Topic: a general question 1978 to 1974

[74cb750]

Thank you Andy, that might help. I changed the equalizer tubes between 1-2 and 3-4. No good. Still spits. Now to try to recheck the timing and...

[dpen]

Could I buy that old harness? I was going to rewire mine but that looks like it'd fit straight on.

[74cb750]

Sorry, but I already put it all back together & it is working now! Am I going to haveto start  a new thread here? My carbs are still spitting.

[750deepsouth]

Seriously Michel, not good. Is the fuel vapor spitting backwards into the airbox you mean ?

I've never had this happen to me. If its happening to only 1&4 it smacks of an ignition problem, but if its otherwise running ok - then is it a jetting problem ?

Andy.

[74cb750]

Harness is all back together..... actually the picture was of TWO harnesses, the other one was from a 1978 KZ750B that I needed a four prong from   Carbs-yes the gas is spitting into the airbox, but upon closer inspection,ie, placing a dark background under the intakes and a bright light above, all four are spitting, but the outer two are worse. So...the timing is on. I took it out for a spin,  and lo & behold it ran rough, but it ran. Noticed Mr Moron, the previous owner , put on short cables. Kinda revved high (6K) when I pulled over with the handlebars to the right. (will fix this today by taking the cables off my 1974) ....anyways, it popped and spit for the first 3 kilometers then started to even out. Stopped bucking and jerking in the 1st-4th gears. Going though the 1,2,3,4 gears ok. Then around 70mph I shifted into 5th and it bogged down while trying to accelerate. It DID accelerate to  80-85mph eventually, but....would not go up quickly. Could all this be from having the wrong size main jets. I ended up with K&N fitlers as the OEMbox has cracked intakes. Getting desparate here.

[750deepsouth]

My 1st thought was that the idle [low speed] jet may be set to rich but if it was you probably would have trouble starting the bike. {Or, it would start dead easy and need no choke when its -5f.  }
It  does sound like carb problems though. Bogging when trying to accelerate ? is that when it's too lean ?
Tip: try fitting the complete carb set from your '74
I have a spare set here, but you won't get them until I find the guy I lent them too 6 months ago...

[74cb750]

Huh! That is exactly what I decided I am going to do in the morro. I think it is narrowed down to either the carbs on the 1975 have a crack somewhere, or the    "timing advance mechanism" is worn. 

Oh, one thing I never did check properly was the condensors.

Today I went for a ride  and again it took 3 kilometers towarm up, then ran ok in 1st-4th gears, then up to 40 mph in 5th gear seemed ok. Accelerating up to 80 it bucked a lot the whole way, and continued to buck at all speeds 40-85mph. oh well.

Oh, my kid got a speeding ticket tonight. I felt rather strange (hyporcitical maybe?) about giving the "lecture". So I kept it to the olde standby of.."if you did the crime, you have to pay the dime..." There goes my family insurance.

[kghost]

Fight say's I. Always better to contest the ticket than just pay it.

I haven't had one of the last six tickets appear on my record.

Perhaps thats another post tho.

[Bob Wessner]

I haven't had one of the last six tickets

   

[74cb750]

Hey Bob, how many did you beat when you were a kid? Besides, she WAS speeding, so she will learn how it hurts, in the wallet. Plus because she's on my policy, my ins. goes way up (more than $600/yr) for her one ticket.

[eldar]

Geez if I saw that bill, I would ask if I still had my back pocket or if the insurance company  yanked it off getting to my wallet!

[74cb750]

With a clean record, a 1995 Ford F150, Honda civic 1998 for minimum coverage it costs us $1,200/year, add the ticket & it usually goesup 50% minimum. (the wife worksfor the ins. co. so we get a break!)

[74cb750]

Hi All. I finally gotit. It was air in the gasline again, just like on my 1974! What the heck? I really don't understand how gas can stay in the line even after I drain the bowls and start all over again and again. This time, I disconnected the lines and filled one at a time to get rid of the air, and it works. Still think I might need to adjust up to a larger main jet though, as there is still some hesitation at high speed rollons, but no bucking.

[turnenwheels]

FINALLY figured it out after taking time out to build a cabin in the woods for the boys...It was a multipleset of problems, bad key connector, and bad grounds on the coils, loose and broken wires and multiple "backyard" wiring problems found and fixed. Now it starts / runs like a top.
see picture
http://www185.pair.com/canukvt/hon/1975_cb750/wiring_problem.jpg
guess I should have checked that 1st huh? 

Oh, lovely sight...Finially when I rewired the knotts outta' my bike I wrapped those wires
with black vinal ties.  incased then into a portective strip/tubing.  A much better sight.  pain to fit
them all back behind the headlight though.  Wish you well friend!

[74cb750]

welllllll.......took the carbs off the 1974 blown motor and now it runs fine. Well, better than it did. Does not bogdown as much in 5th gear. Looks like another project for the winter. Now time to work on the Kawasaki S2 and CSR305. Ring-a-ding-a-ding