GTS OWNERS CLUB

Innocenti · Posted: Thu Jun 21, 2007 12:39 pm Post subject:

talk about leave it to the last minute before belgium !!!!! go on Russ ride it down just dont thrash it to much Shocked

yea as if!!!
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russpeed · Posted: Thu Jun 21, 2007 12:48 pm Post subject:

russpeed · Posted: Thu Jun 21, 2007 12:55 pm Post subject:

No dyno time available today so MP3 it is.

All this To Be Continued....................
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Creator of the fastest VESPA GTS in the world!....(until proven otherwise!)

Innocenti · Posted: Thu Jun 21, 2007 3:21 pm Post subject:

will discuss over a belgian beer m8 Wink

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GTS OWNERS CLUB

LONDON LAMBRETTA CLUB

DARKSIDE

ITS ONLY A SCOOTER !!!!!

russpeed · Posted: Thu Jun 28, 2007 9:17 am Post subject:

Back to scratching my head again, the dyno proved that the pump ain't up to the job, losing .5 bar under load which throws mixture about all over the place on closed circuit.
Been told I should sort this before looking at widening throttle body to find that missing bhp.
I feel like I'm most of the way up Everest, so near and yet so far.
Petrol tank gotta come out for __enth time and then a trawl about for an uprated pump that will fit within the pump/filter/regulator assembly.
I'll be glad when I know what I'm doing as each job will only have to be done once then.
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Rhoodman · Posted: Thu Sep 20, 2007 6:49 pm Post subject:

A bit of an update as to how things are going :

I've been running the tuned GTS for about 3 weeks now, and all is going well. Gave it a baptism of fire by thrashing the hell out of it to mersea and back, no problems, went like stink, and pulled like a train up hills!

Got it dyno'd at Mersea, only showed 18bhp on that dyno, (but that dyno seemed down, as we achieved 19.74 at Mallory park. The thing that interested me was the torque. The graph showed that it maintained around 24ft/lb throughout. The standard GTS torque, from what I can gather on the internet is around 17 or 18 ft/lb. So we could be approximately 33% up on torque.

This extra torque was really noticable up hills, as the GTS just pulled up them with no problem whatsoever, hauling 17 stone of me and luggage!

We've since tried 16g rollers in the polini variator, and these made the front wheel leave the floor from a start, but made it lack in acceleration from around 40mph upwards. I've got myself a set of 14.7g rollers now (thanks Phil) so I'm going to stick them in when I get the opportunity, and see how it goes!

Unfortunately though, as sod's law would dictate, I'd got it back, cleaned it, polished it, running sweet, only to meet White Van Man , who pulled out with no indication "Sorry, I didn't see you mate," on the road next to Rev & Go. It's still rideable, but looks a bit worse for wear now Crying or Very sad

Waiting to hear from White Van Man's solicitors. Rolling Eyes

Opportunity for a custom spray job perhaps? Watch this space! ....
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smirnoff · Posted: Thu Sep 20, 2007 8:13 pm Post subject:

russpeed · Posted: Tue Sep 25, 2007 12:58 pm Post subject:

I'll also mention in response to Phil that we ain't finished yet.
It still hasn't been on a diagnostic dyno session since the first time.
I have made further modifications to the injection system since then so we could be all over the place for all we know.
And still got some things to try out and investigate.
Didn't you mean right with you until hill climbing time?
I knew it was up on torque but 33% is a big increase.
Reckon we could use that torque to pull even higher gearing and maybe get a true 100mph.
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smirnoff · Posted: Tue Sep 25, 2007 5:50 pm Post subject:

CheekyThomas · Guvernor Joined: 18 May 2007 Posts: 1374

Have you sorted the injector/fuel pump issue out yet Russ?? Last time we spoke you were still looking for a supplier of bigger injectors??

Have you got any pictures of the flowed head? Is there much visual difference in port sizing?? Or was or more flow and shaping?

I wish we got more into tuning these things.... gets too addictive though! Laughing

russpeed · Posted: Wed Sep 26, 2007 8:18 am Post subject:

We use the stock injecter but at a higher pressure after finding and discarding the injecter from a euro 2 master engine.
The porting is for 360 degree flow around the back of the bigger valves so it's just shape rather than size that concerns us.
What is holding us back now is the size of the throttle body but I have found a bigger one that is otherwise identical so when that turns up we begin again maybe on another machine that I can keep here.
The throttle body is the reason the valve job gives 4-5 bhp on the carb 210's we done but nowhere near on the 250's I reckon.
In a way it was disapointing but we are still ahead of the game so folks keep telling me. Wink

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Rhoodman · Posted: Wed Sep 26, 2007 8:38 am Post subject:

Well you'll be getting it back soon Russ, although not in as good nick! Insurance company have arranged a courtesy bike whilst the GTS is off the road. So you can have a play around with it then. Cool

EDIT : The insurance company have given me a Yamaha Majesty. I'd rather ride a crash damaged GTS!
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CheekyThomas · Guvernor Joined: 18 May 2007 Posts: 1374

Ah throttle body conversions now too Laughing

Man you are getting serious! Twisted Evil

Did you fit a higher pressure pump in the end, or just alter the pressure regulator? Just being nosey now....

russpeed · Posted: Thu Sep 27, 2007 4:44 pm Post subject:

Adjustable regulator but still may go for a pump depending on where we are now and in the future dyno sessions.
Our pressure loss under load was down to the injector feed circuit length combined with lack of amps at the pump.
Sounds like I know what I'm on about don't it, I bloomin wish!
Laughing

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CheekyThomas · Guvernor Joined: 18 May 2007 Posts: 1374

I suppose the standard pump will be struggling now so a upgraded pump will be the way to go... one day ill have to have a ride on one of your tuned machines... just to see the difference its made. Wink