Binding carb slides

How tight should the slides be in the bore of a typical Amal concentric? My buddy has a '72 that the slides need a push to move through the bores (both sides, though one is tighter than the other). In fact the throttle barely returns to rest on its own accord with the standard carb springs. The slides on mine will fall in easily under their own weight.

His carbs were sleeved years ago and he thinks it's been this way since. It feels wrong to me.

Maybe a little work in the bores with some 1200 grade wet & dry would sort it? I think the bodies can become distorted by overtightening the fixing nuts especially where thick heat insulating gaskets are used,

Dave.

John Healey uses a tool to straighten out the carb bores and this was featured in one of the TIOC magazines. It's pretty simple and I made one. I have straightened out ten Amal carbs. Can't post any pics today but I will next week.

Dave

Semichrome the high spots.

drp said:

John Healey uses a tool to straighten out the carb bores and this was featured in one of the TIOC magazines. It's pretty simple and I made one. I have straightened out ten Amal carbs. Can't post any pics today but I will next week.

Dave

Click to expand...

LOL, I saw a guy walk in the old britbike shop with the same trouble. The 70YO 50 year master took it from him, slapped it in a bench vise, and cranked a calibrated twist on the handle. 18 seconds later, the slide fell through the bore. I'd guess that'd be a pattern failure, the overtightened flange bolts deforming the body.

I use this stuff on my slides and carb body bores. Reduces wear and smoooooth operation as well. http://www.p-b-l.com/pbl2002/Neolube2.html

concours said:

drp said:

John Healey uses a tool to straighten out the carb bores and this was featured in one of the TIOC magazines. It's pretty simple and I made one. I have straightened out ten Amal carbs. Can't post any pics today but I will next week.

Dave

Click to expand...

LOL, I saw a guy walk in the old britbike shop with the same trouble. The 70YO 50 year master took it from him, slapped it in a bench vise, and cranked a calibrated twist on the handle. 18 seconds later, the slide fell through the bore. I'd guess that'd be a pattern failure, the overtightened flange bolts deforming the body.

Click to expand...

+1 I have seen an 8 blade reamer just for that purpose.

Yes a vice squeeze! reaming an oval hole simply makes a bigger hole, but a correcting squeeze will free off a slide with no more clearance. But drop in a steel mandrill a few thou smaller first. prevents over doing the correction pressure.you soon feel the bore comming right!