Riding My Honda CB750 Cafe Racer Motorcycle Rebuild Project | Old School Motorcycle Clutch Fix | 35

[@Paul-m4h]

I'm enjoying your CB750 series. I believe I saw on a previous episode that when you were taking apart your clutch, the clutch hub has the ID "405" stamped in the bottom (by the spring posts). This hub was used by Honda on the '77-78 models and was made marginally taller than the earlier clutch hubs - stamped "300" - in order to accommodate a "double steel" - two steels riveted together (also known as a Type B clutch plate). This was supposedly introduced to eliminate clutch chatter. (It's kinda "springy".) If you have a 405 clutch hub, you need the Type B clutch plate to get the clutch stack height right, otherwise you get clutch slip. Added another friction disc, as you did, sort of does the same thing but a proper steel would probably give you the best result. Hope this helps. Happy riding and greetings from Canada.

[@SPANNERRASH]

Thanks Paul, I will investigate this further. The clutch pack I bought from CMSNL does have a different plate, but it isn't a "double steel" it has wider tabs and the friction material is positioned differently. This bike has been through many hands before mine, so there could be any mixture of parts. I do want to get it right in the end. Oh, and I have bought a new clutch lifter plate, but I am not using it until I have the rest sorted. Maybe getting a "300" hub might be the answer. Strange that the clutch worked fine at first! I would love it not to be the Oil I had been using :)

[@SPANNERRASH]

Paul. Having investigated it I have found the plate you mean, PN 22322-371-020. I suspect the extra thickness is the answer. I think the last PO had put in a new clutch not realising this, like me. Looks like there will be fourth clutch video, but it is working at the moment so I am going to put most of my attention to fueling. Thanks once again.

[@davidevelyn530]

The problem with the type B clutch plate is that they tend to grenade. The rivets break and the little spring plates in-between get loose and stack up against each other rendering the clutch useless. Not a great idea from Honda. OTOH I got 100K kms out of mine before replacing it on my 97 Valkyrie. Rear of the engine in front of the tire, crappy access. Part may be hard to come by as well....... Enjoying your good clean work.

[@SPANNERRASH]

@@davidevelyn530 Interesting! Thanks for sharing that. I am learning a lot about these clutches. 😃

[@bytio]

A really good video reliving all my issues i had rebuilding 410 engines. The clutch spring plate snapping is a common issue rebuilding until i found out the correct method. You must ensure that the springs are seated on the top plate (the one that breaks) tighten one bolt barely fingure tight check again that spring is seated, move to next and so on, every half turn recheck and re seat the spring using small screw driver. I never broke a lug again using this method

[@SPANNERRASH]

Thanks for the advice. I have a new plate, which I am going to fit next time I am in there.

[@roum22]

I ride an old Honda twin of similar vintage to yours. As I don't get out on it as often as I'd like, I remove the ethanol from the petrol to save any hassle with the carbs. There are many vid's on youtube showing how it is done, I use two clear 20ltr plastic containers, add about 10% red coloured water (food dye added) to the fuel, the ethanol attaches to the water instantly, then you siphon the fuel from above the heavier red water ethanol mix into the second container. You will find the ethanol content is rarely as high as 5% it ranges from as little as .5 - 3.5% in my area..

[@SPANNERRASH]

Thanks for this info. I may give it a go, might even make my own video. I will have two carbed bikes so it might well be worth the effort. At the moment I turn the fuel off around 1/2 a mile from home, runs out on the drive, with a bit of luck :)

[@Aussie_Wild_Adventures]

Only taken me all day to watch the entire series back2back and I’m still wearing my PJs! Absolutely gripped to watch the progress and so glad you managed to get out for a ride, even if it was to find more issues. Love it when you say was “hoping to find a smoking gun”, not sure you ever did! but made me smile all the same. I’m over in Sydney Australia recovering from an operation. So this series made for great entertainment and all important knowledge gathering for when I step into a cafe racer build. All the very best for completing the build… do we ever?

[@SPANNERRASH]

Thanks for commenting. Not sure why this appeared twice, but I really do appreciate it. Take care, and get well soon.

[@stephencroft6481]

You meet the nicest people on a honda

[@SPANNERRASH]

True. But the noise of this one stretches it a bit :)

[@markjohnson6130]

Love watching your videos, always nice to see people overcoming adversity. The clutch issues you have are likely due to the later clutch hubs from 78 K,s and 78 F models not having the correct clutch packs. My two bob's worth on the neutral light is that when the clutch plates are new and not scuffed in they stick together like sh#t to a blanket and make finding neutral difficult. When you have got the clutch pack heights correct, ride until oil is warmed up nice and do about half a dozen hard accelerations through the gears and even try flat changing a few times to help scuff in the new plates. If after that still having problems I would put some more tension on the neutral lever wheel spring by winding or a new spring. Ive seen them with almost no tension to drop in the neutral position, I think from people not installing them correctly and over stretching them. Have fun cheers Johno

[@SPANNERRASH]

Thanks Johno. There is a lot of wisdom in what you say. The video was genuinely of the first ride, so as you can imagine there is a lot going on! I have been out on the bike again, and I can find neutral and the light does come on. I suspect you are right about drag, that, along with the reverse gear change confusing me as well. It certainly isn't perfect now, but it is workable. I have a lot more to do with the fueling though. Cheers.

[@HIPNAUTIC.]

I'm so happy to see that this is on the road again. I have a '73 750 that I run in a similar configuration. It was getting really smokey towards the end of last season, so I've bought everything to do the valve stem seals, but haven't been up to removing the engine again after just putting it in last year. (I should've done the top end while I had it out.) And, my Ducati 996 has kept me occupied in the meantime. I hope to get my CB back up and running soon. I've been following this series for a while, and can't wait to see the next installment. -HIP

[@SPANNERRASH]

Thanks. I did the valve stem oil seals. The ones I took out where completely hard, and split. I'd love to have a play about with a 996, bet that's a lot of fun. I was out on the CB again today. In truth it is going pretty well, even finding neutral, but I really do need to sort out the carburation. It's great up to around 3000 rpm, but definitely not happy cruising at anything above, I think it is rich.

[@HIPNAUTIC.]

@@SPANNERRASH Some will point to rough carbonation being caused by your pod filters. (Full disclosure: I run ONLY velocity stacks on mine.) I jetted the bike according to what I found on forums, and still had a lean-running issue. Solved it by getting the carbs to properly seal on the boots, and resynching them with a vacuum gauge. It still has a little stumble around 3k RPM, but it’s never going to be perfect with my setup. Besides, she likes to be a lot higher in the revs. 😁

[@SPANNERRASH]

I have been thinking that I might try either using velocity stacks, or a stock filter (or similar) It picks up quite well but is quite fluffy from 3k up. I think it is rich. I have 125 mains, and 42 pilots, at the moment, not sure what I set the needles to, but they are all the same. I would be interested to hear your jetting with stacks.

[@TheoldBiker-bi1ho]

Nice to see your old CB750 🙂

[@SPANNERRASH]

Thanks more to come! If the weather allows :)

[@dcmotive]

Looks like a mess of fun!

[@SPANNERRASH]

The demands of riding it at the moment make it more satisfying than you would think. Almost a shame to fix the issues :)

[@bluehazeboy]

If you have an esso petrol station near you,fill up using their E5 ,there’s no ethanol in it,I have an esso station near me,& I fill up there,I left the fuel in my kettle for 6 months & it was still good,anything longer than that & then ,then it starts playing up,but all I did was clean the plugs filled up with new fuel & it’s good to go

[@SPANNERRASH]

Thanks I'll keep that in mind. Somebody else suggested de-ethanolising the fuel. I may just have a go at that :)

[@kennethmoreton6036]

5% ethanol in E5

[@bluehazeboy]

@@kennethmoreton6036 esso states on their website that there’s no ethanol in their E5

[@bytio]

Just a thought, I see you have the 410 (F2 or K7) carb rubbers on with the older K6 or earlier carbs that may play a part in the issue you have?

[@SPANNERRASH]

I will have to check that when I can get to it. I do have a variety of carbs and rubbers available. I did think I had swapped to the right manifolds but I will check, you are possibly right. Although I may just swap the carbs for the later type in the Spring to see how that works out.

[@dvsdev2403]

I have a Honda GL400 which is obviously different but of the same era, and the clutch pack has a singular “special twin metal disc”, are you sure your engine isn’t missing a special plate from your assembly

[@SPANNERRASH]

Thanks for the comment. Yes, I've come to the conclusion that this is the problem. It really isn't clear which bikes would need them, and when I bought a set of plates including a "B" (but not double thickness plate) from one of the best suppliers there was no indication it wouldn't be right. At the moment I believe that it is to do with different clutch inner clutch hubs. I think that the ones that need the double plate are marked 405 and the ones that don't 300, but this might not be the whole story. On the plus side I have done around 30 more mile on the bike since the bodge and the clutch works perfectly. I suspect that I won't be exploring this any further until Spring, it has been raining continuously for the past couple of weeks, maybe I'll start an Ark series :)

[@MrSventasPetras]

good day sir, I know this video about motorbike but I've watched your other video where you changed oil cooler on your transit van. I can't find the answer anywhere else so I thought I'd ask you. So, I bought this oil cooler from eurocarparts and the whole housing is different from the one is on my van and does not fit, it has some extra hole and hasn't got angled tube where the pipe goes on. If I swap new cooler on its own to my old housing would that work? would pressure has anything to do with these coolers? I recall you mentioned on your video that you wanted to swap just the cooler but it cost you less to buy new unit. I hope you could answer my question. All the best

[@SPANNERRASH]

I suspect that you should be able to swap the cooler onto the other housing, but you will have to ensure that the joining faces are the same shape. I know you can buy the housing and the cooler separately so it must be a swappable item, and they frequently use the same parts across many different vehicles. Good luck.

[@MrSventasPetras]

@@SPANNERRASH wonderful, thank you so much.

[@trompelemonde4728]

Did you verify the neutral switch?

[@SPANNERRASH]

Yes the neutral switch does work. And having ridden the bike again I can find neutral and the light does come on. I suspect that it is wearing in a bit now, and I am getting more adept at judging which gear I am in with the reverse change.

[@wokeybrokey8006]

I love the look of it and respect the dedication… but buy a Kawasaki 🤣

[@SPANNERRASH]

Ha, there's a few on my list. But only three places, and they're all full at the moment. :)

[@Aussie_Wild_Adventures]

Only taken me all day to watch the entire series back2back and I’m still wearing my PJs! Absolutely gripped to watch the progress and so glad you managed to get out for a ride, even if it was to find more issues. Love it when you say was “hoping to find a smoking gun”, not sure you ever did! but made me smile all the same. I’m over in Sydney Australia recovering from an operation. So this series made for great entertainment and all important knowledge gathering for when I step into a cafe racer build. All the very best for completing the build… do we ever?

[@SPANNERRASH]

I love watching a series back to back. I was really hoping to be on to the cosmetics now, but I am still looking at the running issues. I have some ideas of what I need to do but the weather is starting to become very Autumnal here in the UK, so I doubt I will get it running right and painted this year, now. Have a look at some of our other playlists, and I am putting a bit of an effort into my Triumph at the moment. I want to have both bikes as riders for the Spring. Hopefully life doesn't get in the way of my ambitions. Take care, and enjoy your Summer.