Author Topic: My K8 re-conditioning  (Read 18941 times)

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Offline madmtnmotors

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Re: My K8 re-conditioning
« Reply #250 on: March 15, 2023, 08:55:51 AM »
I have used a pick between the plastic and the bung. Once you have an opening between the filter and the bung large enough to get needle nose pliers on the filter I just grab the filter, twist, and pull.

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Offline denward17

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Re: My K8 re-conditioning
« Reply #251 on: March 15, 2023, 09:27:05 AM »
Good tips Guys, will try later today.

Offline Gamma

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Re: My K8 re-conditioning
« Reply #252 on: March 15, 2023, 09:36:47 AM »
Good to see it running 👍

Offline denward17

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Re: My K8 re-conditioning
« Reply #253 on: March 15, 2023, 10:19:05 AM »
Used a tap to screw into the old filter sock and was able to get it started out, then it broke off inside the tank.

Little while later and shaking the tank upside down, it fell out. 

Will be rinsing the inside with some alcohol or something later before installing the new petcock.

Offline denward17

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Re: My K8 re-conditioning
« Reply #254 on: March 16, 2023, 12:54:51 PM »
Spent the day cleaning up the inside of tank using Evaporust (soaked last night), then some Dawn dishwashing liquid, followed by a good rinse.

Added some alcohol to help remove any residue, then used air compressor and let it sit in the sun for about an hour to dry out.

Installed new petcock, added some fuel to make sure it didn't leak, then installed on the bike, along with side covers and seat.

Still need to set the timing with a timing light before going on the first ride.

After a few miles will try to sync the carbs (they were bench synced but need to be set with vacuum.

Offline Mark1976

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Re: My K8 re-conditioning
« Reply #255 on: March 16, 2023, 01:59:29 PM »
Gotta love it when a plan comes together. Get looking ride, well done.
Start with the end in mind...

Offline grcamna2

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Re: My K8 re-conditioning
« Reply #256 on: March 16, 2023, 05:39:15 PM »
The bike looks good sitting there after it's nice top-end rebuild and just waiting to get on the road  8)
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
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Do your BEST...nobody can take that away from you.

Offline denward17

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Re: My K8 re-conditioning
« Reply #257 on: March 17, 2023, 02:50:28 PM »
I took it for a short hop this afternoon, as rain was moving in.  I only went about 4 miles.

It ran ok as long as I stayed above 2500-3000 RPM.  Might have some fine tuning to do next week.

Is it best to put a a few miles on it before syncing the carbs, or should I go ahead and do that?

Offline RAFster122s

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Re: My K8 re-conditioning
« Reply #258 on: March 17, 2023, 03:14:21 PM »
Go ahead and sync the carbs. There should be no reason to delay it. You don't expect cables to stretch and affect carb tuning, nor anything else I can think of off the top of my head.
Never hurts to strobe check the timing again after sync.
David- back in the desert SW!

Offline grcamna2

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Re: My K8 re-conditioning
« Reply #259 on: March 17, 2023, 04:49:20 PM »
I find the carb. synch does change after the engine fully breaks-in on all 4 cylinders.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline BenelliSEI

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Re: My K8 re-conditioning
« Reply #260 on: March 17, 2023, 08:03:33 PM »
Do it ASAP, and then after a few hours of run time. You’ll be rewarded.

Offline PeWe

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Re: My K8 re-conditioning
« Reply #261 on: March 17, 2023, 11:06:29 PM »
Make sure that valve lash and ignition are correct before carb sync.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline grcamna2

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Re: My K8 re-conditioning
« Reply #262 on: March 18, 2023, 12:03:42 AM »
Make sure that valve lash and ignition are correct before carb sync.

Cold valve lash checks and check that the cam chain is adjusted.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline denward17

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Re: My K8 re-conditioning
« Reply #263 on: March 20, 2023, 12:26:53 PM »
Was having a few idles issues.

Changed the condensers, didn't seem to help with a backfire condition.  So today I changed out the points to some I purchased form vintagecb750, I didn't hear anymore backfire after that change.  They were made in Taiwan, hopefully they are ok for now.  Want to get the bike running better on old ignition system before I change over to electronic.  I purchased a Dyna knockoff, if it doesn't work will try Hondaman's system.

I also synced the carbs, they were pretty close from the bench sync, but using #2 as reference, I did adjust 1, 3 and 4 just a little.
See pic attached, good enough for now.

Adjusted Fast Idle (choke).  It was idling good at about 12-1300 RPM, so left it be for now.


Argh.....  as I was taking off the right side cover, both top tabs broke off.  Not surprising since these were original.  The PO had already attempted some type of glue fix.  I will try some JB Weld plastic epoxy before buying another set.

Will go for another short ride when weather warms up later this week and see how it runs.

 



 

Offline Stev-o

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Re: My K8 re-conditioning
« Reply #264 on: March 20, 2023, 12:54:30 PM »
Yes, I'd go for a few testing rides and see how she does.

What car is that in the pic above? Looks Japanese?
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Offline denward17

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Re: My K8 re-conditioning
« Reply #265 on: March 20, 2023, 01:03:43 PM »
Yes, I'd go for a few testing rides and see how she does.

What car is that in the pic above? Looks Japanese?

It is, '21 Mazda MX-5 (Miata).

Offline denward17

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Re: My K8 re-conditioning
« Reply #266 on: March 27, 2023, 10:48:56 AM »
Installed an electronic ignition today (ebay Chinese brand), it seems to run fine at idle in the garage.

Need to take it for a spin to see how it runs on the road, waiting for rain to clear out.

Offline BenelliSEI

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Re: My K8 re-conditioning
« Reply #267 on: March 27, 2023, 03:41:36 PM »
Share a photo, curious which one you bought?

Offline denward17

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Re: My K8 re-conditioning
« Reply #268 on: March 27, 2023, 05:18:32 PM »
Share a photo, curious which one you bought?

Looks like the one in this post #282, not my pic.

http://forums.sohc4.net/index.php/topic,158702.msg2238802.html#msg2238802

Offline PeWe

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Re: My K8 re-conditioning
« Reply #269 on: March 27, 2023, 09:30:08 PM »
I ordered 2 of those Dyna-S knock-offs. From USA.

Only the label that is missing and blue box

5 ohm coils (Dyna look) from China.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline denward17

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Re: My K8 re-conditioning
« Reply #270 on: March 28, 2023, 09:39:48 AM »
Visited my son for a quick stop trying to get my riding legs back, so to speak.

Put about 28 miles on it this morning to check the electronic ignition, seems to run good.

No WOT as of yet, only about 48 miles since top end rebuild.

Offline PeWe

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Re: My K8 re-conditioning
« Reply #271 on: March 28, 2023, 10:26:23 AM »
Congratulations!
It is a very nice feeling to ride after an engine restore.

More happiness when it does not weap oil either ;)
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline denward17

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Re: My K8 re-conditioning
« Reply #272 on: March 28, 2023, 10:46:25 AM »
Congratulations!
It is a very nice feeling to ride after an engine restore.

More happiness when it does not weap oil either ;)

Absolutely a good feeling, and no leaks as of yet (fingers crossed).

Offline BenelliSEI

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Re: My K8 re-conditioning
« Reply #273 on: March 28, 2023, 02:07:32 PM »
Bike looks great! Well done.

Offline HondaMan

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Re: My K8 re-conditioning
« Reply #274 on: March 30, 2023, 06:34:49 PM »
My, but that's a good-looking bike!
:)
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

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