New 32cc vs 30cc

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From the info I've found the 1107 is a 990 with a choke some places say it has a 12.7 venturi and other say 13.5 should wake ur 32cc up if ur running one of the smaller carbs
 
And if it has a bigger venturi would that be a problem? I saw some people still recommend the 990 for a stock engine, not the 1107.
 
Ice_2k said:
And if it has a bigger venturi would that be a problem? I saw some people still recommend the 990 for a stock engine, not the 1107.
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I run the 990 on a 29cc with no probs

If the 1107 is the same carb with a choke it will be easier to start
 
Yes, that's why I would prefer it. However, I don't know enough about this to know if a bigger venturi could present any problems or performance deficit in this particular case....
 
Ice_2k said:
Yes, that's why I would prefer it. However, I don't know enough about this to know if a bigger venturi could present any problems or performance deficit in this particular case....
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All I know is it's HEAPS better than a 668 stocker
 
So you're saying I could go with the 1107 and have no disadvantages? Just the added advantage of the choke?
 
Ice_2k said:
So you're saying I could go with the 1107 and have no disadvantages? Just the added advantage of the choke?
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If it's the same as the 990 you'll have greatly improved performance with the convenience of a choke.

Now that I know they exist I'm thinking of changing from my 990 just for the choke.
 
That's the problem, they're not *exactly* the same, the 1107 has a bigger venturi. Trouble is I have no idea how this affects things :(

How do you start yours with the 990? Is it difficult?
 
Ice_2k said:
That's the problem, they're not *exactly* the same, the 1107 has a bigger venturi. Trouble is I have no idea how this affects things :( How do you start yours with the 990? Is it difficult?
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I usually prime it then give it 2 slow pulls before giving it a good pull.

This looks much better and says it's a 990

Bigger venturi equals faster intake speed meaning more mixture entering the cylinder in a given time.

http://www.davesmotors.com/walbro-wt-1107-carburetor-585727601-zenoah.html
 
New 32cc vs 30cc

So you're opinion is that it should be at least as good as the 990? Is there such a thing as "too much mixture entering the cylinder"?

Btw, if you just need 2 slow pulls before starting it, what would you consider upgrading your 990 to a 1107? Seems like you're doing alright without the choke.
 
RampageHopUps said:
The 990 is a pain in the butt if you live in cold weather.
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Even in warm weather I sometimes find I have to richen the LSN to start it then retune when I get it going.

A choke would be much easier.

Can't seem to find one locally so it looks like Dave gets the sale.
 
I run a wt813 on a obr 30.5 prostock and that is the double pumper of the rc carb with the accelerator pump.. You can run the 1107 on a 29cc with no problems. If you are new to this I would stick with something that has a choke.
 
The pump kicks in further up on the throttle... At idle the pump diaphragm is not compressed by the ball in the shaft. It starts the same as a 990, the needle settings are a little different because of the pump.
 
Phill said:
If it's the same as the 990 you'll have greatly improved performance with the convenience of a choke.Now that I know they exist I'm thinking of changing from my 990 just for the choke.
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Great idea!! Let us know how it goes, actually wait do you have the new 32cc motor.

Some of us were inquiring about more flow to supplement the xtra displacement.
 
I run the 990 and 998 which is the 813.i spray ether in a rag and hold it over the filter and starts right up and it's gets cold in the north east.by doing that it's chokeing the motor.but not washing out the air filter which can damage the engine.
 
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