Speedfight Problems

Hi all,
Ive had my Speedfight 50 for around 7 months.

Current setup is:
Doppler S3R exhaust with rollers and jetting to suit
Polini Variator
Polini evo clutch.

The problem is that when I take off it 'under revs' and really struggles upto about 20mph clock speed and then is suddenly fine.

Also the top speed is pants ! On my old Gianelli Extra it used to reach around about 50mph clock speed. Now it only does like 43mph.

So far ive checked:
Rollers- there fine
Jetting- Spark plug is tanned.
Variator ramps- fine
Clutch- Good
Belt- Dunno

Feels like somethings slipping but ive tried everything to do with the transmission. When its on the stand it struggles to initially rev up, 'juddders' a few times then its fine.

Cant make sense of it at all.

EDIT: The variator was second hand and didnt come with any 'shims'

 

if the throttle response is bad when on the stand, then that would suggest to me its a carb problem...

also...was your transmission set up with the extra, and your problems started when you fitted the Doppler pipe??

The Doppler S3R is a very revvy pipe, and doesnt have the low down torque of the giannelli extra, so you will more than likely need lighter rollers and more tension on your clutch springs...

 

Well ive put the rollers that came with the doppler in.

It does sound like carburation but ive tried everything jets, needle positions, gaskets, air filters, cleaning and checked everything to do with the float.

 

I would of thought it would be a simple mixture screw issue myself.

 

also i forgot to say, dont take what rollers you get with a pipe as gospel...

 

Ha same here.

Everytime im out i have to pull over to try a different mixture screw position.

For the record its fine when its running just after coming off choke.

And i know. I have some 5.3s spare

 

mixture too rich maybe, a cool engine will tolerate a rich mixture better than a hot engine :glare:

 

Oki.

Might slap my open air filter on tomorrow. Getting a Polini sports kit soon so there no point spending money on jets when they wont be used again.

 

Right ive uploaded a vid showing the transmission.

Any suggestions on what is going on would be appreciated.

Tried everything everyone has suggested. This is just to show what exactly is going on down in the transmission area.

Thank You.

 

your idle is very lumpy, your mixture isnt set properly :glare:

 

Oki dokie.

Will have a look.

Also I noticed that the belt seemed 'loose' as well. You can see it on the video.

Ta Dave.

 

they all flap around a bit when they are running....its normal

 

Oki dokie.

Just find it strange that it wobbles like that.

When I bought the variator(polini) it didn't come with any washers/spacers as shown in the pics of it.

I think a new variator and belt is in order.

 

The belts do tend to be stiffer when they are new, and go softer once worn...

 

Right this is my spark plug after i changed the throttle needle to the top notch. ( was on the bottom notch for some strange reason, hence the reason for the awful idle)

Take off is really strong now. But top speed and mid range acceleration isnt very good.

Is it running lean now? Or is it something else.

 

thats well lean either put the airbox back on or you need to upjet.

 

Lol. Ill do it tomorrow.

Thanks