Weaving In The High Speed Sweepers

[bdento59]

So... hmmm, do all (relatively) stock 80's weave in high speed sweepers above 75 mph, or is mine broken? It was scary unstuck today on I-195 heading into Trenton. Data: stock 35mm front end with fork brace, 10 psi air press., new Bridgestone S11's, CB1100F rear shocks. Pls advise, tks.

[Terry]

I doubt all of them do and my 79 has never had that problem. I have stock forks but with ProSus springs and 20w fork oil and a brace. I run Konis on the rear. When that happened on my 82 it was the rear shock going out. Once it was rebuilt it now handles fine in high speed sweepers. If yo have the OEM springs and that transmission fluid weight fork oil, that might be the cause. I also don't have air forks like the 80 so I don't know how that might make a difference. Good luck!

[new shorty]

Broken front fork spring, unequal amount of oil in the fork tubes, steering head bearings gone South, worn swing arm bearings or bushings???

And that's just a very short list of possible causes.

Has the bike undergone any modification lately, or did the problem come as a complete surprise?

[EMS]

While I never considered it a problem on my '79 and was never bothered by it, I believe all early CBXes have a lousy chassis. At the time the bike was chastized for it and soon achieved fame for a being a terrible "weaver". I remember, they even cracked jokes about it in Germany, being a "Pendler" , using the double meaning of the word for "commuter" and "sverver/weaver" during times when driving was restricted because of fuel shortages.
And don't nobody tell me the adjustable shocks in the rear "helped somewhat". European versions had these in 79.

[Rick Pope]

Bill,
Try a fluid change in the front. 15w seems to be a good compromise for me, maybe 10w for a normal sized person.

Try overfilling the forks to within about 7" from full w/ springs removed and forks collapsed fully. No air pre-load. You'll be amazed.......

[alimey4u2]

Had the same problem quite recently. Checked the fork oil level & one ( dunno how or why ?) was about an inch lower. Replaced the oil with a higher viscosity & ensured the levels were spot on & the result was dramatic.. I had 10 weight in but that was for too underdamped for me

Now if only I can get an effin dry spell in this GD weather to take it for a good long blast.. Wettest July in recorded history...

[Terry]

"Now if only I can get an effin dry spell in this GD weather to take it for a good long blast.. Wettest July in recorded history..."

Sorry to hear about your bad weather but had you heard of the record breaking heat wave in NW WA State? You must have switched weather patterns with them. That area of Washington is almost always cool(er) and WET, yet they had 100+ degree temps.

[Mike Barone #123]

So... hmmm, do all (relatively) stock 80's weave in high speed sweepers above 75 mph, or is mine broken? It was scary unstuck today on I-195 heading into Trenton. Data: stock 35mm front end with fork brace, 10 psi air press., new Bridgestone S11's, CB1100F rear shocks. Pls advise, tks.

Background: A Path To An Early Model Not Wobbling On Straights or in any turns/sweepers
Below is the chronological progression and results to finally making the Ole Dawgie handle with econo changes and finally.... no wobbles on straights or any turns. Keep in mind back then there was no internet proven turn key solutions to make a CBX handle ...not wobble...just an ole guy and ole bike trying to work all this out without spending alot of money and still ending up with a bike that looked like a CBX.

Dawige Handling History.....Timeframe: 1980 to 1990 or so
1. Adjusted air in forks at 1lb pressure increments. Still wobbled

2. Different weight fork oil starting at 5wt....in 2.5wt increments ....to 15wt. Still wobbled and brutal ride with heavier weight fork oil combinations.

3. Installed a steering damper. Still wobbled

4. Installed a fork brace. Still wobbled

5. Replaced rear shocks with Koni adjustables. Installed Progressive front fork springs. 15% better handling...still wobbled.

6. Watermellon on the gas tank at speed. No wobbles

7. Oversized front tire. Less wobbling......but it chewed 3" or so off the front fender tip at speed

8. Latest sport tires (12 sets or prior to item 10). Still wobbled

9. Gusset steering head, reinforced frame backbone, braced stock swing arm. Still wobbled

10. Complete 1100f 39mm complete front using 1100f triple trees 1100f and 1100f back. No wobbles.

Note: Long ago an article in the Xpress stated that 35mm CBX tubes flexed 55% more than 39mm. Massive clue in my view.

Long trip....trial and error over ten plus years, but I finally got to the promised land an no weaving or wobbles at any speed or in the twisties.

2009 Update
For early models my recommendation now is to replace the current 35mm early model fork tubes with a late model forks, 1100f triple trees and Race Tech Gold Valves....go from there. Use everything else you have on the front now.

I used to recommend 1100f full front inc 1100f triple trees only because they were 39mm with all the adjustablity along had anti-dive that really worked and had great success with this myself for 15 years or so. However, 39mm late model forks, 1100f triple trees and the Race Tech Gold Valve did yield a far superior result to the 1100f front with triple trees and is more compliant, less nose dive, less expensive, no technical or fitment issues and finally weighs less........plus the Gold Valve is adjustable. (Note: Use 1100f triple trees. One report of handling problems using late model triple trees has be reported.

Now you do just this you still end up with your single piston early model calipers and stock rotors, but getting better calipers on the front is a future step....and doing the 39mm and Gold Valve fix now will ensure you live long enough to actually start being worried about better front calipers to be added to this truly superior front fork setup.

Summary
Item 10 above was the only thing that resulted no wobbles, but this plus items 8 & 9....and finally the all important Race Tech Gold Valves yielded absolutely the best handling the Dawgie has ever had. 30 years of experimentation and econo parts....but I think it is done now....and the bike still looks like a CBX....and yes...it was well worth the wait.

At your option, you can proceed right to "Go" if you want ...come on out.......ride the Ole Dawgie and see if this is what you are looking for in handling and absolutely no wobbles.. Hope to see you soon...and yes.....bring that Yamaha 920 along if you can.

Hope this helps


Mike

[bdento59]

Thanks for all the input, especially MB for the great background info. I guess I'll look forward to the SA and front end changes over the winter.

BTW, the '80 CB-X SA pivot bolt arrangement is the most complicated fiche I've viewed in a long time. When doing the CB1100F SA conversion, how much of the CBX (pivot bolt setup) stuff, if any, do I need to use in order to mate the new SA with the old frame? The main reason I ask is that I don't have "any" of the CB1100F pivot bolt setup, except for the needle bearings, which also may need to be replaced due to their grittiness.

TIA for allowing me to semi-hijack my own thread... lol

[Don]

Bill,

Dave McMunn can tell you everything you need to know - He's done this to several bikes and an '80 model was the last one

Don

[EMS]

BTW, the '80 CB-X SA pivot bolt arrangement is the most complicated fiche I've viewed in a long time. When doing the CB1100F SA conversion, how much of the CBX (pivot bolt setup) stuff, if any, do I need to use in order to mate the new SA with the old frame? The main reason I ask is that I don't have "any" of the CB1100F pivot bolt setup, except for the needle bearings, which also may need to be replaced due to their grittiness.

TIA for allowing me to semi-hijack my own thread... lol

The CB1100F swingarm should be an easy bolt-on to an 1980. They both had a 16mm axle. 1979 would be difficult as they had a 14mm swingarm axle and you either have to drill out the frame holes or have someone make you a 16 to 14mm reduction sleeve to use the stock swingarm axle.
On the wheel end, you will need the CB1100F rear axle as the CBX axle is too short for the box profile CB1100F arm.

[Mike Barone #123]

BTW, the '80 CB-X SA pivot bolt arrangement is the most complicated fiche I've viewed in a long time. When doing the CB1100F SA conversion, how much of the CBX (pivot bolt setup) stuff, if any, do I need to use in order to mate the new SA with the old frame? The main reason I ask is that I don't have "any" of the CB1100F pivot bolt setup, except for the needle bearings, which also may need to be replaced due to their grittiness.

TIA for allowing me to semi-hijack my own thread... lol

The CB1100F swingarm should be an easy bolt-on to an 1980. They both had a 16mm axle. 1979 would be difficult as they had a 14mm swingarm axle and you either have to drill out the frame holes or have someone make you a 16 to 14mm reduction sleeve to use the stock swingarm axle.
On the wheel end, you will need the CB1100F rear axle as the CBX axle is too short for the box profile CB1100F arm.

Thx Mike.....

Bill...please disregard how it looks in a shop manual....micro fische ....the 80 is much easier than a 79 to add a full and complete 1100f rear end assembly. One reason is the 80 frame has threaded adjusters for fine tuning the end play of the 1100f arm once it is in place. However with both adjustments set to max width the 1100f and grease caps in place ....the 1100f arm still did not quite fit on the Dawgie. I took the grease caps off each end and filed a weeee bit off until it the arm slid in and fit perfectly.

Also before doing all this you should remove the 1100f arm grease fitting ...and replace it when everything is done. If you dont....... there is a good chance you will snap off the grease fitting......dont ask me how this could happen.

One thing to remember on all this is to not do the back first and leave the front to a later date because in my view the 35mm early fork tubes are the real culprit in this weaving so putting the back on first will not make the weaving go away. Two CBXers and good riders did this and one crashed his and other had a near death experience on Rt150 above Marlinton right in front of me. Do both front and back at the same time or the front if you can only do one..........and live.

[Don]

The CB1100F swingarm should be an easy bolt-on to an 1980. They both had a 16mm axle. 1979 would be difficult as they had a 14mm swingarm axle and you either have to drill out the frame holes or have someone make you a 16 to 14mm reduction sleeve to use the stock swingarm axle

One would think so . . . . but if I recall correctly, Dave had more difficulty putting the 1100F swingarm on the '80 model than he did on my '79

For my '79, all it required was having a sleeve machined and then everything fit perfectly but on the '80 model, there were some side to side clearance issues which had to be addressed

Dave will sort them out for you if you PM him . . . . or wait here for his response

Don

[Terry]

Sheesh, after reading all this, one might think that CBXs are all too dangerous to ride So, after personally riding about 30,000 miles on my 79 (50,000 total) and nearly 40,000 miles on my 82 (96,000 miles total) I guess I...shouldn't have

Come on guys, are they really that bad Compared to most other bikes of the same era, wouldn't you (we) do the same things to them after 30 years Things like better fork oil and springs, better brake lines and pads, better tires and better shocks You're scaring off the new guys you know

[Don]

Read 'Target CBX' by Shiro Irimajiri in the nex Xpress

For the time, an early CBX was pretty . . . . bad - Now 30 years later that we've all ridden a modern sportbike or two, an early CBX is just . . . . terrible - This assumes of course that you're trying to ride it like a sportbike which is actually a bit outside the bike's capabilities. Nevertheless, it's exciting to try ;)

The good news is, as you say there are several small things you can do to make it markedly better . . . . they're more fun (and less scare) to ride then. I'd add better forks, shocks and a swingarm to your list . . . . maybe some updated wheels and tires while you're at it. Then of course, you gotta get some BRAKES

Don