Springer Fork Modification for the Honda Spirit 750
(In-line Springer Fork)
I completed this modification
Now for the disclaimer: Be prepared, this modification requires a lot
of parts and planning. You need to line up all your parts ahead of time for a
trouble-free install. You should also be aware that the in-line style springer
fork does not have the offset clearance of the stock forks. This means the stock gas tank may not work
because the risers and/or top fork bridge (top triple tree) with hit the stock
gas tank speedometer housing. Solutions
include smoothing the stock tank to get rid of the speedometer housing, replacing
the stock tank with an
Here are the parts you will need to complete the modification:
Essential (required) Parts
1) A stock Honda Spirit 750 steering stem (used is cheapest).
2) A new steering stem lower inner race, bearing, steering stem lock washer and dust seal. You can use stock Honda or a full aftermarket roller bearings, races and seals like “All Balls”, if you want to switch to roller bearings. Either way, you should replace bearings if needed and the race/dust seal in all cases. I recommend new stock parts from Service Honda, aftermarket parts from Billski.
3) A springer fork – wide glide width. You should get one with the ¾” axle, spacers and risers included (get the best deal you can on Ebay).
4) A Harley 21” front wheel and disc (it’s a good time to move to that 21” front wheel). Make sure your seals and bearings are good and the true the wheel if needed. Note: you could use the stock 19” wheel with a bearing swap. The advantage is it’s cheaper, but the 19” looks a little too small in my opinion.
5) A springer brake caliper and springer brake caliper bracket. I used a steel bracket fabricated by Fabricator Kevin and a Tokico 4 piston caliper (sold by Fab Kev) – or you can search for Springer Brake Caliper Bracket on Ebay. You can also used a stock Harley front caliper that was a “take off” from a low mileage Harley. These are cheap and readily available on Ebay. Make sure you get the correct caliper for side your brake will be on (remember you need the right side caliper for the left side disc because the springer bracket reverses the caliper position.
6) A new headlight and mounting block – any aftermarket Harley headlight will do as long as it has a bottom mount. I used a Bates style headlight.
7) Front turn signals and clamps – ditch the stockers, if you haven’t already, and get some aftermarket signals. I used 1” P-clamps to mount my bullet turn signals just below the top fork bridge – this creates a very clean look. The top fork bridge is the equivalent of the top triple tree on your stock hydraulic front forks.
8) Axle spacers (3/4”) – you can get the axle spacer material from J&P Cycles (or others) and cut to size as needed to precisely space your front wheel.
9) Speedometer and Speedometer pick-up (sender) unit. In most cases you will be eliminating the stock Spirit front wheel speedometer pick-up with the 21” wheel swap. Your options here are to either go with a digital, analog or combination speedometer and a rear wheel pick-up, or get a Harley front wheel pick-up. If you have the money, a Dakota Digital is cool. I’m currently running a 16” Harley rear wheel and rear disc brake with a Harley rear wheel sender and bar mounted speedometer.
1) New brake and clutch lines – want to switch to stainless steel? This is the time, or you can use stock.
2) Gas tank – see disclaimer for discussion.
3) Honda neck stem tool. Honda Part No. 07916-3710100
4) Honda race press tool (optional).
5) Handlebars – get the style you like, but do not get the knurled variety, unless they are knurled specifically for the springer riser spacing.
to installing the springer fork is the stock Honda Spirit steering stem. The
You will need a stock Honda Spirit 750 steering stem. If it is still pressed into the lower triple tree, have your local machine shop press it out with a hydraulic press. You may need to heat the base of the stem to press it out. Warning: be careful, the stem is hollow and a 30-ton+ press can bend the stem.
Figure 1. Stock Spirit 750 Steering Stem and Lower Triple Tree
Remove the lower bearing race from the stock stem too. It’s pressed on and you can remove it with a piece of pipe with the right inner diameter to slide over the neck stem and allow you to pound the race off, or have the machine shop do it.
Figure 2. Bearing Race and Dust Seal
Remove the race and seal after you press out the steering stem
How do you modify the stock Honda steering stem? It’s simple, especially if you have a friendly neighborhood machine shop down the street. Here’s how it’s done: The stock steering stem is hollow. You need to obtain a round steel slug, approximately 4 or 5 inches long, with the diameter as the base of the (Harley) steering stem. Machine (turn down) the slug so that it can be inserted into the stock steering stem being sure to leave the bases of the stem the same diameter and thickness as the (Harley) steering stem. The idea is that the stock stem will have the same base as the (Harley) neck stem that fits the Springer fork.
Note: the Honda stem is tapered and the Harley stem is not. The Honda stem is slightly longer. The Honda stem is modified at the base to match the Harley stem.
Have the machine shop drill a hole through the neck stem with the slug in place so you can insert a steel pin through the neck stem and the slug. This pin will hold the slug in place and secure it when it is installed in the springer. You should now have a Honda neck stem that is modified to fit the springer fork
Figure 3. Base of Modified Spirit 750 Steering Stem
Note: machined steel installed in the end of the hollow stem
Figure 4. Comparison
Note: the ends of the two stems are the same diameter. Also note the steel insert on the Honda steering stem is secured to the stem with a steel pin.
Follow these steps to get ready for the fork install:
1) Mod the steering lock
You will need to cut off the stock steering neck lock so that the metal piece holding the lock is flush with the lower neck – otherwise you will not be able to turn to the right because the fork lower triple tree will hit the lock. Trim and file the area down smooth and flush. You will want to use rattle can black to touch up this area before you install the new fork.
Figure 5. Modified Steering Lock
2) Mod the springer top bridge
The springer fork top bridge is like a top triple tree. It simply clamps across the tops of the two rear fork tubes and neck stem. The stock top bridge will not fit over the neck stem locknut (the one that actually holds the fork in place on the frame neck) because Honda’s locknut is a larger diameter than the Harley bolt. Modify the top bridge by grinding it out with a grinding wheel so it can sit over the neck stem locknut. It does not take a lot and you can do it without making the top bridge look bad.
Note: the locknut is larger than the opening on the top bridge
3) Install the modified steering stem
Remove the steering stem from the springer fork by loosening the setscrew and sliding the steering stem out of the fork through the lower triple tree. Pin the slug in the stock stem, slide it into the springer until it bottoms out, and tighten the setscrew. You now have a springer that will fit your bike.
4) Install the lower dust seal
Remove the top bridge; slide the seal over the stem until it rests on the bottom triple tree.
5) Install the lower bearing race
Slide the lower bearing race on the stem as far down as it will go on the steering stem (flat side of race down). The stock Honda neck stem is tapered; so the race needs to be pressed on to reach the bottom (against the dust seal). Here’s how you can do it – suspend the fork so that it is resting on the bottom triple tree (I put it over a sawhorse where the fork legs could not touch the floor). Either use the Honda race tool or a piece of pipe that will fit over the stem, but push against the race, to press it on. Gently tap the race down using the tool/pipe until it rests against the dust seal and bottom triple tree. Your modified neck stem should now be held securely in the fork by the setscrew and the pinned slug with the race pressed in. The fork is now ready for installation on your bike.
Figure 7. Modified Honda Steering Stem Installed in
Note: the setscrew on the bottom springer bridge. A new bearing race and dust seal are also installed
The hard part is over. Installation of the springer is now straight-forward. You should be able to remove the stock forks and install the springer in reverse order (from the removal of your stockers). You should use the stock fork top bearing and torque settings. You may have to add a washer to the top of the stem to get it to tighten to the stock setting.
Part II of this write-up will provide the step-by-step on the forks, wheel, risers and the rest.