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Best way to tweak carbs?

935 views 8 replies 5 participants last post by  Kensuki 
#1 ·
So I've had my 1983 Honda Shadow 750 for about a month now, I've had XRs and CBs and CBRs before, but this is the first bike I've had that I can't just take out a few bolts and get to everything, but that's not for trying. So anyway, my question is, what's the best way to work with the carbs? I took off the muffler and want to just baffle the headers, how would I best do that?
 
#2 ·
Trial and error along with plug chops to see what you engine is doing is the only way to tweak carbs. That means pulling them and switching your jets and adjusting the A/F setting until you find the right combination of slow and main jets and needle settings. It can be a real PITA which is what so many bikes run like crap because people chop or mod the exhaust and air intake and get tired of pulling the carbs and give up. If you are doing something custom, the kits don't work well because those companies do a lot of work for you using readily available after market intakes and exhaust. That what you pay for with their kits. Jets are cheap.
 
#3 ·
Just out of curiosity, what could be the disadvantages and consequences of not adjusting the carbs at all? I know it would destroy the MPG and cause backfiring, which is definitely not something you want between your legs, but would there be any other issues?
 
#4 ·
If your running with straight headers I don't see how you'll be able to avoid re-jetting the carbs, it's going to run like crap.
 
#5 ·
I do want it to run right, but I want to keep the rat rod look I have in mind. I bought it completely stock but I want to transform it into a rat bobber, and it's proving harder then a CB or Bonneville, and even Harley's.
Any suggestions which jets to buy?
 
#6 ·
If it runs lean, it will run hot. Run it too hot, too long and you blow the engine. They already run lean from the factory to meet emissions so not hard to make it too lean. Run it too rich and you have fouled plugs, drop a cylinder, flooded carbs, gas in the oil, blown engine.
 
#7 ·
Before you cut anything, is the bike CURRENTLY running correctly? How many miles have you put on it since you bought it?
 
#9 ·
Honestly? I wouldn't know if the engine is running best or not, it's my first time with a Honda V-Twin, like give me a CBfour and I'd be fine but the best I can do is idle rev, exhaust color, engine sound, and rev bogging, but even without the carbs at all, it seems to be running better without the muffler. Maybe it's being 5,000 feet in Colorado?
 
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