I'm back again .. my 1994 Ninja 250, is actin up a little bit, there are noticeable "dead spots" in the throttle in the mid range, and the idle goes high when its hot.. A little backfire on decelleration but not too bad.. I'm swapping the plugs out tomorrow, the air filter, and the valve adjustment is due, (every 20k miles ???)

Back to the purpose of this post.. When I bought the bike it came with a Yoshi installed (pipes and all) and i've read that the carbs need to be jetted with this pipe.. So back to my two part question .. #1 How do I tell if the bike has already been jetted? and #2 Am I looking at causing damage to the bike if I don't jet the carbs? Tnx in advance!

 

1)Read the plugs. A lot of good information in reading your plugs.

 

2) you mention 1994, check for bad, cracked or loose rubber fittings and boots. Spray wd40 or better yet starting fluid around rubber components and listen for the engine rpms to change.

 

I'll be sure to do that, (always works on big block V-8's ) and i'll fill you in once I change the plugs out tomorrow. Any advice on finding out if the carbs have been jetted?
Thanks a million.

 

See what size main jets are in there now. Probably 105. If she's been jetted it would have a bigger jet in.