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Rear wheel spoke tuning 1973 CB350

GaryJames

GaryJames

Veteran Member
Joined
Jul 7, 2022
Total Posts
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Total likes
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Location
Auckland, New Zealand
Previously I laced and trued up both my wheels , first time I have done this.
while going over everything on the bike before it is submitted to local certifier for a new Vin and registration I ran it through the gears , motor running while on the main stand.
I noticed that there was some side ways run out on the rear wheel.
Went around each spoke and tried to re tune it. then noticed a few spokes appeared to be slightly bent when coming out of the rim drilling going to the hub.
So took wheel off, rubber off and took to a spoke specialist for advise and re tuning.
He couldn't get it right either.
It would seem the second hand rim I bought off our local version of ebay ( trademe.co.nz ) may not in fact be for a CB350 as advertised.
It is an 18" x 36 spoke rim but comparing to my original rusty as anything rim everything is identical except it is slightly wider about 2mm.
I am now wondering if it is from a CB360...and meant to be laced up to a CB360 Hub.
Anyone know if CB350 and CB360 rear rims are different?
cheers

PS. I have ordered a new chromed Rim from Thailand for CB350.....supposedly!.
 
Hard to say with nothing to look at. I hope you didn't get the 'A' and 'B' spokes mixed up and in the wrong positions. A slightly wider rim may not be the problem but a bent one would. Also the drilled flanges of the hub should be true and no bent portions. If you don't know what I mean by A&B spokes then ask.
 
Thanks BB,
yes I know about the A and B spokes, slightly different lengths.
The spoke guy thinks the CB350 hub is what is causing the problem with this rim.
It is obvious which side the spokes go through. Before being taken up to the rim.
He even tried turning the rim over but still same problem with bent ( slightly curved when tensioned ) spokes.
I think the counter sunk holes in the rim are at a slightly different angle from the proper CB350 rim.
I will search for any rim stamped numbers take a pic and post for comment.
cheers
 
Is the rim marked with the size at all?

I used a couple of those Thai rims on my CJ360T a few years back. They worked ok.

They were 18x1.85 I believe.
 
The rim needs to match(O.D. and width of)the hub.
I've went looking for a rim before and made sure to match the orientation of the angle of the spoke holes,compared to the original rim.
I've done this when shopping for a used rim also;most of the time I'll just purchase a good,complete used wheel,then remove the rim.
I carefully viewed used Ebay wheels so I could see the width of the hub and notice the curve of the spokes as they were installed in that wheel(the way the holes were drilled in the rim)and see if they compared to my stock hub and rim,before I purchased one.
 
Yes the spoke head angle is to match the location in the hub flanges, ie , spoke heads in or spoke heads out. Mixing them up would cause spokes to curve.
 
Mmm, I am now wondering if I got it wrong.
I will check with the spoke guy tomorrow.
thanks for all the advice team.
cheers
 
My spoke guy ( very experienced… he is a Triumph specialist and has a couple of veteran triumph racers he uses on the track regularly) he confirms it is not mixed up A or B spokes and he showed me on his rig that when laced from the rim toward the hub after two or three are positioned the next one does not point to ward the appropriate hub hole.
I have a new CB350 aftermarket chromed rim coming from Thailand.

so what to do with the second hand rear rim I have?
it is. 18 x 2.145. 36 hole?
cheers
 
I'd love to see what this problem actually looks like. Outside of mixed length spokes, an egg shaped rim or defective spoke hole drillings in the hub (I have seen that),or the rim, it defies all my logic and experiences.
 
Rim is oval, checked on his rig.
Spoke holes look okay and the rim has been used before.
When lining up the spokes toward the hub he was pressing the through-rim nut into the countersink ....

Whilst waiting for my new rim to arrive I was checking the rim tape and tube and reflecting on why there is 2 x Inflation stem nuts supplied.
When I built the wheel last time I used one nut inside the rim and the other outside on top.
Is this the correct way?
cheers
 
In my experience tubes have one nut on the stem already (and I leave it there, so it's on the inside), and the other nut goes on the outside of the rim.
 
Thanks AD, I ve done the same but never seen any advise about it.
I note in my earlier post I said the rim checked out as oval. I meant round of course..!
cheers
 
ancientdad said:
In my experience tubes have one nut on the stem already (and I leave it there, so it's on the inside), and the other nut goes on the outside of the rim.
Click to expand...

I had a tube fail on the 550 because of the double nuts. One was on the inside.

What I do now is make sure that dished washer is on the inside and use both nuts on the outside.
 
Now that reasoning makes perfect sense Maraakate.
I did see the dished washer which is not removable on the tube I have and seems to be fused to the rubber.
In fact I took off both nuts and positioned the tube inflater through the rim with the dished washer only against the rim. It seemed to fit there abouts but in the end I installed with the one nut on the inside. I am now in two minds…
both tubes I bought new had the lower nut on really tight with a felt tip mark on one nut flat and a corresponding mark on the rim … as if this is the way it is supposed to go.
my new rim has arrived but I am waiting for my paint to dry hard around the inside over the spoke holes.
I will investigate this more after the spokes are on and trued.
cheers
 
ancientdad said:
In my experience tubes have one nut on the stem already (and I leave it there, so it's on the inside), and the other nut goes on the outside of the rim.
Click to expand...


Way back in the day that's how I was taught, to put one nut in and the other out and I never really questioned it and never had a problem because of it. (I think the reasoning was that it locks the stem into the rim without stressing it?)

If you google around there are a lot of varying opinions as to stem nut placement but I didn't really find a definitive answer from an authoritative source.
/nuts
 
I had a problem with a slow leak around the valve stem of tubes when I put both nuts on the outside of the rim.
I have since tightened one nut down onto the valve stem down onto the tube to tighten the dished washer,which seals the stem very well;then the remaining valve stem nut on the outside of the rim:no more slow leaks.

I find the number 1 thing most bikes have a problem with when it comes to tires,is low tire pressure from not adding air regularly. The quality of the rubber in the tubes are very poor(imo)and I always check my tubes every 10 days or sooner;it doesn't take long for tires to lose air.
 
I can't speak for the slow leak and changing the nut arrangement fixing it. All I know is that the inside nut eventually helped tear the whole valve assembly from the tube. This was not an old tube. It was 3 years old and it was installed professionally. It wasn't eBay junk and actually I bought it from the Honda dealer via the part number.

It's possible it just simply failed, but it was a lot of "fun" having the rear go completely flat 3 miles from my house at 50mph. At first, I thought it was a burst of wind because of the sliding. Corrected myself and noticed it did it again a few feet later. That's when I started reducing speed slowly and pulled over and looked. Since I was so close to the house it wasn't worth spending $75 to get towed and waiting hours. I just lugged that engine at 2-5mph with my feet dragging on the ground.

20230403_141620.jpg

I talked to other motorcycle career techs who have changed many a tire and I was told they double nutted on the outside. But, it appears everyone has a conflicting opinion.

Considering the dished washer fits the contour of the rim I believe this double nutting on the outside is how it works.

EDIT: Additionally, in response to your dished washer not being removable... it was on this tube and on the replacement tube. I'm pretty sure this was a Dunlop tube but I really cannot recall.
 
I have a stash of those valve nuts and some are much thicker than others. I try to use a thinner one for inside against the dished washer.

Different tube manufacturers have used different methods to mount the valves in the tubes, some are simply vulcanized, like the one that ripped out of Frank's, some have a large flange and are removable from the tube but can leak if not clamped sufficiently with a nut inside.

Bill's comment about air pressure is a big factor to keep the tire/tube from slipping on the rim and doing a rip out. That is why rim locks were invented for low pressure usage on off road wheels.
 
I will say the tire pressure was correct as well. If you ride your bike enough you will notice you sit down on it and it just feels lower. That's usually the first clue for me the pressure is low. I keep a magnetic tire gauge on the rear fender for checking periodically. Those mini "pen" ones that are about 3 inches long you can get at the auto parts store as an impulse buy. The one I have is accurate. No idea the brand... and bonus points that it hasn't caused a rust spot where it sits.
 
I've been purchasing Sedona tire tubes recently;according to their advertising :rolleyes: it says they have a good grade of rubber/mix to hold air in,I think.. :neutral:
 
Maraakate said:
I will say the tire pressure was correct as well. If you ride your bike enough you will notice you sit down on it and it just feels lower. That's usually the first clue for me the pressure is low. I keep a magnetic tire gauge on the rear fender for checking periodically. Those mini "pen" ones that are about 3 inches long you can get at the auto parts store as an impulse buy. The one I have is accurate. No idea the brand... and bonus points that it hasn't caused a rust spot where it sits.
Click to expand...

A long ago Christmas, I got a digital talking pressure gauge that, surprisingly, was pretty accurate. It was fun listening to it say, "Thirty....P..S...I". Maybe I need to get out more and not be so lonely.:) No British accent but a pleasant female voice. It doesn't talk anymore so perhaps the honeymoon is over or it needs a battery.
 
I pulled mine off the CM400 and amazingly the UPC was still there so I was able to figure out who made it. It's made by Hopkins/Monkey Grip. However, nobody seems to sell it outright. It's still in their catalog.

With that said, after much research Slime has one. It looks exactly the same, has the same description. I suspect it's just rebadged from Hopkins. Available from Walmart.com and others. For $3-$5 I think it's a worthy addition to hide under the seat/rear fender. Don't be fooled by how cheap it is. It's surprisingly accurate.

Slime-A-Mini-Magnetic-Pencil-Tire-Gauge-10-50-PSI-1-each-sold-by-each_2a797493-89a9-408e-bdac-7e.jpg

https://www.walmart.com/ip/Slime-A-...Gauge-10-50-PSI-1-each-sold-by-each/168605250
https://shop.advanceautoparts.com/p...ltiple-color-options-compact-20108/12061412-P (This is likely where I got it from at the counter years ago)
 
I've had cheapies that were bang on and expensive dial types that were off. Grab a handful and comparatively check them to find a good one. Don't use your good ones to check a wheel with sealer in it, that stuff can plug up a good one after awhile.
 
Having a closer look at the new rim after painting the inside, out to the tyre bead grip, to hold the rust at bay, I note that the surface the Valve stem abuts to is almost flat. (allowing for slight curvature of the rim..)
Yet the dished washer vulcanised to the tube is convex. if installed without the nut on the inside I would think the valve stem is likely to be able to wobble about a bit.
If a nut was there the Valve stem would be much more stable against the rim.
I am now thinking that having the nut on the inside as AD suggests is the correct way to go.
cheers
 
Picked up my rear wheel last week all nicely tuned.
Fitted the tube and tyre and installed on the bike.
Oh also decided to fit the new sprocket since the chain is new.
Did a static hand spin balance ( without the main chain on ) so it rotated to a stop at random points after fitting one small spoke lead weight.
wheel spins without rim/tyre lateral movement or ovality... nice.
Chain on and adjusted and now ready to rumble..... once the rainy weather has gone away.
Next step is a few test rides in the neighbour hood then down to the re-certifiers...
IMG_2430.JPG
IMG_2431.JPG


Cheers
Gary

PS I have been experimenting with doing the Cam Shaft Ball Bearing modification.
I bought some second hand items locally and will post what I did when the large bits come back from the vapour blaster.
 
350 and 360 rear rims are the same.
Personally, I would never re-build wheels with original narrow rims, pretty much always fit WM2 front and WM3 rear. (except when I fit WM3 both ends)
Yamaha XS650 18" WM3 rear rim is exact size and spoke angle for front drum brake on 350/360 (PCD of spoke holes is same)
I haven't had pictures of mine since Photobucket got greedy a few years ago, guess I should take some new ones?
 
GaryJames said:
Thanks AD, I ve done the same but never seen any advise about it.
I note in my earlier post I said the rim checked out as oval. I meant round of course..!
cheers
Click to expand...
The problem is generally people crank the second (nut outside rim) way too tight. Personally, on road bikes, finger tight is enough and off road, run nut up against valve cap so you can see when tyre is turning on rim (valve leans over) It's surprising how many 'professional' mechanics don't know this basic 'rule'
BTW, you don't measure wheel rims across the outside, you measure inside the flanges where tyre bead seats
 
Maraakate said:
View attachment 23963

I talked to other motorcycle career techs who have changed many a tire and I was told they double nutted on the outside. But, it appears everyone has a conflicting opinion.
Click to expand...
See above reply.
If you can find them, British Dunlop tyre fitting films from 1950's are probably the best instructions for tyre and tube changing and contradict what MANY professional mechanics (and You Tubers) tell you
 
I'm sure that they didn't come from the factory with a nut on the inside. I had enough punctures on my two new Hondas back in the day, I would have noticed this. I only ever put nut(s) on the outside.
 
crazypj said:
See above reply.
If you can find them, British Dunlop tyre fitting films from 1950's are probably the best instructions for tyre and tube changing and contradict what MANY professional mechanics (and You Tubers) tell you
Click to expand...
To play a little devil's advocate, I saw threads elsewhere when looking this up online where they contacted tyre manufacturers about this and even they had conflicting opinions, lol.
 
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