Another FNG

Posted: Mon Feb 16, 2015 8:48 pm

Hello and thanks. I started with printing the manual and reading the new member posts. So thanks for my FSM!
I have a 1981 cb750c. Bought it for $750. I was/isn't running. Carb problems. Previous owner had a liner in the fuel tank, let the bike sit, cleaned the carbs to get it started, and then sucked all the liner the ethanol had eaten up into the carbs...again.
I've put a battery to it. All electrical seems to be in good shape. Spark seems light, but I'll clean all connections and see if that helps. So now it's carb time and cleaning the inside of the tank time. Hopefully it will be good to go soon.

Hope my sig is attached!

Posted: Mon Feb 16, 2015 9:23 pm

Welcome to here.

Posted: Mon Feb 16, 2015 9:23 pm

Welcome to here wave

No, you have no sig, I checked your profile and there isn't one entered there. Check the directions again, holler if you'd like help.

Posted: Mon Feb 16, 2015 9:49 pm

Welcome to the site Oilfieldtrash ... Smile

Posted: Mon Feb 16, 2015 10:26 pm

Lol. First time and a fail. I can only go up from here!

Posted: Mon Feb 16, 2015 10:32 pm

Welcome. Not a big fan of tank liners. Always seem to cause problems......

Posted: Mon Feb 16, 2015 10:40 pm

Agreed. I asked why he put a liner in it. His answer was "so I didn't have problems with my tank in the future." I then laughed and asked how that worked out for him.

Posted: Tue Feb 17, 2015 12:37 am

Welcome to the board. If you have a nice tank on the outside and want to do it right my recommendation is GTL Advantage. They use a airline epoxy and guarantee it as long as you own your bike. They are not cheap $300+ but I didn't want to have to worry about messing up my carbs on my CBX and they did a great job. I know it isn't realistic for everyone but just wanted to make you aware of a good option even though it is spendy. I am a tight ass myself but sometimes it is better to do it right the first time.

Posted: Tue Feb 17, 2015 5:44 am

Welcome!

Posted: Tue Feb 17, 2015 11:00 am

hello

Posted: Fri Mar 06, 2015 12:21 am

First and foremost a very big thank you to Gene, Sean, PD, holysmokes, and many many others. If I had read in college as much as I have in the last two weeks on this forum it would be Dr. Oilfield trash. When I bought my 81 cb750c it had not run in the better part of a decade.
First a deep carb cleaning. I went with Sean's guide, software and hardware kits, and Honda rebuild kits. I invested in an ultrasonic cleaner and lots of brake cleaner.
While the carbs were off I checked valve lash. I have one intake on #2 @.0025, otherwise all else are .003-.005.
Carbs went back on and she fired up quickly.
Then I went through all my charging checks...good to go!
Next I freshened up the ignition with the relay mod, new plugs, a set of cbr600 f3 coils, new wires, and new boots.
Now new fork seals and a cleaning of the front braking system. She purrrrrrrrrs. Soon I'll be on the road!
This is basically a long winded thank you for sharing your wisdom and time.

Posted: Fri Mar 06, 2015 12:24 am

Oh...my compression made me smile #1-132 psi, #2-125 psi, #3-130 psi, #4-137 psi.

Posted: Fri Mar 06, 2015 12:29 am

Posted: Fri Mar 06, 2015 12:27 pm

OFT - go get a set of extra plugs (cheap ones, cuz you'll throw them away after this), and get a can of SeaFoam (white can with red writing). Pull your existing plugs out and set them aside for later use. Drop about 1-2 tablespoons of SeaFoam down each plug hole, put in your new "throw-away" plugs, and then go ride her like ya stole her for about 15-20 miles. That'll clear off a bunch of that built-up carbon you got on the valve faces and seats. Replace with your original plugs (your "throw-aways" will look like chocolate brownies), and ride her normally. You'll probably find that your compression numbers go up a bit after doing that.

BTW, you should recheck your valve clearances - we recommend .004-.006" not .003-.005" even though the book says those are OK numbers. Seems our book is based on a factory engine without the cam journal slop taken into account.

Glad your bike is ready for the road, bro! BTW, keep the rest of the SeaFoam for use in winter storage of your gas, or for cleaning out the fuel system in the future - it's really good stuff. About the only "snake-oil" out there that actually does what it says it does. Cool

Now it's time to start considering some 900 cams in your 750 for a REAL performance boost...

Posted: Fri Mar 06, 2015 5:57 pm

use injector cleaner in every tank for continued cleaning and lubrication

i used to use diesel or kerosene

Posted: Fri Mar 06, 2015 6:45 pm

Thanks for the extra info. Before I did anything to it I put a kerosene and marvel mystery oil blend in each cylinder and let sit 2 days. Then I changed the old oil and mixed some kerosene and 15w-40 castrol diesel oil with a new filter and filled it. Once she was running I left that blend in for about 15 minutes of idle and neutral revs (with two high speed shop fans blowing). Changed the oil and plugs again. Those plugs and oil looked as dirty as the old crap.

I'll do the sea foam now. I have a couple cans laying around. With modern crap fuel I've always been a fan of a capful of marvel to a gallon of fuel. Always open to trying something new though.

BTW- already have my 900 cam. Got it off Kevin Ramsey. I forget what he goes by on this forum, but he's somewhere here.

Thanks again everyone! Y'all have been very informative.

Posted: Fri Mar 06, 2015 6:47 pm

Also, reading all this has become like reading a book. It sounds crazy, but you start reading in different voice and building characters...just like a good book. Maybe there will be a movie based on this book!

Posted: Fri Mar 06, 2015 6:54 pm

I have done the Seafoam deal that SeanG is referring to and it did result in better compression. It is just not much but it can be between 5 or 10 PSI which can matter, at least in my case.

Be prepared for the bike to run like shit and blow a fuck ton of carbon out of the pipes. The plugs will indeed be trashed.

Posted: Fri Mar 06, 2015 8:09 pm

Oilfieldtrash wrote:

Also, reading all this has become like reading a book. It sounds crazy, but you start reading in different voice and building characters...just like a good book. Maybe there will be a movie based on this book!

The Life and Times of a DOHC Fanatic ... Wink

Posted: Sat Mar 07, 2015 6:13 am

there is a movie, it's called family guy

i also have done more reading since i got internet in 02, than since 77 when i got out of high school

i enjoy research

it has also boosted my reading comprehension 10 fold