Ping centrepetal clutch fettlers.

*Luckily*, WE didn't do many miles outside getting the scoot home but
I've no idea home many miles the PO did with it like that (two missing
clutch return springs). When he handed it over he did tell us how he
overcame the initial startup_drag_engine_stalling thing and I thought
it a bit strange at the time? Also possibly luckily I believe he only
used it on straight (quickish) runs to_-from the airport so the clutch
would have been locked most the journey?

I was quite pleased to note that after about 20 miles of use the brand
new clutch was showing signs of the fricitionable material touching
the drum over nearly 3/4 their length.

And I've looked again and the clutch disengages on the way down
between 10 and 20 mph?

And how hoes that generally affect the ride comfort? I ask because I
did a suspension upgrade on the kitcar [1] ready for when I took out
the 1300 Kent and replaced it with my 2L Pinto but I haven't
gotroundto doing the engine bit and the front end is now very hard.
;-(

I think mine was 34 PSI for our weekend test run (being between the
solo 2 and 'above' 2.5 bar) but maybe I'll try it a touch higher at 38
PSI?

Ok (they seem ok).

I think the power of the YP25 and the CB Two Fifty are similar but I
think I"d have to work the CB quite hard to be able to keep up with
the YP (to be fair the CB has 50,000 miles on the scoot).

And how we laughed. Just like I did when I came out of college one day
and found my Messerschmitt KR200 up on a flower bed. It wasn't that
they had put it there that pissed me off it was how they put it there
and the damage they could have done had it gone wrong (to the
irreplaceable Plexiglass dome to name one bit). I found out who they

Yup, I spotted that (but gave them it on a bit of poetic / marketing
licence). The rollers on mine would never get that close to the edge
of the centre plate (as confirmed by the wear pattern).

Yep, *if* bikes were the only thing we were into and *if* we had more
spare cash and *if* I had another 50 years left on this planet I'd
probably play as well. ;-)

T i m

[1] Anti-roll bar arm, track control arm, radius arm, and steering
rack bushes, strut inserts and road springs.

 

Yes, the big spring is the contra spring that goes on the clutch pulley,
they can degrade and need replacing. It's not a common thing to replace
though. I usually keep a CVT service kit in my toolbox, that consists of
a belt and rollers. Usually replace a few sets of rollers to one belt
though. When the acceleration starts going down, I strip the CVT and
check the belt width / condition and the rollers, then just replace
what's worn.

Wouldn't mind giving them a go. Someone else I know seems to use them,
they last longer and improve acceleration apparently. But.. are more
expensive. When I next get some money I'll buy a set.

Heh... very dry.

Small capacity Honda engines seem to crop up everywhere, I'd have
thought they're the most widely used small capacity motor... who knows?

I don't think the Chinese have the materials and production quality
quite right yet. I'd be more tempted to go to a good breakers and source
a nice 2nd hand one. I use;

http://www.stainforthonline.co.uk/blackknight/

I can't fault them at all, they've come up trumps every time for me.
Good on prices too.

I've seen bike shops put both 80W90 and 10W40 in scooter gear boxes,
depending on what they had most of I guess. Personally, I put 80W90 with
added molyslip gearbox treatment in there. Some scooter gearboxes have
helical cut gears, some have straight cut gears, some run a mixture of
plain / roller bearings / ball bearings. I'm happiest sticking an EP oil
in there due to the potential for high temperatures. A non EP oil may
just not be enough protection on a hot day with the throttle wound back[1].

[1] No oil cooler, back drum brake generating heat and less than a tea
cup of oil.

 

Thought so, so why do they show it beside a variator kit?

I thought it might not be. Once I'd seen how powerful it wasn't (when
the guy in the bike shop held the spring compressed with his hands
while I took the (pre loosened) big nut off) I didn't think it was one
of those things that was under a huge amount of stress.

Oh, they flat as fast as that eh? FWIW I'll keep an eye on these ones
I trued up in my lathe (and still above the minimum diameter) and see
how well they last. I will get a new set or two and a belt in ready
though (good idea).

Is that typically the first sign of issues then, lack of acceleration
rather than top speed?

I might too. ;-)

So Honda made this engine did they?

Yes, I think they are where now where Taiwan were when they first
started (not geographically of course). ;-)

Mind you, more and more 'Big name brands' seem to be getting their
smaller models (or engine units thereto) from China now.

Ah, thanks, another handy bookmark.

Well I agree sometimes that is the case ... or they think it's a
better solution or what they are used to. [1]

Ok and if yours have been ok etc ...

So it could just be a drag thing, thicker oil lowering the MPG etc?

Mind you, I guess the CVT would offer less shock loads to the
transmission than a manual solution?

Indeed!

Whilst on the subject of lube. The Service manual states 3 different
types of lube for the CVT components. I know your variator runs dry
(ruling out one) but what do you use on the clutch sheave pins /
shaft, and the variator splines please?

T i m

[1] A guy I used to race EV's against (Cedric Lynch) developed an
electric outboard motor and we saw him testing in on a 'Solar Canadian
Canoe'. I say 'developed' as electric outboards existed but they were
fairly inefficient and not suitable for solar powering. Most
eoutboards place a traditional electric motor in the actual underwater
part and bolt a prop straight to the motor shaft. Whilst this is
direct drive the motors themselves aren't very efficient (electrical
design plus water seal drag etc). So, on his unit he placed one of his
highly efficient motors when the engine would be on an IC OB but there
was still quite a bit of drag in the underwater part (because it had a
bevel gear and bearings so had to be lubed and needed seals etc). So,
he developed his own gears and bearings that could be lubricated with
water and ran the casing with holes to allow water in and out.. ;-)

 

It usually affects the vibration levels you get through the floor and
handle bars. My engine runs pretty smoothly for a stroker, but still
hurts me if I ride for too long.

I should have said that it's a scooter, so it's not designed with
handling in mind. People have modified the frames to much reduce the
hinge in the middle thing though.

If you're a larger chap, I'd try upping the pressure a little, say to 36
at first. Does it have a two up tyre pressure listed? Decent rubber
improves things a lot, both in grip and smoothness. I'm running Michelin
Pilot Sport SC tyres, excellent in the dry, OK in the wet. They have a
more progressive break away, not the sudden 'letting go' sensation like
cheap nasty scooter tyres.

Usually scooter steering head bearings are the older ball type bearings.
You can get taper roller bearing conversion kits, which are worth it
imho, when your old ones are worn out.

I knew someone with one of those! What a strange device that was.

Well, I'm going to keep fiddling with my scooter until I can't any more.
With luck I'll have the free time and health to pursue some nifty
scooter related engineering projects in the coming year.

 

It's been fine since I rebuilt after a numpty bike shop got to it and
the gearbox ground its self to bits.

Would prefer gearbox life over a theoretical (measily?) mpg increase any
day. I bet you'd get better mpg increase by keeping your plug, engine
oil and air filter replaced at a regular interval.

Not sure, there are the shock loadings from the wheel? I know off road
scooter racers use cushioned final output shafts to lessen instantaneous
loads on the gear train. They're rather like the cush drive on a
conventional chain driven bike.

Now I use marine grease on everything as corrosion seems to be the
biggest problem with scooter CVTs. The cooling air fan sucks in water on
a rainy day and blasts everything inside with wet air. I used to use
corrosion block grease, but ran out and haven't had the money to buy an
more yet. Sheave pins?

Heh.. still using bevel gears eh? I've got a design I came up with for
something that does away with all that.

 

They can be a source of trouble, and can sometimes get deformed by the
pulley. I know my rear pulley turns as it moves in and out, this can
distort and weaken the spring. There are little plastic sliders you can
put between the spring and the pulley to prevent this happening. They're
only really used if you've fitted a stronger contra spring though.

On a good day, I can usually push the rear pulley back against the
contra spring if I use the belt as a wedge. Mind you, it's time for
diazepam and pain killers after.

A mate (Gary) just told me he uses the sliding variator weights and
they're good stuff. I'd be inclined to listen to him, as he knows his stuff.

It's more a gradual process that one day you think.. hey, this is slower
than it should be. My two stroke has a on / off power band, when things
aren't right, the motor starts coming out of its power band when
accelerating.

I'll believe they've made quality improvements when I start hearing of
less Chinese components like ball bearings failing.

Oh boy.. must be getting tired, forgot to reply to all the post.

 

Oh. ;-(

Well, true, but I guess there is such a thing as OTT lube wise. No
point having a perfect final drive and the rest of the bike worn to
bits. ;-)

Engine oil and filter (although the filter on the Maj is huge and
cleanable) I'll give you, and if yours is a stoker I'll give you the
plug <g> but thinking out loud, when did anyone actually have a plug
fail on a std road vehicle these days? I mean, the plugs in the kit
car have been in there 20 years and as far as I know they are fine? If
I had to change all ~25 spark plugs I have in various machines here
every year just 'because' it would be an expensive deal?

Oh, good point then.

Ah, I wondered why it looked a bit corroded *inside* the CVT casing.

Is that across the board would you say? I think this Maj has a rear
facing intake cover and a few fins and a filter before rain could
actually get in there. I guess water vapour loaded air etc ...

I bought some super marine environment proof white grease a while
back. It was like putty and felt as sticky!

Sorry, not sure if that's the right name for them ... the 4 (in this
case) 'Pins' that guide the moving sheave (pulley face) open and
closed on a spiral track?

And more efficient I hope? ;-)

Our kitcar front road springs also work that way (MkII Escort based),
most vehicles even at the time had a bearing in the top mount.

I was considering the 10 tonne hydraulic press but daughter power is
easier and quicker. ;-)

Any idea how much they cost and can you get them over here? If the
traditional rollers need changing as often as you suggest then they
could end up being a money saver?

The funny thing was this lower tuned Maj was quite nice to ride with
the dragging clutch as it pulled away from tickover with few revs.
Shame it dragged at the lights etc though.

I think that has been the case for ages though, skimping on the little
bits because they all add up when making thousands of the things. My
Clarke steel cutting band saw had it's bearings collapse and I
replaced them all with decent (FAG I think) for about 20 quid. I think
that's nothing on a £200 item but it's another 20 quid off their
bottom line.

;-)

Thanks for all the help / advice so far though ... all a brave new
world for me (well, since my Lambretta SX150 anyway and I never needed
to do anything to that in two years of daily commute).

T i m

 

When you're talking a tea cup full of oil, I'd be inclined to use the
best stuff you can get. Less wear means less friction and heat.

I use 'race plugs' these days, you know, the ones with the really pointy
electrodes (It's late and my head is a bit fuzzy ok..). I'm not talking
about plugs failing, I'm thinking of getting a nice fat spark and
putting less strain on the ignition system. Hence getting a nice bang
every time.

Heh. When I finally CNC that custom crank case out of aluminium billet
for my V twin two stroke, I'll get it anodized to help prevent all that.

The rear vent is usually an outlet I thought. There are usually fins on
the end of the crank shaft pulley to pump cooling air through the CVT
housing.

Oh yes... I used marine grease on that too. The blue coloured stuff I
think it was. Topped up every time I changed the belt.

Could be, it reduces the parts count somewhat. That means cost savings
in production, and a premium price for 'new' technology.

I'll make myself a tool to compress the contra spring one of these days.

Apparently, these people do them over here. http://www.crossan.co.uk/ .

I've got one or two nice ideas for CVT related / scooter related
engineering projects in the pipe line. Among them, push button
selectable rpm for the clutch engagement. Coupled with some other
things, it would give you a soft / medium / hard setting for power
delivery. This would be useful in the winter.

This twist and go scooter stuff was all new to me a few years ago,
still, it's nice to pass on some stuff I've learned.

 

Yeahbut <devils advocate mode>, lets say 10W30 actually lubricated the
final drive to such a degree that it ran for 200,000 miles and with a
fraction of the drag of 80W90 and saved even a few gallons of fuel in
the process ...? <dam/off> I still believe it is possible to make
things worse (actually *causing* overheating etc) by using to thick or
to much lube, however, in the case of this final drive I don't think
80W90 is going too far. ;-)

I know of them but not used them. I'm old remember so have seen all
sorts of plug designs come and go. In the days when 2/s would whisker
their plugs easily they did one with a ground electrode that was free
to rotate so break any whisker as it formed. ;-)

Fair enough, so, can you actually tell when a plug has 'gone off' and
what happens to the plug when it does and what do you do to fix it? I
mean is it a gap adjust or clean etc?

And I guess having that done won't be the expensive bit! ;-)

It is, a fairly large rectangular port at the back / underneath. There
is also a baffled drain hole at the very bottom of the casing.

Indeed, what I meant to say was the actual intake to the CVT is via a
rearward facing cowling. The intake is as you say at the front, driven
by a crank mounted fan / variator pulley_sheave_half and the cover
that sits over the filter has an input port that faces rearwards by a
couple of inches, plus it's all sorta behind the side panels ... so,
for rain itself to actually get in there you would have to be going
backwards. ;-)

So you would have to take the clutch off / down to do that (mines
pretty well sealed up with 'O' rings and covers etc)?

That reminded me of old technology ... my first scooter (when I was
14) what in fact my Dads, then my Uncles Lambretta LD150, my first
shaft drive bike. ;-)

Mate in the bike shop initially lent me a tool he'd made up himself.
It seemed pretty basic and whilst not as fancy as the pukka thing it
looked like it would do the job. I might make one for myself (for when
the Daughter-press isn't about) so maybe when I do I'll make a couple
(and send you one)?

Thanks, bookmarked and I've dropped them a line.

That would be nice but I could see for most people / road work
wouldn't it be set once then forgotten?

You mean on your 'racing' type scoot or all machines?

It all helps to paint the bigger picture ... how different people
consider their mounts and what they like do with them etc.

I quite like the satisfaction gained by bringing something that has
been a bit neglected back to good functionality, partly because in so
doing you often learn stuff you wouldn't otherwise (like I wouldn't
have taken this CVT down had it been working ok) and that can help you
use said machine better and / or be in a better position to fix /
upgrade it when the need or opportunity arises. Like the replacement
clutch I was given ... I wouldn't have recognised one as a potential
replacement (as the part numbers didn't tally) had I not had need to
closely inspect the old one to see why it wasn't working properly etc.

T i m

 

Well, engine and gear oils are tested differently... This may explain
some of the differences.

http://www.vintagetriumphregister.org/maintain/oil-overview.shtml

If the electrode starts getting blunt, I replace, simple as that.

I'll be doing the design and programming, a mate will be doing the
cutting on his machine. I'll have to pay for a big bit of billet though.

Your pulley assembly must be made differently to my one. There's a
spacer that goes through the middle of my clutch, that comes out and you
can then lube up the pins.

It's useful to be able to launch quickly in traffic light races. It's
also useful to soften things a bit when grip isn't too high. The new BMW
super bike has different engine settings, it's got race / normal / rain.
I think people would regard the ability to soften things up as a safety
feature.

On my two stroke, I've come unstuck a few times when the power kicks in
when riding in the winter and the rain. Going sideways is fun, but
falling off isn't.

I like to understand things, then set about improving them. It's what
I've been trying to learn how to do (formally) for the last 4 years. lol.

 

Interesting ta.

This was the sort of thing I was talking about (re using a 80W90 where
a 10W30 was specified): "An oil with too high a viscosity may not pump
to the proper parts at low temperatures and the film may tear at high
rpm."

Ah, no. The variator is like that but on the clutch that would get you
near but not actually on the pins on mine.

Agreed, on a 'super bike'. I would suggest the YP250 is already soft.
And I also have some extra control with the handle on the right. ;-)

Sounds fun. ;-)

T i m

 

It's a roller coaster ride that you pay for after having been on it.