Saw these on ebay

ebay

OK Dave, I see what you were geting at now, its similar to the idea of elongating / ovaling the bracket holes to allow the engine to drop a bit.

After wondering what a bell mouth was google is my friend. Problem is finding a supplier, lots of info about them on other forums - there is a local weber guy in my area so I thought I'd check with him.

thanks for the pic.

Quote:

Tapered full radius bellmouths are similar but different to your velocity stacks. Yours are the semi radius, parallel type. The concept of the full radius is to improve the air speed entering the bellmouth [much like an aerofoil] and the tapered tube is yet another improvement in the ram effect of air entering the carb throat. Another point worth mentioning is that air typically enters the velocity stack in a doughnut shape, entering from the edge of the ram tubes rather than from the front, in the middle of the tube.

see pic for example.

Evan, what I meant was that the A14/A15 mounts are higher than the 1200 mounts. They look close but are not close enough. They will work but... With just a flat plate it will sit higher... check out the wiki for photos and more details.

To lower the mount, I think you can redrill the holes in the bracket that mounts to the engine. This will fit the bracket higher on the engine.

What I did years ago was to cut the brackets in two and section out about 3/4 inch and have a welder put it back together.

all good ideas, appreciate it.

I thought of the elongating the bracket to block holes & dropping the whole motor down about 1/4" TO 3/8", that might provide enough clearance for everything including the velo stacks although I think the easiest solution to those are shorter ones, just not sure where to find them.

I also thought if I lowered the motor by that much I might be able to easily shim down the trans at the tunnel mounts by am equal amount with just washers as shims, that way everything will still be in alignment.

Benny - what are tapered full radius bell mouth stacks?

Tom - are you running 2 or 4 flat slides, congrats on the bike - should be fun.

so when people are talking about cutting mounts or fitting smaller ones what are you using, I'm not sure where one starts with that.

Yep, your flows look close alright. I,ve had a similer prob in my car, what I did was fit a smaller engine mount, it dropped the engine about 10mm and the flows now clear.

If you are going down the road of replacing the velocity stacks I have seen good evidence that tapered full radius bell mouth stacks are the way to go...

That velocity stack for sure will be milling the master cylinder............shorter stacks are in order. You could go with the half round filters common on the webers but I have to admit I like the big airbox set up..............I'm thinking if you use a liter bike unit adapted to fit, say use the inlets for the back two cylinders then block off the front two. Not sure if that would adversely affect the flow.

What I did to get around this was buy the flat slide carbs. My header is really close as well, that's why I used header wrap. Of course it is much dryer here so the usual hear wrap issues are not a problem.

The set up looks very nice.............wish my engine bay looked that clean.

Now off topic thread hijack............I put another bike in the stable; the latest is a 77 CR125m Elsinore, more power than my 76 YZ, 0 bottom end like my old 125 road racer but the suspension is a leap from the YZ. (Happily I still have the piston port preload the throttle riding style)

OK back on topic.................whatever you do the car should still run very well.

Tom

Your 5/16 lift on the passenger side of the engine is actually helping the clearance issue by lowering the header a small amount.

You could gain a bit more space at the header by lowering the left side of the engine a small amount. Is there enough meat in the motor mount bracket to slot the holes where it bolts to the block? It would not take much as the header will move more than the bracket is moved on the block.

Keep in mind that the header side of the engine will be lifting up under acceleration so you need to have some vertical clearance above the header.

I was just reminded that the manifold side of the A-series lifts at launch when I broke the motor mount at the Astoria autocross a few weeks ago. Broke one of the Rover polyurethane mounts with a stock 1200 motor. Go figure...

D, I like your idea of a filter box, I'd been thinking of something like that as well, for now though maybe shorter horns will do the job faster & & fab something up later for the box. I think you pic showed a cone type filter on it which seems like that'd allow it to breath well.

David, not sure what you mean byQuote: - its the stock cross member & all I did was make the offset mount plate for the right side of the engine compartment as the A15 sits about2" forward of the A12 mount, on that side its only 5/16" higher then stock.

The reservoir itself doesn't seem to have clearance issues rather the MC housing only & as you see in the pic its just the air horn thats banging into it, I think when I get the tranny in it'll all be revealed.

I also checked with the paint mfg & they said they think the paint will hold up fine but my feet will get really hot!

I'll look for shorter air horns Sidedraught, thanks.