Makita EA3601...the most intriguing saw to date

[paragonbuilder]

Piston is smooth sided, no strato ports in it. All that happens down below.
And the machining on this cylinder and the transfer port angles are truly the best I have ever seen.
I'll get more pics this weekend and we can start discussing it


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[GCJenks204]

I've been studying the crankcase and it's interesting! Both halves fit in my hand, Lol

I need to study the intake and reeds to fully understand how this is working. But I want to run the saw a bit stock for a baseline before I tear it down.

Nate is there an IPL you can send me?


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The way you are holding those halves makes me think 72CC V-twin build...

 

[paragonbuilder]

The way you are holding those halves makes me think 72CC V-twin build...

It could happen...


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[fordf150]

@paragonbuilder

 

[paragonbuilder]

Thanks Nate!
A quick look shows that the second reed valve that goes up against the crankcase is reversed...
Interesting....

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[ajschainsaws]

Great stuff your making this build , it's like the wheel being re-invented
Watching waiting hoping dying to find out the ins and outs

 

[porsche965]

two ring saw also.

 

[Duane(Pa)]

Interesting, the pages say EA4300. Next size up from 36?

 

[paragonbuilder]

Interesting, the pages say EA4300. Next size up from 36?

Nice catch!


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[Terry Syd]

A quick look shows that the second reed valve that goes up against the crankcase is reversed...

Yeah, now what is THAT all about? The reed allows pressure from the crankcase to vent OUTWARDS. I wonder what is going to happen when someone removes that second reed and places a blocking plate in there. The crankcase compression is going to go up - sounds like a good idea to me.

Perhaps someone can identify the carb. The diagram shows an extra jet in the wet side, but it appears to be associated with the high speed circuit. If we can get a better flow on the reeds down low, then we are probably going to need to be able to increase the low speed circuit fuel flow. If this carb doesn't have an idle/transition jet to mod, perhaps there is another carb available.

 

[paragonbuilder]

Yeah, now what is THAT all about? The reed allows pressure from the crankcase to vent OUTWARDS. I wonder what is going to happen when someone removes that second reed and places a blocking plate in there. The crankcase compression is going to go up - sounds like a good idea to me.

Perhaps someone can identify the carb. The diagram shows an extra jet in the wet side, but it appears to be associated with the high speed circuit. If we can get a better flow on the reeds down low, then we are probably going to need to be able to increase the low speed circuit fuel flow. If this carb doesn't have an idle/transition jet to mod, perhaps there is another carb available.

It looks to me like the backwards reeds allow a secondary path up through the transfers during primary compression. I think I will try removing the reeds and also blocking them off and see what happens.
I can check on the model carb when I get home in a couple hours.


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[Duane(Pa)]

This is going to be cool! A real mind bender building a better mousetrap...

 

[166]

Interesting, the pages say EA4300. Next size up from 36?

Typo

The EA4300 is the PS-421 Dolmar.

 

[Terry Syd]

I think I will try removing the reeds and also blocking them off and see what happens.

You've got to start somewhere to figure out what this freaking reed block does. I've got a few 'theories', but theories probably won't last very long with this set-up. - I've never seen anything like this before.

It could be that the primary reeds tended to 'resonate' at some RPM and the reverse flow from the secondary reeds helped with the flutter and made them more precise. You may find that out when you block off the secondary reeds. In which case, why didn't the factory put some reed stops on the primary reeds instead?

Here is where a sick puppy like me would be going. I'd figure out a way to turn those secondary reeds around to make this a 4-reed engine. The intake to the strato system will be the limiting factor to the reed system, which also helps to keep the reed lift down on those 4 reeds, so there should be less of an issue with reed flutter. The reed system could start flowing a little earlier without the extra tension on the reeds.

If the low speed torque drops off because it is going to lean (by getting a good flow through the reeds), then a quick fix may be to use a stronger metering spring and then dial in some more flow with the low speed needle. A bigger carb with a low speed jet to drill is a much better option.

When you get the carb off, take a picture of the inside of the carb. Maybe we'll get lucky with a good design.

The 4-reed system may work, but it may also require a bit of experimenting with reed thickness. - This is all new territory for all of us... Good luck!

 

[paragonbuilder]

The carb has these markings
120007a
6za



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[paragonbuilder]

You've got to start somewhere to figure out what this freaking reed block does. I've got a few 'theories', but theories probably won't last very long with this set-up. - I've never seen anything like this before.

It could be that the primary reeds tended to 'resonate' at some RPM and the reverse flow from the secondary reeds helped with the flutter and made them more precise. You may find that out when you block off the secondary reeds. In which case, why didn't the factory put some reed stops on the primary reeds instead?

Here is where a sick puppy like me would be going. I'd figure out a way to turn those secondary reeds around to make this a 4-reed engine. The intake to the strato system will be the limiting factor to the reed system, which also helps to keep the reed lift down on those 4 reeds, so there should be less of an issue with reed flutter. The reed system could start flowing a little earlier without the extra tension on the reeds.

If the low speed torque drops off because it is going to lean (by getting a good flow through the reeds), then a quick fix may be to use a stronger metering spring and then dial in some more flow with the low speed needle. A bigger carb with a low speed jet to drill is a much better option.

When you get the carb off, take a picture of the inside of the carb. Maybe we'll get lucky with a good design.

The 4-reed system may work, but it may also require a bit of experimenting with reed thickness. - This is all new territory for all of us... Good luck!

What would turning the reeds around achieve that removing them wouldn't?


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[paragonbuilder]

The first set of reeds flow through the top rectangular holes on the upstroke

On the down stroke, the second set flows out of the oval middle holes and up through the rectangular holes feeding the transfers.
The bottom hole appear to be weep holes for any accumulation of mix in front of the reeds.


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[Philbert]

Nice thread. Very interesting.

Philbert

 

[166]

 

[166]