Flash IV

[bakaracer]

hey Wheel did you get rid of that yms chamber pipe you got from jiangwayne? the one with the blue silencer.

[Wheelman-111]

Greetings:

Yes the YMS is gone to a deserving Forumista. It was pretty good, high-revving but awful loud for Civilized Persons such as myself. I do think the PG Long is a bit better, but then again I keep blowing up Ruimas.

I was this close to scoring an OKO 24 used on eBay, but someone bid it up to more than 50% of the price of new, so I bailed. Still in the market. Starting point advice for jetting equivalent to the 60/160 in the 28/30mm OKO would be welcome.

[Wheelman-111]

Greetings:

Risked a 2-mile errand ride despite super-rich 138 main in the 24mm OKO. Half-expected to foul the plug, but I was able to 4-stroke coax it to 35-ish, at which point it actually ran decently. As long as throttle was limited to half or less it burbled along, temp gauge struggled to reach 250 or so. I guess it still works.
Heavily-loaded variator limited RPM to 6500, but begs the question: When one lightens the variator, should one anticipate the need to richen the jetting to cope with increased intake demand? Same thing when the PG goes back on?

[elitedio]

Wheelguy
Have you ever considered doing a pressure test on your crankcases/engine assembly? With as much as you have spent on that scoot.....

[Bear45-70]

Greetings:

Risked a 2-mile errand ride despite super-rich 138 main in the 24mm OKO. Half-expected to foul the plug, but I was able to 4-stroke coax it to 35-ish, at which point it actually ran decently. As long as throttle was limited to half or less it burbled along, temp gauge struggled to reach 250 or so. I guess it still works.
Heavily-loaded variator limited RPM to 6500, but begs the question: When one lightens the variator, should one anticipate the need to richen the jetting to cope with increased intake demand? Same thing when the PG goes back on?

I would think no enrichment would be necessary. On my first race boat (basically stock powerhead but turning about 2000 RPM above factory recommendation) I used to run 4 different props with my gear ratio remaining at 2 to 1. But whether I ran the 20" pitch (short course prop which topped out around 85 mph but gave neck snapping acceleration off of tight corners) or the 28" pitched prop (long course or speed record run topping out around 105 mph with sluggish acceleration but screaming fast top end) there were no changes in jetting for the engine. Altitude and ambient air temp had far greater effects on jetting than anything else.

As to limiting the RPM on break-in, I would think that not limiting the RPM an using judicious throttle application would we better for the motor. Lugging an engine is never a good thing, especially on break-in.

[Wheelman-111]

Greetings:

EliteDio axt:

Have you ever considered doing a pressure test on your crankcases/engine assembly? With as much as you have spent on that scoot...

Nope, never pressure-tested the block. Hafta get all them Marine Plugs and things - Ugh. Anyway, on disassemblies there was no evidence of leakage - usually a telltale mist or streak of oil. I really think it's a case of bad jetting on the second go, and the bore survived. Seems to be going well now that I've opted for the 24mm OKO and Way-Rich break-in jetting with low RPM pipe and heavy weights. I haven't seen it hit 300 yet.

I'll swap the drilled-out 131 for a Factory 128 or 125, based on Bakaracer's suggestions and see what the plug/temps do. After a few more miles I plan to reinstall the PG Long, so I'll stick with too-rich. For sure I'll need to go lighter on the Variator weights, so the RPM will increase.

Bear, the HD crowd really believes in jetting up whenever the RPMs increase or the pipes lose restriction. Like comparing Apples to Microwaves, you might say, because 4-Stroke 1200+ccs breathing through a single and relatively tiny Keihin CV40 carb might just need more fuel, but still... In a Premix engine, the fuel also supplies the oil, so I intend to play it very safe.

[bakaracer]

if you see 350 deg temps thats ok too. if it gets close to 400 then I would be concerned.

[808BMW]

Well my memory is shot, as I previously thought I was in the 120 range. I'm not

Finally got around to taking my carb apart, I currently run a 45/105 combo I used this with my old expansion chamber pipe (the same one you ran for a short while) and temps were under 350 almost always. Now with a goshi exhaust I rarely glance at the temp gauge, LONG pulls at WOT daily.

[Wheelman-111]

Greetings:

Installed the Genuine Keihin 128 Main last night, just in time for the skies to open up and the rain didn't quit all evening. I could not abide anything messing up Wheeman coiffure. Testing aborted.

With the 52 pilot and 131 drilled-out Main, the scooter would not accept full throttle at all. Just killed power and dropped RPM to go anything above 3/4. I expect the 128 not to be much better, and the 52 is probably too big as well. I was going to drop to a 50, but it turns out my next size down in Pilot jets is an off-brand 46. I foresee yet another jet purchase in my future.

Oh-Eight, I assume your 45/105 is working with supplementation from the Power Jet? Did you happen to look and see if there's a size imprinted on your PJ? It's stamped very tiny, but I was able to read "25" on mine.

It has been very helpful to share this information and get me into the ballpark. Thanks, dawgs!

[808BMW]

Powerjet is disabled now, but was working before. I pulled it out anyway, and after searching for any tiny marks, I cannot find a number. Maybe "YSN" chose to forgo stamping numbers on their PJ's?

[Wheelman-111]

Greetings:

Thanks for looking, Oh-Eight. Uhhh, whut's a YSM?

So now I'm feeling pretty stupid going to all the trouble to swap down from my 131-ish hand-rolled to a 128. You running anything close to my setup with a 105 Main?! Sheesh, no wonder Flash feels rich. My 52 Pilot will have to stay for now. The midrange isn't horrible, and I'm not ready to let go of Break-in Rich for my own 46. Nothing in between on-hand. I may get to run some errands tonight if the rain holds off. I'll let you know how it runs.

[808BMW]

YSN is my off brand carb. They're all copies anyway, but I just wanted to point out that mine isn't a genuine OKO.

[Wheelman-111]

Greetings:

It ran quite a bit better with the 128, still not great. Best power was at 2/3 throttle, where it went 40 or so. More throttle caused the revs to drop along with power.

Had time to screw in the 125, and that cleared its throat in the midrange along with improving to 45MPH, but still killed power a bit during brief WOT attempt. Temps never exceeded 290. I'll check the plug and perhaps run it another hour like this.

Then I intend to lighten the rollers to suit the PG, and see if the pipe fits the 125 main before deciding on the next main size. Got a better plan?

[Wheelman-111]

Greetings:

The plug, as expected, was reassuringly Black:

F4Plug125_52.jpg (22.15 KiB) Viewed 4554 times

I didn't clean it at all prior to taking Wheeman "Pic". Evidently this Motul 800 Offroad stuff doesn't make much ash; that plug has over 2 hours run time on it! I really like the smell too.

[Wheelman-111]

Greetings:

More errands tonight, another half-hour of run time. Approaching 3 hours. RPM seldom exceeded 7400, and speeds up to 45 using 52/125 jets in the OKO 24. Still won't take full throttle, just loses power and slows a bit. Sure burbles a lot in the midrange, but can "adjust" with throttle hand. Ordered up a 50 - 48 - 45 Pilots. My temp gauge did creep above 300 or so briefly once or twice, during application of 3/4 or more throttle. That's why I don't want to drop the Main too much more.

I decided the variator was too heavily loaded even for the low-end Hot Surfaces exhaust. Dropped down to 30 grams (Stock Kymco spring) to see if I could touch 8K RPM for the next half-hour of run time.

Came within a whisker of scooter-slaying a suicidal squirrel. Reminded me of the time I ran over an adult raccoon with my XS-750 Triple, but now I'm dating myself.*

Wheelz

*The sex is good, but conversation is trite.