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Post by joneill4 on Aug 4, 2007 11:36:13 GMT -5
This is my first year with an SR that has all the standard modifications done by some previous owner. I know that the carb is bigger than stock, but I don't know which it is. It also has a K&N filter and a SuperTrapp. She's tuned rather well, except for the last 25% of the throttle. When I go from 100% throttle to 75% throttle, I can feel the bike gain power. I realize that this is probably undiagnosable with the information given, but I'm not much of a carb guy. If someone could tell me where to start, I may become a carb guy.
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Post by Tominaga Akira on Aug 4, 2007 12:11:30 GMT -5
It depends on what kind of carb is attached (CV, VM, CR or FCR) and I don't know much about CV carbs, but it seems like that the gas mixture is too rich around 100% throttle.
My suggestion is
(1) First, clean the filter,
(2) Change the main jet smaller one,
(3) Or make the clip of the jet needle upper
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Post by chew652 on Aug 4, 2007 14:18:01 GMT -5
"She's tuned rather well, except for the last 25% of the throttle. When I go from 100% throttle to 75% throttle, I can feel the bike gain power. "
I have been told by and oldtimer that this is the symptom of a too small main jet. I experienced a similar phenomenon and went up one size on the main jet and cured it. Keep going up one size at a time until you don't get a power increase when you back off,then double check with a plug chop.
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Post by StewRoss on Aug 4, 2007 17:24:48 GMT -5
Hi, I agree, go up a size and see what the difference is...you can also raise the needle to see if that makes a difference. Raising the needle richens; lowering leans. Carburetion is a matter of some trial and error to get right. Plug chops give you a good idea of MJ sizing. SR  |
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Post by Tominaga Akira on Aug 4, 2007 22:37:34 GMT -5
Muuuun, it seems that I made a mistake for the same symptom some times happens on my FCR when it's too rich. Anyway starting from richer gas is safer for the engine, so try it.
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Post by StewRoss on Aug 5, 2007 1:42:40 GMT -5
Yes that can be right as well Akira for sure...the plug chop should assist to determine the difference there. I am going over to Japan in November to go to the Honda museum...it would be really interesting to see other people's garages in Japan. There seems to be so much going on. The Japanese seem to be as mad on this stuff as I am. I hear that there is a Japanese magazine just on people's garages...excellent! SR |
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Post by brokenicarus on Aug 5, 2007 2:07:36 GMT -5
Hey Stew,
what's a plug chop?
I love the japanese styles, robomod got me hooked on Custom Burning magazine, that one's got crazy SR's every month. check it out while you're there!
and take some great pictures of the Honda museum!
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Post by StewRoss on Aug 5, 2007 3:16:28 GMT -5
Hi, Take the bike out and find a place to give it a high speed run...away from people...often it's better to use a new plug as well...ride the bike at high revs for about a KM in a higher gear then pull the clutch in and kill the ignition straight away. Coast to a stop... Pull the plug out and if it's a tan colour the jetting isn't too bad. If it's white it lean...(needs a larger main jet)...and if it's black it's probably too rich and will need a smaller main. Unleaded can be harder to get a good colour on as well... I'd put the needle back in the centre position on the clip before doing it as well. See how you go. SR |
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Post by StewRoss on Aug 5, 2007 3:18:07 GMT -5
As Akira said as well...the type of carby makes a difference...some later types aren't readily adjustable. Do you know what type of carby you have? SR |
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