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Back to stock(ish) part 2

In part 1 of Back to stock I decided I would give the original carbs another run to see if I wanted to spend more money getting the GSXR750 carbs properly tuned for my bike.

First order of business was to clean the old carbs before I mounted them back just in case I had a little build up in the tiny idle jets. During re-assembly I spent a few minutes to understand the accerator pump mechanism on carb#2 and discovered that I had been starting my bike wrong all along.


When I had switched over to the gixxer carbs I thought they helped my bike start much easier because I was getting the engine to fire within 2 cranks reliably where the OEM carbs took minimum 3 tries on most cold starts.


I discovered that the accerator pump mechanism squirts a healthy dose of fuel into the carbs only on full throttle twist, something I never did. In the past, I always pumped the throttle 2 or 3 times but I never gave the throttle a full twist and so never actually primed the carbs.

My first start with the OEM carbs and 3 good squirts of fuel (yes, you can hear the fuel spray) resulted in the bike starting after only a short press of the starter. Easily the fastest cold start ever for me and this cb750.


Score 1 for going back to stock.


While I was running the gixxer carbs last year I had a momentary lapse of common sense and threw out the insulators thinking it ran so well I would never go back to stock. The roughly $65 for the 4 insulators was still cheaper than getting new jets for the gixxer carbs.


Note to self (and any other people contemplating gixxer carbs). Don't use the radiator hoses because they melt with the high engine temps. This means if I go back to gixxer carbs, I would need a jet kit, silicone hose for the insulators or oem 1-1-4-4 insulators... more money.


The $10k I spent on a newer bike should more than make up for the need to improve the performance of the old cb750. I want reliability and I want a working package that does not need finessing or fiddling.

Should I sell my gixxer carbs? The scale is tipping to yes.

Part 1
Part 2
Part 3
Part 4

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