Front Suspension Tuning with Progressives

[Cdnlouie]

When I first purchased my 85VR, I replaced my original fork springs with progressives. The spacer length is a key part of tuning your front suspension. I followed the recommendation supplied by Progressive in the information provided for the Venture Royale and ended up with setting the plastic spacer on each side to 1.25 inches.

 

I prefer to use the "oil height" measurement method since you never can tell just how much oil has really drained out and you really want to end up with an accurate amount of oil in each tube since it does seriously affect ride quality. To set up your forks this way you need to take the weight off the front end (with a floor jack under the front of the engine). There is an excellent article in suspension tuning by Jack Chalais showing all the details of getting things out of the way to access the fork tubes.

 

The "oil height" measurement must be done with the forks completely compressed and the springs removed. You can block under the front wheel to compress them, I prefer to take the wheel off and compress each one much more easily while still in the triple tree.

 

Now the setting for the oil height following the Yamaha specification results in a 5.5 inch air space from the top of the fork tube to where it first touches the oil. A simple tape measure works great for this job. Just shine a light down the tube until the end of the tape hits the oil and check your measurement.

 

When you're done, extend the fork tubes and install the springs. This makes the fork cap install easily, as there is very little pressure on the springs at this point. You only need to lightly tighten these caps as the pinch bolts lock these in very tight (Don't try to remove them without loosening the pinch bolts first). Put some silicone grease on the o-rings to keep a good air seal.

 

Now the results of all this setup proved disappointing. Everything was set to spec but it rode very harsh and did not turn into corners without significant pressure on the bars. I even removed the air line from the compressor and left it open to the air so there would be no residual air pressure at all (the system retains some minimal pressure as long as it is hooked up, you can only get zero air pressure by removing it from the compressor). I decided to put a few miles on with these settings and next fork oil change do some tweaking.

 

Before my ride to the White mountains this summer I drained the fork oil and set about reducing the plastic spacer height from 1.25 inches to 3/4 inch on each side. Others have used this setting and seem to have achieved a more comfortable ride quality. In addition to cutting the spacer I felt that I would also reduce the amount of fork oil in each tube. I put in about 375cc which resulted in an "oil height" of 6.5 inches, an inch lower in each fork than the recommended amount (400cc). I used 10wt Belray fork oil as my own personal preference.

 

Dropping the oil height increases the depth of compressable air in each fork which changes the compression rate of the air shock effect. The net effect is you have a softer ride with the lower oil height. This is something to consider for anyone who is complaining of a harsh ride on the first generation Ventures. It would be good to know "how low you can go" to maintain adequate damping but 25cc seems to be in the safe zone (I put 4000km on through the Adirondacks, Green Mountains and White Mountains fully loaded and the VR handled like a sport bike).

 

Now, I tested the bike with these settings (for the record I am an 185lb rider) and noted that it rode like a cadillac. No more bull riding with the Venture, hitting raised pavement at highway speeds (100km) no longer created bone jarring reverberations. Now, I anticipated that loaded, I may be a bit too soft for good stability, so I hooked up my front air line to the compressor again and left the setting at the normal residual amount just in case I might need some air when riding two up and loaded.

 

The results this time were fabulous! Riding two up and fully loaded I never added air to the front more than the residual pressure in the system. The suspension was compliant and comfortable at all times, what a treat! Cornering was a whole new experience, as the Venture would fall into the corners through the White Mountains of NH with minimal effort and stand up coming out of a corner by simply rolling on the acceleration of the great V-4. This is the way a motorcycle should handle!

 

I can't guarantee that this will work for another Venturer's bike, but when using progressives I highly recommend using the 3/4 inch setting to start and reduce length for soft or increase for hard. If you are still too harsh reduce you oil level (by the oil height method) and see if that does not put a smile on your face.

 

If you're going to ride, it might as well be a good ride!

[bongobobny]

Fantastic info!! You are welcome to come down and supervise when I redo the replacement later 1st gen front forks I have for my scoot!!!

 

 

Ask Wizard 765, we feed you well!

[Condor]

Cornering was a whole new experience, as the Venture would fall into the corners through the White Mountains of NH with minimal effort and stand up coming out of a corner by simply rolling on the acceleration of the great V-4. This is the way a motorcycle should handle!!

 

Ain't that a great feeling........

[GeorgeS]

Remember, If you Install the Progressive Springs in the 1st Gen, the Progressive springs, are made of Larger Diameter material. Which takes up more space in the tubes.

 

So, you must Reduce the amount of Oil, to maintaine the same Oil height as the Stock set up. As I recall, I put in about 1 Oz. less oil.

 

You can also, play around with #15, #10 wgt oil, to adjust the ride.

 

I went with #15, ride seems good, however next time I change the oil, I will try #10.

[Cdnlouie]

Hey Bongo I would be happy to help anytime. We are pretty close neighbours once I looked up where you are. We should connect up some time here or there. I actually scoot over to Buffalo a fair bit to pick my grandson up at the airport and bring him up. I have not been able to meet up with any fellow Venturers and would love to do so some time.

[mother]

great write up Louie, i did my progressives over the winter, 1 inch spacers, 200 ml each fork, which is about 1/2 inch below top of forks with units compressed. rides like a cadillac,

Cheers, Scott

[rhncue]

great write up Louie, i did my progressives over the winter, 1 inch spacers, 200 ml each fork, which is about 1/2 inch below top of forks with units compressed. rides like a cadillac,

Cheers, Scott

 

Being the inquisitive type, I was wondering how you were able to measure the oil level in the compressed forks?

 

Dick

[Gearhead]

Do you think that the improved handling (as opposed to the ride quality) came as a result of the front end being lower, reducing the rake angle?

 

Do you have a stock rear shock? If so, you are almost definitely sitting low in the rear, even at full pressure. A Progressive spring or shock assembly helps get the rear up which has a similar effect on the rake angle.

 

Thanks for your input. I like the Progressive fronts better than stock (mush), but I too find it just a bit harsh with factory oil quantity and just over an inch of preload.

 

Jeremy

[bongobobny]

Hey Bongo I would be happy to help anytime. We are pretty close neighbours once I looked up where you are. We should connect up some time here or there. I actually scoot over to Buffalo a fair bit to pick my grandson up at the airport and bring him up. I have not been able to meet up with any fellow Venturers and would love to do so some time.

 

 

Any time, brother, any time!! We share a lot more in common than you think!! Perhaps Marcarl and wizard 765 and us can meet for dinner in Ft Erie or St Catharines or something as well!

[Cdnlouie]

Time to answer some of your keen comments:

 

George, you are absolutely right on the larger diameter (thickness of spring) progressives, as well as the longer spring length, which is going to displace more oil and increase the oil height once installed. Progressive recommends a maximum O.H. of 5.5 inches or 140mm but I am sure that would exceed the stock O.H. using OEM recommended 400cc (or 400ml), thereby making them rather harsh.

 

Scott, you may have answered the question "how low you can go" with 200cc per tube. That's half the recommended amount (from dry). If you refilled wet that may equate to about 250cc (guessing on that one). I would like you to clarify what you mean by an oil height of 1/2 inch below the top of the forks, as O.H. is normally measured with the springs out and the forks compressed (ie. blocked up without spring pressure)? With 220ml I would guess that would put you at least 8 inches (of air) below the top of fork tube with the springs removed.

 

Jeremy, cut the spacer and reduce the oil height to 6.5 or lower and you will be very happy. The turn-in cornering feel is definitely related to front triple tree height in relation to the rear height. I have the original rear shock, so I definitely ended up with being too high, and too harsh in the front until I made the changes noted above.

 

The oil height and spacer adjustment is a critical part of suspension tuning when installing progressives. Get these two settings right and it is a marked improvement, get them wrong and you wonder why you spent all this time and effort to end up with an uncomfortable ride.

 

Good thoughts on this topic guys, installation is one thing, tuning is another.

[cimmer]

Thanks for the information as I plan on doing the progressive swap out this winter on my 89VR. I would prefer it to be a nice riding good cornering upgrade then too harsh. I am sure I will use your information and get it right.

Thanks again.

Rick F.