CB250G5 1st Gear

[boxie30]

Hi all,

Hope someone can help me!

I have just finished rebuilding the engine, following the Haynes manual.

I am not able to get it into 1st or into neutral.

When i tried to put it into 1st with the engine running, it died and then never went back into neutral.

I have removed the clutch, to check the drum selector, which looks in the right place

A couple of questions:

Does the gearbox mainshaft always spin with the back wheel when not in gear?

Why would it not go into 1st, it goes into all the other gears, 2nd to 6th and back again.

Cheers.

[Bryanj]

When testing its necessary to turn both gearbox shafts to select gear. Possibly a selector pin has fallen out of the selector?

I can't remember which selector does what but the centre one has a loose pin to locate in the drum groove hald by an "R" clip that can come out if not fitted correctly

With engine out you can remove lower crankcase without disturbing any of the top and observe what is going on when the drum is turned

[AshimotoK0]

Agree with Bryan.. check that spring clip and roller and condition of the relevant selector fork and selector drum & drive pins (143 in diagram) . Also check the condition of the dogs on the relevant gears. The corners should not be significantly 'rounded' off.

If you have no joy I can check what it says in the Genuine Honda manual for you. I also have some Australian service manual for it...I guess you already have the Haynes one.

The parts book is here in my Dropbox: (courtesy of Chris on here).

https://www.dropbox.com/s/mvcm4kgrcyntkp0/Parts%20List%20CB250%20CB360%20G5.pdf?dl=0

Here is the 'R' clip  & roller Bryan is talking about.

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[boxie30]

Thanks Bryan and Ash,

I will have a look this weekend.

Thanks.

[boxie30]

Finally got chance to strip it down!

The only thing that i can see that may be causing any interference is the neutral switch.

When the bump on the gear change drum tries to go into neutral or into first, it hits the side of the neutral switch, stopping it from going any further. If i pull the gear change drum out by 1mm it goes into neutral and passed into 1st gear?

I can see no washers or shims, on any of the parts lists, to push the gear drum out to enable this.

Also when looking at the Genuine Honda manual, it is asking for a washer 35751-333-003 (195) as well as the neutral switch. The Haynes manual does not reference the washer as a separate item from the switch.

David silver has the washer, so i might have to just purchase it in case it is needed and solves the switch poking in too far. But it seems a little strange as the switch already has a washer half way along its length....