Topic: CB650 Swingarm Felt Dust Seal ??

[CBJoe]

1980 CB650

Can someone please remind me.....  Is there supposed to be a Felt Ring under the Swingarm Dust Seal (#8 in the picture).

I don't have no pivot free play, but there's a tiny amount of side to side movement (ie. swingarm sliding on pivot bolt).  Felt Seals would explain this.  Been too long since I took everything apart.

thanks, joe

[seaweb11]

My 750 has felt rings.

[CBJoe]

Anyone found a good source for felt dust seals?  I see them listed for the CB750 but not the CB650....

I wonder if the CB750 ones would work.

I need ones with appx.
16.5mm ID
34mm OD

Joe

[HondaMan]

They are all the same on SOHC4 bikes that have them: some of the bikes had flanged bushings instead.

Honda sells them: I also have some improved (i.e., thicker) ones I had made for my Lifetime Warranty rebuilds on these arms. If you don't like Honda's price, e-mail me for mine: mgparis@concentric.net . 

[CBJoe]

Thanks... I was just reading an old post of yours about making them from 2mm felt.   

Your comment about the flanged bushing raises the question again about whether the 650 had the felt washers since it used flanged bushings (see diagram in first post).

I assume the washers cant hurt.

Joe

[CBJoe]

I measured the tolerances for the bushings and collar and everythings still in spec.  Bushing ID - 23.6 mm / Collar OD 23.4 mm

Specs
For the CB650 Custom A/B (1980/1981) and CB650SC (Nighthawk 1982
only):
service limit swing arm pivot bushing (in.dia.): 23.7 mm (0.93 inch)
service limit swing arm center collar (out.dia.): 23.4 mm (0.92 inch)

Since everything is in spec, I'm going to assume the small side to side movement (sliding on pivot bolt) is due to the missing felt rings.

Joe

[HondaMan]

I measured the tolerances for the bushings and collar and everythings still in spec.  Bushing ID - 23.6 mm / Collar OD 23.4 mm

Specs
For the CB650 Custom A/B (1980/1981) and CB650SC (Nighthawk 1982
only):
service limit swing arm pivot bushing (in.dia.): 23.7 mm (0.93 inch)
service limit swing arm center collar (out.dia.): 23.4 mm (0.92 inch)

Since everything is in spec, I'm going to assume the small side to side movement (sliding on pivot bolt) is due to the missing felt rings.

Joe

Is it sliding on the pivot bolt, or on the collar? If the bolt, something is not assembled properly, as it should be pulling the frame tight up against the ends of the collar. If it is sliding side-to-side on the collar, then either the flanges on the bushings are broken off or severely worn, or missing, or something...

The clearances involved: not more than 0.0080" worst-case between the collar OD and the bushing ID. This translates to side-to-side movement of the rear axle and tire, as [clearance]*27". The distance/geometry ratio is one-and-one-half (roughly) of the length from center of the collar to the center of the axle. Typically, clearance of more than 0.003" will result in a bike that feels unfriendly when going from a turn one way to a turn the other way: it wiggles in between the two leans.

[CBJoe]

I measured the tolerances for the bushings and collar and everythings still in spec.  Bushing ID - 23.6 mm / Collar OD 23.4 mm

Specs
For the CB650 Custom A/B (1980/1981) and CB650SC (Nighthawk 1982
only):
service limit swing arm pivot bushing (in.dia.): 23.7 mm (0.93 inch)
service limit swing arm center collar (out.dia.): 23.4 mm (0.92 inch)

Since everything is in spec, I'm going to assume the small side to side movement (sliding on pivot bolt) is due to the missing felt rings.

Joe

Is it sliding on the pivot bolt, or on the collar? If the bolt, something is not assembled properly, as it should be pulling the frame tight up against the ends of the collar. If it is sliding side-to-side on the collar, then either the flanges on the bushings are broken off or severely worn, or missing, or something...

The clearances involved: not more than 0.0080" worst-case between the collar OD and the bushing ID. This translates to side-to-side movement of the rear axle and tire, as [clearance]*27". The distance/geometry ratio is one-and-one-half (roughly) of the length from center of the collar to the center of the axle. Typically, clearance of more than 0.003" will result in a bike that feels unfriendly when going from a turn one way to a turn the other way: it wiggles in between the two leans.

Thanks for the info... I will inspect in more detail when I get back from Mid-Ohio Vintage Days.  I've got 2 spare swingarms that I can pull and compare.

If memory serves it was sliding on the bolt so I'll double check the assembly.  I think that one of my spare frames still has the arm assembled, so I'll use it for comparison.

Joe

[HondaMan]

Okie-Doke.
If it has flanged bushings, the flanges and the cup washers should be making up the distance. The collar should only stick out a max 0.008" longer than the ends of the flanged bushings (or end caps, if rebuilt with CB750 parts). Typically, the collar is about 0.004" longer, which should be the only "sliding" movement available: when the bolt is torqued to 25 ft-lbs., the collar usually shortens most of this amount, to end up with a 0 clearance fit-up.