Shifter continually coming loose on the shaft. Is there a trick to it?

[Tomas]

I had shaft welded up and machined to correct size  with new splines cut. Instaled shifter using  high tensile bolt(8.8 ) with washer and  spring washer. Check tightness before every ride. No dramas so far.

[Mick D]

I had shaft welded up and machined to correct size  with new splines cut. Instaled shifter using  high tensile bolt(8.8 ) with washer and  spring washer. Check tightness before every ride. No dramas so far.

That would be the go if you cannot find a new or good used shaft,
But I think the question also has a bit of just a reliable fix without opening an otherwise good in season use race engine?? Maybe?

This is the go if you don't want to pull the engine down
Get one of these diamond encrusted 3.15 pencil grinder bits and a tiny round file for the lever bore if you want.


Like others have said clean lever bore and shaft spotless.
Put it exactly where you like it. Mark it.
Then remove it and grind a half moon in both the shaft and lever, in the spot where shown


It will take a little while, obviously don't do too far.
Loctite everywhere except pinch screw thread.
Make it so you can tap in a small piece of 3.15 mm Satincraft welding rod.
Use one of those really thick section spring washers under the head of the screw of an 8.8 unbrako socket head


No loctite on the thread but a nyloc nut on the end if you have room, so you can nip it up if  you have a shitty stretching lever.
I guarantee this is a reliable fix, unless you have a lever made from always gunna stretch pure Chinesium.

[Momus]

Just a thought on gear lever bolts. 8.8 grade is not really high tensile. You need the harder to find 10.9 grade if you want hex head. Socket head cap screws- SHCS- are about twice the yield strength and thread-strip strength as 8.8 and your strongest, and toughest, ie not 'brittle' commercial fastener. High tensile M6 nuts are Conelock or the nylon insert type with the h/t marking code- most nylock nuts are made from free machining steel and strp at about the tension a shcs requires to stretch enough to be functional.

[shelpi]

valid point Momus, I'm a believer and a user of 10.9

But its all to late for me, ive just welded up all gear levers and kick start lever's as a precaution! non of them needed it as they were all in excellent condition, I am just not willing to accept the fact that one of the blighters may loosen on my watch
all done with great care and attention to detail, all prep grinding done before full penetration welds

Now does anyone know how to change a heat affected seal that's leaking? with out removing the levers in question!
thank you in advance

[Mick D]

So what you are saying is that an 8.8 SHCS will fail before the alloy thread does in the new alloy lever that he has fitted?
Forum full of ........ s

[shelpi]

So what you are saying is that an 8.8 SHCS will fail before the alloy thread in the new alloy lever that he has fitted?
Forum full of ........ s

yep that makes sense in the alloy like your saying, but tugging together that old stealy  10.9 is a better option (me thinks )

[Mick D]

Hi Guys,
I have been battling with the shifters on the two bikes I am racing at the moment, the 84 CR250 and the 89 CR250. I continue to have the issue of the shifters getting sloppy on the shaft. Each time I prepare the bikes, I tighten the bolts just that little bit more to within an inch of stripping the thread, but by the time I get the bikes home after a race day they are dancing around again. On the 89 I bought an OEM shifter from Honda for $100 and while it was a nice snug fit when I fitted it, within a few race meetings it is doing the same. I know fitting a steel shifter will help but I would prefer not to have to go that way. Is there a fix for this I don't know about?
Cheers,
Kenneth

[shelpi]

yep fare cop

[Tony Two Times]

Modern bicycles, until recently, mostly used a square tapered shaft for the their cranks.

Why not for motorcycle kick starters and gear levers?

T2X

 

[Mick D]

The finer the spline the greater the choice of positioning Tony.
I have a habit of causing neutrals when I stretch way back on to the rear of the seat. My boot toe. To stop this ridding error of mine, I simply set my gear lever one or two splines higher than most do. Depends on the bike but works for me.
And I greatly prefer it that way.

The thing is these things dont all ways play up or strip out.
Depends alot on previous owner maintenance and as we all know the are a lot of shite sub standard after market levers and repo parts around too.

[Mick D]

For example there have been some real shite after market Maico gear shift cranks about at times. Some real disappointments.


I am nearly finished my first batch of new Mega 2 ones. I thing they will be better than some of the past choices

[Tony Two Times]

The finer the spline the greater the choice of positioning Tony.

Ah yes! Of course!

T.

[shelpi]

this post has reminded me of my RM250 N had the alloy gear lever on it, was always coming loose fixed it by removing it and putting a steal one on
yes the finer the spline the more adjustment, on the Suzuki with its coarse spline I have had to heat and bend the gear levers to be able to get it in the right positon, now I cut them at the weld rotate to my preference and weld, just looks better!

[Mick D]

this post has reminded me of my RM250 N had the alloy gear lever on it, was always coming loose fixed it by removing it and putting a steal one on
yes the finer the spline the more adjustment, on the Suzuki with its coarse spline I have had to heat and bend the gear levers to be able to get it in the right positon, now I cut them at the weld rotate to my preference and weld, just looks better!

Yes sometimes you just have to do whats best. Its great to have that sort of experience and background, to be able to do so.

On Maicos for example. I never had trouble with the early alloy ones. But they don't fold.
So I have collected NOS latter chrome plated forged steel ones. Usually at great expense.
I don't like to add weight, but they are brilliant if maintained.

[shelpi]

this post has reminded me of my RM250 N had the alloy gear lever on it, was always coming loose fixed it by removing it and putting a steal one on
yes the finer the spline the more adjustment, on the Suzuki with its coarse spline I have had to heat and bend the gear levers to be able to get it in the right positon, now I cut them at the weld rotate to my preference and weld, just looks better!

Yes sometimes you just have to do whats best. Its great to have that sort of experience and background, to be able to do so.

On Maicos for example. I never had trouble with the early alloy ones. But they don't fold.
So I have collected NOS latter chrome plated forged steel ones. Usually at great expense.
I don't like to add weight, but they are brilliant if maintained.

AHH I'm a tight ass over the years I have collected stripped bent fold one's and welded to the the spline/clamp of choice, but luv to keep the original gear levers for well you know that original look