[Dave Burroughs]

I have been riding for 43 years; two Yamahas, a Zundapp, a Norton and 8 BMW's. I am guilty of nearly a million miles all over the country. If there is an adjustment on suspension systems I have tried it.
I have discussed at length the affects on adjusting PRELOAD. Preload is not for making the suspension softer or harder. It simply is there to increase the suspension travel, as when you are riding two up. Harder and softer is a function of coil spring cross section, whether you have progressivly wound springs and the damping rates that the shocks provide.
Usually when folks change the preload on their shocks they notice no difference in firmness. This is normal. Putting the preload on the highest setting will simply raise the ride hight of the bike. It will also quicken the steering responsiveness as is tends to change the fork rake.
My opinion is, concerning the hard ride problem with the Burgman is that Suzuki had to cut costs somewhere to keep the price as low as possible so they saved money on the suspension. We will have to find good shocks (IKONs?) then possibly change the springs in the fork. If possible we may be able to go to a lighter weight oil in those forks; however my manual does not indicate fork oil change intervals. This may mean that they are sealed or THEY USE ONLY SPRINGS (UGH). Perhaps I will inquire of Suzuki about the forks and shocks. I will keep you posted.

Columbus Burg-Man

Dave

 

[Ted White]

Do keep us posted. I never thought about whether the forks have oil in them or not. Horrors! Also, I wonder if progessive springs are available or gold emulators?

As for rear shocks, Pauljo swears by Ikons, as do others. Don't know if Koni makes one for the Burgie.

 

[pauljo]

Ted,

Koni is out of the motorcycle shock business. They sold their patents and tooling to an Austrailian firm. I think part of the deal was that the shocks could no longer be called Koni (because Koni is still in business making automobile shocks). So the Australian firm moved the "i" from the end of Koni to the front - Ikon. The Ikons are identical to the Konis I used to run on my bikes back in the 80's. It is old (but decent) technology.

 

[pauljo]

Dave,

I just checked my service manual. The Burgman 650 forks contain 482 ml (16.95 oz) of "Suzuki Fork Oil #10". I assume that is a 10 weight oil. I'm wondering if 15 weight would provide better damping action, especially in conjuction with using the Ikon shocks.

Unfortunately, like most newer Japanese motorcycles, there are no drain plugs. The forks must be removed and disassembled to replace the oil.

Interesting. The picture of the fork spring shows it to be a progressively wound coil.

 

[allwalk]

Dave,

I just checked my service manual. The Burgman 650 forks contain 482 ml (16.95 oz) of "Suzuki Fork Oil #10". I assume that is a 10 weight oil. I'm wondering if 15 weight would provide better damping action, especially in conjuction with using the Ikon shocks.

Unfortunately, like most newer Japanese motorcycles, there are no drain plugs. The forks must be removed and disassembled to replace the oil.

Interesting. The picture of the fork spring shows it to be a progressively wound coil.

I bought 15w oil a couple of days ago and think I will tackle the replacement on Monday. I will take some more pics on this project and report back. I want to measure the oil in there and see how much actually comes out. Will keep you posted.

 

[pauljo]

I bought 15w oil a couple of days ago and think I will tackle the replacement on Monday. I will take some more pics on this project and report back. I want to measure the oil in there and see how much actually comes out. Will keep you posted.

Excellent! I'd love to try that too, but I was a little intimidated by the instructions in the service manual. I'm sure that if I had the dealer's shop do it, it would be a sizeable labor bill. I noticed that the instructions advise replacement of the O-ring when you re-assemble the shocks. Did you get those also?

 

[Al Davison]

thanks for the info

Having a fair amount of experience and theoretical knowledge of suspensions (motocross, sports car racing, high-end mountain bikes, etc.) I am interested in what you all find that works and doesn't. I have not pushed the suspension on my scoot because I can't yet ride it all that well (still practicing) but, over the bumps, my seat of the pants tells me that the spring rates are OK for me - a little on the soft side but, acceptable. The damping on both ends is somewhere between fair and poor. I think the comment about Suzuki saving money on the suspension is especially true of the rear shocks. I am spoiled by having compression and rebound adustments, I guess. Compression damping is pitiful on the rear - rebound may be OK but it's hard to tell because the overall performance othe shocks is just marginal.

I think my forks are too soft but, I'm withholding judgement until I get more miles on the bike and get used to the ride. I know it's not a sport bike, after all.

Al

 

[wasions]

Dave,
I'm sure you were just attempting, for our sakes, to simplify things with your original explanation, but preload doesn't exactly increase the suspension travel. In fact, unless you top out the shock, it won't change the travel at all. And if you do top out the shock (that is, unload the motorcycle - as in a jump - such that the shock is completely extended) it will, in effect, decrease the suspension travel. (Yes, I'm picking nits. That's what I do. )

Maybe it's just me, but I find the suspension is nearly ideal. However, I'm tempted to remove the centerstand for more ground clearance.

 

[abm]

Have to weigh in

Have to weigh in:

Im troubled - Regarding something related:

I feel the ride has, at 3600 mi, deteriorated badly. When I ride over uneven pavement and potholes now, I feel the bike is really not damoing well, nowhere near as well as when new and the first 1500 mu.

Also, there seems to be very subtle knock or clunck when I go over sharp irregularities. I had someone help me raise the front up and I tried to feel the forks for steering head play, but no luck.

Something's wrong in my Burgie. It seems to be front end related. Didnt someone post about steering head out of spec on torque, and a loose axel nut?

 

[Jim]

abm,

Had it to mine too at 2,600 miles, check the front axle, with it off and parked turn the handlebars full right then left a few times. I heard a clunk in the front, thats when I found the loose axle Front End
As per a previous post.

http://burgmanusa.com/forums/viewtopic.php?t=1268

Sunday Morning I started on the front end wich still seemed to wobble a bit at high speed (70). Increasing the rear suspension helps but it still wasn't right. I found the steering head was about 1/4 turn too loose, snugged that, but there was still some left. I was going to take the front wheel off to chechk that out. Removed the pinch bolt then startetd on the axle. Well guess what It's supposed to be at 47 ft. lbs. and it was hand tight. I pulled the axle out and tried to drop the wheel (I did not take off the calipers because the bolts were too tight) I couldnt get it passed the fender. So checked out the the bearings with it in there, they seemed OK, but a little dry, so I added some bearing grease befroe re assembly. Trying to set the wheel back I couldn't because of the Brake pad clearance, so I removed the pads. Well that was really easy, 1 cover screw and 1 allen bolt, then they just slide down. Plenty of room to reinstall the wheel, Torqued the front axle and pinch bolt. Reinstalled the brake pads, again real easy. No more slop and the wheel turns free.

Since then it feel like a new machine, 3,000 miles on it now.
Check steering head (only needs about a 1/4 turn) and the front axle, too be sure.

 

[hatman]

Preload/hard ride

Very interesting and relevant thread - I'm especially looking forward to the feedback on experimentation with fork oil viscosity and quantities.

However, one aspect of all this that no-one's mentioned yet is tyre pressures - bikes/scooters are very tyre-pressure sensitive from my own experiences. I bought a Yamah TMax, a big scoot with the ability to out-handle sportsbikes in certain conditions, rode it the 250 miles home in rain and wind (after dark too, so it was a reasonable test of a new machine!) and it handled like a drunken pig on a skateboard. I couldn't believe how bad it was. In the light of the next morning I checked the bike over and found that the tyres were at exactly half the recommended pressure. Pumped up to the requisite 29/33 the legendary TMax handling was miraculously restored.

Learning from this experience I made a point of asking the guy that I was to buy the Burgman from to check the pressures before I collected, to be told that he made a regular thing of it and as he'd been carrying his wife on the pillion the rear tyre pressure was higher than the recommended 36. The ride back home (200 miles) was OK on smooth surfaces but liver-loosening on less-than-perfect roads.

My next-day check revealed that, far from being over pressure, both tyres were 9lbs down on book. Correcting this improved matters out of all proportion to the effort involved.

Now, either the guy was lying to me (unlikely) or he'd merely set his tyre pressures using the notoriously inaccurate garage forecourt equipment. I've found from personal experimentation over many years that all tyre pressure gauges are liars; check a tyre with different gauges and you get different results. In fact, with the electronic digital ones, potentially the most accurate, you often get wildly different results, even from the same gauge! If you do three immediate consecutive checks with the same gauge on the same tyre it's a fair bet that you'll get different readings each time.

Clearly, if the tyre-pressures are off (likely) then any tinkering with suspension gubbins and set-up will largely be a waste of time, money and effort.

 

[allwalk]

Paul , I hadnt picked up the O rings. I reread the procedure after your post and will go and get them this morning.

As far as tire pressures go I own a digital gauge that I keep locked in the glove box. My front pressure is 33 -33.5 and my rear I run usually around 39-40.

The wife has me running around this morning doing errands and driving her to the doctor. This fork oil change is being postponed for 24 hrs. I want to give myself alot of time to do and complete before I have to leave for work.

 

[pauljo]

Re: Preload/hard ride

However, one aspect of all this that no-one's mentioned yet is tyre pressures - bikes/scooters are very tyre-pressure sensitive from my own experiences. I bought a Yamah TMax, a big scoot with the ability to out-handle sportsbikes in certain conditions, rode it the 250 miles home in rain and wind (after dark too, so it was a reasonable test of a new machine!) and it handled like a drunken pig on a skateboard. I couldn't believe how bad it was. In the light of the next morning I checked the bike over and found that the tyres were at exactly half the recommended pressure. Pumped up to the requisite 29/33 the legendary TMax handling was miraculously restored.

Hatman. Very true. I've ridden a few miles on that "drunken pig on a skateboard". My Burgman 650 was delivered with only 20psi in both front and rear tires!

This is so basic, that I quess we forgot to mention it, but it is very important. I run 33 psi front and 41 psi rear. I used to run 36 psi rear, but I used up my original rear tire in just 5300 miles. I now have a Pirelli on the back, and I've been running the higher pressure to see if it will extend tire mileage. I check my tire pressure weekly. I use a fairly expensive brass dial type tire gauge that has an air release button on it, so I can slightly overfill the tire and then bleed it down to the correct setting.

I have also found what you said about tire gauge inaccuracies to be true - and very frustrating. But at some point, I think one has to pick a gauge that seems to be of good quality, and stick with it.