Yamaha forks on a BMW F650GS Dakar

I agree.
People seriously need to have their brains scanned wanting up to $500 for a wheel...

I just payed £110 (140 shipped) for a 17" rear incl axle, cush drive, sprocket and disc (pretty worn) and £35 (62 shipped) for a 19" Pegaso front (no disc or axle) and €20 (33 shipped) speedo drive for the Pegaso wheel to use as a spacer.

Just trying to gain a little height in the rear and keep geometry. Its a little easier to find 18" tires but thats not what im going for so much. The main thing is that I want to run spoked wheels instead of the aluminum wheels that came stock with my bike. And since Im blowing all this cash on the suspension and lifting the bike and will be in the market for a new rear I might as well go to an 18" while im in the process. Makes sense to me anyways.

I'm in the US and they either wont ship or it will cost so much it wont be such a good deal afterwords. The 215 wheel is just overpriced for how trashed the wheel is and Im a jerk and dont want to pay that much for such crap. Haha thanks though!

I remembered you have the cast wheels right after I hit send....

Try these guys. I've had good luck finding BMW parts from them at a decent price: http://www.re-psycle.com/

On another note I got my forks in the mail the other day and they are beefy as all hell and Im dying to get my rear shock. The bike is painted Il post some pics soon and im picking up a front wheel and tire next weekend for 100 bucks with brake caliper and master. LIfe is good its friday!!

What are your thoughts on rebuilding the forks myself? I have done just about everything mechanical to cars and bikes and know that I can do it but is there a big advantage going to a suspension guy and having them rebuild and respring? For the money I figure I could get the tools and parts I need and save a bunch of cash for beer all while learning a bunch and in the future be able to do it all myself even easier? Am i thinking clearly or dreaming?

Also would special valves like racetech gold valves or any similar product make a huge difference and are they very hard to install?

Im a newb to a lot of this so sorry for all the questions

Will look ten times better once the suspension and wheels are on!


Those damn rubber nuts in the windscreen bracket tore apart so im waiting on some new ones to mount the windscreen. Its painted the same OD

You're not going to gain much height with an 18" vs 17". On the face of it, it looks like 1", but only a 1/2" that is below the axle. Even less, because typically the overall height of the tires really isn't all that diffrent because the sidwall is typically taller on a 17" tire than an 18".

Your other reasons...all well and good, but don't expect a noticable height change.

Usually there is worse selection for 18" DOTs than 17" DOTs. There is a better selection for agressive 18" DOTs.

Just about every tire I would like to use comes in an 18 and every one of them are either the same height or taller in some situations than the 17" version. So an 18" wheel with tire will just about always be taller than a 17" with tire. Im a little confused here?

Also Im putting yz forks on my gs i would say it should be obvious that im looking for aggressive DOTs.

love the green!

i like the color!

g'day, i revalved 46mm yz forks two years ago . brake dive is the problem you will get with home tuning. a shop can sort this out ,but could take them a few try's to get it about right. i was about to revalve for a 3rd time to settle for a offroad,onroad combo, that give's a plush feel,but firm's up progresively,and eliminates brake dive.....but ive busted my foot.if you want to learn from scratch like i have,buy racetech's suspension bible. goldvalve's are awesome. it's a journey, but rewarding and enjoyable to.

If the tire is the same height (overall, installed) you will not see any Increase in ride height, no matter what wheel diameter you have.

Selection is a major reason to go to an 18".

Still confused...

If a 17" tire is sized at 140/80/17 then its height is 80mm from the lip of the rim to the top of the tire.

If an 18" tire is sized at 140/80/18 then its height is 80mm from the lip of the rim to the top of the tire.

So the 18" tire is an inch larger overall every time.

Am I looking at tire sizes all wrong?

Thanks for the insight. I read that most of the fine tuning is done with the amount of fork oil used. Of course this is after you find the right spring rate and oil weight but I was sort of hoping to get a decent base line from all the people who have already done the swap.
I weigh about 165 and my bike is only slightly lighter than stock I will remove the abs, iv ditched a few bits of plastic here and there and have already gone with a ballistic battery which weighs about 2lbs. From what I have read so far Im thinking something like .50 or .49 springs.
What oil weights are you all running? If i can get those two questions close to answered I figure I will just put the least amount of oil possible and then just fill accordingly to do the fine adjustments. What else is there to tuning the forks? There must be some people on here who know what they are doing with the fine adjustments. Tell me your secrets!

The changes done are in shims, and will make a big difference, one shim only was changed on the one I have seen

It is a mistake to think a dive problem can be resolved with fluid weight and level alone

80 doesn't indicate 80mm, but rather 80% of the width (aspect ratio). The 1 inch rim difference only makes up 1/2 inch height difference if you put both next to each other on an axle. The second 1/2 inch only fill in the air between the rim and the mudguard.

https://www.denniskirk.com/help_center/tire-sizes.jsp
http://www.goodyearautoservice.com/content/content.jsp?pageName=TireSize
http://www.autobytel.com/car-ownership/maintenance-repair/car-tire-sizes-explained-what-the-numbers-and-letters-on-your-tires-mean-105706/

an inch in diameter of the rims with the same tyre will only gives you an half inch rise...
Why... Because you have to remember that the radius of the rims from the lip to the centre of the axle.
It is like switching from a road tyre to a full knobbies tyre. There are other ways to raise the rear. Longer shock, shorter dogbones, full knobbies and etc.
Like most of them have said, going 18' rear or 21' front gives more options of running full mx tyres

I have done the fork conversion with 03 yammy forks (46mm) and am chasing some .52 or .54 springs. Not having much luck getting hold of any here in sunny Queensland or Australia for that matter. Can any one point me in the right direction where I could get a pair?

You need to find the specs for the overall installed height of the tire/rim combo and divide the difference from stock by two.As gravel seeker mentioned the number is an aspect ratio, but even then the accuracy of that number is often a little off. Even more so with aggressive knobbies, because every manufacturer might choose a slightly different place on the knob height to call the sidewall height due to wear...knobbies tend to have very deep treads compared to other tires.

I knoW for a fact that 18" and 19" wheel/tire combos have very nearly the same overall height, the reason for the narrower sidewall on the MX bikes is better handling on groomed MX tracks, where the enduros get 18's and a taller sidewall too help deal with roots and rocks.

In the above scenario you would get a "lift".of about 15mm or 5/8" assuming that the numbers are accurate, If you used 130s it would be less but again you are better off finding the installed overall heights if you can.

"The 130 designates the tire's width in millimeters, measured in a straight line through the tire from one edge of the tire's tread to the other. The second number, 90, is a bit trickier to understand. This represents the aspect ratio between the tire's width and its height, or how tall a tire is in relationship to its width. Simply put, the higher this number is, the taller the tire will be. In this case, the tire is 90 percent as tall as its width, or 117mm."

From here:
http://www.americanmotorcyclist.com/Riding/Street/Resources/TireDesignations.aspx

So if you are looking at the same tire a 130/80 will be the same height in a 17 or 18". Same height from the rim that is...

If the rim itself is 1" bigger diameter then you'll have 1/2" above and 1/2" below the axel so 1/2" of added height.

I'm not 100% sure of it works on the F650GS shocks but another way to raise the rear ride height is to add a shim or stack of fender washers on the shock clevis. This is done the GSXR-750 to raise the rear up for race use.