So I picked up my 93 B4 this weekend and i've put a couple hours on her and learned a few things. I'm devising a plan of attack for getting her tuned right and would like feedback.
First the symptoms: Starts very easy w/o choke (running 90+ degrees F around here right now). Idle is rough and tends to die, adjusted the idle up to about 1200 and now she stays running no problem. Throttle response on the "blip" is sluggish and rough. She pulls pretty well from about 3000 rpm up to 8-9000. then she gets rough and not as strong, though in the lower gears it comes back around 10k. On the highway, in top gear it won't pull past 85 mph or about 9k, but will do it in 5th gear. When cruising at 4-5k, steady throttle, she is a little rough and burbles a bit.
Equipment: has a Yosh 4-2-1 and thats it. bone stock everywhere else.
Goals: get her tuned up and running nice and smooth with proper set-up for the pipe. Attempt to learn as much as possible about her state since she's new to me
The plan:
1. Valve adjust: prev. owner did NOT adjust valves for the 3000 miles he had it. I suspect its been much longer. I know from my past experience that its a big deal on these little guys. I think this may actually be a BIG part of her problems and am anxious to get it done.
2. Carb synch: I know this hasn't been done either and the throttle response tells me its WAY off. I know you usually do this last, but I think its so far out that it would help to get dialed in before moving on to other things. I hopeful that a good carb synch will eliminate some of the "background noise" and help highlight any of the real problems. Recently I've read somewhere about balancing carbs using the pilot mixture screws, what's up with that? In the past i've always done it with the balancing screws between the carbs.
3. Replace the thermostat with 190. actually, I'll probably do this in step 1 while its all apart for the valve adjustment.
4. Ride the piss out of it and figure out what's going on, including testing without the air filter and with a taped up airbox hole. speaking of, my airbox is missing the snorkel on the intake. I imagine this could introduce some pretty serious turbulence there and may lead to a rich condition. Thoughts?
5. Rejet as needed for that pipe, any suggestions for a starting point? A local shop claims they'll sell me jets and needles etc seperately so no need to do the whole kit thing. I know to replace the o-rings while the carbs are open too... So step 5 here is obviously a whole series of steps on its own, but I want to sort of get everything else worked out so I'm just working on one issue when it comes to rejetting -- getting the jetting right -- without being distracted by other crap.
6. re-synch the carbs.
Anything obvious i'm missing here? suggestions much appreciated.
thanks
A
Topic: Plan of Attack -- tuning a new B4 (Read 2532 times)