Still running bad

[Trojan]

Hi Gents, following up from previous notes, I have recently changed the Drive sprockets of my Lambretta from 18 x 47 to 19 x 46, when taking it out yesterday, it was really struggling to get up hills or any incline...Have also thought the carburation may be the cause...

RAPIDO 225 RACE
FRANSPEED SUPER TOURER
30 MM PHBH
MAIN 130
PILOT 55
CHOKE 70 ATOMISER AV266 NEEDLE X7 SECOND CLIP FROM TOP..FLOAT VALVE 300

Wondered if it may be the jetting as it seemed a little boggy and the setting off felt like I was starting in fourth ??? Also would like to know on the NEEDLES...Whats the leanest sizes and the Richest sizes is it to do with the length of the taper on the Needle ???

Thanks for looking and hopefully I ll get some good news

[mick1]

I'm a bit confused ? Your change of gearing will make the gearbox taller and harder to pull up hills. keeping the 47 and changing the 18 down to 17 would make going up hills easier.......but more revvy...

[Trojan]

Thanks for replying Mick, and YES you are right mate, its a struggle.....It was suggested that I put a 19 x 46 o as to make the Box work more than the crank...Plus my weight would equal to carrying pillion so thats why its 19 x 46... would there be a benefit of 16 x 46 = 5.75 or would that be TOO revvy....forgive my ignorance on this as its all figures and confusion lol

[Adam_Winstone]

The smaller the front sprocket the more strain put through the clutch so going to 16 front sprocket is a bad move. I assume that you've got a GP200 gearbox in there? 18/47 with the standard 82 link chain is your best move, if running the GP box. Long gearing with a race pipe and Rapido Race is means that you'll struggle to pull 4th as the bike cannot make any power if it cannot rev high enough, basically, to make any power you'll have to rev the heck out of it, especially if you're not slight. Drop out of the revs and you'll drop out of the power, chasing it back down the gearbox.

It sounds as though your jetting combo might be knackering your low rev running and the gearing is killing your top running. In your shoes I would try a 50 pilot and/or putting the needle clip on the top notch, just to see if you can clean it up a bit... BUT ONLY DO THIS AS A TEST as you may run too lean at low settings and I am not suggesting that you simply change it and assume that all is well. A worn slide, worn needle, poorly adjusted float height, etc. can all influence low rev carburation so make sure that you're not trying to 'jet away' other issues that you may have.

Best of luck with this and keep us up to date with how it progresses as we may be able to offer more ideas.

Adam

[Trojan]

Thanks for that Adam, It was originally an 18 x 47 set up and was doing just as you described, I checked around and in previous messages, that's where I got the jetting set up...but as you say I will move the clip just one and see how that fares, with caution of course...I was thinking of going AV264 with an X13 Needle to see if that would improve the running...But on the gearing side ...would it benefit from a 17 X 47 set up ???...I just hope it gets a result, as its been more than a few attempts to find the balance....Lammies...don t you just love them......cheers Adam

[Adam_Winstone]

Try the needle clip change first. Normally the AV266 X7 combo works but it can be boggy low down. The AV264 with X13 or X2 combo can work but it can also the too restrictive / weak low down. I've used the AV264 X13 combo well on an iron 175 with remote filter.

Frustratingly, Dellorto used to produce an AV265, which is no longer available and they refuse to put th em back into production (I asked Eurocarb to press Dellorto). A kind pal was good enough to ream a couple of AV264 to AV265 for me and these have worked wonders, especially cleaning up low rev set off. I also sent that UK jet manufacturer to prompt them to make them but I didn't even get a response... might be worth everyone sending them an email so they realise that they're missing out on sales.

Good luck getting it sorted.

Adam

[YAMLAM]

If you are using a GP125 /200 box you have gone from 5.22 overall ratio to 4.84 , why not try 18 x 46 (5.11) or 19 x 47 (4.95)
was your jetting ok before ?
google delorto x needles and you will find a chart givingall dimentions and taper lengths.

[joespeed]

why did you alter the gearing in the first place?

[Adam_Winstone]

^... I'd certainly not look to make any further gearing changes, unless it is to put the 18/47 back in and to be done with it. If you look at any of the gearing charts (AF, Sticky's, etc.) you'll see that revvier kits with revvy pipes often run 5.2 4th ratio and I think that you'll struggle to pull anything higher (lower number) than 5.2 on a Race Rapido with JL Race pipe, especially if you're a man with a fuller figure.

If you don't want something that's going to need high revs then you've potentially got the wrong kit and the wrong pipe. However, these should work perfectly well if you fit short gearing and let the kit rev hard. Indeed, this combo could pull very nicely with excellent performance but you will need to allow it to rev hard. Low revs on this combination will mean low power and an inability to pull long gearing.

Adam

[Trojan]

Thanks Gents for all the replies, certainly something to look at and consider....Just out of interest...what is the difference between the 5.22 set up,compared to the 4.82 ...being a novice with this im thinking the higher 5.22 would be the better of the two for pulling up hills etc....would like to know what the differences make....Thanks