elcochinato
CB750 Member
Hi, I'm stuck. It's been a while and I can't seem to find the key.
SYMPTOM: It starts hot on the first rev, but accelerates from 4 to 5,000 rpm, then normalizes until it drops to around 1,100 rpm. It stays there for a while, then gradually decreases until it shuts off.
valves regulated within their margin. Ignition light calibrated, new spark plugs, old spark plugs, I have tried different sets of spark plugs all NGK 7 8 9 Japanese (cold and hot) normal regulator voltage at 2000 rpm more than 12.5 volts. new intake nozzles (they have no air intake) cylinder compression (although I do not have a clock to measure by covering the nozzles one by one with your hand they maintain a vacuum, also it does not blow through the intake. I changed timing chains a while ago, short and long but not the primary .... if I already know a stupid thing on my part, do not crucify me.
Carburetors... goodness gracious carburetors. I've mechanically cleaned them, completely disassembling them according to "MacGregor Carb Cleaning Services," but I have two problems. One, the boost pump injectors don't seem to be working properly; I feel like they're clogged. These should shoot a clean jet directly to the intake hoses or be more passive and shoot a lower-intensity jet. How can they be disassembled?
On the other hand, just in case, I increased the low-pressure jet to 0.70, but it's still the same.
The idle jet screw's best working position is between the 2nd and 3rd turns.
The fuel tank levels are relatively good; perhaps the 3rd is a little high, but when the bike is stopped for more than 3 hours, it raises the level a little more, but without overflowing.
In short, this is the general overview.
I hope for some feedback on this.
It's a shame you can't upload videos.
https://photos.app.goo.gl/xGP2nS79StppqWqz8
Here's a video and some photos.
Translated with Google Translate
SYMPTOM: It starts hot on the first rev, but accelerates from 4 to 5,000 rpm, then normalizes until it drops to around 1,100 rpm. It stays there for a while, then gradually decreases until it shuts off.
valves regulated within their margin. Ignition light calibrated, new spark plugs, old spark plugs, I have tried different sets of spark plugs all NGK 7 8 9 Japanese (cold and hot) normal regulator voltage at 2000 rpm more than 12.5 volts. new intake nozzles (they have no air intake) cylinder compression (although I do not have a clock to measure by covering the nozzles one by one with your hand they maintain a vacuum, also it does not blow through the intake. I changed timing chains a while ago, short and long but not the primary .... if I already know a stupid thing on my part, do not crucify me.
Carburetors... goodness gracious carburetors. I've mechanically cleaned them, completely disassembling them according to "MacGregor Carb Cleaning Services," but I have two problems. One, the boost pump injectors don't seem to be working properly; I feel like they're clogged. These should shoot a clean jet directly to the intake hoses or be more passive and shoot a lower-intensity jet. How can they be disassembled?
On the other hand, just in case, I increased the low-pressure jet to 0.70, but it's still the same.
The idle jet screw's best working position is between the 2nd and 3rd turns.
The fuel tank levels are relatively good; perhaps the 3rd is a little high, but when the bike is stopped for more than 3 hours, it raises the level a little more, but without overflowing.
In short, this is the general overview.
I hope for some feedback on this.
It's a shame you can't upload videos.
https://photos.app.goo.gl/xGP2nS79StppqWqz8
Here's a video and some photos.
Translated with Google Translate
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