Questions about jets and excess oil...

[LOUD MOUSE]

I'd say if ya used that oil ya will be OK.
Some folks use engine oil and it plugs the foam. .......lm

I used the Unifilter-recommended oil that came with them. Should I not? I thought about that before. Maybe I'll pop them off (and keep the hoses on) to see how it runs-- better or worse. The ignition was set and I check it almost every time I ride with the timing light to make sure it's still in check. Can't rev it too high since I'm still breaking it in.

[MBellRacing]

So update time...

Ran the bike for about 100 miles today on 145 mains and no filters. Awesome ride. Still a bit lacking in full throttle and it acts like a poorly-tuned 2-stroke going from full to maybe 80% throttle. It actually seems to accelerate MORE backing off from full throttle sometimes! I figure this means I'm still a hair lean but I don't have any 150 jets, only one 155, one 160, and four 170s.

The oil leak turned out to be my tach drive and housing. Tightened the bolts and replaced the tach drive itself and, voila, no more oil leaking!

The bike got lots of attention today, especially as I rode by Alice's. The only casualty was the right side center stand bolt. Not sure how it backed out, I made a point to nut-and-bole the whole bike last night and didn't notice it being loose. Oh well, easy fix. And yes, I'll tidy up that rear wiring, guess I missed the hook! As soon as I can get my hands on some bigger jets, I'll continue my quest. Thanks for the help so far!

[Vince Lupo]

Now I am definitely no mechanic, but seeing that I'm in the thick of doing my own jetting tests, I have a teensy bit of knowledge -- with the emphasis on 'teensy'....

If your bike is accelerating when you back off the throttle from WOT to 80%, that's what they call 'nosing over', and is a sign that your main jets are too big. In other words, it's getting too much fuel at the top end, causing it to 'bog down'.

In your first post you mentioned something about a 'dead spot' -- where was that on the throttle?

Maybe you might want to look at my 'Japan Meets Britain' thread to read about my own jetting trials and tribulations, and hopefully might give you a bit of insight.

How was it running at the other throttle positions today? How do the plugs look? Have you explored the fun-filled world of plug chops?

[brewsky]

You can also test the main jet by closing the choke slightly while under WOT and see if the engine picks up power. If so, your main jet could be too small.

If you test by simply closing the throttle, the needle jet comes more into play and complicates the situation.
More info:
http://www.mikuni.com/fs-tuning_guide.html
http://www.carbparts.com/keihin/needles ... r_carb.htm
Vince is dead on about the dead spot....where is it on the throttle?
The chart below can help identify the problem circuit.
If you mark your throttle with a pin or tape it will help identify where you are when it happens.

[MBellRacing]

Hmmmm... Well that is confusing then. Here's essentially what I'm feeling:

Imagine first that the bike is idling in the garage. If I slowly crack the trottle it jumps up in RPM happily and very quickly. If I snap on full throttle quickly, it sputters and even chokes to death. I got this with every single jet I've tried (110, 120, 125, 130, 140, 145). Yesterday I rode on the 145 main and it was best it's been. Whenever I hit a hill and eased it into WOT the bike would be very unresponsive to the change, as if I had left the trottl only 1/2-3/4 open. At the crest of the hill, where I'd close it a bit, the bike would lunge forward again with more power and sort of "skip" like you hear a 2-stroke do.

Since the best change was up to the 145 I figured progression was the best change, obviously wrong!

The engine has Wiseco pistons (stock size), no filter, stock intake hoses, stock pipes with no baffles, stock carbs (with the exception of the ClassicHondaRestorations.com needles which I'll replace with the original ones again).

I'll read through Vince's thread today and see what's in there! Thanks!

[Vince Lupo]

So have you checked things like the gas flow, the petcock, screen, lines etc to make sure that everything's flowing okay, and evenly (left side/right side)?

One thing I would do is to have a look at those spark plugs to see what they're telling you. The mains affect 3/4-WOT (more or less), and you might want to see how the other components (needle, etc) are situated, as they would affect other throttle positions. Maybe what you could do are plug chops that concentrate on different throttle positions, read the plugs after each session, then you can narrow down where the bike is having trouble. Or you could put it on a dyno, like everyone's been telling me to do!

Here's another thing that just popped into my head -- are your coils producing a good spark? Think that weak coils might be a factor in any of this?

I'd definitely put some kind of air filters back onto the bike -- if you want to have any kind of longevity with the engine, air filters are essential. As well, by removing them, you are taking away one component of the jetting formula that's not being factored into the equation, and should be. Just my opinion, mind you!

Please bear in mind that all these suggestions are coming from a person (me!) who has someone else work on his bike, but does have a pretty good 'seat of the pants' perspective of his SuperHawk. So take them with however many grains of salt you choose!

[brewsky]

Hmmmm... Well that is confusing then. Here's essentially what I'm feeling:

Imagine first that the bike is idling in the garage. If I slowly crack the trottle it jumps up in RPM happily and very quickly. If I snap on full throttle quickly, it sputters and even chokes to death.

That is a common trait of non-CV carbs, not necessarily an indication of anything wrong with the jetting. It causes an instantaneous lean by the quick opening and loss of vacuum. This was addressed in later years by adding accelerator pumps to squirt extra gas in only when the throttle was quickly snapped open.

I would choose an air filter and put it on before tuning any further.

You may even want to try some baffles in the exhaust if they are straight thru, as that allows less influence by exhaust wave reversion.