Topic: Project Ginger Racer! 1975 CB750K COMPLETED!

[Mayor08]

Starting/Starter issues.

The Magnetic Switch is clinking when I push the start button when I short the magnetic switch the starter spins without clicking.  I did a search here for a list of possible culprits and so far I have checked:

amps at battery while idling 13.3 v (a little higher when I increase the revs) so I think the charging system is working
amps at negative terminal of magnetic switch 12+ v

I've also cleaned the terminals to the magnetic switch



I pulled up the wiring diagram to see what I should be looking at in the head light bucket- green/red, orange white etc. I went back and checked all of my connections and everything was tight (is there anything in particular I should look for?)
Next I tried pulling in the clutch while hitting the start button and although it labored the starter motor did turn over and fire the bike (the magnetic switch still "clicked").  Next I checked the wire under the motor (neutral switch right?) and decided to give it a coat of dielectric grease anyway.  Next I'll double recheck the connections to the starter motor but am looking for suggestions on what else to check.

The bike fires with 1-2 kicks and idles/revs well.

I'm going to do another search for starter problems to see what I can find....

What do you guys think I should check?

[Mayor08]

Well, hopefully a pic will help with some suggestions as to what to troubleshoot next on the starter...

just a cell phone pic...

[Roach Carver]

First off, that is so much better than before.

Is the starter solenoid good? Its hard to diagnose over the internet but if you are shorting it and getting the starter to turn over but otherwise clicking, then that is what I would be looking at. Good luck.

[Mayor08]

Roach Carver- you're not kidding!

I agree, everything points to the magnetic switch the only thing I haven't done is go back into the wiring and disconnect then reconnect everything to sure I have good connections. 

Can anyone offer a guess why the starter will turn the motor over albeit labored when I pull in the clutch lever?

[Mayor08]

I haven't had any time to work on sorting out the starter/magnetic switch issue hopefully tonight I can make time to for an hour or two.  Another problem I am having is a leaking oil line last year it was weeping though I did not know exactly from where now it is a steady leak when under pressure.  Last weekend I started looking for replacement options: Cycle X, Carpy, Classic City Cycle, used parts on ebay or craigslist I even checked the forum to see if someone was offering a kit or rebuild service.  While on ebay I saw a set of stainless braided lines with 5 days left sitting at $50 they looked like Classic City so I asked the seller and sure enough they were.  He never put them on the bike so I waited to bid on them until under the 2 minute mark.  These go for $130 new so I figured if I can get them for half price I am way ahead!  I don't think the other bidders knew what they were or if they didn't really want them but I put my max bid in and with 30 seconds to go I confirmed my bid.  There I was the high bidder for $56 and no one even tried to up their bid and I won them!



It's cool that their stainless but I'd be happy with a used replacement set I knew wasn't going to leak!

If they arrive today then tonight I will swap them on weather permitting.  My one car has NO room for anything but minor stuff and everything I want to do now must be done in the driveway. 

After work I am going to look at 1975 CB750K for my best friend these old bikes are contagious!  Plan is to pick it up on Sunday if it's in good shape.  The owner says he's been out on it a few times this year so if that's true we'll ride it home instead of getting a pick up.

[Mayor08]

Last night I only had time to drain the oil (I swear I can't drain the oil tank without making a mess!) but today the new oil lines will go on!.

Yesterday I went and looked at a 75 CB750 for my friend and was it ever in good shape!  runs fantastic side covers and emblems are intact! really only needs tires and fresh brakes to be safe on the road. 



We're planning to pick it up tomorrow morning and while back at my house I plan to borrow the magnetic switch to see if mine is indeed defective or if I have to do more digging.....

[Mayor08]

There has been little time to work on the bike since the last post but I did manage to install the new oil lines before heading up to Rockerbox in Milwaukee.  The bike ran well but i still have to sort out the starter I now think the problem is in the start button and housing hopefully this week I will be able to find time to open it up.  The carbs still need a bit of tuning I want to raise the clip on the needle to lean them a bit before rejetting throttle response is good but could be better. 

Here's a pic from yesterday's ride......



The project is nearly completed fingers crossed I can call it 100% before the end of the month.

[zzpete]

There has been little time to work on the bike since the last post but I did manage to install the new oil lines before heading up to Rockerbox in Milwaukee.  The bike ran well but i still have to sort out the starter I now think the problem is in the start button and housing hopefully this week I will be able to find time to open it up.  The carbs still need a bit of tuning I want to raise the clip on the needle to lean them a bit before rejetting throttle response is good but could be better. 

Here's a pic from yesterday's ride......



The project is nearly completed fingers crossed I can call it 100% before the end of the month.

NICE JOB MR. MAYOR!!   If you need a button let me know I'll look and see what I have!!

[Mayor08]

Thanks ZZPete!!

I opened up the right side controls housing and checked my connections as I had to re-sodder a wire when I replaced the starter button and everything is okay.  So far I know it's not the start button, not the Magnetic Switch (solenoid) and not the battery as it is charging and always has plenty of power (the headlight does not fluctuate when revving the engine at idle) so it has to be what? 

Also I have been noticing some slippage in the clutch mostly at highway speeds when going over our wonderfully bumpy roads.  I have adjusted the clutch per the manual and still have some issues.  I can get most of the slippage to go away but it is still happening and now sometimes when accelerating with enthusiasm it slips...

Tonight I  will readjust the clutch but my question is- what is the difference between the 1/4- 1/2 turn as it relates to the clutch fully disengaging?  Would an 1/8 turn help stop the slippage in the short term?  Or does it need to be a 3/8 turn?  I'll play around with it tonight and see.  At the end of September I want to take the bike on a 1500 mile road trip and would like to have all of these issues worked out.

[brettster26]

Hey Bro where did you get that seat?  Really like the style and how it flows...

Thanks

[Mayor08]

Brettster26-  I bought the seat from an ebay seller who is in Asia it was relatively inexpensive but shipping costs $80.  He puts them on sale every once in a while and you can save a few bucks.  The vinyl is a little thin but overall I was happy with the seat be sure to tell them which side your latch is on.  I really liked the look/shape of the seat too it's a little different than a lot of the cafe builds though I did think at first I would have been happier with a bum stop but not anymore.

Not sure how far back in this build you went but the seat was damaged when this dick in a Lexus hit me (seriously his name really is Dick!) and I had it recovered in marine vinyl and am very happy with it now.

[brettster26]

Read through the whole thing bro!  Very nice build!  I hope my bike turns out something like yours trying to just get it all back together now, and will then start doing different things to it i think!  Great Build!

[Free Booter]

Fabbed up a rear fender while I was waiting for the seat to come back

So did you chop your original fenders front and back?
I ask because I've been considering the same...
If so...Did you mount the rear up just like stock in the stock locations?...just chopped?

[Mayor08]

Brettster26:  Thanks for the compliments!  I could not have done it without this forum everything I wanted to know is here I only had to search for it or ask.  I'm not ready to call the project completed yet but am very close (in my mind anyway) to the finish line. 

Free Booter:

I did use the original front and rear fender as they were not in great shape.  The front fender had a a big dent on the bottom and this dictated where I cut it and then I cut the front of the fender to look proportionate in relation to the other cut.

For the back fender I took masking tape and blocked out everything I didn't want to see until I was happy with the profile.  Before cutting I made sure that the brake light would work under the fender- tucked up tight.  It would so I then laid out my cut lines so they were equal on each side of the fender and took the 4" grinder with a cutting wheel to it. 

Once this was done I eased the sharp edges and temp mounted the fender to the bike.  Next up was the fabbing of the bracket to support the brake light assembly.  I had to do some repair to the brake light housing as it was damaged from the accident and I no longer could find this brake light in with LED.  I haven't checked recently but I think you can now get it in a clear lens but not sure.

Long story short I put everything back together and it looks pretty good to my eye.  It follows the lines of the back of the seat and is just big enough to hold the brake light and cap off the back of the frame/bike.

[Mayor08]

Still no progress on the starter issue I've asked a local forum member for help and hopefully together we can find the source of the problem.

last night I did some fine tuning on the carbs (adjusted the needle clip) first I leaned them out and the bike was not able to rev properly so I went the other way and increased the richness to one position more than where I was before I started and WOW!!   The bike was good before but now it's an animal!!

I'd LOVE to call this project completed but I can't until I address the starter issue and maybe replace the clutch plates.  I've been able to remove about 90% of the clutch slippage through adjustments but still see some at high speeds over bumps.  So now I am looking at plates and where to buy them. 

[SOHC Digger]

CycleX Super Clutch Kit!


I'm a big believer in CycleXchange.  I put this kit in the motor I just built.  I haven't tried it out yet, but for the price, the claims, and the warranty, I would suggest it for you!  $109.99 with a lifetime warranty.

[Mayor08]

Clutch kit ordered though not from Cycle Exchange was a late night on line order and I was not able to order either of the kits they offered without phoning in. 

Parts will arrive this week and I am looking forward to my first clutch replacement! 

This past weekend I spent time trying to figure out why my starter still isn't working but no progress was made.

I also decided to paint my header because compared to the rest of the bike it was starting to look shabby but...it did not come out well at all.   I see sanding in my future......can't wait.....

[Mayor08]

Clutch parts arrived and the fiber plates are in oil since last night if it's not too cold when I get home tonight I am going to see if I can knock it out in an hour or so.  I'll add some pics after it's completed.

Still no resolution to the starter issue I'm thinking I may have a bare wire inside the handle bars that is grounding out.  Not sure how to check a specific wire but will be reading up on it hopefully a search will turn up something.

[Mayor08]

I was able to get to the clutch this afternoon and though this is the first one I have ever done I did a lot of research and thought I knew what to do.






Dis-assembly is always easy and I took my time putting everything back together but it would not shift to neutral or anywhere else.  So off go all the parts and a quick search here and I had the lock washer on wrong side in. So on go all of the parts and now it will shift to neutral first, second and third but not into 4th and 5th.  Not sure if I need the bike to be running and rolling for this?  I started the bike and while in the garage put it in first and eased out the clutch and the bike wants to roll so.....is everything okay?

It's pissing down rain today and no chance to get out and test but I thought I'd ask here for opinions until I can get on the road.

[SOHC Digger]

It needs to be able to roll a little.  Sometimes you can't hit all the gears while the bike is sitting perfectly stationary because the cogs on the gears don't line up with the holes.

[Mayor08]

Digger- thanks for clearing this up that means I did it right!  We're supposed to have sunshine later so I'll be giving the bike a spirited run to see how the new clutch works.

[Mayor08]

Clutch works fine though I must confess to taking it apart again after a test ride the other night because if some excess noise but I did something goofy when putting it back together that for the second time and nothing worked.  So everything came apart AGAIN and I reset the springs, plate etc. and reassembled.  I don't know exactly what I did differently (other than reset the clutch lifter) but it is quiet and function better than the first time!

 Now only one item on the check list before I can call this project DONE!

[maduncle]

Ha, must have been the phase of the moon that changed the clutch performance.

Well done - I am pleased to hear it is on the road.

[the architect]

That looks fantastic, buddy!

[lucky]

When doing these projects you have to look ahead or else when Thanksgiving rolls around you cannot get anything ordered or shipped until after Christmas.

Lots of time for cleaning but you better have your parts you need.