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Author Topic: Need help with a 970 big bore project  (Read 1859 times)

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Offline PeWe

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Need help with a 970 big bore project
« Reply #50 on: August 10, 2018, 10:07:21 am »
If stock advancer is used, or similar that hook in to the crank.
Check if it has a play before tighten it.
I noticed that my advancer has a play about 3-4 degrees.
At true TDC, T lines up correctly if advancer unit is turned max counterclockwise position.

I have mine at max clockwise position and have therfore punched additional case mark 2-3mm beside stock mark. To the right (after).
I set ignition related to this mark too. Same thing with 2 different crankshafts and 2 different advancers. Stock, Pamco or Dyna-S affected.
If I should tighten advancer in max clockwise position and set ignition to stock case mark, the result will be too advanced ignition with pinging, less power despite Shell V-Power fuel.
« Last Edit: August 10, 2018, 10:11:45 am by PeWe »
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Offline Bill/BentON Racing

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Re: Need help with a 970 big bore project
« Reply #51 on: August 11, 2018, 03:18:07 am »
Yah, they make good paper weights! Good luck.
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Offline Big Jay

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Re: Need help with a 970 big bore project
« Reply #52 on: August 11, 2018, 05:38:16 pm »
So there were no bent valves?

Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #53 on: August 13, 2018, 05:48:56 pm »
So there were no bent valves?

I put some gas in as you suggested, looked okay. I’m just trying to figure my way through this degreeing process and getting it set up correctly.


Offline dragracer

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Re: Need help with a 970 big bore project
« Reply #54 on: August 13, 2018, 06:46:08 pm »
So there were no bent valves?

I put some gas in as you suggested, looked okay. I’m just trying to figure my way through this degreeing process and getting it set up correctly.

I've been silent as this thread has moved along but now I feel compelled to offer a bit of information. If you've never degreed a cam before, I would suggest buying the cam degreeing video and kit from Schnitz racing. It'll take you step by step on what needs to be done. You'll also have all the equipment you need to do the job without piecing a kit together yourself. We could all sit here and walk you through the process but that video will be your best investment in my opinion. I had access to the old Dale Walker video years ago and played it at less three times before actually applying the process in real life.

Offline Bill/BentON Racing

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Re: Need help with a 970 big bore project
« Reply #55 on: August 14, 2018, 03:41:57 am »
I agree with Frank/Dragracer. When you checked the valve seal with gas, hold , no fluid? Or some leakage?
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Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #56 on: August 14, 2018, 08:30:25 am »
So there were no bent valves?

I put some gas in as you suggested, looked okay. I’m just trying to figure my way through this degreeing process and getting it set up correctly.

I've been silent as this thread has moved along but now I feel compelled to offer a bit of information. If you've never degreed a cam before, I would suggest buying the cam degreeing video and kit from Schnitz racing. It'll take you step by step on what needs to be done. You'll also have all the equipment you need to do the job without piecing a kit together yourself. We could all sit here and walk you through the process but that video will be your best investment in my opinion. I had access to the old Dale Walker video years ago and played it at less three times before actually applying the process in real life.

Please don’t remain silent if you don’t need to, I really appreciate all the info I can get. In regards to buying a kit, I actually did but I bought a comp cams kit. It comes with degree wheel, piston stop(i had to make my own though), pointer, dial indicator, mount for it, and some other pieces, as well as a cd on how to degree a cam. Would this suffice, or is there a preference to the Schnitz racing set up? I’ve watched my video multiple times, read and reread santanic mechanics page on degreeing, and taken into account other sources (a previous post on here). I spent time last night, and made some progress with it and wrapping my mind around the correct procedure, and it’s starting to come together. I got my exact tdc, using the piston stop method and degree wheel, installed the adjustable sprocket and valve train. Got to the point where I can start degreeing, but had to leave for my birthday dinner haha.


Offline MRieck

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Re: Need help with a 970 big bore project
« Reply #57 on: August 14, 2018, 11:49:29 am »
I would turn the engine the engine over on the other side of the crank use the large, slotted nut used to hold the advance unit on. Use only the large, slotted nut to turn the engine over. Using the bolt holding the wheel on can move the wheel especially when you consider you are loosening the bolt when turning the engine in the correct direction.
 I also urn the wheel over so I can see it from the right side (adanvcer side) of the engine. Much easier.
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Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #58 on: August 14, 2018, 11:56:28 am »
Here are my numbers for degreeing the cam, there are no markings on it but was told it was a D-grind cam, numbers are close but not perfect, you guys tell me what you think.

D-Grind Cam Card:
Intake:
Lift: .345 (i got .335)
Duration: 277 (i got 276)
Open: 32 (at .040 32, at .050 26)
Close: 65 (at .040 75, at .050 70)

Ill follow up with the exhaust numbers once I do them. 



Offline Bill/BentON Racing

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Re: Need help with a 970 big bore project
« Reply #59 on: August 14, 2018, 07:58:01 pm »
I would turn the engine the engine over on the other side of the crank use the large, slotted nut used to hold the advance unit on. Use only the large, slotted nut to turn the engine over. Using the bolt holding the wheel on can move the wheel especially when you consider you are loosening the bolt when turning the engine in the correct direction.
 I also urn the wheel over so I can see it from the right side (adanvcer side) of the engine. Much easier.
  I do it also use Mike's method,  real easy to turn, read, and doesn't move easily.
BentON Racing Website
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
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Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #60 on: August 14, 2018, 08:41:32 pm »
SUCCESS!

I degreed the cam, checked my plug wires and everything electrical and I was able to get it to kick over, and run. It sounds like a drag bike, nothing like my 71 cb750. 

More questions though, my oil pressure gauge isn’t reading anything (like 5 psi while running), but I had oil going up to oil cooler near the neck of the bike. I had a loose fitting and oil was pouring out. I have a oil pump built by Cyclex, and I triple checked my metering jets were installed. Any ideas on what would cause this?

I need to tune the carbs up next, it has good throttle response in neutral, but doesn’t stay on if you let the throttle off.

Offline scottly

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Re: Need help with a 970 big bore project
« Reply #61 on: August 14, 2018, 09:08:48 pm »
Do you still have low oil pressure after fixing the loose fitting?
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Offline MRieck

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Re: Need help with a 970 big bore project
« Reply #62 on: August 14, 2018, 09:28:57 pm »
I would turn the engine the engine over on the other side of the crank use the large, slotted nut used to hold the advance unit on. Use only the large, slotted nut to turn the engine over. Using the bolt holding the wheel on can move the wheel especially when you consider you are loosening the bolt when turning the engine in the correct direction.
 I also urn the wheel over so I can see it from the right side (adanvcer side) of the engine. Much easier.
  I do it also use Mike's method,  real easy to turn, read, and doesn't move easily.
Thumbs up brother.
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Offline dragracer

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Re: Need help with a 970 big bore project
« Reply #63 on: August 14, 2018, 10:34:20 pm »
SUCCESS!

I degreed the cam, checked my plug wires and everything electrical and I was able to get it to kick over, and run. It sounds like a drag bike, nothing like my 71 cb750. 

More questions though, my oil pressure gauge isn’t reading anything (like 5 psi while running), but I had oil going up to oil cooler near the neck of the bike. I had a loose fitting and oil was pouring out. I have a oil pump built by Cyclex, and I triple checked my metering jets were installed. Any ideas on what would cause this?

I need to tune the carbs up next, it has good throttle response in neutral, but doesn’t stay on if you let the throttle off.

Excellent. Tune the carbs, check for leaks and heat cycle it a few times.

Offline Bill/BentON Racing

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Re: Need help with a 970 big bore project
« Reply #64 on: August 15, 2018, 06:22:47 am »
That gauge ....don't know,   pull ex tappet caps and check for oil flow... Engines not getting enough oil won't idle well, but enough throttle overcomes it...but not for long. Make damn sure you getting enough. Now. Lol.
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Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #65 on: August 15, 2018, 07:43:19 am »
Do you still have low oil pressure after fixing the loose fitting?

Yes, I fixed the fitting before seeing the low oil pressure gauge

Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #66 on: August 15, 2018, 07:44:18 am »
That gauge ....don't know,   pull ex tappet caps and check for oil flow... Engines not getting enough oil won't idle well, but enough throttle overcomes it...but not for long. Make damn sure you getting enough. Now. Lol.

Excellent idea, I will do that this afternoon and let you guys know what I find.

Offline NitroHunter

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Re: Need help with a 970 big bore project
« Reply #67 on: August 15, 2018, 08:51:57 am »
pull ex tappet caps and check for oil flow... Engines not getting enough oil won't idle well, but enough throttle overcomes it...but not for long. Make damn sure you getting enough. Now. Lol.
Wouldn't be the first one in SOHC history to experience hear of this.  ::) ::) ::)
« Last Edit: August 15, 2018, 08:54:40 am by NitroHunter »
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Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #68 on: August 15, 2018, 10:46:07 am »
I would turn the engine the engine over on the other side of the crank use the large, slotted nut used to hold the advance unit on. Use only the large, slotted nut to turn the engine over. Using the bolt holding the wheel on can move the wheel especially when you consider you are loosening the bolt when turning the engine in the correct direction.
 I also urn the wheel over so I can see it from the right side (adanvcer side) of the engine. Much easier.

The reason I didn’t use the advancer side of the motor is the optical ignition. The optical ignition removes the advance plate and weights, and the new ignition has a static tdc light built into it. I set the tdc light based on my piston stop and degree wheel findings, and that was my constant tdc location. If my degree wheel or pointer got bumper (which it did) I could reset it easily using the tdc light on the advanced side. I used a breaker bar and slowly turned the motor using the 19m exposed rotor nut, worked really well, just went slow.

Offline calj737

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Re: Need help with a 970 big bore project
« Reply #69 on: August 15, 2018, 10:58:19 am »
The reason I didn’t use the advancer side of the motor is the optical ignition. The optical ignition removes the advance plate and weights, and the new ignition has a static tdc light built into it.
If you haven't, mark the case for TDC 1/4, then whatever timing mark you put in also. That way its very easy to recover should something change.
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Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #70 on: August 15, 2018, 01:50:39 pm »
That gauge ....don't know,   pull ex tappet caps and check for oil flow... Engines not getting enough oil won't idle well, but enough throttle overcomes it...but not for long. Make damn sure you getting enough. Now. Lol.

I pulled the exhaust tappet covers, and ran the bike. I definitely have oil up there, but I’m not sure how to tell if its “correct”. While running, I had oil slowly dripping out of the two covers I removed, but it wasn’t spraying out or anything.

Ken from cyclex suggested installing a different oil pump, the one in there was rebuilt by them, but he said they sometimes have a valve that gets stuck. Is there any chance that I just got a bum oil pressure gauge?

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Need help with a 970 big bore project
« Reply #71 on: August 15, 2018, 01:52:50 pm »
The gauge would be my first suspect. Replace it. Too easy and not expensive. Have you said if the dummy light is going out?
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Offline Bill/BentON Racing

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Re: Need help with a 970 big bore project
« Reply #72 on: September 02, 2018, 04:02:53 am »
Morning,  hows it going? Update please,  thanks,  Bill
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
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Offline awiertalla

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Re: Need help with a 970 big bore project
« Reply #73 on: September 08, 2018, 09:28:15 am »
Morning,  hows it going? Update please,  thanks,  Bill

Bill, thank you for asking. I hit some snags, I had a leaky neutral switch. It was actually the switch, not the O-ring so I was waiting for the new one to arrive. I swapped the oil pump with a rebuilt one from Cyclex (I already had a rebuilt one in, but Ken said he wanted to cross it off the list). The bike actually stopped  running, but I am willing to bet that I slipped the cam sprocket, so I will need to dial that back in. Waiting to figure out the clutch to put oil back in and get it running.

The big question I have, and I have a post in the regular section about it, is my clutch. I had an old issue with it, and it turned out to be overtightened and broken pressure plate. Now it shifts well into and out of gear, lever feels great. But once it is in gear, if I pull the clutch lever, it doesn’t remove it from gear, I have to shift into neutral. Wondering what I missed on this.

 I have a new clutch in (Cyclex, with a spring plate in the middle), it was oiled before install. I removed a friction and steel plate becase its technically a 78 and has a smaller clutch pack. The tabs going into the basket are about 3/16 smaller than the basket itself. Stock springs, no shims, torqued to 6ftpds. Turned the adjuster till pressure felt, 1/4 turn back out.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Need help with a 970 big bore project
« Reply #74 on: September 08, 2018, 09:45:37 am »
The 77/78 basket is slightly longer to accommodate the double steel middle plate
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