Author Topic: 1976 cb750k project-tube diameter question (Read 8072 times)

bigtexan449 · « **on:** March 21, 2011, 04:35:48 am »

I got my first bike a month or 2 ago and figured I would start a project thread. I will try and keep everyone updated. I will probably use this mostly for asking questions since I am very green to sohc world. Not exactly sure what I want to do with this yet, but figured I would at least get it road worthy and then go from there.
With out further ado...some pictures:

bigtexan449 · « **Reply #1 on:** March 21, 2011, 04:51:03 am »

Alittle history, I found this bad larry on craigslist, emailed the guy back and forth for a bit then went and checked it out. PO said he rode it all last summer, even though when I went to look at it he said it doesn't run. PO said the carbs just needed cleaned. Not a problem. He was asking $900, I payed $300 and he even loaded it into the truck lol. Had my buddies dad go thru the carbs for me. Figured he would be good since he had a 750 back in the day that he dragged and he also works on bikes for a living. Anywhoo, he said someone had gone thru them before and jacked them up, so a few days later go them back threw them back on and she started right up. Pretty much figuring things out as I go and researching here on the forum. I have have a paint scheme that i think I like. OD green with black stripe down the middle on the tank and on the hump of the cafe seat. With that in mind, do I get black clubmans or chrome? I will be replacing the speedo and tach with a pair from partsNmore, which are chrome...thoughts?

Things To do:
Pods
clubman bars
cafe seat
go thru front forks
replace brakes
replace throttle and clutch cable
New exhaust
new wiring harness
new headlight bucket
new signals
new grips
repaint tank

Done:
Carbs cleaned
new battery

bigtexan449 · « **Reply #2 on:** March 21, 2011, 04:59:03 am »

I have been outta town the past few days, but the before I left I was trying to get the oil filter bolt off with no success. I got liquid wrench, a hammer...still nothing. I would rather not have to grind it off and go from there...I saw someone mention a chisel and hammer, I may have to try that or a pipe wrench.

Question to all the veteran cb builders/res-erectors...if putting air pods on the carbs is any modifying to the carbs needed? thanks

MasterChief750 · « **Reply #3 on:** March 21, 2011, 01:22:30 pm »

pods are a pita, you will have to rejet, they run better with the stock airbox

Coyote13 · « **Reply #4 on:** March 21, 2011, 01:49:44 pm »

Truth ^

I have 'em on mine and while they do work "well enough" that isn't gonna cut it for most people

liPPy · « **Reply #5 on:** March 21, 2011, 02:17:18 pm »

Quote from: bigtexan449 on March 21, 2011, 04:51:03 am

Alittle history, I found this bad larry on craigslist, emailed the guy back and forth for a bit then went and checked it out. PO said he rode it all last summer, even though when I went to look at it he said it doesn't run. PO said the carbs just needed cleaned. Not a problem. He was asking $900, I payed $300 and he even loaded it into the truck lol. Had my buddies dad go thru the carbs for me. Figured he would be good since he had a 750 back in the day that he dragged and he also works on bikes for a living. Anywhoo, he said someone had gone thru them before and jacked them up, so a few days later go them back threw them back on and she started right up. Pretty much figuring things out as I go and researching here on the forum. I have have a paint scheme that i think I like. OD green with black stripe down the middle on the tank and on the hump of the cafe seat. With that in mind, do I get black clubmans or chrome? I will be replacing the speedo and tach with a pair from partsNmore, which are chrome...thoughts?

Things To do:
Pods
clubman bars
cafe seat
go thru front forks
replace brakes
replace throttle and clutch cable
New exhaust
new wiring harness
new headlight bucket
new signals
new grips
repaint tank

Done:
Carbs cleaned
new battery

I'd be interested in buying them off you if you choose to go that route

PM me... Tx

bigtexan449 · « **Reply #6 on:** March 21, 2011, 06:28:24 pm »

thanks masterchief and coyote. Lippy, i will keep you in mind when i change them out. I will give you a heads up, the speedo isn't working, not sure why....It was working fine then it stopped.

Question time:
1. Bike runs with starter button...let it sit for a bit...bike won't start with starter button, but will kick right up. Any thoughts?
2. I got a replacement K&N air filter to throw in the air box, and it seems that it won't fit. Has anyone had this kind of problem?
3. If doing a Carpy 4-1 exhaust is rejetting necessary?

Thanks guys. Any votes to chrome or black clubmans? I'm thinking chrome...

liPPy · « **Reply #7 on:** March 22, 2011, 06:25:34 pm »

Quote from: bigtexan449 on March 21, 2011, 06:28:24 pm

thanks masterchief and coyote. Lippy, i will keep you in mind when i change them out. I will give you a heads up, the speedo isn't working, not sure why....It was working fine then it stopped.

Question time:
1. Bike runs with starter button...let it sit for a bit...bike won't start with starter button, but will kick right up. Any thoughts?
2. I got a replacement K&N air filter to throw in the air box, and it seems that it won't fit. Has anyone had this kind of problem?
3. If doing a Carpy 4-1 exhaust is rejetting necessary?

Thanks guys. Any votes to chrome or black clubmans? I'm thinking chrome...

Thanks Tex - That might work out. As luck would have it I have a working speedo but no tach !

liPPy

bigtexan449 · « **Reply #8 on:** March 31, 2011, 06:46:11 pm »

decided to the left side cover off again and just stare at this mess...any thoughts?

bigtexan449 · « **Reply #9 on:** April 05, 2011, 02:55:15 pm »

well, it was nice out today decided to take this old lady out for a spin (knowing the wiring looked like this) Rode about 6 or 7 miles and was headed home...got 200 meters from my drive about to pull out onto the road and bam, engine shut off. idiot lights were gone....now a week ago i went to fire it up in the garage and the light didn't come on when i turned the key, so i poked at the wiring and then they came one. So i did the same thing at the intersection today, lights came on, hit the starter button lights went off. Alright wiring gods, help me out any thoughts? I ended up pushing the bike home and up my mt. everest of a drive. I am going to order a new wiring harness tonight. Help!

bigtexan449 · « **Reply #10 on:** April 06, 2011, 04:09:54 am »

I forgot to mention that the speedo does work!

Toxic · « **Reply #11 on:** April 06, 2011, 04:32:06 am »

First off get rid of that e-tape on the green ground wire that runs transversely through the picture. See what is under it. Trace this wire to it's most rear ward position and then check for continuity to it's most foreward position. Whatever the case, even if your meter shows there is good flow replace whatever bodge job is under the tape.
You've got a severely damage multi point connector on the bottom so that has to be replaced.

Lots of brilliant electrical gurus will be along to point you in the right direction

bigtexan449 · « **Reply #12 on:** April 06, 2011, 01:40:43 pm »

toxic,
thanks for the pointers...i've got a new harness on the way, so hopefully when i get a day or two i will see how my wiring skills are.
On a side note, i messed around with a few things, and it seems the bolt on the neg. terminal on the battery was loose and it wasn't connecting fully. Tightened it up and everything seems to be working, knock on wood.

Old75_ratafe · « **Reply #13 on:** April 07, 2011, 12:39:59 am »

I had the same ground issue on mine too. Wire brush the hell out of it and some dielectric does wonders. Also on the ground the main bolt that goes through the frame try loosening and tightening it again... You might be surprised. My lights doubled in brightness and I'm sure it effected my spark. Also with the new harness make sure to clean every connection and then dielectric. I did it on mine and still had a miss here and there. Another thing I ended up going back and doing later is on the (female?) ends of the connectors the part the other pushes into I got a pair of pliers and very gently closed the loop so when I plugged everything back together it forced the connector open making a tighter fit. Good luck if you need pics let me know, I actually got half my bike apart and its a dead stock harness.

Toxic · « **Reply #14 on:** April 07, 2011, 04:13:43 am »

Life will be easier with a new harness but as said above you must clean every connector that is not being replaced. Where you have a green ground wire, make sure it connects to bare metal. You can wrap some 400 grit paper around a bamboo skewer to get into the female bullet connectors. For the white plastic multi-pin connectors you can clean them as well if you take your time. Use electric contact cleaner in a spray can, available everywhere and the dialectric grease mentioned above.

One of the best things you can do for a 40 year old bike

WhyNot2 · « **Reply #15 on:** April 09, 2011, 08:56:33 pm »

I'm in the same boat, cannot get fire to the points and plugs....................

Watching intently.

bigtexan449 · « **Reply #16 on:** April 13, 2011, 07:48:11 am »

well, i have been riding a few days. did like Old75 suggested, loosened and tightened the ground bolt... haven't had a problem till this morning...I was heading out to ride into work, and as i would release the clutch and give it some throttle to head out, it just would kill its self. I may not have let it warm up long enough, as it was a bit colder than the past couple mornings. As it finally acted right i got about half way down the road from where i was going to turn and it just didn't feel right, so i turned around and headed for home. As i was shifting getting to 4th then 5th, i started to hear popping sounds as if it were coming from the exhaust. Before that i would give it some throttle around 50-55mph and it just felt like it wasn't going anywere...any thoughts? thanks
AJ

bigtexan449 · « **Reply #17 on:** April 13, 2011, 04:57:10 pm »

well, went to ride into work today, and the bike started acting abit funny. fired her up...let her warm up a bit, went to let the clutch out in 1 and it shut off on me....shruged it off did it again....same thing....finally got her going started down the road and it felt like it was bogging down...real slow to accelerate. got about half mile down the road decided to turn around and drive the truck into work...as i got into 5th i started hearing poping...any ideas? also saw some white smoke coming from the exhaust this after noon when i got home and fired it up to see what was going on...any thoughts?

BR · « **Reply #18 on:** April 13, 2011, 05:21:38 pm »

Start with the basics BT. How do the plugs look right now??? Have you cut the plug wires back where the plug caps screw into them if not do so. Have you cleaned/replaced the points and replaced the condensors??? Finally are you shutting the fuel off with the tank petcock every time you shut the bike off? if you aren't you could be filling the cylinders and or airbox with fuel and or soaking the air filter. Are you still having problems with starting it with the electric starter after it has run for a while??? those yellow wires with the melted connector are coming from the charging system, you may have a large draw on your electrical system due to this. Looks like a little time invested and doing the basic tune up stuff will probably help but you may need to look into the charging system also. Good Luck it will all be worth it when it's done.

Old75_ratafe · « **Reply #19 on:** April 13, 2011, 10:08:24 pm »

Weak spark or flooding maybe? Like BR said pull a plug, could just be fouled out.

bigtexan449 · « **Reply #20 on:** May 08, 2011, 12:30:16 pm »

well been riding the bike for while now, haven't any problems. I pulled the oil dipstick today just to take a gander and there was some white gunk. I have read it can be condensation in the oil. I did get caught in a rain storm yesterday heading home from work. How do i resolve this problem? Thanks guys!

Old75_ratafe · « **Reply #21 on:** May 11, 2011, 12:51:56 am »

change the oil. It happened to me after a few rides in the winter. Hot cold hot cold. Just formed after awhile.

bigtexan449 · « **Reply #22 on:** May 17, 2011, 06:37:49 pm »

I am wanting to start putting together a parts list for rewiring my 750k6. I am wanting to run LED turn signals and brighter headlight. So...electrical pros, what do i need, other than new wiring harness, to make LED turns and a brighter headlight work? thanks!

Old75_ratafe · « **Reply #23 on:** May 26, 2011, 11:08:54 pm »

Quote from: bigtexan449 on May 17, 2011, 06:37:49 pm

I am wanting to start putting together a parts list for rewiring my 750k6. I am wanting to run LED turn signals and brighter headlight. So...electrical pros, what do i need, other than new wiring harness, to make LED turns and a brighter headlight work? thanks!

The LED signals you are going to need either a flasher relay made for LED's or put the correct resistors inline with the lights.

A brighter headlight there are a few ways. First I would wire in a relay from the battery to the headlight so it is getting direct power this will make a big difference. If the bulb is a older bulb go buy a brighter modern bulb like a sylvania silver star or equivalent that have halogen capsules inside them Vs. the old filament sealed beams. Another option is to get a h4 setup and do the same thing but with capsule H4 bulb which are a bit more common now a days than the sealed beams. And the last alternative is do a HID bulb. I personally am not a fan of this cause I find them obnoxiously bright (read blinding and pisses off other drivers in vehicles much larger than you) and the beam pattern isn't real predictable with the cheaper non projection kits, but some members do like them. (its kinda like the conventional oil Vs. synthetic HID Vs. Halogen the debate can go on forever lets not discuss that one here do a search you'll find tons of threads). I use the stock type bulb but the modern halogen sliver star version of it and am quite happy with it. Anyway minimum I would do the relay and suggest the relay mod.

WhyNot2 · « **Reply #24 on:** May 27, 2011, 06:27:20 am »

Quote from: Old75_ratafe on May 26, 2011, 11:08:54 pm

Quote from: bigtexan449 on May 17, 2011, 06:37:49 pm
I am wanting to start putting together a parts list for rewiring my 750k6. I am wanting to run LED turn signals and brighter headlight. So...electrical pros, what do i need, other than new wiring harness, to make LED turns and a brighter headlight work? thanks!

The LED signals you are going to need either a flasher relay made for LED's or put the correct resistors inline with the lights.

A brighter headlight there are a few ways. First I would wire in a relay from the battery to the headlight so it is getting direct power this will make a big difference. If the bulb is a older bulb go buy a brighter modern bulb like a sylvania silver star or equivalent that have halogen capsules inside them Vs. the old filament sealed beams. Another option is to get a h4 setup and do the same thing but with capsule H4 bulb which are a bit more common now a days than the sealed beams. And the last alternative is do a HID bulb. I personally am not a fan of this cause I find them obnoxiously bright (read blinding and pisses off other drivers in vehicles much larger than you) and the beam pattern isn't real predictable with the cheaper non projection kits, but some members do like them. (its kinda like the conventional oil Vs. synthetic HID Vs. Halogen the debate can go on forever lets not discuss that one here do a search you'll find tons of threads). I use the stock type bulb but the modern halogen sliver star version of it and am quite happy with it. Anyway minimum I would do the relay and suggest the relay mod.

Old-75, can you show a wiring diagram or steer us to the right thread?

Would you not have to wire in a seperate switch to turn the headlight on and off?

Also, if someone were to change from a sealed beam to a h4 setup, could they just use the stock wiring?

Thanks.

Jack

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Author Topic: 1976 cb750k project-tube diameter question (Read 8072 times)