High revs when up to temp

[Gio695]

Hi Guys,

I've been having some problems with my Li the last two weeks.
I've tried a few things, changed some things around and can't find the problem (for now).
I would love the engine gurus, the riders, the experts...well...everybody if someone can give me an idea of what it can be.

First the specs:
Li 125 engine
Used to have a Gori sport (modified by Gori himself) kit, but managed to destroy it, 
so now i have an unworked cilinder, basically a stockDL bored to 66mm, no tuning, stock portings
60mm GP Crank
Li150 gearbox, 15/46, MB selector
LTH chainpuller
Surflex B clutchplates with stronger springs
Gori Sport exhaust (36mm) slightly modified with bigger silencer (These are LOUD)
Keihin 28PWK on MB intake, normally with LTH elbow and remote filter
I run 3% Motul 800 (maybe a bit too much)
Variotronic at 23° at 2000 to 4000rpm with NGK B9ES (maybe i should go down to 21° or less)
If i've forgotten something, please ask

Now the problem(s):
Engine always ran well, pretty torquey for a low power engine.
A few weeks ago i had to re-weld the exhaust because of poor fitting. I also checked piston, head, cilinder
(light scoring around exhaust port after less then 1000km with this cilinder)
The base gasket is 1mm aluminium, normally i put some sealant on it, but because it was al clean i put it on whitout (maybe one of the problems)

Two weeks ago i went for a longer ride. Noticed it started not on first or second kick with choke, like usual.
Thinking the mixture screw or pilot jet maybe wasn't perfect after i've put on the bigger silencer i didn't think much of it.
When cold the bike ran as usual, except maybe a bit less smooth...
Then after a couple of km's the engine began to rev high when letting loose of the throttle, changing gears and standing still at lights.
Pulled aside and it looked like the rubber on carb maybe was a little bit loose, or it was the mixture screw.
Turn off lammy, fettle a little, starts perfectly, first kick, runs great....form a km or so!
Then it starts again.
I carried on to where i was going, and checked everything. After sitting a while (cooling down)
everything seemed normal...then it started again...worse and worse.

In the week i changed the rubber carb mount, checked that everything was tight, changed sparkplug etc.
Then checked jets, mixture screw and did some adjustments. Tried it a few times on the streets and everything looked good.

Next day on a longer ride...again!! High revs and shaking when letting go of throttle, changing gears and standing still.
If i let go of clutch a bit when standing still it lowers rpm a little (i now, not so good for clutch)


I've checked everything i could think of: gaskets, rubbers, bolts, checked for oil/gasoline leaks etc
I don't have a tool for an air leak test, so do the old school way with brake cleaner

btw, no blue smoke!
Anyone that has worked on same kind of problem?

Sorry for the long text

Gio

[T5Rainer]

The base gasket is 1mm aluminium, normally i put some sealant on it, but because it was al clean i put it on whitout (maybe one of the problems)

may be the main reason.

[oli-san]

Check your exhaust flange.

Got the same behaviour last week, the exhaust came loose at the cylinder.

[Gio695]

Thanx,

Checked exhaust flange, looks ok and tight.

Was changed only 300kms ago (MB one, these tend to blow once they get air)

I will probably need to get engine off and seal the base gasket!

Other ideas are always welcome.

[Gio695]

Today i had a bit of time to check some things.

Re-checked carbfitting, gaskets etc... nothing to see.

So wanted to do air leak test, but because i didn't have the material i decided to start and strip some parts of the engine.

 

One of the things was ignition.

This is what i found behind the stator:

 

 

 

 

 

Grease, and something that looks like oil/mixture or melted grease??

 

So i guess this is the problem...

I'll replace both seals, and best to check all other while i'm at it.

 

How can this much grease pass two pretty new oil seal and a new crank?

Bad quality?

Difference in size? (somebody maybe had this problem?)

Or maybe just bad luck?

[swissscooter]

To much grease when assembled?

[Gio695]

Possibly it was too much, or maybe not high temp grease? I don't remember what i used.

Could this give the high revs?

Or should i continue looking?

[T5Rainer]

 Could this give the high revs?

imho not

 

 Or should i continue looking?

i think so

[swissscooter]

Possibly it was too much, or maybe not high temp grease? I don't remember what i used.

Could this give the high revs?

Or should i continue looking?

Probably not the Reason for the high revs. Is the trottle cable correctly installed? High revs only when you sit on the scoot? A slightly to short trottle cover gives also high revs. I know, Sounds stupid, but sometimes the Problems are easier solved then we think... Bearbeitet 5. August 2015 von swissscooter

[Gio695]

I've checked the cable. It looks ok. And it revs even when not on it.

But i've already decided to change it anyway!

If by misstaken the Grease i used is not the right high temp one, can this hurt?

Anyway i want to think you all for the ideas!

[abdo]

Was the problem solved?