Topic: CB750K4 - new updates 04.18.24 All issues resolved and ready to ride

[Johnie]

Atta boy Andy...I will keep that connection in mind. I have not gone any further with my "clunk" yet either. We have not had the heat as bad as you, but still pretty humid and hot. I plan to push the front tire to the wall and give it a few hard dips to see if I get the clunk. If I do then it has to be in the lower All Balls tapered and not the caliper. As I said, I already put on a caliper with 4,700 miles and no change.

[andy750]

Hit 70,000 on the speedo today...although real mileage is more like 71,500 as my speedo cable broke on one country cross trip.





I got rid of my annoying "clunk" as well....what was it? Well yesterday I tightened up the steering head bearings once again (4 or 5 times now) and they were fairly loose. Got all fork pinch bolts snug and all this combined with the new front wheel bearings have solved the clunk. No longer vibrating at stop signs. Now just to get some silcone grease for the very squeaky front brake!

cheers
Andy

[nancy]

That's great Andy. A clunk is not a happy noise while airborne. I have just received my bearing kit - which is branded LINK, made in Japan. Looks same as All Balls/ David Silver kits. I read a Hondaman article on these JAP kits - he advised a very specific installation which tends to contradict that which you followed from his book Andy. The article states that the JAP kits need bearing down work during install, involving moving the handlebars L & R repeatedly while you tighten the nut till movement is nearly impossible - then,..back off HALF a turn. This also helps to minimise future wear on the set.
If u get time - you might pop over and install mine - it's a couple degrees above freezing here at the moment. Can't be foo'd installing anything currently - except a glass of Shiraz...
Regards
Mark

[andy750]

Hey Mark,

Actually I was following Hondamans book - page open at steering head bearings when I did the bearings over the winter . I followed this and Johnies photo pictorial. Both were very helpful. Well I hope thats it for now! Next is the squeaky front brake and now I have a semi-sticking starter button that engages the starter motor but then gets stuck and starter keeps whirring away..not good!

For a glass of Shiraz (hopefully from NZ) and my flight paid sure Ill come and sort out your steering head bearings 

Almost too hot here
cheers
Andy

[DedHed]

Andy,
Thanks for the postings!
I am about to take delivery on a 1974 CB750K4 Four this weekend - Orange!
The motor is in great shape (No leaks and no smoke) and there is some cosmetic damage, a little rust here and there. I hope to get it as clean as the one you have pictured in this thread.
Thanks for the GREAT information!
Philip

[andy750]

Thanks Philip and I try my best

Good luck with the orange K4 and post some pics when you get it...in this new thread...all about the orange

http://forums.sohc4.net/index.php?topic=74014.msg822238#msg822238

cheers
Andy

[DedHed]

Wonderful! I will check the other post and perhaps even start one on my "New" bike.

I am scheduled to pick it up tomorrow, I tried to take it for a test ride last weekend. I showed up and the owner fired the bike up with a tad of choke, and gave the throttle a few twists. The bike sounded GREAT, then he twisted it one more time ... SNAP... The throttle cable broke. I can't be upset about that... it was only 36 years old... A new set of cables are on their way and should arrive today.

I plan on taking pictures "As is" when I pick it up, then more as I clean it up.

Again many thanks Andy, this thread has given me some insight as to what I need to look for!
I'll be in touch.
Philip

[Johnie]

Congrats on the new K4 there Ded...yah, post up some pics when you can. We really like pics here and welcome to the boards!!!

[andy750]

Saturday - went for a 250 mile round trip ride to Vermont with the g/f- started off in 95F heat and ended in Vermont at a popular swimming river (being Vermont it was clothing optional ). Only problem I was riding the VStrom...so Sunday had to make up for it and take the CB750K4 out for a good ride...180 miles of back country roads mixed in with some residential/small town riding...

This time I went South to ride crossing into RI and CT......that was my first mistake.......every turn I made thinking this would be a good road...turned into residential areas...not all but mostly. However, plenty of country roads too which made it ok but it was still 92+F..hot! Overall 6/10 for fun.

However problem occurred...I had taken Rt 146A south and took a wrong turn...stopped the bike to check the map and went to start again....no juice in the battery...bugger I thought must be the alternator connector again....only it wasnt that obvious this time...first tried to kick it..no good...pushed it over to the shade and tried to kick it again...no good....checked connector....tried again and it started and I rode off...next time I came to stop and restart same problem....only connector seemed to be good. This happened the whole way back.....bike started on kick start only. And starter button is still getting hung up on something engaging starter in a horrible sounding way....

So....got home and threw battery on charger for 3 hrs...tested it on bike...everything works - lights, starter button (sounds bad though - not getting stuck but not sounding normal), blinkers (but not idiot light blinkers for some reason  - may need to check wiring as did install 1` risers on the bars at start of day)....

So battery can be re-charged but it dosent 1) hold charge or 2) not getting recharged by alternator. New rectifier, regulator, alternator seemed ok when checked last week with multimeter......so must be the battery no? Battery never gets fully charged on the charger....the red light saying "charged" never comes on...even if left on for hours and hours....

Thoughts?

cheers
Andy

[Johnie]

Andy...what is your tester showing as far as battery voltage when you take it off the charger? I wonder if it is just not producing the needed amps. I had a 6 month old AGM from Batteries Plus that went bad. It showed me the 12 volts, but was producing no amperage. And it was only 6 months old. Got a new one for free at least.

[andy750]

Well I got a new battery on Friday and tested out with a 110 mile ride on Sunday (in the 90F+ temps and high humidity!). Bike is running great, no charging issues anymore, nice bright lights once again...and super smooth ride with the new front wheel bearings and refurbished swingarm. No front end clunk anymore either re-tightening the steering head bearings....

Now just to figure out if its my starter button that's sticking or starter motor that's getting stuck when starting it up... .change of oil first though...too hot for 10W-40 so 20W-50 for next month or so...

cheers
Andy

[DedHed]

Now just to figure out if its my starter button that's sticking or starter motor that's getting stuck when starting it up... .change of oil first though...too hot for 10W-40 so 20W-50 for next month or so...

Thanks for the unintended tip! I'm in Alabama and the heat is a killer (As it is for most of us) planing on changing the oil in my new girl as well this weekend..... 20w-50 it will be!
Thanks!
Phil

[Johnie]

Now just to figure out if its my starter button that's sticking or starter motor that's getting stuck when starting it up... .change of oil first though...too hot for 10W-40 so 20W-50 for next month or so...

Thanks for the unintended tip! I'm in Alabama and the heat is a killer (As it is for most of us) planing on changing the oil in my new girl as well this weekend..... 20w-50 it will be!
Thanks!
Phil

So at what temp do you guys figure 20/50 is best?

[andy750]

So at what temp do you guys figure 20/50 is best?

For me...prolonged periods over 80F...

[nancy]

Andy - I fitted a new LINK brand tapered bearing set to my K3 last week. Just got the thing back together today. Had 2 nightmares - the headlight wiring - you know about that huh.. and the damned front mudguard. It took me better part of  4 hours just to get the wiring mess sorted out. Thought I was on the home straight - just throw on the wheel, mudguard, adjust brakes and i'll whizz off down the road. NO. Took me another 2 attempts over a day to get the stupid mudguard/wheel setup. So simple yet so damed awkward.
Got it on the road today - but it felt AWFUL. Like riding a trick bike with a hinge in the middle. Felt like it did ages ago when I had an alignment problem front/rear wheels (I had one front fork 7-8mm higher than the other at top tree and the rear wheel 1/2 notch off on one side) . So I rechecked front fork heights are level, released and retensioned pinch bolts on the trees - still felt nasty. Steering on front OK - but it felt twitchy in rear. Removed brake caliper and refitted that, re-adjusted, rebleed line. Now it rides 50% better. Still seems to wiggle about when I accelerate off. I've given up for today. I guess I'll figure it through. Anyway - no clunks yet..

[Jerry Rxman Griffin aka MuthaF'er]

So at what temp do you guys figure 20/50 is best?

For me...prolonged periods over 80F...

OR prolonged periods over 80mph

[andy750]

Hey Mark

Sorry to hear about your alignment issues  -not experienced those myself. The front mudguard for me was pretty easy since the front wheel was off at the time - was this the same for you? If yes where did the problem arise in fitting?

I have since discovered my starter motor is sticking - its not the starter button after all...so need to remove starter and check or replace...

cheers
Andy

[nancy]

Andy
Yes to front wheel... I had it all off. I refitted the wheel 1st - then fitted the mudguard. That was the problem. Also, I noticed that the back of the hydraulic hose fitting on the LHS guard is very close to the tyre - like 3-4mm - is this normal? Wondering still if that indicates something amiss.
I have yet to retest the bike since my last worrying wobble. But, I've only done 3-4 miles on it since the bearings were done. Weather has been #$%*e on a stick here. Have pulled off the wheel, reset the pinch bolts on the forks, reset the wheel mounting to be sure it's centered and we'll see.
I'm wondering if I have the top stem retainer cranked too tight. Read on forum some advice to lighten up on that adjustment as too tight a bearing fitting causes it to be unstable. My wheel is not free to flop with a finger push - it is firmish - but I read Hondaman's advice to have it on the stiff side while bedding in. I might slacken it off. Are you are to flop your from side to side if that's not too personal?
Regards
Mark

[andy750]

Hey Mark

Good info on your end. I fit the mudguard first before the wheel as it makes it easier to get it on. Your brake hose should be running outside the fender and I dont see a way off it rubbing on the tire -do you have the little clip that holds the rubber grommet (that is around the lower hose) in place? If so should be ok.

Are you sure your lower fork/wheel clamps - those u-shaped objects at the end of your forks are in the right direction?

As to your steering -when my front wheel is off the ground my bars can flop easily over to one side with a finger push. If yours cannot then I wager its too tight. MikeR showed me a tool he has  -a spring-loaded mechanism that attaches to the bars so you can measure exactly the amount of flop it should  have. I didnt use that but got it to a spot where I was comfortable. I think you have over-tightened yours. Not good in the long run for the bearings. Loosen up just enough so your bars fall under their own weight or with a slight push.

Other "wobble" factors to consider:

1. Tire pressure. Depends on what tires you are running
2. Forks aligned? Same level at the top of the triple tree?
3. Wheel bearing in ok? No free play in the axle?
4. No free play in the swingarm? This could transmit to the front - just a thought.
5. Lower and upper triple tree bolts tightened ok?

Thats all I can think of for now.


good luck
Andy

[nancy]

Thanks for the help Andy - I wanted to hear your confirmation of the flop factor. I was uncomfortable with the amount of force I was using to lever this top stem nut with - but the Hondaman article insisted on doing this up till the bars were virtually not moveable, than back it up a bit. I never reached that - I gave up with it at a firm stage.
Yes - I have a "wire" clip to attach the brake hose to the guard bracket and the backside of that protrudes very close to the tyre. I guess it's OK - it has a gap - which may be as little as 2mm as I seem to have some slight rotational wobble. Need to learn spoke adjusting next!
All other factors you've mentioned are AOK. All was running well prior to my pulling the front off. So I know it's forks, front wheel, bearing, trees or stupidity related. I'm voting on the bearing tightness now I've heard from you. I'm heading out to the shed shortly to turn that back.
Cheers
Mark

[nancy]

And also Andy - you mentioned did I have the axle retaining brackets on right way - well I hope so,.. I have them with the gap facing FRONT and tightened rear bolts 1st. BUT,....when I took them off - I had been running the bike for a year with the gaps at the BACK!! I wonder what effect the reverse of correct has? Are they in fact wrong now! Sigh..
Again, I used a Hondaman article to check this - but could you confirm you concur?
Mark

[andy750]

Mark

I use the F mark on the retaining brackets as to me that indicates "Forward" - not sure if thats true or not but works for me I tighten both bolts evenly  - not one first then the other. Basically as long as there is no gap in between bracket and axle you should be ok.

Sounds like you over-tightened the bearings though. I had the HM book open as I was doing it as well...anyway as you read above it took me 4 or 5 times of re-tightening the bering retainer to get it right after riding it, checking it, riding it etc...worth it in the end though.

Good luck!

cheers
Andy

[nancy]

Yep - thanks Andy. Job now done. Reduced top nut by by about .5 of a turn and now I'm flopping nicely. Bad news,...it's pouring with rain. Can't do a test ride. Damn...
Front axle caps: GAP GOES TO FRONT. But many have it the other way and it seems to make little diff. Check this topic for the gory details: http://forums.sohc4.net/index.php?topic=56844.0
Regards
Mark

[andy750]

Thanks for the link Mark  - very interesting! I had no idea..Ill check mine to make sure....not sure I have really noticed a gap though...got a pic to illustrate this?

cheers
Andy

[nancy]

I'll getya one tomorrow.