GSX750 1981 rpm dip at 3k problem

[Guest]

Hi guys,

Basically the bike pulls away well until it looses power around 3000 RPM. It's like someone is squeezing the fuel line and cuts petrol going in to the engine. After 1-2 seconds of 2/4 open throttle it picks up like a normal bike again.


Bike Info:

I changed the jets on the carbs back to original spec after buying the bike, because it had pod filters and I wanted to switch back to airbox. The bike has a 4into1 exhaust system so I don't know weather I should have got bigger than oem coz it's not the original exhaust.

Valve clearances have been set. Valves were a little worn and cam shafts also, the exhaust side one was worse than intake. The cam chain had jumped a tooth. Idk how long previous owner ride the bike like that.

Thank you very much

[chef1366]

Check the petcock.

[60ratrod]

Inline filter?

[Jedz123]

Hi guys,

Basically the bike pulls away well until it looses power around 3000 RPM. It's like someone is squeezing the fuel line and cuts petrol going in to the engine. After 1-2 seconds of 2/4 open throttle it picks up like a normal bike again.


Bike Info:

I changed the jets on the carbs back to original spec after buying the bike, because it had pod filters and I wanted to switch back to airbox. The bike has a 4into1 exhaust system so I don't know weather I should have got bigger than oem coz it's not the original exhaust.

Valve clearances have been set. Valves were a little worn and cam shafts also, the exhaust side one was worse than intake. The cam chain had jumped a tooth. Idk how long previous owner ride the bike like that.

Thank you very much

Welcome aboard!

Firstly lets get some information. Like where are you located? Tell us about the Bike. Pictures? The more base info we have the better we can help.

So explain what you did when you returned the carbs "back to original spec". What size Mains and Pilots are you using? Is the needle jet still an aftermarket needle jet? Need more information to help....

4 to 1 systems will work just fine. Some prefer them. I personally do for they weigh much less then stock. Anyway with a picture of your bike we could help see what your working with.

Ok here's where I'm getting lost. Is there damage to the lobes on the Cam shaft? I'm lost to valve wear? Those bikes use a rocker assembly so the valve is not in direct contact with a shim or cam shaft. Did you break the cylinder head down for overhaul?

Cam chain's generally dont just jump a tooth either. Your bike would likely not run if it was out of time. Once again pics and info.

Good luck!

I Highly reccomend using the search feature on this site and start becoming proficient with these bikes. Great info on here.

[mrbill5491]

You did put a filter in the air box right? And everything has a good seal on it?