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Hi all, hope everyone had a great Christmas. Now I’ve fitted the air ride system to m6 trike and fitted Brembo 4 piston callipers I get a knock when hard breaking. I’m guessing it’s the front forks bottoming out. When I jack the front up I’m supprised how much of the fork tube comes out the sliders. Any one ever beefed up the front forks. I have the 2” conventional forks not the 64mm inverted. I’ve changed the fork oil. I can live with it just wondered if there was was a spring upgrade. Thanks

The later model front suspension (at least from 2007)spring tension is adjustable; if you have that, it should solve your problem.
Look on top of your triple tree, above each fork tube for a machined hole (might have a removable cap covering hole) that will have an allen screw inside. Turn it clock-wise with an allen key to increase tension on fork springs.
Rick

On my previous 2000 Big Block which had the conventional front end, I added a longer preload rod which gave me more spring preload which corrected my fender hitting the fan issue. When you unscrew the allen cap which has long threads, there is a steel rod that the threaded allen screw/cap pushes down on creating more spring preload. Pull out the that rod, and cut one longer, drop it in, and reinstall the cap. You'll see it takes a little more strength when pushing that cap back in to start the threads. At the time i did this, there was no spring upgrades that i knew of, hence the choice to length that preload rod.

Thanks Orlando. That I think that’s the way ahead. I believe the early forks were bespoke so finding stiffer springs like progressive would be difficult. Do you remember how much longer you made them ?. I’ll have a look at the weekend. Thanks again.

Grand Canard wrote:The later model front suspension (at least from 2007)spring tension is adjustable; if you have that, it should solve your problem.
Look on top of your triple tree, above each fork tube for a machined hole (might have a removable cap covering hole) that will have an allen screw inside. Turn it clock-wise with an allen key to increase tension on fork springs.
Rick

Thanks Rick, unfortunately I have the old forks. No preload adjustments.

You may try to "overfill" the forks by 100ml and use a heavier forkoil. Worked pretty good on my own and other bikes.

No unfortunately i don't remember the total length. I might have added about 1/2 in.

Good luck.

Just for an update I lifted the front and measured the fork fully extended then dropped the weight back down. I went for a quick ride with Zip ties around the forks. The results are. There is 3” of sag stationary and I have 1” of dive with heavy breaking. No wonder I’m bottoming out !!! Bit of experimenting I think. Thanks to all.

Seems like to me you should be riding at about half
or less of the full travel. If it's dropping 3 of the 4 inches
of travel you have maybe you should add a spacer
over the spring to bring it back to the middle of travel
or a little above the middle. In the old HD glides
a 350 Honda fork tube was just right.

Paul H

Paul H wrote:Seems like to me you should be riding at about half
or less of the full travel. If it's dropping 3 of the 4 inches
of travel you have maybe you should add a spacer
over the spring to bring it back to the middle of travel
or a little above the middle. In the old HD glides
a 350 Honda fork tube was just right.

Paul H

Thanks Paul. That’s pretty much what I thought and what others have said. So today I went about it. I cut two .6 spacers from some 1.5” tubing I had. I did the R leg and reassembled. When I did the left leg the spring had a plug cap on it. I assumed they would be the same. I left it where it was and added the spacer. I will also add more oil. It’s done the job . Brought the front up another 1.5”. Any ideas thoughts or opinions on the cap appreciated.

No reply’s to my question about the spring cap so I’m going to assume there should be one both sides so I’m going to get a pair made with the added 1/2 “ unless someone has one available ??