Loosing power when rolling throttle

[nemesis_morte]

Well i have an interesting issue here guys. Everytime i roll the throttle and hold it at that spot my kat will just drop RPM something serious and just shut off. I thought it was the battery however two batteries later and a no go for the fix. She runs fine on choke so i dont see a problem with the fuel or fuel line as she seems to be getting plenty of that. I have also replaced the spark plugs thinking that was the problem yet still didnt help the issue.

Any ideas?

[sharpie6]

PM Arsenic. He's the freakin katana master.

[hardlydangerous]

its a fuel delivery issue
ruuning ok with choke tells us its not getting fuel...
chances are you carbs will need a proper cleaning the pilot circut is usually the cause but all the circuits will need to be properly cleaned

[arsenic]

carbs need to be cleaned, no doubt.

[Wild-Bill]

Here's what's happening: When you're running on the choke (at idle) you're dumping a bunch of gas into the intakes via the choke circuit. Airflow is kept low by the butterfly plates blocking the carb throats. When you roll on the throttle you open the butterfly plates, allowing a bunch more air into the intake but you're not getting any more gas because the jets are clogged. Instant fuel starvation!

[nemesis_morte]

thanks for the advice ill check into that. This will be the first time cleaning carbs. This should be interesting.

[nemesis_morte]

Ok here is an update on the problem. She started leaking fuel and it was because of a carb floater being to low. I reset all the floats with a micrometer as the factory manual says to 13mm. The leaking now fixed i fire her up and she run so much better than she did however there is now an issue on her running without the choke on. Now i only took the bowl off the carbs and reset the floats along with checking all the jets, etc for gummy junk and the carbs are in beautiful condition when it comes to cleanliness so no problems there. She will run fine on half choke, fluxing between high and low RPM. I figure on carb problem so i buy some pressure gauges in a carb sync tool setup just to see if maybe the carbs are seriously out of sync as well as checking the vacuum pressure. Well to my dismay the vacuum pressure is reading 5lbs and to my understanding it needs to be min of 15 - 20 lbs am i correct on this? If this is the case id assume there is a leak somewhere in the manifold? Any thoughts or sugguestions would be great. Thanks guys,

[Wild-Bill]

Vacuum level doesn't mean much as long as they're all the same. (The reading will vary with rpm and valve adjustment.) Go back to theory 1. There's a whole bunch of little bitty fuel passages inside the carbs. Clean them and the jets and I bet your problems go away,

[RaiderRC]

1. i'm a newbie offering advise

What kind of vac guage are you using? the vacuum number is really irrelavant due to the fact you need to equalize the pressures.

Also what wild-bill said if part of your carbs needed cleaning chances are the whole set needs to me cleaned. Dirt gets in EVERYWHERE

[grslightn]

This happened to my brother's Kat 600. We had to replace the jet needles after cleaning everything twice.

[nemesis_morte]

well i have gone through and replaced the needles and jets on the carbs, still running like crap though the replacements did help. I found that the problem is the intake from the carbs to the engine has a few small gaps in it so its leaking there also one of the ign. coils had a snapped wire i re soldered just to limp the bike along till i have the money for new coils. After all of these repairs ill give you guys an update on if it is 100% again.

[Wild-Bill]

Holy revived threads, Batman!

[cintidude04]

Holy revived threads, Batman!

lol I think its a fair revival since he was the original poster.

[Wild-Bill]

Completely fair! You'll notice I was in on this one from day one, too. kinda cool.

[Rod]

Good luck Phenix