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Fecked 4th gear - Fireblade
gingerprince - 15/7/08 at 09:16 PM

Got my crankcase apart to, amongst other things, investigate gearchange issue. Having stripped it I thought the only issue was the fact that the selector shaft seemed to have a lot of stiction, so that the return spring may have trouble overcoming.

However now I'm putting it back together I've had another look at the gears/dogs, and I think that 4th gear might be quite badly worn (3rd-4th is what usually misses clutchless). There is ever so slight wear on some of the others, but it's just the odd shiny corner rather than noticable removed material. I've not really had issues with other gears anyway.

Below is a photo of the "dog grooves?" on 4th gear. I'm guessing they are, but do these look worn beyond servicable use and need replacing?

And if so, does anyone happen to have a good condition one lying around before I give Honda another 80 quid?

Fecked 4th Gear
Fecked 4th Gear


This is a picture of "worst of the rest", on 2nd gear. It's a lot less pronounced than the wear on 4th gear, and I've never had an issue with 2nd gear, and all the others are less worn than this. The photo's not as clear because I couldn't get any light in there

Better 2nd Gear?
Better 2nd Gear?


[Edited on 15/7/08 by gingerprince]


clairetoo - 15/7/08 at 09:26 PM

Yep - thats fecked................best to replace the mating gear as well cuz thats probably on the way out as well


rf900rush - 15/7/08 at 09:33 PM

Looks just like my RF900 2nd gear.
Had the same problem but on second gear.
Bought another ebay enging, and that was worse.

So after a bit of google-ing.
Resulted in changing 3 gears and selector forks.
Not much change from £200.
Did the job though.
Now done 3K miles.
No gear problems so far.

Have a look at the 'dog' that drives that gear. Proberbly knacked too.

I was also told the meshing gears both need to be new.
But I skimpt on one.


moochofun - 16/7/08 at 07:10 AM

Yep, ideally you would want to replace the gear on the lay shaft as well as it will have some wear, to an extent anyway, and may accelerate wear on your new gear. The dog does look very worn though so would reccomend replacement.

There is a chap who advertises in Autosport who can regrind the dogs and reckons that it does little to effect the strength of the dog - he might be worth a shout. I'll try and find a name/telephone number/email address for you......

What does the dog ring look like?


Mr Whippy - 16/7/08 at 09:00 AM

Just a question being a novice really with bikes. I keep getting told that I don't need to use the clutch when shifting up the gears on the bike but TBH I hate the whole idea of just slamming it into gear and so always use it. I'm assuming that the wear shown in the photo is the result of shifting without the use of the clutch???


gingerprince - 16/7/08 at 10:04 AM

moochofun, I presume by dog ring you mean the other gear that engages into these grooves? It did look in good condition but I'll have a closer look at it. The gear teeth themselves seem spotless so I don't think there's any real reason to replace the on one the mainshaft?

May be worth having a word with the gear cutter guy, but having read up websites that do "backcutting" (cutting with an angle on race gearboxes so they don't slip) they say they won't backcut worn slots. Presumably because it'll leave a lot less material by the time they're back and square. I'd assume there'd be more lash-clunk as well due to bigger slots.

Forks etc seem fine - ends are within tolerances and they line up to a straight edge so not bent.

Just checked on fleabay and by chance there is a complete gearbox for a 'blade - sadly it's for a 2001 RRY, and havnig looked at the fiche they're totally different ratios. That particular gear has the same teeth, but it's a different part number so presumably it's a different width, or the countershaft has different splines or something.


gingerprince - 17/7/08 at 08:45 AM

This is the dog that engages in the worn cog. Looks very slight to me: -

Dog
Dog


moochofun - 17/7/08 at 11:18 AM

gingerprince,

Yep, t'was those drive teeth that I meant (dog rings are generally in car boxes). The mans name is Nick Shrigley-Feigl (not sure how to pronounce it though! His email address is nsf13'at'hotmail.com (replace 'at' with @) or his phone number is 01624 880315.

I think my old man is getting some of his dog rings done with him for his FGC box so will let you know how it goes.......

Ta


rf900rush - 18/7/08 at 08:27 PM

You have to ask yourself do you want to fix it the cheapest way. I started out with that idea.
Even looked into re-cutting/undercutting the DIY way.
Wrecked a few tools trying.
even bought a set of GSXR750 gears form ebay for £30 and ended up spending another £30 on a head.

or do it once. No short cuts.

In the end I bit the bullet and bought new parts.

I still have not learned from my own experience.
Coverted to Megasquirt a few years back just to avoid a rolling road tune up.


markko - 18/7/08 at 09:15 PM

Hi Ginger Prince might have a spare gear cluster in the garage i've definetely got 2 off 918 rrx will check to see if I've got a earlier one as well, know i've a full rrs motor but its sort of spoken for.


simoto - 19/7/08 at 09:58 AM

quote:
Originally posted by Mr Whippy
Just a question being a novice really with bikes. I keep getting told that I don't need to use the clutch when shifting up the gears on the bike but TBH I hate the whole idea of just slamming it into gear and so always use it. I'm assuming that the wear shown in the photo is the result of shifting without the use of the clutch???


Not really its a matter of technique and mechanical feel, If you time your change properly with a tiny lift to unload the drivetrain for an instant it will go in without the slightest baulk and far smoother than any clutch change, same applies going down the box but the technique is harder to master and innaproprate on the road when executed properly(well in town it would be as a blip is needed)
These boxes prefer a clutchless change if its done right and with some degree of mechanical empathy.
Hope this helps.