[HenryNorfolk]

I bought this motorcycle last year. It had been rebuilt and nicely painted but I have needed to troubleshoot quite a few problems. I didn't notice clutch slip on my first few rides but engine wasn't making good power. Now that the engine is running better I find the clutch slips when I give it some throttle. I didn't know what iol the PO used so I have changed it a couple of times and I use 10W-40 mineral oil that's okay with wet clutches. One thing that surprises me (and this may be a clue) is that lever pressure is surprisingly light. My CB77's clutch lever requires a lot more strength, and that's made me wonder if the CB350's clutch springs are weak or even coming undone? I've tried adjusting the clutch release adjuster then the cable, according to instructions, and with cable adjuster too slack the clutch drags, and with the cable a bit tighter it doesn't drag and gear changes are sweet, but the clutch slip persists. Before I take the r/h cover off to examine springs and plates I thought I'd run it by you people.

 

[DD23]

Hi Henry,

You know of CMSNL.com.

What is the exact model and year please ?

If this bike were mine I would remove the clutch cover to flush out sump, check oil pump filter, check/clean clutch plates and basket etc. , Centrifugal oil filter and a few other things under that cover, as a matter of course right at the begining of ownership.

You say the bike had been "rebuilt", so as a matter of interest, what problems did you have to attend to ?

You have a manual ?

Friction plate thickness, spring length and any etching of the steel plates ?

Exact model and year and a picture would be good.

Dd23

 

[HenryNorfolk]

Thanks Dd23. The bike is a CB350K2 first registered in USA, but was imported to

UK much more recently. I have a dating certificate that says it was manufactured in 1/70.The previous owner (PO) had the fuel tank, side panels, headlamp and fork shrouds re-painted, and he also replaced the rims and spokes as well as polishing up the hubs and engine side cases. It looked good. After it was delivered to me I started it and was pleased that the engine is mechanically quiet, however it suffered fuel starvation. I discovered that the fuel tap was clogged with a chalky deposit and the fuel tank was very rusty inside. One of the carb floats broke (it had been badly repaired) and the front wheel rim was not aligned centrally. The centre stand lugs had been sawn off the frame at some point and the PO had made a weak repair that failed on me (I very nearly dropped the bike). I rectified those problems, and worked on getting it into tune. I've just fitted a Boyer electronic ignition kit, and a battery voltage indicator which tells me the alternator is overcharging the battery, so I plan to fit a combined rectifier/regulator.

I have a Haynes workshop manual for the machine. I think you're right to suggest I take the side cover off, clean the centrifugal filter and pull the clutch apart and measure springs and plates.

 

[mike in idaho]

Before you rip everything all apart, have you tried re-adjusting the clutch lifter?

 

[HenryNorfolk]

 

[HenryNorfolk]

Before you rip everything all apart, have you tried re-adjusting the clutch lifter?

I've adjusted it again and taken it for another ride. It's still slipping, but I remember that my CB77's clutch wasn't good when I started riding it, but it did improve with use, so hopefully the CB350 clutch will also improve. I try not to let it slip too much as I don't want to overheat the plates and warp them.

 

[PoiPio]

If it slips toss the whole friction and steels. Don't want to mess with that horseshoe staking clamp too many times or it cracks down the middle. If NA, I'd almost have a bead welded down the center of both sides so that one last try snaps it in half.

Frictions leave burnt bits to travel up the oil pump, scratch rolling parts... Stop and replace already.

 

[HenryNorfolk]

I hear you PoiPio. You're making a good point regarding potential damage from debris shed by a slipping clutch.

 

[brekken15_8979mb]

I had a leaky carb once and had gotten gas in the oil. It shifted different and slipped bad once I changed all of that gassy oil out it was night and day difference. Any gas smell to you oil just thinking about the bad float and fuel issues.

 

[HenryNorfolk]

I replaced the bad float with a new one, and I think float levels are correct. But I'll double check.

 

[vtcycle]

brautiful bike

 

[HenryNorfolk]

Thanks vtcycle. I think it's beautiful. I wasn't sure if I'd like this colour, but it's grown on me.

 

[HenryNorfolk]

I don't think I should keep riding it as I've tried adjusting it again and the clutch slip isn't going away. So I'll pull the clutch apart and examine/measure plates and springs.

 

[DD23]

Check CMSNL views for release mechanism and if any of it is stiff/sticking/not releasing/hanging etc...just in case.

 

[HenryNorfolk]

The lever action is smooth and light, and the clutch doesn't drag when the handlebar lever is pulled. I'm also making sure there's some free play (backlash) in the cable so that the inner cable is relaxed when the handlbar lever is released. Clutch engages/disengages fine and if I ride gently it's feeling okay, but if I accelerate hard through the gears the clutch will slip.

 

[sfruechte]

Well over 200,000 miles on my GL1000 and the ONLY time my clutch ever slipped is when the clutch cable became sticky. The new cable was unbelievably easy to operate. I had become used to the very stiff nature of the old cable and it eventually did not comletely engage the clutch anymore. Focus on your cable. If you know how to ride,clutches last forever.

 

[HenryNorfolk]

I took the clutch plates out, washed them in petrol (gasoline) and measured them. All good. The springs were a little short so I found some washers that fit under the springs as packing to increase the pressure a touch. I've just taken the bike for a ride along the coast road and the clutch slip seems to have gone now. Thanks everyone for your input.

 

[HenryNorfolk]

Not sure if the problem was the slightly tired springs, or residual oil from previous owner using wrong oil. Either way, I'm pleased to say I went for another ride this afternoon and the clutch is still behaving well.

 

[rokonosan]

Well, that's cool!

I had a similar problem that a new cable seemed to fix. I'm still looking for a proper lever return spring though...