Topic: Swingarm ID question -CB750K4

[BobR]

   Well recently discovered I have an F2 engine in my K4... one thing leads to another. Lets check the sprocket offset...yep 10mm off. Lets take the wheel off and check the spacers and of course there's a small amount of play in the swing arm so lets take that off and have a look...which leads me to my question...
   How can I ID the swingarm  as a K4 or perhaps a later one if its been changed. The swing arm has only 341L on it near where the axle goes. It has steel later bushings in it which is odd since it was my understanding the bike sat untouched from the mid 80's until I got it in 98. Everything looks like an early set up (for what I know) Bushings, felt "seal",plastic thrust collars and dust caps....On a positive note everything was very well greased.... TIA Bob

[Jerry Rxman Griffin aka MuthaF'er]

I can't say for sure but the -341 was an earlier/mid K designation. I think you may find as you cross-reference the parts that the spacers are identical for the 750's. The offset differences are in the later swingarms as well as the later sprocket carrier. The later swingarms 77/78 with the 10mm offset (F anyway) have the different style axle adjusters and the axle opening is not closed at the end. The later chain guard is set up for the differences too. 

[754]

If has bolts thru the axlecend it's 76 and earlier.
 Seems like  extra chainguard mounts on that one.
After I finally clicked the top pic, I see it has regular chainguard mounts, i mistook shock mount for one..

[HondaMan]

Your swingarm is the K1-K6 type. The "341" designation began when the swingarm bolts lost their grease zerks and the arm received instead a single grease zerk in the middle of the amr.

...which doesn't work...hence the steel bushings...which are also probably worn out and have taken the collar with them...

[BobR]

Thanks guys. Its definitely a 71-76 . So far only the engine itself seems to have been changed. It has grease fittings on both ends of the swing arm bolt and no place for a fitting in the swing arm so parts weren't swapped. The collar looks pretty good. The assembly was very well packed with grease and probably the only thing that saved it from being chewed up. Bob

[PeWe]

My K6 swingarm has a grease nipple. It has also a narrowed shape close to front bolt while the earlier has straight shape.
Red is my old K6 that lost the chain guard bracket when the drive chain snapped on Autobahn without cracking the case! This swingarm has a solid bolt for fastening it.

Black in front of the chromed swingarm is the one I'll use on my ongoing K2 build. Probably a part that belongs to just that frame registered as K2 1975 (We got no K3-K5 here).  This has bolt with grease nipples.

Same with the last black swing with needle bearings that my K6 got as replacement a few years ago. K2 swingarm I use my K6 bolt on, no grease refill at all. My k6 swingarm looked OK when I removed it with about 40.000 km since I assembled and greased bearings after repaint, needle bearings had grease.

[BobR]

I can't say for sure but the -341 was an earlier/mid K designation. I think you may find as you cross-reference the parts that the spacers are identical for the 750's. The offset differences are in the later swingarms as well as the later sprocket carrier. The later swingarms 77/78 with the 10mm offset (F anyway) have the different style axle adjusters and the axle opening is not closed at the end. The later chain guard is set up for the differences too.

 That would be nice. Going to have to do so. (cross reference) I have a 77-78 sprocket carrier on the way.

[BobR]

My K6 swingarm has a grease nipple. It has also a narrowed shape close to front bolt while the earlier has straight shape.
Red is my old K6 that lost the chain guard bracket when the drive chain snapped on Autobahn without cracking the case! This swingarm has a solid bolt for fastening it.

Black in front of the chromed swingarm is the one I'll use on my ongoing K2 build. Probably a part that belongs to just that frame registered as K2 1975 (We got no K3-K5 here).  This has bolt with grease nipples.

Same with the last black swing with needle bearings that my K6 got as replacement a few years ago. K2 swingarm I use my K6 bolt on, no grease refill at all. My k6 swingarm looked OK when I removed it with about 40.000 km since I assembled and greased bearings after repaint, needle bearings had grease.

 Thanks for the pics! The differences are fairly obvious by looking at them. Going to deal withthe bushings first then work out the offset issue. Bob