Author Topic: bought a 1973 cb750 ......Passed inspection..ready for the road : ) (Read 4363 times)

scooter1 · « **on:** August 07, 2011, 03:52:47 PM »

Hey guys I just bought this 1973 cb750 and I have a few questions!!!
1. I noticed the front fork seals leaking and I have a new set for a 1972 cb500....will these work or are the forks different diameters???

2. the bike is also missing the grab bar...Are other years on the cb750 interchangeable???

scooter1 · « **Reply #1 on:** August 07, 2011, 04:01:34 PM »

just a fe wpics

dhall57 · « **Reply #2 on:** August 07, 2011, 04:27:48 PM »

I believe fork seals are same for both bikes. OEM #91255KBH003. size 35x48x11. I think grab rail is the same for years 72-76.

Stev-o · « **Reply #3 on:** August 07, 2011, 07:48:58 PM »

Looks nice, how's it run? I'd put a seat cover on it...

Congrats!

VTCBike750 · « **Reply #4 on:** August 08, 2011, 03:12:35 AM »

Nice looking bike. Congrats on the buy!

ekpent · « **Reply #5 on:** August 08, 2011, 04:10:22 AM »

Do not see many of those brown 73's,mostly the orange or green,nice looking bike. The grab bar and signal set up has to be from a 72-74 as the 75-76 used a larger more rounded turn signal that also has a thicker stem and different spacing on the mounting holes. If you are looking for a grab bar buy one that has the rubber mounting and metal clips as they are hard to find and may not be available from Honda now.

Johnie · « **Reply #6 on:** August 08, 2011, 05:54:59 AM »

You area correct Eric...those clips and rubbers are not available from Honda anymore. I had those on my K4 and needed to do some digging to find a good pair. However, if you don't want to have a cheesy looking repair for the seat you can get a cover for it or better yet still get the OEM seat from Honda for about $250. I got a new Honda seat for my K4 and it is so comfortable. Your OEM foam in that seat may be hard on the butt...you decide. Good luck with a cool looking bike.

bjatwood · « **Reply #7 on:** August 08, 2011, 07:59:18 AM »

Looks like the HONDA lettering on the tank Badges is BLACK. Which I believe at this point to be correct for a 73K3. I ask about that when I bought my bike and some members said they were supposed to be WHITE. But, I think HONDA must have made a design change sometime during the K3 run from Black to White lettering.
Beautiful bike by the way.

Johnie · « **Reply #8 on:** August 08, 2011, 08:24:52 AM »

I know the K4 tank had the HONDA tank badge white letters on black base. That is how it shows in the dealer ad too. In looking at the site below they show your brown K3 the same with white letters. I think if they were black you may as well not have them on there...who would see it.
http://www.cyclechaos.com/wiki/Honda_CB750K#1973

bjatwood · « **Reply #9 on:** August 08, 2011, 10:31:27 AM »

The HONDA letters are not all black. Just the inside area of the letter is Black and it has some dimples in the letters too, the edge of it is Chrome.
As for seeing it, I can.

Johnie · « **Reply #10 on:** August 08, 2011, 11:36:23 AM »

Sounds like the letters on my KO. Dimples are cool too.

Here is another 1973 with OEM paint and white letters. Go figure...wonder if the 1973 USA model had white letters and the 1973 European model they list as a K2 had the black?
http://pittsburgh.craigslist.org/mcy/2527068590.html

bjatwood · « **Reply #11 on:** August 08, 2011, 06:21:51 PM »

My late year K3 CT70 had no rear hand brake lever, but early year K3's did. Honda played it by the seat of their pants on alot of this kind of stuff. But you could be onto something about the UK bikes having different colored lettering than the North American bikes.

scooter1 · « **Reply #12 on:** August 08, 2011, 08:28:24 PM »

Hey guys....well I replaced the fork seals tonight and It all went well!! I took the bike for a little spin and and its seems to bog down at high speeds.....Im guessing It needs a carb cleaning. I also noticed a few little oil leaks on the head, so I think it might be a winter project to replace the gaskets!!!
I also ordered two new tires and tubes and hope to get the carb issue sorted out so I canride it for the rest of this season!!!
If any of you guys have any tips on these carbs on the 73 please feel free to shoot away!!!

Thanks
scooter

bjatwood · « **Reply #13 on:** August 09, 2011, 06:41:44 AM »

K3 carbs are pretty straight forward. Make sure you get the float height set correctly, Clean all passageways and jets. Lube the throttle assembly. I bet ya dollars to donuts your carbs probably have never been off that bike. That will make pulling off hard, but not impossible. Look under your throttle cap boots and see if the yellow paint is still there. If it is, the carbs have never been tinkered with.

VTCBike750 · « **Reply #14 on:** August 09, 2011, 10:38:12 AM »

Id plan on not tinkering with the sync nuts, if painted yellow leave them alone and work on just cleaning the carbs.

scooter1 · « **Reply #15 on:** August 09, 2011, 11:27:46 AM »

Ya thats my plan.....can someone point me in the right direction on the specs for float height....needle setting...etc!!!

Thanks

Johnie · « **Reply #16 on:** August 09, 2011, 11:59:21 AM »

Here are your specs:
http://www.hondachopper.com/garage/carb_specs/carb_specs.html

ekpent · « **Reply #17 on:** August 09, 2011, 12:52:27 PM »

Have a good heat gun handy and warm the rubber boots holding the carbs well. It will really make them easier to get on and off.Wiggle them up and down while pulling,or pushing. I like to leave the rubber boots attached to the head and they do have to be orientated correctly to fit back correctly.Good leather gloves are handy also,good potential for a little knuckle bashing.

Johnie · « **Reply #18 on:** August 09, 2011, 02:01:13 PM »

Be sure to put everything back in the carb they come from. Slides, jets, etc. Might want to take some pics as you dismantle as it really helps when putting them back together. Be sure you remember which is the top on the floats as others have put the floats back in upside down. Try to stay away from aftermarket parts if you can help it. Just cleaning the OEM items is probably all you will have to do and those OEM parts are far superior to the aftermarket stuff out there. Good luck with it and let us know how you come out.

VTCBike750 · « **Reply #19 on:** August 09, 2011, 02:39:02 PM »

Quote from: Johnie on August 09, 2011, 02:01:13 PM

Be sure to put everything back in the carb they come from. Slides, jets, etc. Might want to take some pics as you dismantle as it really helps when putting them back together. Be sure you remember which is the top on the floats as others have put the floats back in upside down. Try to stay away from aftermarket parts if you can help it. Just cleaning the OEM items is probably all you will have to do and those OEM parts are far superior to the aftermarket stuff out there. Good luck with it and let us know how you come out.

+1, A GOOD CLEANING

scooter1 · « **Reply #20 on:** August 09, 2011, 04:28:53 PM »

Thanks johny...and everyone else....the carbs are off!!

Prospect · « **Reply #21 on:** August 09, 2011, 04:48:04 PM »

There is a supplier of excellent seat covers in Alberta. Several forum members have used his covers with good results. I have one but havn't put it on yet. He sells via ebay for about $80. Unfortunately he doesn't sell the foam.

http://www.ebay.ca/itm/CB750-seat-cover-Honda-CB750K-CB-750-K-Duck-tail-/160360307866?pt=Motorcycles_Parts_Accessories&hash=item2556381c9a

scooter1 · « **Reply #22 on:** August 09, 2011, 08:53:55 PM »

Well I gave the carbs a good cleaning and also did an oil change!!! When I was cleaning the carbs I noticed one of the rubber Gromets on the top cover of the slide assembly was almos gone,,,will this affect the carb or is it just like a dust seal?

So I took it for a ride after I got it all back together and the bike died about 5km from the house...crap!!!
To make matters worse I left my cell phone at home...Crap!!!
So I sat on the side of the road for about 15min and finaly got the bike to start....not to sure what the problem was.
At the time when it happened the bike was like it had no power...the min I let off the throttle it died!!!
Might have to check the tank vent and the fuses!!!

I should also add that the bike has been off the road for a bout 4 years....I guess it might also be the battery...I checked all the fuses and they are like the day the bike left to dealership in 1973....I will take some pics later today!!

Johnie · « **Reply #23 on:** August 10, 2011, 07:57:31 AM »

Be sure the ignition switch is not causing a power problem. Turn it on and move it around while watching the lights to be sure they do not flicker on you. Some guys have had to clean or replace the switch. Be sure the tank is clean too. I would get the Hondaman plug in fuse system that I pictured below. Far superior to the OEM set up. Click the pic to enlarge it and note the fuse box from Hondaman on the left side.

scooter1 · « **Reply #24 on:** August 10, 2011, 11:44:26 AM »

Hey john....I put the battery on charge last night and I fired it up at lunch today!!
I put the volt meter on the pos/neg on the battery and brought the rpm up to about 3 to 4 rpm and it read 14.3 volts is this a sign that my charging system is working correctly!!

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Author Topic: bought a 1973 cb750 ......Passed inspection..ready for the road : ) (Read 4363 times)