Upside Down Forks Part II

[aviationfred]

This project actually started the day back in August that I purchased this FJ. I contacted Dan (giantkiller) about a set of fork extensions for a set of 2008 GSX-R1000 forks. I was in no hurry, as I knew the project would not fully kick off until after the new year. Too my surprise, he delivered a set a week later at the Central FJ Rally in Wisconsin. Fast forward 8 months and the project is now under way. The old front end has been removed, the ABS system has been 90% removed, all that remains is the rear brake system. The plan is to get the new front end installed tomorrow then begin the FZ1 swing arm install.


Fred

[Pat Conlon]

Looks cool Fred Are you thinking about keeping the ABS function on the rear wheel?
One thing I found out with a '93 I worked on, to keep the ABS working on the rear wheel I needed to keep the ABS front rim with the sensor to keep the computer happy so it ruled out a 3.5" FZR front rim.
I did disable the front ABS with a FZ-1 m/c, ss lines, and R-1 calipers. I did need the 3 wire m/c switch mod to keep the ABS trouble light happy.

[aviationfred]

Looks cool Fred Are you thinking about keeping the ABS function on the rear wheel?
One thing I found out with a '93 I worked on, to keep the ABS working on the rear wheel I needed to keep the ABS front rim with the sensor to keep the computer happy so it ruled out a 3.5" FZR front rim.
I did disable the front ABS with a FZ-1 m/c, ss lines, and R-1 calipers. I did need the 3 wire m/c switch mod to keep the ABS trouble light happy.

I am disabling the ABS system. In the photos that you see the yellow shock coil. The ABS pump has already  been removed. The Suzuki wheels that are being installed do not have ABS hubs for a sensor to mount in. You can also see in the photo with the connectors ty wrapped together, the ABS computer has been removed


Fred

[aviationfred]

I went a different route with the steering stem with this mod. The upper triple uses a similar bushing to take up space as the first mod. The lower triple had the hole enlarged slightly and a bushing made that is a very tight press fit into the lower triple. The steering stem is then press fit into the bushing. As an added measure, I added a threaded hole in the lower triple and installed a set screw that bottoms out on the steering stem.

Fred

[fj1289]

Fred - what year are those triple clamps?  Do you know what the offset is?

Looks good!

[aviationfred]

Fred - what year are those triple clamps?  Do you know what the offset is?

Looks good!
[/quorte]



The triples are from a 2008 GSXR1000. Honestly, I don't know what the offset is.


Fred

[racerrad8]

I went a different route with the steering stem with this mod. The upper triple uses a similar bushing to take up space as the first mod. The lower triple had the hole enlarged slightly and a bushing made that is a very tight press fit into the lower triple. The steering stem is then press fit into the bushing. As an added measure, I added a threaded hole in the lower triple and installed a set screw that bottoms out on the steering stem.

Fred

Fred,

I thought about the bushing aspect of the FJ stem in the lower triple. My concern with the R1 lower was that it is "thicker". The stem lacks about a 1/4-5/16 of an inch within the lower. I also thought about the set screw installation but, that too did not give me any confidence in the strength required.

I thought I posted a photo of the stock stem next to the modified stem I had machined, but it in not in my build thread. When I get to the shop this weekend I will snap a couple of shots of the difference. I lengthened the stock stem by welding and then a should was machined into it to replace the snap ring. There is zero percent chance the lower triple can ever slip down or off of the stem now.

The biggest thing that changed my mind about the bushing and the use of the shorter stock stem with a set screw really boiled down to the factory snap ring. The snap ring prevents the stem from coming up through, or the triple slipping down on the stem. The load of the triple is high to slip down or off of the stem due to bumps in the roadway compressing the forks. So, large, sudden jolts to that compression might cause the triple to slide down the stem.

I never gave it any thought until I saw the factory Yamaha snap ring and started really giving it a lot of thought. My concern is if the triple slip on the stem, the bike can come down onto the front tire; that would be catastrophic.

I will post up some pics in both topic this weekend.

But until then you can go over to my build thread and see the finished stem: http://www.fjowners.com/index.php?topic=17424.msg178197#msg178197

Randy - RPM

[aj52]

Fred - what year are those triple clamps?  Do you know what the offset is?

Looks good!

Got it from a Suzuki site when I started my project December

[aviationfred]

I went a different route with the steering stem with this mod. The upper triple uses a similar bushing to take up space as the first mod. The lower triple had the hole enlarged slightly and a bushing made that is a very tight press fit into the lower triple. The steering stem is then press fit into the bushing. As an added measure, I added a threaded hole in the lower triple and installed a set screw that bottoms out on the steering stem.

Fred

Fred,

I thought about the bushing aspect of the FJ stem in the lower triple. My concern with the R1 lower was that it is "thicker". The stem lacks about a 1/4-5/16 of an inch within the lower. I also thought about the set screw installation but, that too did not give me any confidence in the strength required.

I thought I posted a photo of the stock stem next to the modified stem I had machined, but it in not in my build thread. When I get to the shop this weekend I will snap a couple of shots of the difference. I lengthened the stock stem by welding and then a should was machined into it to replace the snap ring. There is zero percent chance the lower triple can ever slip down or off of the stem now.

The biggest thing that changed my mind about the bushing and the use of the shorter stock stem with a set screw really boiled down to the factory snap ring. The snap ring prevents the stem from coming up through, or the triple slipping down on the stem. The load of the triple is high to slip down or off of the stem due to bumps in the roadway compressing the forks. So, large, sudden jolts to that compression might cause the triple to slide down the stem.

I never gave it any thought until I saw the factory Yamaha snap ring and started really giving it a lot of thought. My concern is if the triple slip on the stem, the bike can come down onto the front tire; that would be catastrophic.

I will post up some pics in both topic this weekend.

But until then you can go over to my build thread and see the finished stem: http://www.fjowners.com/index.php?topic=17424.msg178197#msg178197

Randy - RPM

I had the same concern. When the machinist opened the bore of the lower triple, he left a 1/8" tall band that the stem seats against, making it nearly impossible for the stem to press through the bottom of the triple. Add in the extremely tight press fit. The steering stem sat in Liquid Nitrogen for 30 minutes before it was pressed into the lower. Then I added the set screw. Also, remember the steering stem goes through the upper triple and has the acorn nut. With everything bolted together, I would think it would take a catastrophic front end hit for the steering stem to move at all.


Fred

[aviationfred]

More progress this evening. Hopefully the front end will be wrapped up tomorrow.


Fred

[andyoutandabout]

It may be frightfully un-British, but I've got a mod boner.

[giantkiller]

Mine has killed a deer. And I'm a little bit addicted to too much power. And have had many a time had to drop the front down hard. And haven't had any problems. Maybe if you don't have everything clamped down good it might. But that's part of why I made the extensions. With the three bolt clamps. Instead of the set screw. Maybe overkill but is pretty solid.

[aviationfred]

Here is the link for the company that I got the handle bars from. https://www.woodcraft-cfm.com/cgi-bin/commerce.cgi?display=home

I used the 50mm diameter with a 3 inch rise.


Fred

[aviationfred]

The front end is complete



Fred

[giantkiller]

The front end is complete



Fred

Looks great! Fred. Like I said I can't do anything like that right now. All my time and money is going to this f in house. So I have to live through you and any other projects on here. Thank you very much.