So after much thought and reading on what guys use to setup their 49mm Mid Glide forks on the Fatbob and Streetbob I figured I would throw in my recent experience. Being that $$ is tight everywhere I thought I would do a budget setup first and see what potential was hiding within these forks. I will give info on 2 setups that I did this weekend on 2 different bikes. First a few pieces of useful info and required items.
The original metal spacer that came in forks is 11 inches by 38.5mm OD
I used 1 1/4 inch Schedule 40 PVC from Lowes 11 5/8 by 43.5 mm OD(more on this later)
I also used the Motion Pro Pt# MP 08-0139 socket to ease reassembly as it can be a pain to do with an adjustable wrench and damage the finish of the cap or worse cause cross threading into the fork. highly recommended to use the MP socket.

The lowdown... I came from riding sportbikes for 20 plus years and racing MX for 5 years and have had many high end suspension setups and many dialed in stock setups on various race bikes so I know what I like and what I was looking for. In stock for on my 06 Streetbob the ride height was riding too low and the damping was virtually non existent. I could blow through the travel hit the bottome bumpers and rebound back to the top out spring on one wave in the road. I chose to setup my suspension to provide maximum travel and proper ride height. I will provide info on a budget lowered setup after this. Total cost Add $6 bux!!

The initial measurements... After much reading the general concensus was that these forks should sag 25mm or approx 1 inch with the rider on the bike. So I wrapped a zip tie around the fork upper and topped out the forks by pulling the bike up onto the kickstand to unload the fork and slid the zip tie down to the lower. I then sat on the bike and pushed the bike down and let the forks come back to their natural ride height with me on the bike. I made sure zip tie was resting on the lower slider and then measured the differnce in where the zip tie ended up compared to where the forks were when topped out. This determined I was riding 5/8 too low.

The oil selection... Stock oil was standard HD Type E (5wt) oil which is total garbage and should NEVER be used on this bike. many guys have used Screamin Eagle Pt#99881-87 (15wt) oil with success but guys weighing over 220lbs complained of this being too light. I weigh 265lbs so I was recomended by Bel Ray to use Bel Ray 20wt for this application. So I did.

Diasassembly... My bike needed the neck bearings greased and the updated Clunk Fix (search Clunk Bulletin) for info. So I followed my service manual for removal of wheel,fender,forks to remove forks from bike as they have to be pumped and drained to ensure complete drainage anyways. Plus you avoid potential damage to the tank or any other parts of the bike resulting from the preloaded springs and easier reassembly later.Follow service manual to remove top cap/ spacer/washer/spring .

After draining the forks for overnight and pumping out the fluid until I was sure they were as empty as they can be short of complete teardown(not needed) I was ready for reassembly. First I needed to cut my new PVC preload spacers with and additional 5/8 length. So I chopped the PVC spacers to 11 5/8 inch. This will give me the 1 inch loaded rider sag I needed.

Reassembly... I bartered Bud Light for additional hands to help on reassembly as I dont have a fork holder tool or a work bench. I put a folded towel on my porch and laid out all of my components needed for reassembly with a measuring cup and new oil. All components are cleaned with brakleen and the PVC is wiped down inside and out. The manual recomends approx 27-30 oz of oil per leg so I dumped in approx 25 ozs and pumped out all air bubbles until action was smooth. I measured the distance of the oil from the top of the leg with a Harbor freight caliper. HD specs 110mm from the top of the leg to the oil with leg compressed to bottomed position. Once satisfied I extended the fork leg and dropped in the spring/washer/new spacer and reinstalled the cap. I held the cap straight and down while my buddy spun the fork leg into the cap I was holding down and LEVEL. Care must be taken to assure no crossthreading happens here. I did the same for the other leg and reinstalled the front end and went riding.

Initial impressions... Remember I like stiffer setups as thats what I am used to. Sat on bike and cycled the forks and they felt great. I had my initial sag of 1 inch and by holding the front brake I could push them down another inch or so. Got up to 40MPH and grabbed a handful of brake and the forks would drop in nicely and still had plenty to spare for bumps. The PVC fit much more tightly in the fork leg and deadens spring noises so I noticed no more noise out of my forks as well.

Gone riding.... I immediately went to the roads that gave me problems and bottomed out with the old setup. I aimed for every wave/dip/ and jacked up pc of pavement I could find. The forks just soaked up the hits and many bumps were not even felt enough to think about. No front end dive,no excessive brake dive,no mid corner fork dive. Well, dive is not a problem.

I would recommend 15 wt Screamin Eagle oil for anybody that weighs less than 220lbs, or if you are more of a cruiser kinda rider.

I setup my buddies bike as well and he weighs 175 so his spacer was a shorter length and we used SE 15wt oil and although too soft for me he was totally happy as well.

I have to grab a couple of part numbers and I will add how to lower your forks while still not killing the performance.

Total cost was $33.00 for oil and PVC.... I highly reccomend to anybody not happy with the performance of the 49mm forks to at least give this a try. You may be surprised how well these forks will work.

 

Sounds like an cheap and awesome upgrade! Thanks for sharing your experience.


I have some progressive springs sitting my garage I plan to put in, I think I'll follow your advice on setting up sag and go with the SE oil. I hope the springs help out a bit more than the stockers, I got them cheap on Flea bay since they are the older, non drop in style. I don't mind tearing down the forks, it's easy to do.

 

As many of you guys remember the Progressive NON Drop in kit required an additional top out spring under the damper rod to limit extended length of the fork. This does require more in depth dissassembly so refer to your service manual regarding this. But here is the part number for the HD top out spring which I will be using sometime in the future to do a budget lowered setup.
HD Pt#46517-01 (2) reqd 1 per leg Total cost $6.00

I will be reusing the stock springs to retain ride quality and would probably reccomend sticking with 20wt oil on this setup as the reduced travel will require the additional damping to prevent bottoming.

I will also be using a 3/4 inch loaded rider sag measurement to net an extra 1/4 of useable travel.

This setup will give a 1 inch lower stance while retaining a decent ride quality. Considering how bad the setup was from the factory this will probably ride better than many of our stock setups all while giving a better looking lowered front end.

I havent done this yet as I didnt want my bike lowered becuse I am thinking of moving back to the mountains where peg clearance is worthwhile. So if you choose to go this route I havent tested it but thought many of you would like to know this info.

 

Nice scientific job of dialing in the forks. Also thanks for the in depth write up. I have the SE fork oil in mine shimmed the spacer for less sag but still have a little fork resonance noise when I hit a sharp bump (steering head has been addressed). So I will take your tip and try the 1 1/4 PVC.

 

I am glad I could help. The PVC fits like a glove and the sound deadening charactaristics is much better than the OEM spacer. I am gonna take the dough I saved and buy new bars and risers.

 

The sag measurement you will use should be approx 1/3 of remaining travel determined by the amount that you lower it. So subtract the amt lowered from the OEM overall travel and divide by 3. This will give you the optimal desired loaded rider sag.

 

That is the thing, I don't want to actually lower the bike at all. Is that possible with the springs I have or are they strictly for lowering purposes? If that is the case, I'm leaving the stock springs in.

 

Depends on what kit you have from Progressive. They have 3 setups for the 49mm forks.

The Drop In Lowering Kit Pt# 10-2002
The Standard height spring kit Pt#11-1525
The NON Drop In kit that required full disassembly of forks to install. Pt#10-1566

If you have the Standard height kit then you will need to install the springs and completely button up the job and check sag, Then if needed you may have to remove the top cap and pull the spacer for adjustment to obtain the 1 inch sag. What part number kit did you get? The only one I would use if I didnt want to lower the bike would be the Standard Height Kit Pt#11-1525 for what you are trying to accomplish.
If you have anything other than pt#11-1525 I would not use them for your application and would either keep them for later use or sell them on Ebay or here on the board to someone who wants a lowered setup. I would suspect the rates will be increased on those kits to reduce bottoming of a lowered setup. The OEM springs are plenty stiff for standard ride height applications especially considering I weigh 265 and they are plenty for me.

 

Could not find a part #, but the instructions say lowering kit...I have the two main springs, 4 smaller springs and two metal spacers.

Looks like they need to go down the road and I'll be keeping my standard springs. I don't weigh that much so it sounds like my stock springs should be fine. Thanks for the help.

 

That is the Pt#10-1566 old style lowering kit. Glad I could help.