I have come across some problems with my 250, and was hoping that I could get some suggestions from the board members. Here is my story:
I have been getting my Suzuki T250 ready for the season, and have come across some problems in my initial testing. My testing has been limited to runs up and down my street, which only accomplished making some neighbors less than happy. I know I will have to do plug chops at the track, but with me being the moron that I am it would be very helpful to get some things to look for.
I bought the bike last fall and have not yet had a chance to get it out on the track. The engine is ported to the suzuki factory specs, and the only thing that I have changed since I got the bike was the pipes to increase lean angles (and later removed the power jets, after experiencing the problems). The pipes I put on the bike are from Swarbricks, made for the factory race spec porting. The carbs are VM32 with jetting that does not seem unreasonable.
The problem that I have is that there is no power between 4,000 and 7,000 rpm, regardless of throttle position. The bike completely falls flat once it hits 4,000, and when it hits 7,000 it pulls very hard and quickly wants to rev itself to oblivion. Before changing the pipes there was power from 4,000 and up. The two sets of pipes have very similar dimensions but the new pipes have tapered header tubes that are a little shorter more with more bend.
Does this sound like a timing issue, jetting issue, or could it be the pipe design? The plugs appear to be wet, but difficult to tell without running WFO. The previous owner has the timing set at 24 degrees BTDC, does this sound reasonable?
Is the answer to solving this problem not letting the revs drop below 7,000 rpm? I know the 250 motor is peaky, but there is definitely a very flat spot that did not occur with the other pipes.
Thanks in advance for any opinions, advice, or suggestions.