Fork Height--5th & 6th Gen Same?

[Trace]

On my 2000, I recently raised my forks from 44mm to 49mm, measured from the flat top of the fork to the top of the triple-tree, as per the proper method in the manual. [note....some bikes come from Honda at 39, some maybe at 44, or were moved to 44 by a prior owner or the Honda shop, etc. You should measure yours, and YMMV]

Anyway, as other have marveled, it makes a huge difference in turn-in and tossy-bility (teckyhnical term!) and quickness and nimbleness, even going a mere 5mm from 44 to 49. I've had no head shake or other unpleasantness as a result of this 10 minute mod, up to 150 mph.

The Question Is: Is 49mm the proper number for a 6th? I assume it is, but I've only been tuned-in to 5th Gen numbers, and I'm going to be doing this on another VFRD member's 6th Gen this coming weekend (and/or raising the rear a tad and lower the front a tad less, so he can keep maximum ground clearance without getting the shakes, etc., the peg-scraping bastid!!!).

Thanks.

[Trace]

Helloooooooo.......anybody home?

<bump, since it quickly went off the page!>

[Adam30]

I would too be interested to hear some more info on fork height, and if there's an "optimum" setting over what the factory has it set at.

[benSV]

I don't see how you can apply your 5th gen changes to the 6th gen bike as they aren't the same bike and the other geometry #s are different.

I would look in the manual and just check that your friends 6th gen bike is set up correctly. It shouldn't have any issues with handling unless there is something wrong with it.

Specifically the 6th gen bike is something like 18mm longer. It gets the extra wheelbase from the swingarm and having 0.2 degrees of rake. Maybe there reasoning is you can get more stability with the longer wheelbase & rake and it should be counterbalanced by the extra mass centralization & bigger forks. ??

That wouldn't help you come up with correct #s to tweak the bike though.

[Trace]

I don't see how you can apply your 5th gen changes to the 6th gen bike as they aren't the same bike and the other geometry #s are different.

I would look in the manual and just check that your friends 6th gen bike is set up correctly.  It shouldn't have any issues with handling unless there is something wrong with it.

Specifically the 6th gen bike is something like 18mm longer.  It gets the extra wheelbase from the swingarm and having 0.2 degrees of rake.  Maybe there reasoning is you can get more stability with the longer wheelbase & rake and it should be counterbalanced by the extra mass centralization & bigger forks.  ??

That wouldn't help you come up with correct #s to tweak the bike though.

<{POST_SNAPBACK}>

It's not about handling "issues", it's about the tweaks. I figger that somebody here has optimized their 6th Gen setup like I've done to my 5th. Certainly the factory setting isn't "optimum" for turn-in.

As for manuals, 1) I ain't got no stinkin' 6th manual, and 2), the number in my 5th is 39mm, which as we know, isn't EVEN optimum!

[Guest Viffed]

Just for you Trace... :D

Chris

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[benSV]

I'll have to apologize to trace.

I'll have to go double check my hard copy of the manual, and then measure it when I go home, but just eyeballing it, assuming that picture is correct, it is very hard for me to believe my bike is anywhere near 41mm...

Which would mean they didn't set the forks right at the factory. :goofy:

edit:Scratch that the picture is with the clip-ons removed. It's probably pretty close then.

[Veefer800Canuck]

Start by raising them 5mm, then try 10mm.

10 might be too much, but you'll know. Also, be aware, and ride in "test-mode", being aware as to what the new changes may mean.

You could also shim the rear shock instead. That would have the same effect and also INCREASE ground clearance, whereas raising the forks DECREASES ground clearance.

[Guest]

hi its my bike that Trace and i are doing this to. the problem we are tring to correct is this. first of all i do somtimes ride aggressive out on country roads, no problem there. the problem is at the track. the bike turns in really slow, that is problem 1. then after about 3 laps or so the front will not hold. it just pushes. I just think there is somthing that can be done to make it better. I have talked to the people of g.m.d and they just want to convert the bike to a total track bike, and also want 3500 to 4000 dollars to do this. so the wife is out of town and Trace is so kind to help a brother out we were going to see what we come up with. so any advice is good advice.

[Trace]

Yep, axman is the peg-scraping, no-chicken-strip bastid!! I'm thinking of raising his triples and lowering his arse-end so's I can keep up with him! :lol:

So.....41 is the stock 6th gen height? Are we all in agreement? Is that correct, or is it bad manual info, too (like the 39mm in the manual for the 5th)?

If 41 is right, we will do the 5mm, 10mm step increase to see what axman (the peg-scraping bastid) likes, and see if headshake is an issue. I have a 160 mph road in front of my house, so that's no problem. Methinks he'll like 10mm if it doesn't shake.

Just for the sake of you 5th Gen guys out there, my bike came at 44, but a mere 5mm to 49 was a WORLD of difference...I can't imagine going around a turn at 39mm, so measure your height, guys and gals!

[benSV]

Yah 41mm is correct. Note the text to "top of fork tube".

To me the picture is a little unclear and makes me think it's to the top of the cap.

Yikes on the front end pushing... definitely haven't experienced that on the track unless I was goofing up big time.

[Trace]

Yah 41mm is correct.  Note the text to "top of fork tube".

To me the picture is a little unclear and makes me think it's to the top of the cap.

<{POST_SNAPBACK}>

10-4 on all that, and thanks for the confirmation on 41mm. Now we have a baseline to go by.

As veefer mentioned (and I mentioned in my original post) we might shim the rear a bit and lower the front a bit for ground clearance, but that's an unknown to me, since I've never scraped a peg, meself.

I use a depth gage exactly like this to measure from the top of the "fork flat" down to the triple. Dead Nuts On.

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Depth Gage

[Guest]

Yah 41mm is correct.  Note the text to "top of fork tube".

To me the picture is a little unclear and makes me think it's to the top of the cap.

Yikes on the front end pushing... definitely haven't experienced that on the track unless I was goofing up big time.

<{POST_SNAPBACK}>

the push only starts after the tires get warm, and then only on fast corners that you start to accel thru the apex. as soon as you throttle it at all it wants to go straight. the guys from g.m.d were at the track and watched me in my troubled areas and said i was over riding my suspension.what they said was happening was that on those turns the soft suspension was pushing flat which makes the bike longer and unable to turn. i ride my wifes f3 and dont have this problem and im at least 6-8 seconds faster on her bike. but would like to get my bike to handle better since i feel more comfortable on it because i dont ride hers except for the track

[wera803]

So.....41 is the stock 6th gen height?  Are we all in agreement?  Is that correct, or is it bad manual info, too (like the 39mm in the manual for the 5th)?

Just for the sake of you 5th Gen guys out there, my bike came at 44, but a mere 5mm to 49 was a WORLD of difference...I can't imagine going around a turn at 39mm, so measure your height, guys and gals!

<{POST_SNAPBACK}>

Where is the manual wrong for the 5th gen bikes?? I just did fork springs and thought for sure the manual said 41 mm from the top of the fork tube to the triple (not the top of the fork tube cap either, just the tube itself). I set mine at 45 or 46, but haven't had a chance to try it yet. Are you measuring in the correct spot?? Do you have a page number in the manual that says it should be 39 mm??

Thanks

[ULEWZ]

If you are not short, raising the rear shock is the preferred method, as you will not loose ground clearance. The end result is the same, but you will raise the seat a bit.

[benSV]

It sounds like the guys from GMD are trying to mess with you.. $3500 or more? That's crazy what are they going to put Ohlins all around for that cost?

Maybe you need new springs and/or shock but you ought to be able to fix this without redoing your whole suspension.

[Trace]

Where is the manual wrong for the 5th gen bikes??

<{POST_SNAPBACK}>

In my jive Clymer's manual, copyright 2001, pg 356, Front Fork Installation (is there a rear fork?), is sez:

Position the fork so that the top of the fork cap (flat surface) is 39 mm (1.5 in)away fron the upper fork bridge surface as shown in Figure 18.

Of course, Fig 18 is the size of a postage stamp and doesn't have the lines (perhaps the misleading lines!!) that are shown on Viffed's post, above. Even with a mag glass, you can't make it out very clearly, but it looks like 1.5 inches. Jive Clymer's! :goofy:

Viffed, is your manual for a 6th Gen?

Yaknow....back in the days of HiJacker Air Shocks on every Camaro and Mustang in town, I used to joke that "He has the ass-end jacked up so high the tires don't even touch the ground!" :goofy: Well...I thought it was funny.

[enzed_viffer]

Yaknow....back in the days of HiJacker Air Shocks on every Camaro and Mustang in town, I used to joke that "He has the ass-end jacked up so high the tires don't even touch the ground!"  :goofy:  Well...I thought it was funny.

<{POST_SNAPBACK}>

I do too.

You're my kinda guy, Mr Trace.

'cept you're not tarded like me. :goofy:

[vfrjim2002]

In my jive Clymer's manual, copyright 2001, pg 356, Front Fork Installation (is there a rear fork?), is sez:

Position the fork so that the top of the fork cap (flat surface) is 39 mm (1.5 in)away fron the upper fork bridge surface as shown in Figure 18.

Of course, Fig 18 is the size of a postage stamp and doesn't have the lines (perhaps the misleading lines!!) that are shown on Viffed's post, above. Even with a mag glass, you can't make it out very clearly, but it looks like 1.5 inches.? Jive Clymer's!? :goofy:

Viffed, is your manual for a 6th Gen?

Yaknow....back in the days of HiJacker Air Shocks on every Camaro and Mustang in town, I used to joke that "He has the ass-end jacked up so high the tires don't even touch the ground!"?? :goofy:? Well...I thought it was funny.

<{POST_SNAPBACK}>

FWIW. My version of the Honda FSM for the gen 5s calls for 39mm. The text states top of bridge to top of tube, the photo uses the flat of the cap as the upper datum. :joystick:

[Trace]

FWIW.? My version of the Honda FSM for the gen 5s calls for 39mm.? The text states top of bridge to top of tube, the photo uses the flat of the cap as the upper datum.?  :joystick:

<{POST_SNAPBACK}>

Thanks, vfrjim.

Yep, well.....that settles that for the 5th Gens. Except that IMHO, that 39 should absolutely be increased to Forty Nine. And maybe it should be increased to 54 or 58 or 63....hell, I don't know! Of course there's a limit at some point, where straight line stabilty or headshake becomes ominous...but I have seen no numbers that suggest that limit, either on this forum or on the witty website of our friends across the pond. Er...that would be the Atlantic pond, Ian.

So.....if 41mm is the stock factory setting for a 6th, are we thinking that 51 is a good number to go to? Has anyone gone that far? Anyone? Bueller?

[FotoMoto]

If you are not short, raising the rear shock is the preferred method, as you will not loose ground clearance. The end result is the same, but you will raise the seat a bit.

<{POST_SNAPBACK}>

You will also lose some centerstand leverage (tire can touch) and sidestand angle will increase. Both non-issues for the track of course.

[Guest Viffed]

Viffed, is your manual for a 6th Gen?

<{POST_SNAPBACK}>

Sure is, scanned that one myself, page 13-29.

I just acquired the 5th gen manual in .pdf, here's a capture of the appropriate spot, it's on page 13-26, sorry the quality isn't as good:

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Seems they also measure to the top of the cap on the 5th gen too.

Chris

[Trace]

Sure is, scanned that one myself, page 13-29.

I just acquired the 5th gen manual in .pdf, here's a capture of the appropriate spot, it's on page 13-26, sorry the quality isn't as good:

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Seems they also measure to the top of the cap on the 5th gen too.

Chris

<{POST_SNAPBACK}>

Wow! Great photo and scan job!!!

It's a MUCH better picture than the one in Clymer's. Clymer just has a pic of a machinist's steel ruler laid alongside the fork, resting on the triple. Of course, that's a perfectly good way to make the measurement, but you can't really tell what is being measured. Of course, the text makes it clear--top of the fork to the top of the triple. Nuff said. :thumbsup:

[tok tokkie]

On a 5th gen there is a little wire snap-ring that fits directly above the clip-on. You have the forks high, fit the clip-on low but loose, fit the snap-ring into the groove. Now move the tubes down so the snap-ring is snug against the clip-on & the clip on is against the upper triple. The upper side of the clip-on is chamfered so the snap-ring is held into the groove on the fork tube.

To quicken the steering do as Veefer800Canuck says & raise the tubes. I set it at 8mm raised & then fell off the bike going over a series of bumps on an apex. Set it back to factory for road riding & have gone over those same bumps (but aware of them now) & made the corner (slower this time though).

[Guest]

It sounds like the guys from GMD are trying to mess with you.. $3500 or more?  That's crazy what are they going to put Ohlins all around for that cost?

Maybe you need new springs and/or shock but you ought to be able to fix this without redoing your whole suspension.

<{POST_SNAPBACK}>

The guys at g.m.d wanted to replace the tripple clams. penski shock front fork rebuild with different internals, then measure it out then set it up for the track.

[Guest]

This might be a dumb question, but wouldn't raising the forks also raise the handlebars by lowering the chassi?

Cheaper Genmar riser kind of?