What am I doing wrong?

[Scooterdude]

Ok so I'm running in a stage 4 iron barrel I had from Harry Barlow with a Scootopia clubman and the original SH1/18 carb, ticks over and runs lovely. Originally I did a plug chop with the 98 main jet that was fitted and found it was running a bit lean then went for a 118 still a bit lean looking probably the exact same grey as the grey trim with the centre electrode insulator the same all the way down but a bit blubbery through the mid range, then tried a 115 and a 112 main jet, plug colour exactly the same as the 118. Probably runs best all round on the 115. Then I took off the carb rubber air hose and what I originally thought was spit back was (from tick over) petrol visibly seeping out of the main carb opening and both air holes and dripping on the floor, am I right in thinking the carb is knackered?? Btw tried a B7 and a B8 plug, both the same colour.

[bazza3004]

Id say your float needle needs replacing as its no longer sealing when float bowl is full. Simple job to replace it .

[Scooterdude]

Ah right, I have replaced it but am guessing the seat to which it seals could be damaged in that case then, will look at ways of refacing the seat. Someone I know last night suggested the BGM jet kit I bought was such poor quality all the hole sizes were the same hence why the plug colour stays the same from jet to jet, something that I had to disagree with. Thanks for your reply bud.

[Padge]

why are you running an 18mm carb on a Harry Barlow stage 4 barrel ??

[Scooterdude]

why are you running an 18mm carb on a Harry Barlow stage 4 barrel ??

Because from day one of the build that's what he's been telling me I want, when I suggested one of the modern Dellortos he almost threw me out of his workshop haha.

What would you recommend ?

[Scooterdude]

Id say your float needle needs replacing as its no longer sealing when float bowl is full. Simple job to replace it .

Fixed it! Just stripped it and put a cotton bud in my drill with a dab of metal polish, gave it a good oll clear out, rebuilt and tried it runs lovely put the 112 main jet back in, all I need now is for it to stop raining so I can go try it, thanks again.

[Padge]

you say stage 4 but what cc is it ?

[Scooterdude]

you say stage 4 but what cc is it ?

its a 175, now then I kept on hearing about stage four this and stage four that so on Friday I rang him to ask just what it was I had, he confirmed it was a stage four, his standard conversion with an increase in performance plus good fuel economy.

[bazza3004]

Hi glad you got it sorted when the rain finally stops get out and enjoy it, bazza

[shocky]

why are you running an 18mm carb on a Harry Barlow stage 4 barrel ??

Im running a HB stg4 200 with 110 rod on 22mm jetex and jl pipe it goes really well and will hit a genuine 70 and pulls from 30 in top with no problem I wanted a usable genuine 55-60 mph cruiser
the carb runs genuine dellorto jets atomiser is modded to flow more in the mide range and the float valve opened up to allow more flow on a calibrated sip speedo it hits 30 ,42,58 and 71 mph going through the gears all on a 35 quid 3 ring meteor piston (new type ) that was supplied by HB