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<  General Scootering  ~  Burble/gurgle method of tuning?
Jeff
PostPosted: Sat Jul 23, 2005 12:58 pm  Reply with quote
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I have heard about the gurgle tuning method that involves cutting throttle at certain speeds in certain gears and if your motor gurgles you are jetted properly. Can anyone tell me more about this? Thanks.

Oh yeah How can you tell if your idle mixture is set correctly? My bike idles OK but I'm not sure it's optimal. What is too rich or lean at idle?
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Derrick
PostPosted: Sat Jul 23, 2005 1:36 pm  Reply with quote
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Been reading Stella Speed again?

I told you to stay away from that! You better start therapy again.
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Matty
PostPosted: Sat Jul 23, 2005 1:44 pm  Reply with quote
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Derrick wrote:
Been reading Stella Speed again?


That's what I was going to ask too!

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Jeff
PostPosted: Sat Jul 23, 2005 1:49 pm  Reply with quote
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Actually Derrick mentioned it a while back. I have seen it mentioned in passing at the ISBBS (where stellas posts are being booted from the main board, stupid but whatever) as well as at stella speed.

I think you guys can understand why I am wanting a better tuning method.

J
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Derrick
PostPosted: Sat Jul 23, 2005 3:35 pm  Reply with quote
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I don't know about the "gurgle" tuning method.

What are you trying to do? Is there a flat spot or are you affraid of seizing?

Setting the idle mixture has been discussed before. I don't know what else there is to it. That is about as simple as it gets.
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Jeff
PostPosted: Sat Jul 23, 2005 4:01 pm  Reply with quote
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Mostly afraid of seizing. The gurgle method, or whatever, involves running your scoot at say 50 in 4th then cutting the throttle, if the engine gurgles as the RPMs wind down you are jetted correctly. If it just winds down you are too lean. I am not sure if I have this right and I am just fact checking really.

I haven't got any flat spots really. I set up the 24G with all the stock stella jetstacks and mixers and it really runs A LOT better. I am running a 102 main and pre-mixing an extra 1% and my plug shows just a hint of color. Based on the plug I would say I'm too rich, but i only have 200 miles on the rebore and I want to break in more before I really tune it in. I probably always will run 1% though.
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Derrick
PostPosted: Sat Jul 23, 2005 5:01 pm  Reply with quote
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The only way I know to jet the main jet right is to go SO RICH that it 4 strokes. Then drop by a step at a time until it just stops 4 stroking. Then you should be safe - AFTER RUN IN. (Some shops say it takes up to 1000 miles on a cast steel barrel for run in!)

Unless you go from the top down jetting you have no reference point. You need to have the 4 stroking reference and then go just below that point. Without the reference point you have no idea where you are. Plug chops don't always work because modern fuels are blends of junk and they don't always color the plug properly. Two strokes will run SUPER GREAT when they are lean. That is why on cold days the run better. However, they will seize at hwy speeds when they are lean. So, jetting is a compromise. You will have to sacrifice some speed to keep things cool.

I have seized afew times myself, before I started jetting this way. Using this method I have not. I'm keeping my fingers crossed!
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Matty
PostPosted: Sat Jul 23, 2005 5:39 pm  Reply with quote
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I still have no idea what they are talking about with the "burble" method, how the hell are supposed to hear that going 50mph? Never heard of it before stellaspeed.

102 still seems lean to me, esp. if you're breaking it in..

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dmarquis
PostPosted: Sat Jul 23, 2005 6:38 pm  Reply with quote
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Hmm. I would go with derrick's method as the worst that can happen is a fowled pulg..... Better safe than sorry when it comes to your precious that you only ride on sunday mornings at 6:00 AM to avoid some one seeing your precious......

Dave :-)
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Jeff
PostPosted: Sat Jul 23, 2005 7:43 pm  Reply with quote
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I'm in uncharted territory as far as jetting goes. Some people say the DR doesn't need upjetting at all, some say it needs 115. I'm guessing big time, but the thing that seems to cause really big jumps in jet size is the pipe and I'm running stock there so I shouldn't need to upjet because of that. So I need to account for the kit and the carb in my jetting. Stock is 94 so I am up at 102 and right now riding nice and easy my plug is nice and safely dark and I'm not fouling either so what can I say?
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dmarquis
PostPosted: Sun Jul 24, 2005 6:20 am  Reply with quote
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Here is a link to NGK spark plugs after runs/chops. Now new gas ect and syn oils might cause different looks/chops it might help you.

http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

Dave
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JoeP
PostPosted: Sun Jul 24, 2005 9:06 pm  Reply with quote
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Derrick,

What does it mean for two-stroke engine to "four-stroke"? When that happens, how can you tell? Just want to learn more.

JoeP
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Matty
PostPosted: Mon Jul 25, 2005 7:49 am  Reply with quote
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Jeff wrote:
Stock is 94 so I am up at 102 and right now riding nice and easy my plug is nice and safely dark and I'm not fouling either so what can I say?


Isn't the stock air filter supposedly really restrictive as well as the cat exhaust? You've ditched both of those so I would think you need to up it just for that, plus the kit?

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Jeff
PostPosted: Mon Jul 25, 2005 9:47 am  Reply with quote
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True. Stock P150 with a 20mm carb has a main jet of 116 according to scooterhelp. A T5 has a 110 on a 24 mm carb but that is with the sito plus like pipe.

I think maybe I should go a bit higher.
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Matty
PostPosted: Mon Jul 25, 2005 9:58 am  Reply with quote
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I wonder if scooterhelp is right, 116 is stock for the P200, but anyway yeah go richer for now. Seizing is fun and exciting but gets expensive after a while!

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