CB450T dies when accelerating

[crazy_eights]

Hello ladies and gentlemen, i am in need of some educated guesses regarding my dilemma.

I'm close to finishing up the project, adding the final touches to the racer, 1982 CB450T Hawk, and after taking it out for a few test rides i never seem to get very far from home before the bike suddenly dies. Last time I had it started, choke pulled, it takes a few tries to start it, the revs seem very low and then when i touch the throttle the revs keep going lower and lower till it shuts off. This happens even after the bike is warmed up and the choke is pushed in.

I cleaned the carbs, changed the jets from stock 70-108 to 75-115, i have pod filters but nothing else was changed. The spark plug looks clean, i tried opening up the pilot screw to let more gas through but it still dies mid ride. The float levels seem fine, fresh gas, put some seafoam in the mix, nothing.

I can't tell if it's a vacuum issue or a fuel/air mix, electrical, mechanical. Would velocity stacks instead of pods make a difference?

Thank you in advance for your help.

 

[Bert Jan]

seems a fuel problem. Did you clean the filter inside the tank?

 

[spotty]

possibly petrol (gas) tank vacuum locking? caused by the bleed hole in the cap being blocked and when you open the tank to check fuel level it breaks the vacuum? could be partially blocked which allows fuel to slowly refill the carbs between breakdowns?could be the fuel tap blocked (partially maybe) which is letting fuel down either intermittently or slowly?

to check this you could try opening the carb drain holes as soon as the engine stops, if nothing comes out you at least know you have a fuel supply problem, then turn fuel tap to 'prime' (assuming vacuum operated tap), if fuel immediately comes out of the carb drain then your tap is at fault. if it ain't that, next step is open the fuel cap and if fuel immediately comes out of the drain hole the problem is with the tank cap

awesome looking paint job too, good luck

 

[crazy_eights]

I will do as instructed, go for a run and check the vacuum in the carbs if it stops again. i was suspecting something related to overheating. Maybe the pipe wrapping, or the paint on the engine is restricting the cooling process and it might cause the gas to prematurely combust in the cylinders because of the heat.

 

[spotty]

. i was suspecting something related to overheating. Maybe the pipe wrapping, or the paint on the engine is restricting the cooling process and it might cause the gas to prematurely combust in the cylinders because of the heat.

unlikely that either of those things would cause overheating to the extent that it would stop the engine, exhaust wrapping actually channels heat away from the heads,thats what its original purpose was. in theory by keeping the whole length of exhaust pipe at a similar temperature it improves the flow of gases and can boost performance

 

[crazy_eights]

Good thing i didn't take it off, it was a biznitch to wrap it, my hands were itchy for two days, even with gloves. I took it out for a 1 hour test ride and it seemed to run good, i opened up the pilot screw to let more gas in, i think that fixed the issue, but when i checked the spark plugs they were white. From what i understand that means it's still running lean. If it does happen again i will be prepared to open the drain on the carb and check if the gas pours out. Till then, thank you very much for your assistance and good luck on current and future projects.