Topic: oil pressure gauge-differences of opinion

[MikeJW]

In my attempts to Search/Research the idea of mounting an external oil pressure gauge on my 750, I encountered a certain amount of questions regarding whether the gauge should be liquid-filled or liquid-damped. More than one poster stated emphatically that it should be. Then I found an eBayer who was selling gauges he claimed are specifically for the 750 who stated equally emphatically that they must NOT be. This person (renobruce) claimed a liquid-filled gauge would work once or twice and then permanently hang up.
So, I have to ask if anyone has a definitive answer to this question and could maybe explain the reasoning involved. I cannot afford to buy one of each to try them out.
Thanks
MikeinMemphis

[70CB750]

I have liquid filled one and it works just fine - see my thread.

Pictures:

http://forums.sohc4.net/index.php?action=dlattach;topic=88103.0;attach=155025;image

http://forums.sohc4.net/index.php?action=dlattach;topic=88103.0;attach=155027;image

from ebay too.

[Bob Wessner]

I have a liquid filled pressure gauge on my K0, been fine for almost 6 years. I had a rather large, fluted non-liquid filled on it for nearly 30 years, including 20+ years in storage. It too worked fine, just didn't care for the size of the thing. I think it's a Marsh or something like that. Too lazy to go out to the garage to check though. I did find the non-liquid filled fluttered about more. Other than that, I think the seller is, well, trying to sell 'his' product.

[MikeJW]

So, it doesn't really matter.......right??
'70CB750' that's a nice looking installation you have there. Do you mind my asking exactly how you did it?
Mike

[bollingball]

I agree with Bob & 70CB have had both type many times over the years and both work. The needle stays put better on this with 2 or 3K miles on it. Just for the 750 HOG wash. Tell me why or how

http://www.summitracing.com/parts/ALM-7122/?rtype=10

PS I have a $10 that has worked fine for years just wanted a pretty one for the 750

[bollingball]

Tell that e-Bayer you have some air made just for CB tires

[dtmmil]

In the non filled gauges the needle will bounce and will be unreadable, thats why we need the fluid filled ones.

[70CB750]

So, it doesn't really matter.......right??
'70CB750' that's a nice looking installation you have there. Do you mind my asking exactly how you did it?
Mike

Well, thank you:)

I made it myself - just a chunk of aluminum and  M20x1.5 die from Enco.  Turned it on my lathe and drilled and tapped for  the gauge.    On the face are two holes for wrenching and to seal it I used just an O-ring from my plumbing mix and match box.

[bollingball]

Mike keep in mind if you don't have the tools you can buy a fitting for the gauge to fit the bike. Didn't know if you were aware of that.
I saw a post awhile back where the gauge was mounted buy the speedometer think I will do this to mine. Take off the sensor and run a line from it to the handlebar area you can see it without having to look down.

[MikeJW]

Yes,I found a website called  tasmotorsports.com that sells gauge mount which looks like it replaces that plug just above the points cover. Then the gauge threads right into it, I think. They also sell a wide variety of gauges all for the same price. In fact, there were so many different looking one I couldn't even make a choice. Sometimes it is hard to order online when you only have pictures to choose from

[mrrch]

TAS has the fittings and the complete kits as well I think, Joker Machine has a really trick looking adaptor(but pricey). I've been running the non-liquid filled guage you were looking at on ebay with no problems (needle jumps around at first when started then it is steady after that). I drilled and tapped my existing oil gallery plug and added a 90 degree elbow then installed my guage.

[70CB750]

Exactly.  You can always install it with few bucks worth of plumbing material using the original plug. 

[octagon]

i've got the basic side-of-the-motor set up with a stewart warner gauge, not liquid filled, and it doesn't bounce at all.

[Jerry Rxman Griffin aka MuthaF'er]

I also have the S-W gauge for 20+ years. Non liquid filled and it has never jumped around. It was meant to mount inside a vehicle and I cut the 2 posts off.

[octagon]

i think the needle bounce people experience in other applications might come from pulses from a piston in a compressor or from extreme vibration. the oil pump on a cb750 doesn't pulse, and the block of the motor doesn't jump around that much either.

[m in sc]

liquid filled will stay more accurate over time. even just road vibrations will jar the needle a bit. given the option thats the better choice, but in the long run doesn't really matter that much