Phbh and GP panel clearance

[dickie]

A mate of mine has just fitted a complete engine that he bought which has a PHBH carb on an unknown vintage AFR inlet manifold.

He can't get the panel on his GP.

Which manifold gives significantly more panel clearance?

Thanks.

[Storkfoot]

Have a look at my posts on this thread. Whilst they relate to the LTH TS1 manifold, the carb elbow mentioned will help panel clearance.

viewtopic.php?f=7&t=15059&p=140127&hilit=Linke+nummer#p140127

[gaz_powell]

If using open mouth you can machine the front down or not put the black plastic surround on

I have just built a GP motor with an MB manfold to use a PHBH.
Its away at paint so not sure what clearance will be like on return.

Side by side with an AF there is more clearance on the MB
Im ready with a tea strainer and a remote filter
Preference will be the tea strainer.

Mate has an RT 225 with PHBH and tea strainer no panel clearance issues, pretty sure its an mb manifold.

Gaz

[dickie]

Thanks both.

@Storkfoot, I think you mean the elbow will help clearance with a filter

@Gaz, at the moment, he has nothing but the carb. The bellmouth isn't even on.

Also, I should have mentioned that it's a mugello 198.

I should probably add that I haven't seen the engine in the bike. It's been on my bench for some kick-start and chaincase repairs, but I didn't notice anything unusual about the carb or manifold. I should really take a look before asking questions.

[Toddy]

I’ve used both the AF and MB inlet on Mugellos on both series 2/3 both fitted a remote filter between panel and carb

Meant to say these were both with flanged type rubbers

[Adam_Winstone]

So many component options here and it sounds as though you have a combination of parts that are resulting in a problem for you. In order to give you informed advice we will need to know exactly what component you currently have (?). Sorry if I've missed you already giving some of these details...

Firstly, PHBH carbs are available in 2 basic body types; rubber mount and solid mount. Please confirm which type we're talking about here? My guess is that we're talking about a rubber mount version as these tend to stick out further than the solid mount type, although the manifold and rubber mounts also vary in length...

Rubber mount - I'm assuming that this is the more common rubber tube type, rather than 2-bolt flange type? If the tube type, rubber or a cut length of rubber hose?

Manifold - The AFR manifolds are a copy of the old CDC manifolds that were designed for use with the older solid mount PHBH body, which were very much more common back in the day. As mentioned above, the solid mount PHBH body is shorter than the combination of rubber mount PHBH body + the rubber mount. This may well be why your carb is sticking out too far: Rubber mount body, tube type rubber mount and long manifold that was originally designed for the solid body.... worst combo of parts.

... but... the AFR manifold, like the CDC before it, is typically modified for use with the rubber mount PHBH body. The typical modification is to machine the manifold considerably shorter, then machine in the rib groove to take the rubber mount. Depending on how far back the manifold has been machined will determine how far your carb sticks out. NB: Worst case, the manifold may not have been machined to suit the rubber mount type, leaving it far too long when rubber and carb are fitted.

There are lots of ways to resolve this issue (incl. get the manifold machined, get a shorter manifold, get a shorter rubber, get a flange type manifold with shorter flange rubber, etc) but knowing what you already have would help us to advise on which way to go.

[Rich Oswald]

Just to add, if clearance is still an issue with a rubber elbow and filter, I would recommend a Chiselspeed panel filter which give much more clearance and are very successful in my experience.

Rich'

[Adam_Winstone]

I note that Chris currently has a short manifold for rubber mount carb on FB Lambrettai parts for sale and wanted page. It has photos that you can compare your manifold length to.