1vj whining in 5th.

[Joly]

Hi everyone,
My 1vj whines in fifth. Other gears are silent. I've heard that this because they are pitted and need replacing and I've also heard that parts are hard to find.
Do 3AJ 5th gears go on 1vj main and layshafts, or do I have to replace all the gears and shafts? If so, do they fit in the 1vj Crankcase and work with the 1vj selector mechanism?

Or, should I find a 3aj engine and just put that in? If I did that, can I fit the 1vj Kickstart mechanism? Also can I use the 1vj alternator and pickup so I don't have to chop the wiring about.

Or can I ignore the wine and keep riding.


I hope you don't mind all the questions.

Yrs,

Jolyon.

[donnybach]

Jolyon, I’ve been in the same situation for a couple of years now, it’s on my list of things to do. You can still get the parts through Yamaha, and the usual channels, and like you said, the slightly later gears are better. Only the two fifth gears (gear and pinion) need to be changed and should go straight on. If yours is a 1986 bike with the plate holding the drive sprocket on, while you’re inside, swap the gear/output shaft for the 1987/ later normal finer splined shaft with a nut. Same dimensions. Just better system for keeping it on. I have the later shaft fitted as my original one was wrecked as most get.
I’ll look for the part numbers again as I really should get on with mine.

[Joly]

Hi again Donnybach.

Mine has the later fine splined shaft for the gearbox sprocket. So, 3aj 5th. gear pairs go straight on?

Jolyon.

[donnybach]

That’s good news about the shaft.
Comparing on fowlersparts, the ‘86 gears aren’t available anyway, but have been superseded by the later.
Gears you need are
2JT-17151-01 (24 tooth, £109) in stock.
2JT-17251-00 (19 tooth, £133) also in stock.
(The -01 and -00 are important)
So both still readily available from factory.
I’ll do mine next winter and do the bearings, piston rings and cam chain etc while it’s apart.
They’ve been whining for a few thousand miles, so I want to do it before it lets go and I have to.
Let us know how it goes.

[donnybach]

Ebay
204154301963
Might be better for you. Location in Japan.

https://japan.webike.net/products/24683869.html

http://www.firstclassmotorcycles.com.au ... 2JT1715101

Seems a lot cheaper over east. Maybe it’s the transport costs to get them to uk makes them so expensive.

[Joly]

That super.

I might amass a pile of parts as money allows and so a complete rebuild.

I changed the clutch plates a few days ago and when I was in there I put in a 3aj oil pump so it would be a shame bits of gears got dragged through that.

Thanks again for your help and advice.

Jolyon

[Speedy gonzales]

Hi !
I like ask a few questions about the 5th gear problem, I have a 86 1vj that I have taken apart the hole engine due to a bad rod bearing and piston. While I`m in there I also change all bearing, seals and oilpump. I see in a few thoot on the 5th gear have some pittings so I would like to change it out to be sure that it don`t breake later nd I have to do the job one more time.

donnybach :
I see you point out this 2 numbers : 2JT-17151-01 (24 tooth, 2JT-17251-00 (19 tooth.
Question is, do I need both gears or can I only change the one that have pittings ?

[donnybach]

Hi speedy. You’ll need the pinion and the gear. They have different amount of teeth compared to the original. They’re slightly improved.
As I asked joly, if you have the ‘86 shaft which has a retaining plate on the front sprocket, see if you can get an ‘87 shaft which uses the normal retaining nut like all modern bikes. The old ones wear badly. The part with the gears sat on it is the same. Just a different end to mount the sprocket.

[donnybach]

Hi again Donnybach.

Mine has the later fine splined shaft for the gearbox sprocket. So, 3aj 5th. gear pairs go straight on?

Jolyon.

Sorry missed the last line. Yes the shaft is the same except for the end piece for mounting the sprocket but yours is already later so cool.

[Speedy gonzales]

donnybach :

I have the old type with retaining plate, as I understand will the gears fit my shaft and I need both.
I will consider get the newer shaft if the price is not to bad.
Thanks for your information.