V-Max Speed Wobble (ran it up to 115mph and...)

[Pighuntingpuppy]

Is that “most” fact or your opinion?

Well...the 1981-1983 Virago frame was a stressed member frame much like the Gen 2 frame is today. The Virago frame also had a single monoshock much like the Gen 2. While the Virago lacked huge power, I think one could say without a doubt that the frame on a Virago is robust even for the era.

Kawasaki H1s, almost any triple, the old GSX-R frames....they like to dance on you. Unsupported 1 inch tube frames cradling 100+ HP engines will cause movement no matter how good you think the construction is. Thats why modern frames are no longer set up that way except on the smallest displacement cruisers.

So I would say this is fact and not opinion.

 

[Shuriken]

Pighuntingpuppy.... I just saw your signature line. You have some awesome bikes in the stable! I'd love to ride that KZ1000. That's one I haven't actually ridden in past years....

 

[Tom Determan]

Fun ! Another good technical and very informative thread turning into a whizzing contest. So productive !

 

[MaxMidnight]

Is that “most” fact or your opinion?

I'll let you decide.
In the meantime I will continue to offer constructive comments on the issue.

 

[Woody]

Wouldn’t it be the height of irony if the high speed wobble turned out to be completely caused by mounts.

Mounts will .make the entire bike. Feel solid. Some people just won't listen. Imo

 

[Pighuntingpuppy]

Pighuntingpuppy.... I just saw your signature line. You have some awesome bikes in the stable! I'd love to ride that KZ1000. That's one I haven't actually ridden in past years....

That one is the last of the pack to get worked on. When I first moved to New Mexico, the first person I met owned that bike. Odometer broke at 50K but the bike kept going. The bike originally had a vetter system on it and whoever did the wiring in the past hacked the main harness to bits. So the bike had no exterior lights. The carb boots tore up on the bike. The coils were severely cracked and numerous other issues with the bike. Minus the headlight assembly, the bike is complete with all parts there. It hasnt ran in about 20 years now.

Its the 1018cc engine if memory serves. Small carb inlets though. Think 32mm. But I could be wrong on that. Is a 5 speed bike and is also the LTD model of the KZ series. The color is a maroon. The one and only time I rode it, the bike ran horribly due to excessive lean conditions and poor spark.

This was from 20 years ago. I started a partial teardown on the bike cause my buddy wanted to get back to riding. But the condition and wiring harness at the time was cost prohibitive for him. So he signed the title over to me. Its been in my shipping container all these years since.


About 4 years ago, I decided to get him another bike. Since he is elderly, I didnt need anything with rip the knob off power. I found a 1998 Kawasaki Vulcan 88. This is a 1500cc 4 speed bike. I got cheap and as non running. Carb and rust issues plagued the bike along with a faulty ignition coil shooting up 35K volts into the 12v fuel pump. Once I got those sorted, I gave him the bike. That bike will also be coming back to me due to my buddys age and leg issue. Thats this one below.




And my apologies for hijacking the thread.

 

[Shuriken]

I'm still working on solving the issue; I don't think the thread is a junk thread. I am completely agreeable with solid motor mounts but am working through options in order and haven't gotten to those yet...

Since I moved to the 93 front end, I've had to go back to maintenance mode first on different parts and that means some need service before installing. The 85 front end I had used new rotors and I cleaned and rebuilt all calipers, installed stainless lines, and new pads, and yes, was rewarded with 2-finger braking on the single pot calipers.

For this 93 front end, I will also have to do another caliper rebuild on the larger calipers and install the larger rotors, as now I know what good braking feels like on this bike. All of the parts are rolling in, including the caliper rebuild kit. For now, it's gonna be tearing down the calipers and cleaning them so that as soon as the kit arrives, I'll be ready to ride test the 93 forks with OEM springs. Yes, I will indeed measure and set the sag.

 

[retrosdad]

Interesting article from J&P cycle regarding wobble, weave and shake. Lotta math involved which is w-a-y over my head. All I can get out of it is that even a one wheeled unicycle can experience weave, wobble, etc. So, my humble opinion is that all one or two wheeled vehicles can exhibit weave, wobble, etc, some such vehicles are more likely to be affected more than others. JMHO. https://www.jpcycles.com/common-tread/what-is-a-death-wobble?utm_source=Facebook&utm_medium=Paid+Social&utm_campaign=Paid+Social-Content-FTP-Common+Tread&utm_content=What+Is+a+Death+Wobble?&utm_term=what-is-a-death-wobble-051624-|tpfn-organic&fbclid=IwY2xjawErZOFleHRuA2FlbQEwAAEdzhpR1T5vvFGRPN-7B4TvEnJTzrNJWbb1uZyPiXcd9nm4vOLyVFveJXJk_aem_KBtr1OOJ7ZChFXmrfK6GZw

 

[Littleschipper]

This thread is getting a workout!

 

[Littleschipper]

Pighuntingpuppy, my first motorcycle was a Midnight Virago 920! That was so long ago I don’t remember the model year (83?) Bought used and needed lots of work. The starter was a recurring headache, the grinding noises the starter gears occasionally made were horrendous. I loved it anyway…..

 

[Fire-medic]

This '05 wobbled getting onto the lift, but she's running after a long nap.



I hope the wobbles don't happen at higher speeds.

PB

 

[Woody]

Pighuntingpuppy, my first motorcycle was a Midnight Virago 920! That was so long ago I don’t remember the model year (83?) Bought used and needed lots of work. The starter was a recurring headache, the grinding noises the starter gears occasionally made were horrendous. I loved it anyway…..

A friend of mine. Just purchased a virago 920. It had been in storage for 20 years. Pretty cool bike.came with a factory fairing.

 

[Fire-medic]

The Virago 920 was a breath of fresh air when it was released, the Japanese started building big V-twins, and the Virago came in a couple different models, They had one which was chain-drive (!) using a fully-enclosed chain, which greatly extended chain life, and reduced maintenance.

European bikes used fully-enclosed chains on some models, Bultaco was one. This made for less exposure to dirt and mud, and because of the design, it simplified maintenance when having to repair a flat. Their Metralla (250cc two-stroke single cyl. road bike), below also used an enclosed chain.



Below, a Bultaco Matador w/an enclosed chain:


The Zundapp Citation 500 was a Horex design, re-badged. Note the fully-enclosed chain:


I also like the heavily valanced fenders. It would make for a much more dry ride I believe. I like the period style of the bike, the gas tank reminds me of a BSA vertical twin and the shape of the engine cases reminds me of the BSA unit construction "power egg" while the fully valanced fenders with a good sized front brake and a trim pair of hydraulic telescoping forks give it a post-war style paying attention to the comfort of the gentleman who rides it and who is responsible for its maintenance.

The tubular seel frame with its loop construction is reminiscent of the highly respected Norton featherbed frame which seemingly was adopted by many manufacturers simply because it worked well.

It reminds me of a Honda Dream, especially when you consider the Zundapp/Horex has a SOHC parallel vertical twin engine, twice the displacement of the Honda, which was available in 250cc and 305cc.

The Virago 920 also had distinctive square LCD tach and speedo housings, and a single monoshock. It was a SOHC design. In one fell-swoop, the Yamaha Corp. showed the American H-D Motor Co. how to build an advanced design motorcycle, when the H-D was updating their offerings with Bold New Colors and not-much in the way of technological advancements. H-D did come out with the Sturgis in the early 1980's which did have some significant changes, first, belt final drive and then belt primary drive and final drive. It was basically a Low Rider with those additions, easily recognized. Their wheels used a black painted wheel w/a red rim pinstripe, which the VMax later also featured.

The monster-motor Munch Mammoth also used an enclosed chain.



This rarely-seen monster used a car engine from a NSU model 4-cyl. the TSS, and it was essentially a hand-built motorcycle capable of astounding performance. One of my acquaintances was an expert on the brand, and at his invitation, Friedel Munch came to the USA to check things out, and I ran into them at Daytona Bike Week, I have pictures, somewhere... . Later in the bike's design life supercharged models were designed and built, with big-bore engines.

The Munch was a motorcycle not inclined to wobble or weave. Despite its 'heavy' appearance, it was far-less heavy than a VMax. There was even a Generation II like the VMax, a completely-new Munch, but because Munch had lost the rights to his name on motorcycles, he used Titan and Horex for his 2,000cc hand-built bikes at the end of the line. Do you recognize that name, Horex?

https://speyer.technik-museum.de/en/friedel-muench-exhibition

 

[Pighuntingpuppy]

This bike has a story that would be much too long to tell. An abbreviated tale, this is my 100K bike. Earned an iron butt award on it. The lead cylinder timing chain guide broke causing the timing chain to roll causing a bent intake valve. Replaced the head but due to the time it was idle, the CV slide rubber deteriorated so the bike ran like garbage. Hasnt ran in about 8 years. It will be restored to the condition in which I repaired the bike to when I re-did everything.

 

[brian hicks]

https://www.geocities.ws/MotorCity/Speedway/2476/wobble.htm
Here's some info on causes and cures.

 

[brian hicks]

https://www.geocities.ws/MotorCity/Speedway/2476/wobble.htm

 

[Shuriken]

https://www.geocities.ws/MotorCity/Speedway/2476/wobble.htm

That was an informative read, Brian. Thanks for that. The author's opinion is that the "weave," which is what I experience at high speed, is more related to the rear of the motorcycle than the front, which is what I have also read with other sources. For certain, the weave involves the rear frame while the headshake / wobble is intended to describe problems in the front of the bike.

I first experienced this weave so many years back (see 1st post) at about 115, the speed the author mentions. Unfortunately, that was so long ago that I don't remember if the front end felt overly twitchy as compared to now or about the same. I will take more care to use the right terms.... currently, the front end is too responsive. I don't dare ride faster than 75-95 because a weave is likely to develop, as it has before.

While I do have new swingarm bearings, a balanced new rear tire, and new rear suspension, these changes have not prevented the high speed weave or calmed down the over-responsive front end, even when I found and resolved a lot of side-to-side play in the old swingarm bearings...

That article moves logically and the author suggests frame bracing, solid mounts, etc. if the weave doesn't resolve through other means.

As many have already suggested regarding bracing and motor mounts, these are absolutely on the list for me. I'm just currently still working on the other more basic items on the list, as motor mounts are bolt-on whereas bracing, especially on the swingarm, involves welding.

Probably all v-max owners have experienced the flexing/weaving/bobbing feeling at higher speed, over bumps, and especially in turns at speed. This feeling, in my experience, is most obvious in turns. But the article you referenced has made me re-think of the straight line speed weave problem even moreso as a possible function of swingarm tube flexion, combined with (as others have mentioned) possible suspension issues and misconfiguration. What is important to keep in mind is that the bike is planted and feels rock solid with a passenger aboard. So as soon as the front end is back together, I am going to go over the suspension settings/configuration again, re-measuring, and trying to measure and set proper sag again!

I will see the 43mm fork upgrade through either way. That's the phase I'm in. And I've realized that rebuilding the dual 4-pot calipers (they are soaking in cleaner right now) means lots of time and money (lots more o-rings for 4-pots!)... dual pot 85 calipers were much easier... So I may not have any test results until next weekend.

I will resolve or significantly improve this issue on this bike or I will replace it. I hear the Gen II is a nice bike....

 

[Fab333]

I think the main handling problem is the rear tyre profile.
it is too tall, so you get side wall flex when cornering
for a fast bike it is a very bad tyre size and, in my opinion, the most problem with the handling for this bike.

 

[brian hicks]

That was an informative read, Brian. Thanks for that. The author's opinion is that the "weave," which is what I experience at high speed, is more related to the rear of the motorcycle than the front, which is what I have also read with other sources. For certain, the weave involves the rear frame while the headshake / wobble is intended to describe problems in the front of the bike.

I first experienced this weave so many years back (see 1st post) at about 115, the speed the author mentions. Unfortunately, that was so long ago that I don't remember if the front end felt overly twitchy as compared to now or about the same. I will take more care to use the right terms.... currently, the front end is too responsive. I don't dare ride faster than 75-95 because a weave is likely to develop, as it has before.

While I do have new swingarm bearings, a balanced new rear tire, and new rear suspension, these changes have not prevented the high speed weave or calmed down the over-responsive front end, even when I found and resolved a lot of side-to-side play in the old swingarm bearings...

That article moves logically and the author suggests frame bracing, solid mounts, etc. if the weave doesn't resolve through other means.

As many have already suggested regarding bracing and motor mounts, these are absolutely on the list for me. I'm just currently still working on the other more basic items on the list, as motor mounts are bolt-on whereas bracing, especially on the swingarm, involves welding.

Probably all v-max owners have experienced the flexing/weaving/bobbing feeling at higher speed, over bumps, and especially in turns at speed. This feeling, in my experience, is most obvious in turns. But the article you referenced has made me re-think of the straight line speed weave problem even moreso as a possible function of swingarm tube flexion, combined with (as others have mentioned) possible suspension issues and misconfiguration. What is important to keep in mind is that the bike is planted and feels rock solid with a passenger aboard. So as soon as the front end is back together, I am going to go over the suspension settings/configuration again, re-measuring, and trying to measure and set proper sag again!

I will see the 43mm fork upgrade through either way. That's the phase I'm in. And I've realized that rebuilding the dual 4-pot calipers (they are soaking in cleaner right now) means lots of time and money (lots more o-rings for 4-pots!)... dual pot 85 calipers were much easier... So I may not have any test results until next weekend.

I will resolve or significantly improve this issue on this bike or I will replace it. I hear the Gen II is a nice bike....

I'm small...150lbs..but with my wife on the back then it is stable with no noticeable wobbles or weave. Maybe a bigger rider than myself wouldn't have the weave problem.

 

[Shuriken]

I'm small...150lbs..but with my wife on the back then it is stable with no noticeable wobbles or weave. Maybe a bigger rider than myself wouldn't have the weave problem.

Right. Same experience here.

We're both under 200 and I think the bike would ride well for a 250lb rider!

So how can we simulate that weight without....the weight? That extra weight will compress all 4 suspension springs much more than riding single. And this could also change steering geometry and stability by lowering the bike also.

When I get everything back together, I will be carefully measuring sag 1 up and 2 up.