Author Topic: CB750K4 New project  (Read 5714 times)

Offline paul G

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Re: CB750K4 New project
« Reply #135 on: August 09, 2018, 08:57:11 PM »
Great looking bike rob. I fitted a Delkevic to the Z650 cafe and the do sound sweet.
Honda CB400 4
Honda CB550 K3
Honda CB750 UK K1 restoration
Kawasaki Z650 C2
Kawasaki Z650 cafe racer (bitsa) ongoing

Offline Rob62

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Re: CB750K4 New project
« Reply #136 on: August 10, 2018, 09:30:23 PM »
Just back from the first shakedown run. No major problems to report, everything seems to work quite nicely.. The suspension is on the firm side but ok (TEC shocks as suggested on the forum),  no clonks or rattles from the running gear. Front brake is a little weak (new pads) rear brake is ok. The engine and gearbox is smooth, no rattles, leaks or burning oil. The gearbix has an audible but quite pleasant whine through all the gears which i guess is normal?. The Delkevic exhaust sounds absolutely awesome although I only went up to 5k revs and part throttle first time out. The throttle is a little stiff, cables need lubricating and the gear lever is way too high and needs adjusting. The engine paint i used is hopefully curing in the garage now its had a good heat cycle, could smell it when i got back. The most depressing thing is that the best summer in living memory appears to be over just as I'm finally finished.. I’ll go for a run to squires cafe tomorrow if the sun comes out, yippeee  ;D

Offline Rob62

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Re: CB750K4 New project
« Reply #137 on: August 10, 2018, 09:33:23 PM »
Just one thing, the engine just stutters ever so slightly when coming off closed throttle, only noticed it as i was almost back home...... a bit of carb fettling may be necessary

Offline hairygit

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Re: CB750K4 New project
« Reply #138 on: August 10, 2018, 09:35:11 PM »
NO NO NO! Never oil cables, most are nylon lined these days, and oil will make the nylon swell and make the cable stiffer! Even most aftermarket cables are nylon lined, and if they are stiff, it's more likely to be cable routing.
If it's got tits or wheels, it's hassle, if it's got both, RUN!!!

Offline Rob62

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Re: CB750K4 New project
« Reply #139 on: August 10, 2018, 09:48:42 PM »
Thanks for the tip hg, although i must say thats a new one on me, nylon absorbing oil...  but i will take heed and see what else i can do to remedy the issue..

Offline hairygit

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Re: CB750K4 New project
« Reply #140 on: August 10, 2018, 09:54:51 PM »
No, it's the oil reacting with the nylon, which is itself a product of oil, it makes the lining sticky and stiff. If they are new cables check they are correctly routed, as it certainly shouldn't be like that with new cables.
If it's got tits or wheels, it's hassle, if it's got both, RUN!!!

Offline Green1

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Re: CB750K4 New project
« Reply #141 on: August 10, 2018, 09:56:56 PM »
Agree with Hairy again  :o don't lube cables.
Cable route is the most likely cause or even the throttle lock screw on the right hand switch
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Honda CB750k1 Candy Gold
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Offline Rob62

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Re: CB750K4 New project
« Reply #142 on: August 10, 2018, 09:58:44 PM »
They are new gen Honda, the routing looks ok although they do bend slightly as they pass the coils and attach to the carbs.... i had them on and off a dozen times when i was rebuilding her, until i was satisfied... will have another look tomorrow. Cheers.

Offline Rob62

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Re: CB750K4 New project
« Reply #143 on: August 10, 2018, 10:00:26 PM »
You might be onto something there G1... the stiffness did seem to be at the throttle grip end come to think of it.... ill be all over it tomorrow morning  ;)

Offline Green1

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Re: CB750K4 New project
« Reply #144 on: August 10, 2018, 10:09:19 PM »
I have spent ages trying to lighten the throttle on my 550 it weighs a ton at 3/4 throttle.
I have now come to the conclusion it must be the return spring so just going to live with it now. But what I cant work out is why it goes light again past 3/4 
Current bikes
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Honda CB750k1 Candy Gold
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Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: CB750K4 New project
« Reply #145 on: August 10, 2018, 10:13:41 PM »
I have a very, very, heavy throttle on my CB550 and mine is definitely the spring. I need to put a different one on but it can wait for a snowy day to be done.
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Green1

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Re: CB750K4 New project
« Reply #146 on: August 10, 2018, 10:16:39 PM »
Is it like mine and goes light again?
Current bikes
Honda CB750k1 Valley Green Metallic
Honda CB750k1 Candy Gold
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Honda CB400 Parakeet Yellow
Honda CG125
Aprilia Pegaso 650
Moto guzzi 1200 sport

Offline K2-K6

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Re: CB750K4 New project
« Reply #147 on: August 10, 2018, 10:32:41 PM »
Make sure you've not taken too much "slack" out of the throttle pull cable.

Honda are specific about this and give a rotation amount of play that should be in the twist grip at rest.

The push/return cable is usually set with no real adjustment possible but if you tighten the pull cable too much it'll give you a conflict as they run differing routes slightly.  It'll also feel different from turning the steering lock to lock and may even stop you from being able to turn the throttle in extreme cases.

It looks and feels odd to have what appears alot of play at the twist grip but they are designed like that.

The effort will vary slightly throughout range as those forks on the carb slide shift geometry as you move the throttle.

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: CB750K4 New project
« Reply #148 on: August 10, 2018, 10:40:59 PM »
Is it like mine and goes light again?
Nope, mine stays constantly heavy, bloody makes my hand and wrist ache after not too many miles. I even have 3 little callus's on my hand and a blister...but I do have very small hands so I'm probably just having to grip the throttle so tight to twist it. Hasn't stopped me doing almost 2000 miles on it though 🙂🙂🙂
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Seabeowner

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Re: CB750K4 New project
« Reply #149 on: August 11, 2018, 10:24:39 AM »
Even fully throttle fully closed the spring on my 500 was still stretched quite a bit. I added a small key ring loop (maybe 9mm) at the top to effectively shorten the distance the spring is stretched over. Not clever enough to work out spring rate change as spring stretched, but still snaps closed and reduced hand fatigue.
Phil
1971  CB500K0
1973  CB500K1
1975  CB550F1
1978  CB550K