Slim

I need guidance from those of you that have performed a front end swap (929, 954, RC-51).

The PO of my bike had a 929 front end professionally swapped. It is in fine working condition with nothing apparently wrong. I have spent a good amount of time playing with fork and shock settings and I can easily set up my 'Storm to handle very well (better than a stock 'Storm that i've been on briefly) ..... but, of course, as we all know, this means there is a compromise.

For any type of long distance riding (like the 400+ km weekend I recently enjoyed) my bike's attitude - meaning the overall geometry of the bike, it's suspension and such - is practically unbearable. I keep humping the tank. I'm getting tired of this. It's almost to the point where I loose concentration of my riding because I can become so uncomfortable ('the boys, folks, the boys!). I won't bother getting into how the stock springs are already too weak to begin with.

I know the swap choices we have from Honda don't leave us with great spring rates (okay, let's be honest - they suck) and I know I need to do something about this, but i'd like to hear from fellow swappers if they've already been down this road.

What would I like to hear? Whatever you have to share that'll help.


Current set up;

rider = 155 pounds without gear

bike =

Front - 929 front end, stock springs, tubes raised 13 mm into clamps (necessity for clip-ons to clear tank/fairing), preload adjusters all the way in.

Rear - stock shock and linkage, no height-altering shims of any kind, preload adjuster set between #1 and #3 position (depends on the type of riding i'll do, but even at #1 position I hump the tank).


I know I need to get springs with a firmer rate in the fork and that this will help and this is my next purchase (within a week or two). I'm trying to look ahead and see if anyone has anything to give me that'll tell me what's around the corner, so to speak. I plan on swapping the springs and putting fresh oil in, then seeing where i'm at and 'going form there'. I know i'll need to play with the fork more to be happy with it, but i'm more concerned with sag than valving at this point.

All/any help is greatly appreciated.

cliby

I would start with measuring the sags so people can see where you are at before you alter the springs. You are light - if someone went to the trouble to professionally do the front forks with 929 forks, they might have put the correct springs in - maybe even too stiff for you. But measure off the bike, with wheel unweighted, bike alone and finally you on the bike. Those will tell you if you have the right spring rate and spacer length. In the end, the other swaps are unlikely to help you with the problem you are talking about and a good 929 front end set up well can perform nearly as well (suspension wise at least).
I don't know how 929 fork length compares to stock forks to know if 13 mm into the clamps is an issue or not- Regardless, that length should ideally be set according to handling characteristics, especially turn in, rather than clip on mounting points - there may be alternative clipons with more rise and you could go under the triples, so set it to handle the way you need first, clip ons second.
Stock seat as I recall was very bad for pushing the boys up agasinst tank - I have had a sargent for a long time and can only vaguely recall this - i think the sargent is better, but others with more recent experience can tell you that.
The stock shock is terrible - very noncompliant - even if the front is sorted the rear will beat you up and any bounce will just bounce you forward onto the tank.
Finally, a good athletic cup as a last resort??

good luck. Lots of info here

Gregw

Even after putting some CBR1000 forks on, I was *****-to-the-tank. I added some memory foam to the front of the seat to change the angle. A lot more comfortable now and I don't slide forward unless I want to. I looked at the Racetech site and it says stock 929 springs are .7s, which sounds soft to me. The stockers on the 1000 are .88 which was closer than what Racetech offered. I'm 155 also.

killer5280

I would find a bar solution (In fact, I did find a solution) that didn't require moving the forks up into the clamps so far. The 929 forks are already 1 inch shorter than the stock Super Hawk fork tubes. Pushing them up makes them even shorter and further compromises ground clearance and chassis attitude.

superbling

My F4i forks weren't much shorter so I didn't have the "attitude" problem plus the PO had a full race tech treatment including springs for a 200# rider installed. I actually had to run full soft pre-load.

nuhawk

I thought you were going to be forced to sell your Hawk, Slim! Good to hear you may be keeping it. I have a set of forks that you may be interested in. They are modded with RT springs for a 155lb rider and have gold valves adjusted to full race. They are clean and they don't leak.

I was having problems finding FE parts when I bought these. The member was a trackday enthusiast - did a RC 51 FE transplant - still was not happy and moved on to another bike. These are his take-offs.

Slim

Front;
Exposed lower tube in millimeters;
full extension = 127
bike weight = 111
with rider = 99
bottom out (provided by zip tie) = 28

Sag is about 28 mm. I'm not taking into account any slop in the fork due to oil condition, spring quality or bushings or anything else. Bike was not bounced during these measurements. Slop in the system is about 12 mm (I say sloppy, others might not).

According to popular sites i'm on the short side of the spectrum of sag (most note 30 - 35 mm for street riding). Ideally i'm alright, even too stiff with the spring rate, however, this doesn't really say anything about the bottoming out (USD/inverted forks have the same oil lock piece that stock forks have, which some remove after careful revalving and playing with oil height) or the attitude.

The kicker? According to Racetech i'm supposed to be on heavier springs ..... but with which bike?!??!??!?! One bike with a different front end ..... different geometry, different weight .....

EDIT - don't joke about the cup. It's SERIOUSLY crossed my mind more than once!

Slim

Interesting fix idea. That is something i've been contemplating, but somehow am most fearful of (but i'll re-valve the entire suspension, front and rear, and buy anything else to avoid that - LOL go figure! ). I'll do more research here.

So you stuck with the stock 1000's .88s then?

Slim

While I was going to start off with saying "a bar isn't a solution ..... " I now realize what you are trying to convey. If I don't have to worry about the clip-ons' clearance of various bike bits then I may gain some front end adjustability in height. That's what you mean, right?

Slim

And here I have a full F4i front end sitting in the garage that I was gonna swap onto my F2 before I decided that would be the bike I sell.

Too bad I only just sold the front wheel a week ago. LOL!

Would that not have been closer to going back to stock in my case though?!?!?!

Slim

Nope, the 'Storm is here to stay. The F2 will get the boot soon enough. Thanks for asking though.

If the shipping wouldn't kill me then the g/f would, so thanks for mentioning the parts, but I can't do it.

Slim

To add;

- yes I squeeze the tank with my knees, but I ain't Hercules. I need a break now and then
- rear sag is 19 mm on preload position #1, but I need to double check this (helper may not have been helping LOL)
- stock tire sizes

superbling

You sold the F4i wheel? No problemo as the VTR wheel/rotors bolts right on which keeps this mod cheaper than others. Sold the VTR wheel too? DOH!

Gregw

I should have been more clear. Yes, I stuck with the stock 1000 springs, but I purchased new ones since the originals were out of spec.

Slim

The PO had the swap done, so no VTR wheel to begin with. (shrug) All I know is I wanna paint mine so it matches the back.

Slim

Ahhhh, that's helps. Thanks!

So by out of spec you mean ..... ? Did you measure the rate on a machine and found they were out or ..... ?

Sorry, not trying to be picky, just trying to be picky. I see a possible inexpensive alternative, so i'm inclined to ask as much as is relevant.

SlowHAWK

If the front end was done right, your only issues should be the one typical HAWK issue... the seat sucks. If you get some Heli clipons and a good seat, you'll be 10x more happier. If you have to choose between the two, get the seat. Honestly, the seat will make you much happier on long rides than a properly set up front end. Although both are best!!

Slim

Okay, well that's starting to make some sense then ..... sadly.

You must have signatures turned off - I do have Heli bars and a stock seat.

Hmmm, time to research more about our seat.

cliby

So yes, you are short on preload, maybe in an effort to maintain geometry with shorter forks pulled up in the triples. Shoot for 30% of available travel (you're at about 20%) by reducing preload and see what happens to free vs. rider sag. This is a handy guide for trying to select the right spring rate from a popular site from peter verdone:

SPRING RATE -
Spring Rate OK - Both free and rider sag within acceptable range.
Spring Rate too soft - Rider Sag OK, but too little or no Free Sag
Spring Rate too firm - Rider Sag OK, but too much Free Sag


SAG -
Front -
Rider Sag - 30-35mm (25-30% of Full Travel)
Free Sag - 15-20mm (60-70% of Rider Sag)
Rear -
Rider Sag - 20-30mm (race), 30-35mm (street) (25-30% of Full Travel)
Free Sag - 5-10mm (extremely light bikes use less) (15-25% of Rider Sag)


Like I said, I don't think any of this has much to do with the issue of crowing into the tank, and everyone seems to agree - the front end just isn't that low to account for what is happening - seat more likely solution.

Slim

Apparently many people have complained about the stock seat from what little research i've done. Maybe i'll put up a wtb ad for a stock unit to re-shape and re-cover and see what happens.

Thanks all! Appreciated muchly.

Gregw

No fancy machines to measure rates. The CBR manual said if the free length of the spring was less than x, replace it. Since the history of the forks and brakes were unknown (bought from Ebay), I tore everything down and rebuilt. I did have one fork seal leakin' a little bit anyway.

Manning

I had the same issues with the back of the tank "getting to know" my boys all too often until I bought a Sargent seat. As good as the foam is in the Sargent, I think a good chunk of the improvement over the stock seat is the shape. The front section is flat rather than angled forward. This alone made a huge difference in my ability to ride my Hawk without the worry of slowly sterilizing myself.
If you can't purchase a Sargent or Corbin seat, try to see if you can find a way to look at one and copy the shape if you recover/rebuild the stock seat.

This spring, I did both the HeliBars and the Sargent seat. HUGE difference in the comfort and rideability for me. I'd recommend both in an instant.

Tweety

I see two things... One is geometry, The 929 forks are shorter than stock and pushed up they become even shorter... If you coud find a way (Bars, adjustable clip-ons like my Convertibars or similar) to have them flush or close to flush, then you would be much closer to stock geometry... The second is the seat... I'm doing the foam experiment... So far I haven't found the right shape but even at this point it's miles better than stock...

SlowHAWK

Shorter front end and stock seat = Sterilization.

J.

Slim

Seat - I think i'll see if I can find a CHEAP stock seat to try my exterior decorating at (ahem). Maybe i'll get lucky. I do notice that when I set the rear shock's spring preload higher, like position #3, that the effect is, obviously, worse. I'm sure that I can do some good here.


Bars - the Heli-bars that are on it now don't seem all that bad. Agreed a full-on riser set-up could leave me with more adjustability here, but i'm really kinda hoping to leave it the way it is now. I have clearance considerations that are kinda forcing it to be this way. I really like the handling and i'm inclined to try to leave the geometry alone as much as possible now.


I think right now with what i've researched i'm going to look into a CHEAP stock seat to play with first. At that point if I need more i'll look into a riser conversion.

2wheelust

Old thread I know but came across it during archive research.....

Don't know if you are still looking for a better seat without dropping the coin on a corbin/sargent. I really didn't want to deal with modding the seat itself so I sent the stocker off to Spencer.

http://greatdaytoride.com/Home_Page.php

He had good reviews in other forums and was waaaaay cheaper than an aftermarket. $75 plus shipping for the gel upgrade for the rider only ($50 for the foam upgrade). In addition he flattened out the seat angle and slightly reshaped it. No more crushing the boys and I long rides are much better. Seat feels harder (kinda like the corbin) but magically keeps the butt burn away for longer.

For what it is worth.....