added a 1/2 spacer and the sag degreased which is good. However, my suspension doesn't move to full fork stroke now. My zip tie stops about the 1/2 inch before it used to and the suspension stops very abruptly like the spring is coil binding. This leads me to believe that the previous owner may have replaced the spring spacer with a longer unit. I have tried to find the OEM length and can't locate it. The spacer in it now is exactly 7.5 inches. Is this correct?

Also, what I can find on the fork oil height is approximately 5 inches. I set it at that with no change and I removed 2 inches to move it to 7 inches again without change, I wanted to make sure it wasn't hydro locking.

Maybe it has different springs????

Any Idea.
 

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The first thing I would try is to raise the "sag" by adding washers the same size as the tube interior under the fork caps. make sure the front wheel is off the ground and free wheeling to take some pressure off the springs. I would start with 1/2" for starters. Changing the fork oil may also help. These are the cheapest options.

There more in-depth options.

From and older post of mine about 10 yrs. ago. I had an '03 but may still apply.

"This last weekend I noticed the sag on the front was lower than usual. I needed another 3/4" or so, as I was down to 1 7/8 " of travel even with the added washers I installed last year. Optimum is 2 3/4", so I remove the metal spacer and all the washers, about 8" total. I inspected the spring, and it was still in spec. (13.42" min), as the the relaxed length was at 13.75". I took some thick wall pvc pipe and cut it to 8 3/4" long and installed it with with 1 washer between the spring and spacer, replacing the old spacer and washers. The new set up is about 8 7/8" long, so I gained about 3/4" - 7/8" of usable travel."

More here
 

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Two friends of mine warned me to give-up on modding the fork other than adjusting the sag: they tried for about 10 years and -basically- failed.
So, starting from there, i've done the only thing they did'nt. I can confirm that the only real improvement are the RaceTech emulation valves: even without changing the springs (so, the valves alone) you'll get so much better forks behaviour.

My 2c.
 

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Discussion Starter #5
Thanks for the info. I was trying to determine why adding the spacer increased ride height but the fork travel stopped at almost exactly the spacer thickness before maximum compression. Just seems that I have a coil bind issue. I wonder if my springs art stock?? Seems from the second post I must have the stock spacer, cause mine was 8 inches total after adding it.
 

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I think it was member Maccecth that posted this gem. This will give you 1 more inch of travel. I have plans to order the #85 or #90 non-progressive spring from 'Sonis Springs' and then use 9 to 10 inches of my factory spring cut down to get the sag back.

You must take the forks apart to add this. It is meant to be done with a 'Racetech' type emmulator so if you do not install one then do not drill out the factory spacer as shown in the drawing.

Fork tube extension.jpg Fork tube limiter.jpg

Fork Tube.jpg Fork tube with Spring.jpg
 

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To answer your original question, I took the forks on a friends bike apart today so I measured the spacer length. 7.5 inches so yours appear to be stock.
 

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Discussion Starter #9
Guys, Thanks for all the additional information. Ill get on it. I love the bike, very easy to use. Just that suspension??? I can't believe after all the years and following, suzuki didn't address it. It is the only thing stopping it from being almost a perfect all rounder.
 

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Discussion Starter #10
Thanks, great read.
 

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Discussion Starter #11
Two friends of mine warned me to give-up on modding the fork other than adjusting the sag: they tried for about 10 years and -basically- failed.
So, starting from there, i've done the only thing they did'nt. I can confirm that the only real improvement are the RaceTech emulation valves: even without changing the springs (so, the valves alone) you'll get so much better forks behaviour.

My 2c.
Ive been playing with the spacers and different weight oils and oil heights. I've done this before on other bikes with good results. But, no matter what the burgman front is always bad. I can make it better in one type of situation but worse in all others. I can't find a compromise. When I added the 1/2 spacer I lost suspension travel. Seems to go solid so I think there is coil bind. It also seems I have the stock spring preload spacer. I am really starting to think that the springs may have been changed. I got the bike used from a dealer, so I have no idea what the previous owner may have done.

I have read that some have made the stock front better, but never good. It seems that many have had luck with aftermarket spring and or raceTech emulators. I have been trying the cheap way first and am probably going to purchase racTech. That is fairly cheap as well.

My question: Do the RaceTech emulators and springs make a noticeable difference. Is the difference barely perceivable or is it night/day? Would you say that it is actually good? Can you compare it to another bikes that you would say it compares to?

I'm not looking for a sport bike characteristics. I want a nice mid speed cruiser for me and my wife to spend a couple of hours on. We have about a 350 lb combined weight with stored gear.
 

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My question: Do the RaceTech emulators and springs make a noticeable difference.
Yes.
A bit of theory (my English is not good enough for it, but i'll try anyway): the fork .... "tube" (this one below) as you know works by opposing "resistance" to the fluid movement.
How much resistance is inversely proportional to the holes diameter and proportional to the square (if i remember well) of the velocity of the fluid. And this is our problem: the harder the "bump", the faster the fluid, the (squared) harder is the fork! This is the opposite of what we want.
(ok, that's enough)

Fork tube limiter.jpg

That's why Racetech valves IS the solution: "constant" resistance to the fluid, in both directions, thanks to the preload spring setting.

Is the difference barely perceivable or is it night/day?
Night and day. The VERY first think i've got after the "awe" was "Wow, rear shocks sucks!".... i did'nt even tought at them.

Would you say that it is actually good? Can you compare it to another bikes that you would say it compares to?
I'm not looking for a sport bike characteristics. I want a nice mid speed cruiser for me and my wife to spend a couple of hours on. We have about a 350 lb combined weight with stored gear.
Absolutely good.
I'm not a biker: not coulting the Vespa, i have got a Majesty 125 and a Burgman 400. I'm 180cm and 126kg, and i never felt "safe" with the front of that scooters, perhaps 'cause i un-balance light scooters too much. The front wheel was always .... "floating", to me. BUT i always got every hard bump to my teeth.
The 650 is the first one that i drive with relax even when i'm scraping the sidestand, and now i (almost) never had harsh bumps. So i have really no comparison to do.

Anyway, i'm ready to promote racetech valves everytime i'm asked to :)
 

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Discussion Starter #13
Yes.
A bit of theory (my English is not good enough for it, but i'll try anyway): the fork .... "tube" (this one below) as you know works by opposing "resistance" to the fluid movement.
How much resistance is inversely proportional to the holes diameter and proportional to the square (if i remember well) of the velocity of the fluid. And this is our problem: the harder the "bump", the faster the fluid, the (squared) harder is the fork! This is the opposite of what we want.
(ok, that's enough)

View attachment 91985

That's why Racetech valves IS the solution: "constant" resistance to the fluid, in both directions, thanks to the preload spring setting.



Night and day. The VERY first think i've got after the "awe" was "Wow, rear shocks sucks!".... i did'nt even tought at them.



Absolutely good.
I'm not a biker: not coulting the Vespa, i have got a Majesty 125 and a Burgman 400. I'm 180cm and 126kg, and i never felt "safe" with the front of that scooters, perhaps 'cause i un-balance light scooters too much. The front wheel was always .... "floating", to me. BUT i always got every hard bump to my teeth.
The 650 is the first one that i drive with relax even when i'm scraping the sidestand, and now i (almost) never had harsh bumps. So i have really no comparison to do.

Anyway, i'm ready to promote racetech valves everytime i'm asked to :)
Thank you for doing a great job of answering my specific questions. I'm going to contact race tech. They also have rear shocks for the burgman on their site.

Thanks again
 

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After riding my ST1300 for years and getting injured and older I purchased an AN650 for local two up riding with my wife.

Compared to the ST1300 the burgman suspension is very inadequate. Over the last two months, I've read everything I can find on improving it.

Seems like the easiest/cheapest thing is to start with increasing the ride height with a spring spacer.
Anyway, I added a 1/2 spacer and the sag degreased which is good. However, my suspension doesn't move to full fork stroke now. My zip tie stops about the 1/2 inch before it used to and the suspension stops very abruptly like the spring is coil binding. This leads me to believe that the previous owner may have replaced the spring spacer with a longer unit. I have tried to find the OEM length and can't locate it. The spacer in it now is exactly 7.5 inches. Is this correct?

Also, what I can find on the fork oil height is approximately 5 inches. I set it at that with no change and I removed 2 inches to move it to 7 inches again without change, I wanted to make sure it wasn't hydro locking.

Maybe it has different springs????

Any Idea.
Pete,

I just bought a 2007 six weeks ago. On the way home from the dealer, going from about 70 to 80 mph on the interstate, the front end beat my arms to death. I have done a lot of research and just some limited testing so far. My suspension works fairly well around town but at high speeds hitting any bumps it evidently is either bottoming out or hydro locking another way to bottom out. I weigh 240. I believe the bike is sprung for 120lb rider. My advice for you, on the cheap, would be, take out the spacer, drain your oil and replace it with 375ml of good 20w fork oil. if you are not happy with that then go to some heavier non progressive springs for two up. A 2004 front end that I bought has 7.875" spacers. I will be working on my front suspension soon and plan to share what I learn here. Good luck! Alan
 

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Discussion Starter #15
Just wanted to add an update.


Front:
I have played with various oil weights from 5 to 20 and in different mixes. I've taken the fork caps off too many times to count. I currently have 7 3/4 of preload spacer in the fork. Anything more seems to lock up the suspension and I don't get full travel, regardless of how much oil in in the fork. I may not have the factory spring installed. There is a lot of fork sag. It only had 2 inches of travel left after sag with my weight. No matter what I've done, it is never good. It is actually best right now. Currently it has Ford ATF, 7 3/4' PVC spacer, which is ticker so acts like a smaller air space, and just enough oil to cover the damping rod at full extension. I know this totally contrary to what most post. The suspension is much plusher over smaller bumps and irregularities and doesn't slam any more harshly on the squared edge bumps.

In the rear: I played with the preload and nothing worked well there as well. I found the post on using Monroe Air shocks for a Corvette and modifying the eyes to fit. I narrowed the top eye, welded the eye on much better, for support. I cut off the bottom eye and fabricated a clevis, supports and welded that on. I made the eye to eye length to match the stock shock length. The compressed length of the monroe shock is almost exactly the same as the burgman factory shock. I adjusted the air pressure to create 1.5 inches of sag with myself on the bike. That would be 1/3 suspension movement. The results: The ride is a bit more firm then the stock shocks. I can feel it moving on rolling bumps and dips. But, on the square/sharp/quick bumps it is very firm. Too much damping. Which I thought because they are made for a much heavier vehicle. With the wife on back, (330 lbs total) It is better then stock. I can feel it moving. It is still firm but the sharp bumps aren't nearly as harsh as the stock suspension. The wife says that it is much better. She would really complain about some of the impacts.
So, I'd do the mod if you ride two up or are heavy. I ride two up most often so the shocks will stay on.

I've decided to buy race tech springs and emulators. I think I'm also going to buy racetechs rear shocks as well, Near 800 but if they work it will be worth it. I used to spend over a 1000 just on revalving each time I got a new dirt bike. Suspension makes such a difference, It is worth it if you can make it work.

Going to do this in mid winter when I can't ride.
 
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