One rich one lean

[Fentible]

Hey.........Sesty no probs.....these things happen, if it hadn't been for XSchris's post I would never have known until I drilled the old ones out.

Thanks for the link XSchris (and the info on the earlier carbs). They are the ones I looked at previously so order will be submitted. I don't know why I didn't compare them to the ebay items (impulsivity) but hopefully the ebay seller will agree to a partial refund in order to cancel the sale.

In any event your help and advice is greatly appreciated.

Fent

 

[Fentible]

Seller graciously refunded the full amount.

 

[Fentible]

Well after the annual sojourn to France I'm once again ready to pick up where I left off. Decided to first try a colo(u)rtune. I used one years ago to tune an MGBGT. If you've never seen/used one they consist of a glass windowed spark plug that allows you to see what's going on in the combustion chamber as the revs change.

Infuriatingly the side that was running rich showed a consistent blue throughout the rev range, indicative of a correct mixture.

The side that is running lean shows a nice blue at the lower end of the rev range but as the revs increase (4,500 plus) there are regular white flashes that become more consistent as the revs go higher. This indicates the lean spots and potentially a sporadic fuel supply. A blocked jet would be my first port of call. I have some limited movement on the pilot air screw on this carb but it didn't seem to make much difference.

I took the carbs off today and both float heights are bang on at 23mm and the jets (pilot and main) are totally clear. I'm going to attempt to drill out the seized and chewed pilot air screws and replace with spares from Mikes XS. I'm not convinced this is the root of my troubles though.

Any thoughts from the collective??

Cheers

Fent

 

[Fentible]

Well the new Idle air screws arrived. I successfully drilled out the old damaged ones and I'm happy to report that the bike is ticking over happily at 1200rpm. The bike also revs cleanly now, no misfiring or hanging revs and both plugs showing a nice tan colour.

Hopefully I can get a few road miles next week to confirm that all is well.

Thanks for all the help and advice

 

[xschris]

Good to hear