Author Topic: Intro/ disappearing and rreappearing oil  (Read 1379 times)

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Offline disinformant

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Intro/ disappearing and rreappearing oil
« on: May 22, 2015, 01:22:22 pm »
Afternoon folks.
I posted a small introduction in the owners registry.
However since I have a slew of issues let me introduce myself.
I'm Ryan Aka NWC Matic.  NWC is portland motorcycle crew made up of mostly cb750 owners who met on hondachopper .  This isnt an ad and that is all I have to say about that.
I picked up the bike in dec 14 on trade and was given the disclaimer it was a mans bike and would require regular tlc. This is my first motorcycle though I spent last summer slowing portland traffic on my FA50 noped. After burning up 2 pistons it got stolen.  Haha suckers and thanks for doing me a favor....  Despite the non functional speedo I have put atleast 1000-1500 miles a month on the matic since ive had it.  Ive had lots of fun with it both on the road,  shoulder, various parking lots. 

Now I seem to have a couple persistant issues. First is a sudden and lasting loss of power mostly bottom end.  Second is the oil.  I check it regularly. The manual says it holds 5 quarts when I change the oil I get 3 out.   A few weeks ago i checked the oil and it was more than a quart over filled.   No big deal time for an oil change anyway but this was shortly after the loss of low end power began.  Despite losing a couple mph and some low end torque/ power.  So wedsnday morning i ride to work and while a little weak it ran fine otherwise. When I got on it that afternoon It was like the bike never heated up. I stall at take of have to put it in idle when stopped or it would die. When I ot home it should i p,nut it on its center stand. I checked it 2 hours later and the oil was half way between the fill and full lines.  I decide to deal with it the next day. I have oil ready to go when i checked it again it was way over fill line.  Reading about the matics tranny and how power is transmitted to it makes me think i've blown some sort of seal. As the coils had been changed and the carbs cleaned in the last 60 days does this sound reasonable? 

Offline raymond10078

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Re: Intro/ disappearing and rreappearing oil
« Reply #1 on: May 22, 2015, 01:29:39 pm »
first - oil replacement volume is 4.2 quarts.

entire volume (i.e., after an engine rebuild) is 5.8 quarts.

Otherwise, I'm not much help here.  guesses only. 
1978 CB750A (upgrading very, very slowly)

Past bikes - Honda: SL350, CX650C, CB900C, CB1000C, CM450A; Kawasaki: several 1972 750 H2's; Suzuki: TC90J.

Bikes I want: CX650ED, a mid-sized japanese V-twin with ABS.

Offline disinformant

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Re: Intro/ disappearing and rreappearing oil
« Reply #2 on: May 24, 2015, 09:25:37 am »
Nice to know I dont need to find a way to put an extra 2 quarts in.  Ill be pulling the exhaust and putting new crush washers in today.  Ill change the oil and filter.Im also rebuilding the number one carb as the rubber  gasket around the float bowl is missing about 5 mm.  When I changed the coils I also put on some premade wires with the silicone cores cuz i ran out of time thay day and a buddy had thrm lying around for a down the road chopper build. I have half a mind to cut some copper core wire and use that instead. This might be a question for the main forum but anyone notice any negative changes switching from copper core to silcone core spark plug cables?

Offline disinformant

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Re: Intro/ disappearing and rreappearing oil
« Reply #3 on: May 28, 2015, 06:00:52 pm »
So Ive pretty much figured out the loss of power. Im running lean. Kept choke on and power restored. So i will clean carbs again, rebuild my ever peeing number 1 carb then get them synced.  I removed the air box after discovering the air filter was saturated with fuel but didnt dry out.(  Ethanol + humidity + peeing carb = sarurated dikter?)This passed weekend I decided to remove my bates bags then proceeded to dewire the bike.  I removed wires to all guages, indicators.  What i have now are low beams , tail and brake lights, charging is still good, key works, only run one fuse, threw a 12 volt jack on.
« Last Edit: May 28, 2015, 06:29:44 pm by disinformant »

Offline stikman

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Re: Intro/ disappearing and rreappearing oil
« Reply #4 on: June 27, 2015, 02:29:03 pm »
I'd assume the lower oil mark after running compared to after sitting overnight would simply be oil from up top and coating everything dripping back down into your bottom end.  As far as what you get out when changing your oil, are you including what comes out of the filter and filter housing?  Because that's nearly a quart right there.

I'd be tempted to get a fresh air filter in there if you plan to keep the airbox.  I would also run the same jets it came with after cleaning the carbs, with a fresh set of plugs, and do a plug chop.  That should let you know basically where you're at for rich/lean and if you need to change your mains.

That's my 2 bits.  Sorry for the late reply.
1977 CB750A "High Horse": 836cc, mild porting, custom cam, K5 roundtops, v-stacks...
1973 CB750K D5 plunger frame chopper currently building..