The K&N's should be here today. I'm going to try them out.
If I get bad results, I will check my jets.
Expect some pictures later today.
I did some research on tuning. Do you guys have any rules of thumb or tips when tuning carbs?
Yup, your situation is the type where we can see if we can get pods working. In fact, it is the type of project bike I want to pick up. Missing key parts like airbox, etc so I don't ruin a complete bike.
Despite what everybody says, Tuning carburetors isn't so much difficult, but you must remember it is more like art. Those with a bit of money can do the full dyno tuning with A/F mapping through the rev range, but for average Joe, don't want to spend a grand on getting carbs done.
So, even without much experience, we can walk you through the steps to re-jetting a carb. If you have a keen ear, and feel of hand, you can tune a carb with patience. My 650, Probably a month of evening rides, etc to get them dialed in to being oh so sweet and running excellent mix. No fancy tools other than a carb sync.
So, to tune and dial in your carbs, will want some bits and bobs first.
1. All the standard carb tuning tools. So ability to syncro and adjust the various adjustments. At this point, more info on your bike so we know the carbs could help.
2. Save yourself some time, and probably money and see if you can find a jetting kit. This way you have an assortment and don't need to fight with one at a time finding jets.
3. Know anybody with a big fan or blower? Airflow will keep the worry about overheating.
Now thing to remember is that the different fuel circuits all work together as the powerband progresses. Here is a good picture to sort of explain what I mean. Keep the concept in your head. Just a random one I grabbed, but should be good.
So jetting. First thing is to get it to idle. You have to sync it before anything else. If carbs not syncronized, then will be alot more difficult to tell adjustment.
So if syncronized, adjust pilot screw. Simple enough to do here. If like other carbs I worked on, 1.5 turns from seat default. If more a turn in from this, then you need smaller jet because are too rich. With pods, expect to be running lean. So adjust out until idle smooths, etc. You can feel this from the exhaust and hear it as popping. If you go more than 3 turns out (so 1.5 turns from your default) you can up your idle jet size a step. Do so until you are within that 1.5-3 turns from seat. This should get your bottom end going.
So this should get your bottom end running proper provided the airflow through the carb is decent. One concern I thought up, and would explain the earlier discussion is resonance. While the filter might meet the cfm, the total air capacity might not be enough to feed the cylinder resulting in insufficient pulse flow (so total CFM might be #, but pulse CFM might be 3*#). Re-sync your carb and adjust.
Following this, you have your main jet and needle Mechanical linkage can be adjusted and tuned for partial throttle. Vacuum operated, you are at the mercy of vacuum. One reason why CV carbs dislike pods. If you have good source of airflow to keep bike cool, can do mid-range with just neutral. Never have in gear on stand, one accidental lean and bike takes off. Without airflow, then partial throttle runs. Mid throttle is usually where you do this testing at lower speeds. Check plugs and exhaust for richening. If you have a buddy, can often smell if rich. Plugs hopefully will show lean if not contaminated bad from idle setting. Get this running smooth.
Finish up by doing above for rides with more full throttle. Do a bit of a highway run. Once more check plugs and do like above. Probably wouldn't hurt to clean plugs between for better accuracy.
After all is done, you might end up with some hills or valleys in your fuel mix. I myself am a slight bit gurgly in third at 50km/h (3200rpmish) and smooth for the rest of the power curve. Nothing I can do about that really, Just a slight rich point where the rest of the curve runs stoic.
Remember, the worst that can happen is cannot get it to work and you put the old jets back in, start over, and you learn alot. That is the best part about reviving something vintage! It will not run perfect, and there is so much for I/R carburetors that maximizing what you have is the important part. Also remember, a little rich just means you get poorer mileage, maybe slight power reduction and some fine soot in your exhaust.
But lean is mean. Better to be slightly rich.
