Raising the front forks - Kawasaki KLR 650 Forum
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

 
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post #1 of 8 Old 09-14-2009, 07:41 PM Thread Starter
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Raising the front forks

I run Dunlop D607 front and rear and have a fork brace with Progressive springs. I an also running a Progressive rear shock, the new 465 series that I like! I have a tank slapper like problem that happens around 75 mph. http://www.klrforum.com/images/smilies/action/41.gif with a rear weight bias on the bike. I am thinking of raising the front forks to get more weight on the front end. Steering head is good and so are the swing arm bushings. Any Ideas?
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post #2 of 8 Old 09-14-2009, 09:58 PM
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faller -

Please be careful working this problem - tank slappers are unnerving and dangerous. But then, you already know that...

Can you try moving a few pounds forward with a tank bag? Have you tried leaning over the tank (which should move quite a bit of weight forward) at the onset of the slapper?

I don't think that raising the forks is going to materially affect the rake of the bike or change the wheel base. Fork rake and trail won't change.

Are you running fairly high pressure in the front tire? If so, reducing pressure may help. If you have the forks set up stiffer with those springs you may be getting a bounce that initiates the slapper.

Did this start with the suspension changes or with the installation of the tire?

Tom
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post #3 of 8 Old 09-14-2009, 10:17 PM
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Are we talking about a speed wobble? I'm not familiar with the term "tank Slapper".

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post #4 of 8 Old 09-14-2009, 11:14 PM
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Hardyreels -

Yes, a speed wobble.

In it's worst incarnation the handlebars traverse nearly their complete arc, almost hitting the tank. Hence the name.

I've only had a severe slapper once - on my CB350 running a bit of a downhill coming into San Luis Obispo at 1 am on Highway 1 at almost 100mph.

A little rear brake stopped the wobble.

I went from 19 years old to about 79 years old in three seconds...

Tom
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post #5 of 8 Old 09-14-2009, 11:47 PM
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OK, thanks Tom for getting me on board.

Here is my list of possible causes.

Check tire pressure fore and aft.

Front tire balance and mount, check the bead of the tire in relation to the rim. Even the slightest bit of out of round in the seating of the tire on the rim will result in bobbing and weaving at higher speeds.

Steering head bearings or loose spanner nut on steering head.

Loose upper or lower fork bridges.

Check to be sure that the mini fairing is in proper alignment with the frame. Stand a distance in front of the motor cycle while a friend holds the bike in a balanced upright position. If the aerodynamics are off that can affect stability at high speeds.

DO you use a tall wind screen?
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post #6 of 8 Old 09-15-2009, 12:24 AM Thread Starter
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The problem was worse before I changed the suspension components. I run the pressures 36 front and 34 rear, almost all paved roads. The guy that set things up for me also works on my 03 R6 that I race in OMRRA 600 superbike and supersport, I trust him. I am going to raise the front forks 5mm tomorrow and see what happens. Will keep you informed. Thanks for all the advice.
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post #7 of 8 Old 09-15-2009, 01:16 AM
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Suggestions are like noses...everybody has one

Take the time to make the changes one at a time to see which ones work. This will tell you more about the KLR and you.

Tire pressures. Run more in the rear. I run 40psi in the rear and 36psi in the front.

Rear shock. Try adding more rear shock. Cirrently I have a stock rear and I normally run it on 3. I can cause highway shake by shaking the handlebars. If I add more rear shock it removes or reduces the highway shake. In theory I am changing the sag without measurement.

Check and adjust the headset.

These items and the others should get rid of the Highway shake.

Tim

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post #8 of 8 Old 09-17-2009, 05:54 AM
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1. Check you fork oil levels
2. Replace your stock springs
3. Install Ricor Intiminators

Sorted.
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