My 300 has mediocre low end!

[GGRider01]

38
172
N3CW #3

Bike is suddenly very tractable and has "grunt" everywhere but even less lofty than before.. Frustrating.

Maybe I should start going up on pilots and then down on the needle (if needed)?

Mind is kind of muddled from thinking about it so long. Weather has been sporadic so jetting results are as well.

 

[Jakobi]

One change at a time. It might take a while longer, but you'll feel the effect of a single circuit and be able to definitely confirm if that particular change was better or worse.

I'd suggest something like this. Keep the 172 main.

N3EW#2
You've tried 38 pilot and it was OK.
Try a 40 pilot. If you see improvement. Try a 42... continue until you see it decline again. Go back to your best setting.

Then go half a clip richer on the needle. If you see improvement, continue. If you don't go back to what worked best.

Finally, repeat on the main. Go richer until you see performance decline. Then go backwards. Stop when you find the best response.

Then if you need to fine tune you'll know exactly where, because you have felt what it feels like when a particular circuit is out.

 

[GGRider01]

OK, here is where I'm at this weekend.

42pj
N3EW #2
172 main

Rolling on the throttle slowly, there is a surge of power from 0 to 1/4 .. right before it gets to 1/2 I can feel and hear a lean spot and right back to aggressive angry mean acceleration from there on out. Still haven't tried going up on the main with this W diameter, that is next. Maybe need to go #3 on the needle if that doesn't hide the lean spot?

Addition:

Decided I was on the wrong track and adjusted the needle first instead. #3 position seemed to do away with the lean spot. Went to a 175 on the main after that and the machine is running how it should, in my opinion. Too many temperature variations to nail "perfect" since it's spring. Some weekends are 60 degrees and humid, this Saturday was 85+ and dry as a bone. Today was 75 with a bit of rain. Summers are dry here and hang around 95 degrees, so might find myself leaning it out later. Right now though, it feels consistent from closed to WOT and has been serious traction issues (partly due to crappy s12 tires) ever since trying the N3 needles. On pavement it will loft in 1st and 2nd.

 

[GGRider01]

I'm sorry to keep beating this dead horse, but it seems I'm getting even closer.

Went to the NEDH Suzuki needle and the bike is just getting better. It reminds me of riding a CR250 I got rid of not too long ago. Revs to the moon but definitely does not require it. Such a minute change has had surprising results. I'm riding in a gear or two higher than I ever was before at the same speeds. I would go to the G diameter, but I have before and was not impressed.

Jakobi, I don't have to look far and I find knowledge you've shared, and more often than not it seems relevant to what I'm dealing with. Your suggestion of going rich was against everything (not much) I knew about jetting but seems to be working out. I'm done pulling the plug, because my tired arms are telling me a lot more than that. I know I nearly seized a RM 125/144 I had Millennium Technologies build for me because I kept going lean. However, the NEDH definitely requires a leaner main jet than the N3EH due to the richer final taper, which I found you had suggested in another thread.

I didn't think I'd like the smooth power delivery of the Suzuki needles but I'm pretty happy, and less hesitant to pop the front end before the PV opens, since you can barely feel that transition now.

Still fighting a fluttery idle. When I first start the bike with the choke on, it revs quite a bit too high, so I back off the idle screw until it warms up, then have to screw it back in when I turn off the choke or it'll die. I'm very conflicted about what this is telling me. I don't have anything richer than a 42, so I guess it's worth a shot to pick up a 45 and 48, even though that seems quite rich for the 300, based on the jetting database. It's undoubtedly going to improve when I get the head cut which will have to wait until fall because I'm a grown child that can't stand to be without my toys. I do have a spare cylinder and head, but it's so chewed up I'd never let this piston touch the walls of that thing to get the measurements.

Here's where I'm at:

172, improved over the 175
NEDH #2 (would like to try the NECH)
42

It's a handful.

 

[Jakobi]

I wouldn't be too concerned with the high idle on cold start under choke.

My bike does the same thing. Choke on, kick it, it revs higher than I'd like. I drop the choke back down and hold it half way for a few seconds until it warms a little (20 seconds at most). Then ride off with the choke off. I won't need to touch the choke again all day. It will idle happily in neutral and start easy either by foot or bump start.

It's not uncommon in many bikes using the PWK, and if you consider the vapours from a freshly oiled airfilter being pulled in, along with the choke circuit pulling extra air and fuel directly into the engine it's not really surprising.

The times I have been genuinely too lean on the idle/pilot circuit the cold engine is hard to start, and will take a long time to warm up before being able to take the choke off.

Sounds like you're very close.

 

[GGRider01]

Honestly, it's such a handful I don't want to know what a perfectly jetted 300 feels like.. but I'm probably going to try anyway. It went from sounding like a Civic with a 4 inch fart can to a top fuel dragster in comparison. The exhaust note says a lot. The rear end is trying to overtake the front in 5th gear on hardpack. Pretty squirrelly.. I reckon with some half decent tires it'll really demand respect from the throttle jockey on the seat.

 

[barossi73]

This is where the frustration turns to satisfaction,now you have a decent base setting and a feel for it,and a rideable bike.now you just fine tweak it to suit your requirements and just ride.as you clock the seat time you may notice small clues that will help.for eg on my last ride my bike had a pretty hard workout for 30-40 minutes continuously and got a little hotter than usual (i was in the zone!)
I noticed it burbled once or twice as i cracked it open,so the mix is just on the rich side when bike gets a little hot,good at normal temp.if it had been a little lean the power would have flattened/thinned as the temp rose