Motorcycle Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
My Yam YZF600R won't rev past 8000 revs. I tried another ICU but with the same results. Recently learned carbs and added new [lugs?
 

·
Super Moderator
Joined
·
12,534 Posts
Where are you located ?
What model year is it ?
How did you go about the cleaning of the carbs ??

In some countries, engines can be rev limited depending on your license classification.
There likely IS a rev limiter on it regardless......and if you are rev'ing it up with no load, it might cut in early to protect the engine from "stupidity".
Have you considered contacting a dealer shop to see what it is SUPPOSED to do ??

P.S. Please proof your posts.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
I'm the UK, and the bike may have been first imported from Poland = Yamaha Thundercat YZF 600R 1997, carb fed.37k miles. I want my bike to do what I want it to do? Bringing it up into the red after the warm-up, is how I test a fresh bike's engine. I first noticed it when I took it up to 8k to test the 2nd gear issue that affects many Thundercat due to idiots doing wheelies. Thankfully, mine did not pop out of gear, but I noticed this cut-out thing, so possibly there is a limiter incorporated into the ICU. I know bikes fairly well and the carbs were already well clean when I stripped and reassembled them and I set the fuel screws at 3 half turns out. Today, I tested it with the choke on, and it went right up to 13k no problem, so I think I may need bigger main jets? This evening I also reset my Throttle Position Sensor and now have it as near perfect as I could get it, but now it is cutting out at around 9k with the choke on, or off? This is the first time I have heard of this limiter thing, but I'll take your word for it. Thanks for your input and any advice is much appreciated.
'
 

·
Super Moderator
Joined
·
12,534 Posts
I want my bike to do what I want it to do? Bringing it up into the red after the warm-up, is how I test a fresh bike's engine.
Those statements are both pretty ...mmmm.....short sighted.
Maybe you mean that you want it to do what it was designed to do ??

As for rev'ing it to redline or above with no load......that's just stupid.
Good luck.

It sounds like it has a slight problem and is not purposely limited.....except by the factory rev limiter which should roughly match the redline.

Before you go tearing the carbs apart, a dose of a good carb cleaner and a little riding might help matters.
Also they tend to run lean if the pipes and/or intake have been changed.
 
1 - 6 of 6 Posts
Top