Author Topic: Problem with initial valve adjustment after rebuild  (Read 710 times)

Offline leadnavel

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Re: Problem with initial valve adjustment after rebuild
« Reply #15 on: May 25, 2022, 04:24:22 PM »


Yes NJ I’ve got it set up like this, any ideas what I can try next?


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CB750K7

Offline Nurse Julie

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Re: Problem with initial valve adjustment after rebuild
« Reply #16 on: May 25, 2022, 04:28:54 PM »


Yes NJ I’ve got it set up like this, any ideas what I can try next?


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I'm not clever enough to know if the pipe to the gauge may be causing the pressure not to build. I'm thinking that as long as the hole is plugged, you should get pressure but maybe someone can confirm this. I'm only saying this because a forum member spent 2 weeks trying to get oil circulation after rebuilding his 750 K0 then he reliased he hadn't fitted the oil pressure switch so there was a big hole letting the pressure out 😂😂😂😂
« Last Edit: May 25, 2022, 04:30:35 PM by Nurse Julie »
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 leadnavel

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Re: Problem with initial valve adjustment after rebuild
« Reply #17 on: May 25, 2022, 05:13:43 PM »
Worth checking basics then as it should be doing something.

First would be supply hose from tank to see if it's impeded, then remove pump to inspect internal and verify passage from feed hose down to pump.

Both oil hoses are new, the oil pump was stripped and refurbed, that's not to say that not where the problem lays though. Which of the two oil hoses is the feed and which is the return?
CB750K7

Online K2-K6

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Re: Problem with initial valve adjustment after rebuild
« Reply #18 on: May 25, 2022, 05:22:48 PM »
Looking at bike from the side,  outer one is return line going to tank.

Offline leadnavel

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Re: Problem with initial valve adjustment after rebuild
« Reply #19 on: May 25, 2022, 05:54:51 PM »
In my next session I’ll remove the oil pipe to see if there’s a problem with that. I’ll also swap the oil pressure gauge (it does have a mighty long tube) for the oil pressure gauge to see if that’s causing a problem.


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Offline leadnavel

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Re: Problem with initial valve adjustment after rebuild
« Reply #20 on: May 28, 2022, 10:14:14 AM »
I was able to get back to the project yesterday and swapped the pressure gauge for the oil pressure switch, pumped the kick start a few times (50) still no oil coming through! Before I remove the oil pipes (hopefully tomorrow) from the oil tank to check those, I thought that I would try a suggestion given by Hondaman on the other place.

http://forums.sohc4.net/index.php?topic=12686.0

Basically it’s a kicking/bursting routine. Firstly using the kick start 40-50 times then a short burst of the starter for 2-3 seconds then do it a second time. I did this routine 4 times, making sure that the oil in the sump didn’t run dry, this didn’t work for me either. All that I’m still getting is the oil from the sump getting pumped back to the oil tank when kicking it over (or using the drill attachment to speed up the process) with the sump running dry.


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Online K2-K6

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Re: Problem with initial valve adjustment after rebuild
« Reply #21 on: May 28, 2022, 10:47:11 AM »
Something definitely odd there, it shouldn't need so much spinning to get any output.

The scavenge side is obviously fine (different segment of pump) and should outstrip the pressure side always by design capacity (else all the oil would end up in the sump when running) so ok there.

I'd definitely check supply of oil to the pump before turning the engine any more without oil supply. 

The pressure guage won't make any difference if there's no oil. It all has to go to the filter first (through that delivery pipe to filter housing) to get to any components, there's no other route. Not worth putting the filter on until you see oil present in that delivery route as nothing else will be supplied.

Without the oil pump fitted, the oil tank content should run through the supply pipe and out the hole the oil pump fits to.

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Re: Problem with initial valve adjustment after rebuild
« Reply #22 on: May 28, 2022, 11:24:37 AM »
Worth checking basics then as it should be doing something.

First would be supply hose from tank to see if it's impeded, then remove pump to inspect internal and verify passage from feed hose down to pump.

Both oil hoses are new, the oil pump was stripped and refurbed, that's not to say that not where the problem lays though. Which of the two oil hoses is the feed and which is the return?

Did you strip the "leak stopper" valve in the oil pump ? as this could give a problem.

Offline leadnavel

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Re: Problem with initial valve adjustment after rebuild
« Reply #23 on: May 28, 2022, 03:02:36 PM »
I’ve got two pumps, I’ve stripped and replaced seals and rings in both of them but not the springs as they A. They looked and felt ok and B. I couldn’t get hold of any. I bought a secondhand pump because on the strip down of my original pump the rotors looked overly marked but I have subsequently done some research on the rotors and found that the marking are pretty standard and I could’ve used my original. If the pipes look ok I’ll remove the pump and double check everything.


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Offline smoothoperator

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Re: Problem with initial valve adjustment after rebuild
« Reply #24 on: May 28, 2022, 04:54:52 PM »
I don't know if this helps but I think the info on this thread might be related. I recalled something about using vaseline to overcome airlocks in 750 oil pumps. Also might be better in a new thread as this one has moved onto a new topic.

http://www.sohc.co.uk/index.php/topic,23297.msg218481.html#msg218481
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline leadnavel

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Re: Problem with initial valve adjustment after rebuild
« Reply #25 on: June 05, 2022, 04:55:48 PM »
Thanks for your assistance guys it’s been a massive help. Sorry for the delay with the update I’m in the middle of a house move and the other half (we’ll the other 3/4) had other plans for me.

Long story short… I’ve got flow to the camshaft/holders and top end gubbins, the problem appeared to be an air lock.

Short story long… I disconnected the oil hoses from the oil tank (my engine is still on the bench connected to the oil tank) to have a look to see if there was a problem. There wasn’t any oil in return pipe but the feed pipe was full. I took both hoses off and blew them through, they were clear.
I removed the oil pump, all three ‘O’ rings present and correct. The ‘stopper valve’ was also working OK. I immersed the pump assembly in engine oil

Oil Pump
https://youtube.com/shorts/WYfMHacZ3iM?feature=share

Oil Leak stopper valve
https://youtube.com/shorts/D7f3qYA43BQ?feature=share

turned the sprocket by hand and saw lots of air bubbles coming from the pump feed holes. After 5 minutes of turning I did notice the bubbles had mostly stopped and I that there was more resistance when turning the sprocket. I then removed the pump assembly from the oil bath, trying not to turn it or hassle it too much then I let it sit for a while raised up above and off the screen at the bottom, about 10mins, only a small amount of oil drained out. I replaced the pump assembly and only had to kick it over 7 times before oil started to show in the hole in the oil filter housing, result!

I did toy with the idea of using Vasoline Smoothoperator when I initially serviced the oil pump but wasn’t confident I could do it correctly, in hindsight I probably should’ve gone this route.

I then fitted the clutch basket and connected an oil pressure gauge to the outlet where the oil pressure gauge is fitted and turned the engine over using the starter motor pressure came up to 40psi after about 5-10 seconds.

Pressure Test
https://youtube.com/shorts/l6NEGcQ0b0o

Thanks again guys for taking the time to offer your assistance it is really much appreciated it's gotten me a whole lot closer to finishing the project.
CB750K7

Offline philward

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Re: Problem with initial valve adjustment after rebuild
« Reply #26 on: June 05, 2022, 06:15:01 PM »
Wish I'd seen this post earlier - I had problems on the 1st of 3 750 rebuilds I've done but on the subsequent 2 used the vaseline method and oil presure almost instantly
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