Author Topic: CB 750 Project 1 - Rides Well but a few tweaks needed (Read 113444 times)

timbo750 · « **Reply #775 on:** November 21, 2016, 12:47:54 AM »

Got the seat on put issues with the lock. I eaither have a lock from a later model or I am missing a bracket.

Terry in Australia · « **Reply #776 on:** November 21, 2016, 01:03:59 AM »

Yeah mate, that lock's for an "F", so no "F"ing use on your bike.....

disco · « **Reply #777 on:** November 21, 2016, 01:08:26 AM »

Timbo,

Your seat lock looks like K type to me. I think you just need a bracket like this.

timbo750 · « **Reply #778 on:** November 21, 2016, 02:45:41 AM »

Thanks Disco, Yamiya have them, have got one ordered already. I thought about making one but I'm too busy and I also needed some retainers for the back of the side cover badges. Now I just need to get the rest of the drain plug out of the carb bowl

timbo750 · « **Reply #779 on:** November 25, 2016, 07:31:43 PM »

Now I have a wiring issue I need to sort out. I have an LED lucas style tail/brake light and at first I thought it wasn't working but now have worked out its wired to switch to the active and not the earth. I know I can over come this with a couple of relays but would rather not if there is a better way.

timbo750 · « **Reply #780 on:** December 03, 2016, 05:03:00 PM »

Well I thought I had it 99% done. I had wheeled it out of the shed and was going to take it for a quick ride up the street befoe taking it off for the roadworthy. But it was not to be, there is another electrical issue.

Today was the first time I put it in gear with the engine running and it blew a fuse. I had forgotten that when I wired the new blade fuse holder I put the main fuse at the top instead of the middle like the original. But there is still something else.

With a 30A fuse in the right position I selected first and was slowly moving the bike in the back yard feathering the clutch and then smoke from the clutch switch.

I turned it off and then selected neutral and tried to start again but nothing. It now seems the clutch switch is stuffed preventing it to start.

My thinking at first is that something is using the neutral and clutch switch as an earth and then when its in gear the clutch switch is copping all the current. Now the searching begins.

timbo750 · « **Reply #781 on:** December 03, 2016, 06:53:30 PM »

I think the electrical issue was the relay I used in place of the starter safety unit, so for now I have bypassed that and will work out something later. I still have a slight fuel leak around the bowl gasket on #1 and the idle is still #$%*.

I got for a short ride though, just around the block, I needed to know that it would change gears. only got up to third and back down a couple of times but all went well. The rear brake was a bit sensitive and would most likely lock up too easily when riding around. But I am very happy with how it pulls through the gears, I didn't rev too high (wasn't watching the tacho) but it did put a smile on the face. Will post pictures and video later.

Terry in Australia · « **Reply #782 on:** December 03, 2016, 08:44:42 PM »

Well done Timbo, as per my earlier advice, get rid of the clutch switch and starter safety unit, you don't need them, I've got the same wiring loom as you and I didn't bother with them and guess what? My bike still starts and runs. I have a fuse blowing issue too, but it's not related, the bike I built has a metal headlight bucket and every time I put the right blinker on, it blows the main fuse. No biggie, I just need to get into the headlight bucket with some insulation tape.......... Cheers, Terry.

timbo750 · « **Reply #783 on:** December 03, 2016, 11:47:34 PM »

Photos

timbo750 · « **Reply #784 on:** December 03, 2016, 11:53:51 PM »

Video

Terry in Australia · « **Reply #785 on:** December 04, 2016, 02:03:03 AM »

Lovely! I bet you're feeling very proud of yourself Tim, and so should! Now if you get bored, I've got 3 CB750's that need restoring, what's your hourly rate? Cheers, Terry.

maduncle · « **Reply #786 on:** December 04, 2016, 02:36:42 AM »

Go Tim!!!

That is excellent work - now come on out to Healesville and we can do a spur run together.

timbo750 · « **Reply #787 on:** December 04, 2016, 03:08:44 AM »

Terry, I have enough parts for the next one and a few more so you will have to wait. The wifr now wants her own bike but she is also goinv to wait.

Cliff, looking forward to the spur.

Just have to find spare time to get it over to Ace motorcycles and the get the reg sorted.

Terry in Australia · « **Reply #788 on:** December 04, 2016, 07:13:21 AM »

No worries Tim, Jeff at Ace is there on Saturday mornings which I find more convenient than during the week. Cheers, Terry.

SOHC4 Cafe Racer Fan · « **Reply #789 on:** December 04, 2016, 09:06:48 AM »

Great job, Timbo!

timbo750 · « **Reply #790 on:** December 04, 2016, 08:43:59 PM »

Another question for you all. After going for a ride I could not get it back into neutral whilst the engine was running, I turned it off and then managed to get it. I also noticed that when i tried to start it in gear with the clutch pulled I could feel a slight surge on that initial fire up.

I have read about this before but can't remember where and the search function on this site does not work for at all. Is it just a clutch adjustment? it would seem to me that maybe the clutch is not fully disengaging.

Terry in Australia · « **Reply #791 on:** December 04, 2016, 09:47:50 PM »

Yep you're spot on Tim, did you assemble the clutch plates into the clutch basket? It's really important that they're in the correct order, facing the right way, and seated correctly.

It's also really easy to stuff this up, but rather than explain it on my iPhone, have you got a copy of Mark's (Hondaman) book? He and I have had this discussion before, so even though I haven't read the copy he sent me, I'm sure it'all be in there somewhere. Cheers, Terry.

timbo750 · « **Reply #792 on:** December 04, 2016, 09:55:44 PM »

The clutch was the one thing I didn't touch. This engine was assembled when I got it and I really only pulled it apart due to the excessive sealer used around the cases by someone else.

So I am now hoping that the clutch is assembled correctly and just needs adjustment. Having never riden one of these before yesterday, my only comment is that it changed gears quite well both up and down but not sure how much an incorrect clutch assembly will affect this.

Terry in Australia · « **Reply #793 on:** December 04, 2016, 11:36:11 PM »

Yep, well if you haven't pulled the plates out and cleaned them, and given them a soak in some nice fresh oil they might be stuck together, which is common. They could also be warped (common again) and you could even have a broken clutch disc in there.

When Mike brought his bike over to me there was black clutch fibres all through it, they'd made their way into his crank and blocked the oil holes on #3 journal, and caused the new bearing shells to burn out, along with the cam, rockers, etc, and the bits of clutch even blocked the oil tank, what a fcuking mess!

Yours is probably fine, but it won't hurt to pull the clutch cover off, disassemble all the plates and make sure they're all good, installed correctly, then put it all back together and adjust it, and you shouldn't have any problem lightly snicking it into gear, and changing back to neutral at the lights. Cheers, Terry.

disco · « **Reply #794 on:** December 05, 2016, 01:43:03 AM »

As Terry has said 40 year old clutch plates disintegrating doesn't do a lot of good for your very fine oil passages. Maybe a good idea to replace?

I had that happen on my K6 & was picking clutch fragments out of the oil pump screen for a while thereafter.

timbo750 · « **Reply #795 on:** December 05, 2016, 02:03:37 AM »

So the clutch is coming out. Not enough time tonight to pull it apart so for now the clutch cable is disconnected so I am not tempted to avoid it.

Terry in Australia · « **Reply #796 on:** December 05, 2016, 10:11:03 PM »

Well done mate, and with the bike on the sidestand, you won't need to drain the oil out first. Cheers, Terry.

timbo750 · « **Reply #797 on:** December 07, 2016, 01:08:10 AM »

Pulled the clutch out, no fragments but plenty of black #$%*. The battery died on the vernier so can't get an accurate measurement but I think they would be about 3.2mm when the manual says the limit is 3.1 but I am not sure what they are when new.

I have a set of 8 Barnett clutch plates and sure if I should use the 8 or 7. The issue I had was not fully disengaging rather slipping. Spring length is good also.

timbo750 · « **Reply #798 on:** December 07, 2016, 09:37:20 PM »

Got a battery for the vernier and they measure within 3.44 - 3.46 , so I am happy with that. I will soak them in clean oil and clean the other parts. I will also be replacing the bearing.

Terry in Australia · « **Reply #799 on:** December 08, 2016, 01:42:02 AM »

No worries, be extra careful of the pressure plate, it's really easy to break one of the tabs off when tightening it, make sure to wind the four bolts down very evenly, or SNAP! If the bearings just a bit notchy, try cleaning it with a strong solvent like carb or brake cleaner, then some nice fresh oil. In all the CB750 engines I've built, I've rarely replaced an original bearing. Have fun!

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Author Topic: CB 750 Project 1 - Rides Well but a few tweaks needed (Read 113444 times)