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intake manifold

Posted: Fri Jul 03, 2020 10:55 am
by budpat105
Would an reed valve intake-minus the reed valve work on an 93A Super Rat to convert to Spigot mount carb?

Re: intake manifold

Posted: Fri Jul 03, 2020 1:42 pm
by matt glascock
The reed manifold would have more volume, length, and contour than the original flange-mount manifold. That would decrease the carburetor signal. As to how much and the resulting performance impact, I'll be interested in hearing from the pros.

Re: intake manifold

Posted: Fri Jul 03, 2020 7:24 pm
by Bullfrog
I'm not sure which reed manifold you are targeting to achieve mounting up a spigot-mount carb, but . . .

. . . if you have one in mind which will 1) bolt on to the cylinder and 2) accept the carb you have in mind, then . . .

. . . sure, that would work. (especially if that mod is what you need to get the machine running in the first place)

What reed manifold do you have in mind?

Ed

Re: intake manifold

Posted: Sat Jul 04, 2020 3:58 am
by Joe Ormonde
A Flange adapter on a Model 93 manifold may be the easiest way to go. Power is lost and found by trying new and at times strange things. Joe.

Re: intake manifold

Posted: Sat Jul 04, 2020 4:45 am
by budpat105
Bullfrog, I have intakes from a dirt squirt and a road toad. But as Joe said "Power is lost and found by trying new and at times strange things." I have a Spigot mount setup from Hodaka parts on my combat Wombat and it has been great. I should just source
a wombat/combat wombat intake. Any one have a spare to sell?Thanks

Re: intake manifold

Posted: Sun Jul 05, 2020 8:31 am
by budpat105
As I read my post- I see someone that wants to throw money at a problem to make it go away. Bullfrog stated " (especially if that mod is what you need to get the machine running in the first place)". Was the mod what I needed? Hmmm. time to look again. Fresh bearings,seal and top end. Guilty of not leak checking after put together. Put a lot of time in new wires for ignition and setting points. Kicked it over with timing light, fire almost perfect. Pulled carb back off, found a small passage on intake side still plugged(tube goes in well with a small hole in bottom of carb).WOW, bike starts if you hold throttle open, as it runs it gets heaver with fuel and dies. If I shut off gas it will "clean out" but when gas goes back on it loads up. Now I am needing help. TIA

Re: intake manifold

Posted: Sun Jul 05, 2020 12:44 pm
by Bullfrog
The last two sentences of your most recent post indicate that the float valve system is not properly controlling the fuel level in the float bowl. My guesstimate is that the float valve needle and seat are worn and need of replacement. You could check (messily . . . and preferrably outside) by removing the float bowl. With the fuel connected to the carb, but shut off at the tank petcock - you can hold the floats up (to shut off the float valve), then turn on the fuel petcock at the tank. If the float valve is leaking, you'll know immediately. If the float valve is working properly, you'll know that too. (in which case it is time to check the float level adjustment).
Ed
PS: Having to hold the throttle wide open for starting suggests that your pilot circuit passages (or the pilot jet) are still plugged.

Re: intake manifold

Posted: Sun Jul 05, 2020 12:54 pm
by viclioce
Another possibility, in addition to Ed’s offering, is the floats could be slightly bent outwards towards the outer bowl edges. This can cause the floats to hang and not rise up and close the float needle valve. A simple bending of the floats gently back toward the center of the carb, enough to allow them to miss the outside edges of the bowl, may be what’s needed.

Yes, Ed’s advice is solid. However, if your needle valve does shut off the fuel flow as he describes, then this could be an option and only requires looking at the floats and their position to the top of the bowl. :ugeek: Victor