Still getting vibration on TS1 225

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Ian Hepworth

Tue Aug 18, 2009 4:06 pm

I didn't take it as a dig, just genuinely interested in getting to the bottom of the problem. (as are the owner and the bloke trying to sort it too I'm sure)

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celt
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Tue Aug 18, 2009 4:52 pm

Fruitjuice wrote:This might sound very stupid, but have you checked the front tire, wheel and hub?
I have an outboard front disc brake and ride my scooter pretty hard and have noticed the tire tends to wear unevenly, which after a certain time leads to an oscillating up and down movement at low speeds and vibration at higher speeds. I'm thinking my hub might even be out of true a slight bit which causes the tire to wear unevenly even quicker...
There doesnt seem to be any play on these, when wheel is spun there is little oscillation
dapper wrote:Couldn't be oval rims could it?
Answer above
J1MS wrote: Ive fitted Three up to now in my engines all vibrated more than before.... Even the Taffspeed one I bought which was built using a Yam rod on Tino full circle webs, vibrates more than the old standard crank on a Yam 110 rod.... But the vibes on my MB (58 x 110) crank were that bad I took it apart twice and had it checked... its true to within half a thou, but it doesn't balance out the piston smoothly below 4000 rpm after 4,500 it starts to smooth out a little above 5,000 its ride-able with still a little more than normal vibes, above 6,000 its like the standard crank smooth..... The same engine using standard webs and a Yam110 rod (Taffspeed built) was smoother right through the rev range with no white finger setting in even on a 3,000 mile Euro rally... I think its more a counter balance issue than it being out of true... well it seems that way on mine... I asked (when I bought it) for an MB (58x110) full circle crank for my engine, I was surprised not to be asked what piston it was for... because if a crank is to be in balance... it has to counter balance the piston being fitted... seems one size fits all... I did once ask what they were balanced to, but never really got an answer...
The crankshafts are well made and upto now for me no horror stories... But for a low reving scooter like mine its to much vibes at certain revs... but on a more revy engine its not so intrusive as its never in the rev range long enough... different rods angle of rotation and length & pistons (weight) will change the way its effected...
Vibration is exactly as J1MS describes, when accelerating through rev range less noticeable at higher revs. If doodling along at low revs, white finger is experienced in such a short time.

As Camel has mentioned in the the process of changing fork bearings even if this is not the case it could be eliminated from the equation. Due to work commitments on both parties this will take place either late next week or the week after :roll:

So to re-cap it still could be the crank
Ian Hepworth wrote:
The cranks are balanced to suit the racetour pistons.
Ian correct me if I'm wrong but I thought MB were selling the cranks before the racetour pistons were made :?:

Scooterdude
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Sun Dec 30, 2018 11:32 am

Ok I know the thread is almost 10 years old but I’m curious as to what was causing your vibration issues. Did you get it sorted in the end?

ricalnic
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Mon Dec 31, 2018 1:55 am

Reminds me of a not too dissimilar post
viewtopic.php?f=7&t=30513

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Sat Jan 05, 2019 6:39 pm

this is an interesting thread. I'm keen to know what the solution was too.
I have just rebuild my engine with new 185cc engine and electronic ignition with medium weight flywheel.

When I first started the engine it revved cleanly with no vibration at all.

A few days later I strobed the timing and altered it slightly . Since then I've had a wicked vibration on the stand when revving the engine.

I'm guessing the vibration is due to the change in timing as the engine had onlt been run on the stand for a few brief minutes and sounded great prior to changing the timing and final torquing the flywheel nut.
I might see if there is any runout on the flywheel too now that it has been fully tightened

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Wed Jan 16, 2019 7:02 pm

quick update that might be of interest to anyone arriving here from a search on vibration.
I have cured my bad engine vibration simply by rejetting ,tuning the mixture and timing on my Li 185
42mm clubman ,22mm jetex 5899-2 Atomiser , 122 Main jet 200cc flat slide 48 pilot 50 choke

I had been having difficulty starting the engine unless I had the stock hose and air filter connected. However once running it vibrated really badly and wouldn't pull through the gears . The engine had that characteristic whaar whaar sound at WOT like it was being starved of air .

I changed to the following spec
42mm clubman 22mm Jetex 5899-5 Atomiser , 122 Main, 150cc slide 48pilot 50 choke and no air filter . I connected the hose to the filter box so it looks stock.

The engine now runs like a turbine , All the engine vibration has completely disappeared it starts first kick, revs very cleanly from cold and just keeps revving and revving .

The engine runs so smoothly that I do not need to use the clutch at all when changing up from 2nd to 3rd and 3rd to 4th gear at full revs .... it sounds like an automatic with barely a change in engine note . Absolutely glorious with good power this engine has never sounded so good.

So I'm now firmly convinced that engine vibration might often be due to nothing more than poor timing and bad tuning

The first part of the video is with the air filter and 200 slide 5899-2 atomiser ..........the second part from 1.0 minute onwards is with the 150 slide 5899-5 atomiser and no air filter.
Its a very steep hill and I weigh 17.5 stone so shes pulling well considering
https://youtu.be/b45bG9djDhI

Scooterdude
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Thu Jan 17, 2019 6:26 pm

You really should use your clutch otherwise you are going to break something.

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Thu Jan 17, 2019 8:07 pm

Scooterdude wrote:
Thu Jan 17, 2019 6:26 pm
You really should use your clutch otherwise you are going to break something.
100% agree with you if don't use the clutch you'll eventually wreck the gearbox and if you've spent this long trying to solve the problem you'll only regret it later when you'll be spending out on the gearbox.
the man don't give a f@@k

johnny650
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Sat Jan 19, 2019 5:59 pm

Scooterdude wrote:
Thu Jan 17, 2019 6:26 pm
You really should use your clutch otherwise you are going to break something.

appreciate your caution but there is no chance of breaking anything .....if you have a thorough understanding of how gearboxes work you'll understand clutchless gear changes they do it all the time in racing . ;)


Its not something I make a habit of but if you match the road speed with the engine speed then you can change up gears without a clutch but it takes some skill. It goes without saying that nobody should try and change gear without using the clutch in first gear obviously and nor should you try changing down the box although its perfectly doable with enough skill

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Sat Jan 19, 2019 6:06 pm

GTFOMWSC wrote:
Thu Jan 17, 2019 8:07 pm
Scooterdude wrote:
Thu Jan 17, 2019 6:26 pm
You really should use your clutch otherwise you are going to break something.
100% agree with you if don't use the clutch you'll eventually wreck the gearbox and if you've spent this long trying to solve the problem you'll only regret it later when you'll be spending out on the gearbox.
your name isn't chickinlicken by any chance is it :lol:


I shouldn't need to explain everything in nth detail but on this forum it seems I do. :roll:
i don't do clutchless gear changes as a rule or ever on a scooter as it happens.

I did a couple of clutchless gearchanges from second to third and from third to forth to illustrate how if you get your engine running right with the correct mixture and timing then clutchless gear changes are possible.
it does take some basic riding skills and a practical understanding of how gearboxes work though, so I wouldn't recommend you try it ;) :)

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