An attempt to stop a GL1000 from smoking

[cfairweather]

This morning, I checked one cyl each on three of my bikes. All of these run perfectly, but the the GL1000 does smoke like all the others... Here are the results:
1971 CB750 with new std pistons/rings. It was only honed. about 110
1971 CB750 with new mild (small dome), high compression pistons. Cylinders were freshly bored/honed to .25 over about 158
1975 GL1000 BOY with honed cylinders and new rings about 135

My tester hose has the Schrader valve in the 14mm sparkplug end, but I have to use a 12mm adapter on the end of that.

[cfairweather]

What do you think about this gauge?
https://www.amazon.com/OTC-5604-Motorcy ... B002W53J6S

[Fred Camper]

This one is less expensive and gets better reviews:

https://a.co/d/4P8SRsM

Same company but better description also. Note it takes an adapter for 12 mm plugs so you loose some pressure as Cliff noted.

[CYBORG]

Seems to me that
snap-on or Mac would-be a better choice if quality was an issue. however, I feel that how close to each other the actual numbers are, combined with a leak down test is the important thing to check cyl. condition. especially on low compression engine like the early Goldwing's

[cfairweather]

Snap-on is great as long as I can purchase one on a used HF budget . How about this one attached to my HF hardware?
https://www.ebay.com/itm/226706588609?_ ... R5C-zKvfZQ

[CYBORG]

I Would say a good gauge. Most of the usable range is in the top part of the gauge. Should be very accurate. But hose and valve are also important. I have two gauges, and each to verify the other using the same hose and valve. I've had them for 20 years, and they remain accurate

[CYBORG]

Back to the smoking. Don't overlook the valve seals. especially if it is continuing after warm up, or on acceleration

[cfairweather]

I had new valve guides installed in the heads with new seals. New valves and the heads were resurfaced. They are as close to new as I could get them.

[gltriker]

[cfairweather]

Cliff- I will try your suggestion in the morning. Also, your 12mm hose should arrive tomorrow.

[gltriker]

[redglbx]

Cedric, just an FYI,,, when testing gauges at work both OTC & Snap-on always checked pretty good. OTC is an old, quality brand that was “the” standard years ago and Snap-on has made a serious effort to be the quality standard ,, their stuff is the best these days, their electronic torque wrenches have no equal for precise lab testing !

Of course the schrader valve in the hose end is a big part of the gauge performance as well.

[cfairweather]

You guys have lots of knowledge on gauges and testing! I appreciate your advice. As Cliff directed, I tried to connect my HF compression gauge hose to my air compressor hose and it won't work. Good eye Cliff. So, I am guessing the Motion Pro hose won't fit my gauge. I will look for a fitting to make it work or just replace the gauge. I doubt if the gauge is accurate anyway.
I also did a leak down test on one random cylinder and I don't see any issue at all.

[CYBORG]

My guess is everything is alright. I would put some real miles/hours on it and then do wat ever testing makes you feel good

[cfairweather]

I believe everything is ok too, but I decided I should get a new compression gauge anyway. After careful consideration, I decided that for me, the OTC 5604 would be the best choice for about $100.00. It is the only gauge kit advertised to be for motorcycles. Thanks for your input.

https://www.otctools.com/products/motor ... tester-kit