Author Topic: 1978 CB750F3 Build/Project (Read 14590 times)

Steven.Burns · « **Reply #25 on:** November 13, 2011, 02:00:51 PM »

Ok that sounds right. Seems like everything thing says just F1 or F2.
So it goes by the serial # on the engine. I always assumed it was an F2 because of the frame #.
Thanks!!

brandEn · « **Reply #26 on:** November 13, 2011, 02:05:37 PM »

Sure thing, I know it can be confusing because you never see "F3" parts for sale. They always seem to be listed as "F2".

MoMo · « **Reply #27 on:** November 13, 2011, 05:39:35 PM »

Quote from: Steven.Burns on November 13, 2011, 01:35:21 PM

I was looking at my serial numbers today and I noticed that the frame said CB750F - 22.... and my Engine said CB750E - 310.....
what does the "E" mean and does that mean my bike is F2 or F3?
Seems like everything I read says something different.

e just means engine

Steven.Burns · « **Reply #28 on:** November 14, 2011, 09:02:43 PM »

Finally got my Motion Pro -3.5" clutch cable in the mail today. Took me about 15 minutes to install and adjust. A lot faster than I expected and a whole lot easier too. Rode my bike about 25 miles today and it feels so much smoother and tighter. Even felt easier to pull in the lever too. Can't wait to ride to work tomorrow morning

Steven.Burns · « **Reply #29 on:** November 16, 2011, 08:51:27 PM »

Alright, so far I've already put almost $500 in parts on my bike that was mainly just maintenance. Here is a list of things I've done to my bike so far.
- New stator cover (stock one cracked from accident within 6 days of owning the bike)

- Barnett Clutch kit (much needed)
- Oil Change
- K&N Air filter
- Rear Tire
- New Fuses
- Fixed ignition wiring (PO didn't know what he was doing)
- New clutch cable
- Cleaned carbs
- Cleaned Bike and polished chrome

Now I'm ready to start making it my own but I have little income so I'm deciding what my next move is.
I want to build a Cafe bike eventually. So for now this I what I want to do till I have enough money to really go at it.
- Progressive Suspension
- 530 Chain conversion
- Drilled Rotors
- Clip-on Bars
- Rearsets
- Cafe Seat
- New controls and smaller gauges
- Lots of powder coating
- Then eventually performance mods

Let me know what you think and if there is anything I should do in the mean time. I'm open to suggestions and critics. I'm really looking forward to this project but I don't have a lot of money or space to do big things right now but within the next few months that should change, hopefully.

Steven.Burns · « **Reply #30 on:** November 20, 2011, 10:39:42 PM »

Finally got out and rode my bike more than just a like 10 mile ride today. It was about 50 degrees and about to rain the whole time but I just wanted to keep riding haha. I ended up putting about 75 miles on my bike and it ran great plus I got a few thumbs up and lots of staring

I have noticed lately when I park my bike that it leaks oil out of the overflow or breather hose (idk what it is). It drips out onto my swingarm and drips off by my axle. I checked my oil and it is at the correct level. Also inside the hose is some thick, white oily stuff. What is that and why is it happening? Condensation inside the oil?

Gearheadgreg · « **Reply #31 on:** November 21, 2011, 09:25:45 AM »

Your breather Hose should have a plug in it from the factory Air Box, This usually is for condensation and is a closed circuit PCV type ventilation, My F3 has a plug and My Valkyrie had one also be for it was removed, We like to call it Drool

when we remove and drain the plug it looks like dirty black water, make sure you check to see if it is not the lower hose going to the back of your motor. Here is a Micro-fiche look under Breather for the Plug #31 http://www.cmsnl.com/honda-cb750f-750-super-sport-1978-usa_model7240/partslist/F++16.html

Steven.Burns · « **Reply #32 on:** November 21, 2011, 03:40:55 PM »

I just got home and looked. I have the breather filter thing that is supposed to connect to the air box but the engine breather hose that comes from the back of the transmission is not connected to it. It just runs to the side by my swingarm. So basically just the valve cover breather hose is connected to the breather filter; The breather filter does not connect to anything just runs to the right side of the swingarm; The breather hose that comes from the transmission doesn't connect to anything either, just to the left of the swingarm. How should it be all connected? Does it really even need to be filtered or recirculated?

brandEn · « **Reply #33 on:** November 21, 2011, 04:09:24 PM »

That breather on the back of your transmission connects to the overfow on the oil tank. The breather from your cam cover connects to the airbox.

Steven.Burns · « **Reply #34 on:** November 22, 2011, 06:16:58 AM »

Got it. Thanks brandEn

tweakin · « **Reply #35 on:** November 22, 2011, 07:38:38 AM »

Following this one. Nice start, and another F getting taken care of.

Freaky1 · « **Reply #36 on:** November 22, 2011, 11:45:47 AM »

Welcome to the wonderful world of "F" ownership! I'm always interested in seeing someone's new ideas come about with one of these bikes, I'm subscribed.

hapakev · « **Reply #37 on:** November 22, 2011, 12:30:16 PM »

I think this forum is the saving grace of the bastard F models. Without the help on this forum, I think most would just give up on them as the rest of the world has (Honda included).

Steven.Burns · « **Reply #38 on:** December 04, 2011, 01:19:27 PM »

I went to the Long Beach Motorcycle swap meet today with my pops. Got a few new things to give my bike a little bit better look out on the road. Folding bar end mirrors ($30), Bubble Shield ($20), and Remove before flight key chain ($3).

Steven.Burns · « **Reply #39 on:** December 06, 2011, 10:46:01 PM »

Took a video of my bike the other day with my buddy behind me in his car. I got her all the way up to about 90mph on a 35mph road

No signs of smoke so I guess she is running fine for now

http://youtu.be/uqep3ulq3jM

Oh and I almost forgot to mention, I got my bike all the way up to 120mph last sunday!!

Scared to blow it up so I don't think I'll be doing that again anytime soon haha

hapakev · « **Reply #40 on:** December 07, 2011, 06:50:06 AM »

Awesome. Nice Vid!

Steven.Burns · « **Reply #41 on:** December 18, 2011, 11:46:48 PM »

So today I started prepping my bike for my hope to be Christmas present, Clip-on bars and some other crap for my Honda (yeah I'm 19 and my parents still think they owe me presents)

Well I started out by buying a spare upper triple clamp. So I don't ruin my stock one somehow. After I had my part I took an angle grinder to it, Grinding off one bar clamp to see what it would look like. I just made them flat at first then I took an 80 grit, flap disk to it to blend the curves. After I got it to the shape I wanted, I sanded it with 220 grit sand paper to smooth out any spots and rounded the corners some more. I'm going to grind off the gauge mounts and get the 2.5" gauges from Dime City cycles and make a bracket to use the inner mounts.

Steven.Burns · « **Reply #42 on:** January 02, 2012, 05:06:57 PM »

The other day I went for a ride with a few friends and went about 110 miles but around 70 miles into the ride my bike started to run really weird. Loss of of power and backfiring were the first things I noticed, also at idle or low RPMs it would want to die on me and bogged out when I gave it throttle. She starts first kick with the choke on and idles alright but once I get going she backfires and sputters. It won't idle at all without the choke on.
So far I checked the plugs and cylinder #1 was a little black but #2-4 were fine. I had spare plugs so I just put them in. I also sprayed carb cleaner in the carb to help loosen things up a bit (if anything was clogged). Changed the fuel lines and filter since the old one started to get bits of run in there.

Spark plug #3 I think is stripped

She just kept twisting without getting any tighter. I noticed that a while ago but forgot about it till now.

If anyone has any tips or suggestions it would be greatly appreciated.

Thanks, Steven

ZanVooden · « **Reply #43 on:** January 02, 2012, 09:23:03 PM »

Consider checking your points. I've had a set a points go bad. The follower that rides the lobes broke off and put cylinders way out. It would start easy but with any engine speed it would act like you described.
That'd be my first check.

Is the inside of tank clean and free of any rust or scale? doesnt take much to clog carbs. Even with a filter inline small bits can work through and build up in the jets.

Steven.Burns · « **Reply #44 on:** January 02, 2012, 10:34:21 PM »

Thanks for the reply Zan. I'll check the points first thing after work tomorrow. I checked them about a week ago and they looked good from what I saw (I'm not very knowledgeable on that, yet).
My tank looks good from the cap but I saw some little bits of rust in my old filter, so I changed that a few days ago. I couldn't find another angled inline filter anywhere so I just bought the smallest straight one I could find.

Steven.Burns · « **Reply #45 on:** January 03, 2012, 07:25:30 PM »

Alright, I checked my points today. #1-4 was about a .250mm gap. The #2-3 points were about .320mm gap. I adjusted the points to about .380mm. The #1-4 adjuster has a little more room for adjustment but #2-3 is completely bottomed out. Guess I need new points pretty soon, right? The sparks were a lot more consistent in size after the adjustment.
After I buttoned her all up I to her out for a test ride and she ran a lot better but still not running right. She still sputtered and didn't have power like it should of. Also its making a tapping noise that is going with the RPMs.
Also if I go with the Hondaman Ignition, do i still need to replace my points?

Anyone have any ideas of what the problem might be?
Thanks, Steven

seanbarney41 · « **Reply #46 on:** January 03, 2012, 08:04:02 PM »

did you reset the timing after setting the point gap? Any change to point gap also affects ignition timing. Hopefully, the tapping you heard wasn't pre-ignition (often known as pinging) caused by over advanced ignition timing. If that's what it was, do not ride your bike until you fix it, especially with large throttle openings and high rpm, it can be extremely hard on piston crowns and ring lands. Also, make sure your ignition advancer isn't stuck/sticking. This is easy to check if you have access to a timing light. Just hook it up and make sure the timing advances smoothly as you rev the engine from idle to about 3000 rpm...then watch to make sure the timing returns to baseline settings at idle...

MikeKato · « **Reply #47 on:** January 04, 2012, 06:25:36 AM »

"Spark plug #3 I think is stripped She just kept twisting without getting any tighter. I noticed that a while ago but forgot about it till now."

That's the first problem that you should address,doesn't make any sense to adjust the timing if there's a possibility of the spark plug launching itself from the hole;that might be why it's running rough.Take a flashlight and see if it's wet around the base of the plug.

Steven.Burns · « **Reply #48 on:** January 04, 2012, 04:30:10 PM »

After work today ran over to harbor freight and bought a timing light and compression test kit. Came home and checked the timing and it was set more advanced, the mark was between the 1-4 mark but leaning more towards the 4 marking. Went to adjust it and that too was bottomed out like my points were. I plan on getting the Hondaman Ignition but do I also need to get a new points ignition to run the Hondaman Ignition? If so Should I get used or new?

I'm about to go check my compression now and I'll come back to let you all know how it turns out

Cheers, Steven

Steven.Burns · « **Reply #49 on:** January 04, 2012, 05:59:52 PM »

Okay, I checked my compression just now and #$%*! I dont know much about this stuff but I'm pretty sure it's definitely not good. I did a dry test and wet test on each cylinder. For the wet test, I put about 1 teaspoon of oil in each cylinder and cranked it slowly 3 times for each cylinder.
#1: Dry- 76, Wet- 83
#2: Dry- 75, Wet- 95
#3: Dry- 70, Wet- 115
#4: Dry- 78, Wet- 112

So I'm guessing I need new piston and rings, and maybe the head gasket is leaking?

Let me know what ya think

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Author Topic: 1978 CB750F3 Build/Project (Read 14590 times)