Author Topic: Squirrely Ride...Concerned. (Read 1855 times)

YoungBlood · « **on:** October 26, 2021, 02:31:00 PM »

Hi everyone,

I am experiencing the bike feeling squirrely. I thought at first I had a small leak in the front tire. Immediately got air: front was at about 25, back 27. So I filled them both up, 30 front, 32 back. The unstable feel still continues, and it seems the bike is compressing more on bumps than normal, barely any stiffness, but a spongey feel. I have Bridgestone BT46's, which another shop installed and mounted a thousand miles ago.
I redid the fork seals after they started leaking from when I first replaced them, 5k miles ago. I accidently installed them backwards the second time (I asked another motorcyclist instead of looking it up myself), had to redo the procedure again. However, I remember losing a copper washer for the hex nut on the lower fork sleeve. I believe it secures the damper in place if I'm correct. I also remember losing a touch of oil when filling them up to spec using 10W-30.
The symptoms I'm experiencing seem to be like it's low on fork oil. I also found a bit of oil underneath the speedometer on the front wheel.
What should I do to figure out what's the cause of this? Get new copper washers, drain the fork oil, refill, and reinstall with new copper washers? If that is what I should do, can I do this without fully dissembling everything again (there are no leaks around the seals themselves).
Is this have something to do with steering bearings, un-trued wheels, misaligned wheels, wheel bearings, rear fork neglect, etc.)?
-a concerned rider

fizzlebottom · « **Reply #1 on:** October 26, 2021, 02:51:01 PM »

You installed the fork seals backwards before reinstalling them correctly, you're missing a copper washer, and you've already seen fluid leaking. I'd say you probably have some very uneven dampening going on and very possibly torn fork seals. Have you taken the dust covers off to make sure everything is dry above the seals?

What you should do is tear your forks apart and rebuild them correctly with all the right parts using instructions from a factory service manual. A squirrely front end is unpredictable, and unpredictable is flat out dangerous.

Stev-o · « **Reply #2 on:** October 26, 2021, 02:52:46 PM »

I have BT's on my K4 and when it feels a little "squirrely", I know I've forgotten to check the air pressure and sure enough they are low. Not sure why you pumped 'em up to 28 & 32, the max pressure is 41 cold...

https://www.bridgestonemotorcycletires.com/content/dam/motorcycle-tires/images/products/battlax-bt46/BT46-product-brochure.pdf

I would pump 'em up to 38, especially the front. [some guys may have a different opinion on this]

Alos, why are you using 10-30 in the forks? Fork oil is highly recommended or at least use ATF. And rebuild them correctly, you should then be good.

TwoTired · « **Reply #3 on:** October 26, 2021, 03:01:20 PM »

Hard to assess (squirrely). But, do check your swing arm bearings. The rear axle allowed to move sideways will surely make the bike squirrely. Kinda like it has a hinge in the middle of it.

I had a rear wheel bearing go out once that also changed to rear wheel alignment when the remaining balls on the sprocket side would vacate part of the race and allow the wheel to shift on the axle when the throttle was twisted. Yeah, squirrely.

Cheers,

Johnie · « **Reply #4 on:** October 26, 2021, 03:14:53 PM »

I was just going to mention the swing arm bushings and Two Tired beat me to it. My K1 got squirrely and it was the swing arm bushings. For sure take care of the fork issue like the guys said. If you still have the squirrelly then check the bushings. Put the bike on the center stand, grab the rear tire and try to move it back and forth horizontally. If you got bad swing arm bushings you will have play there.

YoungBlood · « **Reply #5 on:** October 26, 2021, 04:26:45 PM »

Thanks everyone. I'll be sure to increase the tire pressure, re-do the forks, and then take a look at the rear fork.

Stev-O I added 10W-30 because that is what the manual calls for. I also wad doing 28/30 because I thought that's what the mechanic said who did the tires:
http://www.dotheton.com/downloads/CB750%20K0%20K7%20SHOP%20MANUAL.pdf
page 94 on pdf
Other questions:
I do not have a snap ring, but a type of circ-clip above the seal that sits in a groove of the upper fork sleeve. Is this normal for a '75?
What oil is the best to use?
How do you tell if a fork seal is "torn" from multiple reinstallations, i.e., taking them out, flipping around, repeat?
Where can I get the copper washers I need? Are copper washes a one-time-use item like a gasket?
What side of the bike is the rear fork grease nipple? I've never greased it, had the bike 7k miles.

I'll report back after I've worked on the bike, or have any extra questions.

Don R · « **Reply #6 on:** October 26, 2021, 04:54:52 PM »

I saw someone make copper washers from a ring type electrical crimp connector. If the seal isn't leaking under the boot I wouldn't worry about that.
My 750 had a PO that jumped curbs a lot, the tapered neck bearings had a flat spot causing a slow wobble. I could stop and rock the forks lock to lock a few times, that would mix up the bearings until the flats all lined up again.

Alan F. · « **Reply #7 on:** October 26, 2021, 05:13:57 PM »

I'm with Don, raise the front wheel and turn your handlebars side to side, do you feel a big notch in the middle?

Replacing your steering bearings is not that hard, and as long as you'll have your front end apart anyway...

ekpent · « **Reply #8 on:** October 26, 2021, 07:11:37 PM »

As for the circle clip do you have a 1975 750 K or F model as they are different. Fork oil or trans oil is better as it does not foam up.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #9 on:** October 27, 2021, 08:12:21 AM »

I have seen conflicting information on the amount of fork oil to add.

YoungBlood · « **Reply #10 on:** October 28, 2021, 02:42:40 PM »

So it's been crap weather, and I've been too busy with school.

But the bike is a '75 F, ekpent, and I added 7.2 / ~7 ounces of oil, Jerry. What is the right amount? Although I don't trust I added precisely the same to both because I lost some oil when trying to screw the 23mm cap nut to the top of the fork while simultaneously compressing the spring down. I know from past experience that it's best to mount the forks on triple tree, then add oil, and lastly screw the cap down. I was in a hurry and being impatient last time.

As to the copper washers, thanks for the idea Don.

Also, I'll be sure to raise the tire and double check the steering bearing, thanks Alan + Don. How can one tell that their forks are "stiff enough"? I mean obviously the bike's forks should be dampening while riding, but what about when coming to a stop? Is there a good rule of thumb to tell if your bike's forks are compressing too far down when coming to a stop?

New question: Can I keep the forks mounted on the bike since all I need to do is drain the oil, replace the copper washers, and fill with exact amount of fork oil? I'm trying not to go through this fully one more time because three times in a couple weeks is upsetting.

Old Scrambler · « **Reply #11 on:** October 28, 2021, 03:54:09 PM »

New Question..........Yes. Be sure to compress the forks by pressing on the handlebars to get most of the old oil out......it tends to shoot quite far

Do as others have advised regarding bearings. I like 15w ATF in my K3 and most other forks.

Tracksnblades1 · « **Reply #12 on:** October 30, 2021, 03:15:33 PM »

Copper washer assortments are available reasonably online if OEM washers can’t be found..

Whaleman · « **Reply #13 on:** October 30, 2021, 03:56:23 PM »

I agree with the pressure being low. The stock tire pressure was stated for the STOCK tires. That was over 40 years ago. Tire tech has changed. Check with manufacturer not the 45 year old spec. Dan

YoungBlood · « **Reply #14 on:** October 31, 2021, 08:29:55 AM »

Anyone know if aluminum washers would work in place of copper crush washers. Also, what are the inner and outer diameter sizes I need for the 8mm hex nut on the lower fork, and the drain port's 6mm nut?

Alan F. · « **Reply #15 on:** October 31, 2021, 09:05:49 AM »

It might work, might behave somewhat differently. Aluminum crush washers seem to be used mostly on larger fasteners where more torque is possible without breaking the head off the bolt.

Your drain washer is 6mm, you need a 6mm copper washer. Or as mentioned snip the ring off an electrical connector of appropriate size and just use that.

You could even take a scrap of copper pipe and drill it 6mm, snip, nip and file it to fit.

Or you could walk into any Japanese motorcycle parts department and ask for a 6mm fork drain screw copper sealing washer, then ask if they have them in 8mm also for your damper rod bolts. Have a look at www.partzilla.com if you'd rather have a list of part numbers in hand.

You can do it!

YoungBlood · « **Reply #16 on:** October 31, 2021, 09:21:57 AM »

Thanks Alan! I also, sadly, realized my spacer washers are missing for the top triple tree bolts. One of them, that holds the steering bearing rod, I never touched. Would that be a good indication the PO might have replaced the steering bearings?

Alan F. · « **Reply #17 on:** October 31, 2021, 09:37:29 AM »

You can never really tell what a PO did until you've had it apart and put it back together correctly.

Get some of those triple tree washers ordered quick!

http://forums.sohc4.net/index.php/topic,187979.msg2181176.html#msg2181176

seanbarney41 · « **Reply #18 on:** October 31, 2021, 11:10:10 AM »

Youngblood, not all top triples used the spacer "D" washers. You need to go to Partzilla website and learn to use the parts fiche to find out what hardware your bike is supposed to have and whether it is still available. Sure sometimes hardware store substitutions work but it does not sound like you have the mechanical experience to make these decisions. Most of this stuff is available from Honda.

YoungBlood · « **Reply #19 on:** October 31, 2021, 11:22:46 AM »

Sean, I know for a fact that the outer two D washers are missing, and they belong there for this bike. I simply misplaced them.

As to the center D washer, I'm unsure if it belongs, so I will look that up--thank you.

Problems I'm having are more of the headache trying to find these parts at a store. I know the D Washer is supposed to be .08''/2mm thick, and it's a 8mm bolt. As to the 4 copper washers--the 8mm allen head nut on the lower fork, and the 6 mm drain nuts--I'm having a hard time locating at a store. I also cannot find fork oil in the city that is available for pickup, like an auto part store.

I think I can make due with the 5/16 electrical connector for the 8mm allen head, like Alan and Don were saying.

Does anyone know what type of ATF oil would work? Someone said 15, but I can't find 15 ATF oil, I don't even know what that means. I'd like to get this work done today, if not, I'll have to wait another weekend.

YoungBlood · « **Reply #20 on:** October 31, 2021, 12:03:05 PM »

Correction, the spacer washers are for m8 bolt. Would an m8 15mm OD thickness of 2mm work? https://www.grainger.com/search/fasteners/washers/flat-washers?tv_optin=true&searchQuery=m8+washer+2mm+thick&searchBar=true

Alloy steel flat washer, $5.28/pckg of 10

seanbarney41 · « **Reply #21 on:** October 31, 2021, 12:39:18 PM »

I dont agree with the belief that the d washers are even really required except for correct restoration purposes. If tighten the clamps to the point that the d washers are pinched, that is too tight anyway. Lord only knows why Honda had them in there anyway. Plenty of sohc4 with the same design clamps came without them. Just dont over torque. The only way to actually pinch the d washer is to over torque the clamps anyway. Top triples just need a good snug. Its the lower clamps doing all the real grunt and none of those have d washers.

RAFster122s · « **Reply #22 on:** October 31, 2021, 02:09:42 PM »

The D washers prevent the aluminum triple tree from being tensioned highly and then then a big pot hole or several big pot have been taken causing the triple tree to crack.
The washer is sized to allow the pinch to be closed up only so much...setting the maximum strain to the metal of the triple trees.

YoungBlood · « **Reply #23 on:** November 28, 2021, 08:15:48 AM »

Hi everyone,

A weekend ago I got around to replacing the copper washers and swapping the fluid with 15W Fork Oil (5oz). I did not feel/find a notch in the center steering bearings when rotating the handlebars right and left. There still is a slight pull to the right, usually when slowing down to a stop it becomes noticeable.
Questions:
1. The allen head bolt for each damper rod would not tighten "tight". From my understanding, this rod rotates internally, and this rotating is minimized when the fork top bolt is secured giving tension to the spring against the damper rod. So what the hell, is it normal for this allen bolt to not get very tight and keep rotating with the damper rod even with the fork cap secured?
2. How long of a life do these fork springs last on a 75' CB750F? I'm over 20k miles with this bike, about 5k done in the city (bad roads). I know you can measure these springs, but I'm suspicious this could be it too.
3. How often does everyone true their wheel spokes (mileage)?
4. Could this issue of looser handling have something to do with the rear fork? 2Tired and Johnnie, I checked for play in the rear axle horizontally. There's no play, but I've still not greased the thing since I got the bike 7k miles ago.
5. What is that string technique one can do to check wheel alignment?

Thanks everyone, and my apologies for some redundant questions.

Don R · « **Reply #24 on:** November 28, 2021, 08:24:18 AM »

1, It should get tight, use an impact wrench on light
4, yes.

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Author Topic: Squirrely Ride...Concerned. (Read 1855 times)