R6 engine - gearbox problems....

[paulodd]

Need some advice/help.....


I have a 1999 R6 thats done just over 14k, the problem is... i knock it into 2nd gear, it goes in and then when i wind the power on at about 8-11k revs it jumps out of gear and back in.

I know that older R6s are prone to a screwed 2nd gear but i didnt expect it only after 14k miles!

After speaking to a few people its been narrowed down to 2 problems.....
Bent fork selector
Worn dogs


The plan was to pick up a cheap engine off ebay and swap it over myself with a couple of mates BUT after looking through ebay R6 engines go for stupid amounts!!!!


This morning i was chatting to a mechanic and he said that if i were to drop the engine, and take it to his he would change the gearbox over and then i would put it back in the bike.

Does this sound like a good or bad idea? Afterall it'll fix it although i wont have any history of the engine.


Another annoying point is i'm meant to be doing Brands on the 25th of this month


Any suggestions / advice??
Paul
____________________
Paul
1999 Yamaha R6
www.coventrybikers.co.uk / www.norfolkriders.co.uk

[dave1rs]

gearbox change is easiest,but if swapping fit an 03 gearbox as it all fits straight on and the fault had been rectified by then.

[Pete.]

From the symptoms it sounds like worn dogs.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Wooly R6]

woof woof
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R6 has been sold - 2004 Honda VFR VTEC now sold too - no bike at the moment

[Paddy Blake]

Try change the whole gearbox unless it is someone that knows that just
changing two gears and a selector in a gearbox may not work as the
selector must match the gear and drum and your old selector may not
match the new gear.Some times it works well on the bench but not on
the road.

Paddy.

[MattEMulsion]

Try a post in the UK section of the R6 Messagenet. There are loads of R6 experts on there willing to give you advice. Here's the link to the page:
https://www.r6messagenet.com/forums/forumdisplay.php?f=36
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Yamaha YZF-R6

[paulodd]

cheers everyone for the input!

I think im going to try and pick up a cheap engine, and just do a straight engine swap.


Cheers MattEMulsion, have just signed up on that site



Paul
____________________
Paul
1999 Yamaha R6
www.coventrybikers.co.uk / www.norfolkriders.co.uk

[Paddy Blake]

[paulodd]

[0ddball]

So swapping one problem for another What if it's not as simple as replacing the gasket, the head might be warped too, it might not even be the problem.

And seeing as 2nd gear is a common weak point it's possible that any replacement engine could have the same problem.

It's astounding that someone would fit another engine rather than do a cheap and fairly easy (albeit time consuming) fix on their existing one.

[Blau Zedong]

I'd dispute that splitting a modern 4 stroke Il4 engine and reassembling it succesfully in the comfort of the average ill equipped garage is easy. Modern engines are not really user servicable items - I agree, skip it and get another engine.
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[paulodd]

[Pete.]

I might know where there's some gearbox bits. A lad at work races them. I'll ask him for you. Stripping and rebuilding a modern inline-4 isn't as difficult as you would believe. Manufactuing proceedures and tolerances mean that the easier it is to build, the cheaper it is to manufacture. I could easily change out the gearbox in an afternoon, not including actually getting the engine out of the bike.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[sickpup]

Engine out, turn upside down and remove lower crankcase, not a large job at all.

[Pete.]

Even better, 'busas are the same no need to touch the top-end. I'm sure they did it deliberately.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[MattEMulsion]

But are you sure that it is a selector fork or worn dog? Have you actually checked the detent spring that is the common problem on these R6 gearboxes? Don't rely on what other people say unless they have seen your bike and actually know what they are talking about.

If it was me I would get hold of a new detent spring and gasket. The bits will cost you less than £3.00, it takes about an hour to do and if it doesn't make a difference you are only £3.00 out of pocket. Its got to be worth trying before you look for another engine/gearbox.
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Yamaha YZF-R6

[Pete.]

The symptoms don't point to a broken detent spring. If it were the spring broken/stretched, then a likely symptom would be poor gear selection or jumping instantly out of gear and once jumped out being difficut to re-select, this is because the index lever isn't holding the pins in the right place for the pawl to catch them and turn the shift drum.

His symptoms are classic worn engaging dogs.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[MattEMulsion]

[craigT19]

as sick pup said its easy to get to the R6 gearbox, engine out, flip over, sump off, lower case off "and there she be!"
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Bikes owned :- 2001 nsr125, 1999 zx6r, 2006 yzf-r1, 2009 xmax 250, 2012 yzf-r1, 2015 MT-07
Current bike : - 2016 MT-10
BCF member pops. sadly missed 1945-2003

[craigT19]

paul as per your pm to me.


the stuff you should take out of your donor box is both gear shafts, the selector drum and the selector forks, also the forks run on 2 shafts....take them too, and they have springs on the end of them that go into the cases first to stop the shafts from rattling...make sure there in good order.

also on the end of the first shaft (on the left hand side as u look at it) inside the bearing is a polished metal washer about the size of the bottom of a cup....make sure its not warped and try to keep the original one if its ok


1. install the primary gear shaft,slide it into the case and push the polished washer onto the output shaft bearing

2.drop the selector fork into its grove on the shaft spin it around and slide the shaft that holds it into place (spring first )

3. install the drum locating the first fork.

4.locate the final 2 forks into the drum and slide the shaft in

5.then fit the final row of gears, slotting the forks in

should work fine but its worth doing this check.....

on the left hand side of the (clutch) gears shaft your se a small brock of metal spin the thing till that block of metal is facing towards u (if u look closely your see a little switch, thats your neutral light switch, the block simply pushes it.

u should now me in neutral, hold the output shaft (where the front sprocket attaches) and spin the other shaft (by the splines the clutch basket mounts onto),it should spin freely

if it does job done your in neutral, just click through the gears making sure it selects them all and it should work fine


hope this helps
____________________
Bikes owned :- 2001 nsr125, 1999 zx6r, 2006 yzf-r1, 2009 xmax 250, 2012 yzf-r1, 2015 MT-07
Current bike : - 2016 MT-10
BCF member pops. sadly missed 1945-2003

[paulodd]

Cheers craig!!!

Will give that ago. Althlough wont be doing it till next month now. but thanks for the info!!! highly appreciated!

If it goes wrong i'll hold you too it nah, thanks tho
____________________
Paul
1999 Yamaha R6
www.coventrybikers.co.uk / www.norfolkriders.co.uk