High-Performance Carb For Mitsubishi Engines

[loquin]

Walbro WYA series carbs are the 'double-barrel' carb for use with stratified scavenging engines.

Walbro WYA-27-1 is the carb that's designated for use with the mitsubishi TLE43.

ref
http://69.16.165.8/category.aspx?id=36 (scroll down to the WYA series)
and here's the PDF version

I don't know if these carbs offer any improved performance or not. They may be just replacement carbs.

 

[pdxrhett]

I worked on my WYK-58 install yesterday.

An adaptor for a WT-butterfly-style carb was ordered from partsforscooters.com It is a simple .125" thick aluminum plate with intake port, pulse hole and bolt holes. It included two paper gaskets and two bolts, cost me $16 with shipping.

Darn, the adaptor won't work on the TLE43 engine, even if I used the WT carb.. This engine's manifold is dual-port/over-under like a shotgun rifle's barrels. The adaptor bolts directly onto the mani, but its port and pulse hole don't line up with the engine, not even close.

The manifold's top port feeds gas mixture to the engine thru a single reed valve. The bottom port is a straight shot of air thru the engine block to the piston.

I need to fabricate a TALLER thicker adaptor and drill it to match carb, pulse hole and manifold. The adaptor will also block off the lower port completely.

THENNN, instead of fabbing an external pulse line, I groove a passage from the adaptor's pulse hole to the 13mm(?) air port that matched the original carb's 13mm(?) air port.

That way the original manifold is left intact in case I reinstall the stock carb.

It SHOULD work.

There is a 15mm upgrade for the mitsubishi 49cc engine. Talk to Jerry (thescooterguy) about it. He helped me find an upgrade. He is also the person who told me about the xcan upgraded exhaust.

 

[Hawaii_Ed]

Did I mention I know a real good metal fab guy? If we take what you have, and what you want to mout it on over to his place he can prob make an adapter, and he is quite reasonable. His 'batcave' is just outside Tripler, and they are there most weekend afternoons.

 

[Hawaii_Ed]

Picked up 5-7 and spent the afternoon with my friend working on his engines. We did not get to the carb adapter, but did fab up some starter pieces he needed. Carb will be Sunday.

 

[5-7HEAVEN]

Thanks, Ed

You're a true friend, Hawaii Ed.

Thanks.

 

[eastwoodo4]

is this it? http://www.scooterparts4less.com/web_gas/22cc_zooma_carb_logo.jpg at scooter parts for less

 

[5-7HEAVEN]

Maybe

eastwood, that looks like my stock carb, but this one is for a 22cc engine.

That site you linked also sells these adjustable carbs:

http://www.scooterparts4less.com/web_gas/Carburetor43cc.htm

That $25 carb is cheaper than my $39 one from DDM. Unsure if it's the same as my Walbro WYK-58 that I'll be using.

 

[Warner]

Interesting thread....I'll be watching this as I have the same Mitsu engine on my ride.....

Warner

 

[5-7HEAVEN]

Warner, I'm very close to installing the high-performance carbs. Air filters, velocity stacks and carbs all bolt together. I've designed the aluminum adaptors from two .25" plates to adapt carbs to engines.

The first plate is fitted into a recessed area that resembles a bowling pin. Then the second plate bolts onto the recessed plate, raising the mounting surface above the recession. The plates' "hips" are slightly wider to accept the wider carbs' bases. Both plates are bolted to the engines with the same four bolts.

Performance should be improved. I'd be happy if this mod cures my lean conditions.

I'll have pics on the weekend.

 

[Hawaii_Ed]

Here is an update from the GKR racing team, they are helping 5-7 with the adapter fab:

We started with Myron's raw 6061 T6 aluminum billet plate.

The larger carb does not have the same mounting pattern as the small carb cylinder head, so this adaptor will comprise of (2) pieces - upper and lower. The lower plate will bolt to the head with the existing (4) holes. There will be (2) additional blind tapped holes for mounting the larger carb.

What we're basically making is a very simple intake manifold where there wasn't any before, the oval shaped "plenum" of the intake is first drilled out and then slotted to port-match it to the cylinder head.

Then the assembly is put together to check if everything is lining up correctly.