Flash IV

[z50r-ghost]

...i will be the one to axe: what mini-stroker cranky did ya order from BeeT Cycles?

(everything else in your thread looks freaking good, dude. nice work!)

hope all is well with you dude,

Later, jon and ang

[Wheelman-111]

Greetings:

Thanks, Jon! I got the 44.1 Ruima job that Burnt is selling at ScootSpecs. Should I use the Ruima-supplied bearings, or spend the few extra coins for Genuine Honda? Snagged another set of 8.4:1s from him too. It may not top out much faster than Flash III, but I have a feeling it'll get there quicker.

I hope this stuff arrives soon. I've been "porting" the car mirrors, apartment walls, my toenails,...

Have Roto-Zip, will grind.

[dem0nk1d]

Honda bearings! Nothing else. I wouldn't trust any other bearings. Honda FTW! Unless your using * bearings which i hear good things about.

[Wheelman-111]

Greetings:

Thanks DK. I was leaning that way. Honda-san spends on the important stuff. * has been producing good stuff for decades, evidently before the name took on the modern connotation. Be assured that I will examine the Ruima's balls closely.
What I'm wondering is where the cred for Honda cranks comes from. Are the cranks really tougher, or do the failures of lesser shafts arise from inferior balls? (bearings)

It might be interesting to examine the results of comparative destructive stress testing. Bend until it breaks. Expensive though, Honda-san wants more than $200 for a crank!

[z50r-ghost]

What's up, Mr. Wheelman!

Good choice on cranks... I had a Ruima crank in my Af16 before I bought the SEF crank. Ruima definitely is some high quality stuff. When you said "BeeT" I thought you were meaning "VT" - or "Vee-T" Hahaha! Good to hear you got it from Mr Toast.

As for the bearings, yes sir, I would go with the factory Honda (NTN Japan) bearings. What I would be interested in seeing is if the Ruima crank actually comes with NTN bearings... I have seen alot of Taiwanese scooter engines (such as SYM and Kymco) which only use Japanese bearings. -I guess that are some things that the Taiwanese still leave to the Japanese, like bearings, oil pumps and in some cases carburetors. I have seen a ton of cheapy Chinese scooters that use genuine Mikuni carbs.

I have ALWAYS heard from the Hawaiian "808" guys about the stock Honda AF16 cranks' reliability / durability. Evidently the stock crank & conrod can handle some high RPM's as well (or would it be those Honda bearings...hmm) My guess is that the Honda crank is absolutely PERFECTLY balanced, they are probably pressed together tighter, use better needle bearings and shims, and are made from a slightly higher quality metal.

However, the Taiwanese really know their scooter performance. The SEF full-counterweight crank I have looks dead-on a stock Honda crank; it is absolutely a beautiful piece of metalwork.
-The SEF crank is cool because it is not quite a "mini-stroker" crank; it's stroke is between a stock stroke and a 44.4 mini-stroker. No one in Hawaii quite knows the actual stroke of it.... From what I have been told, the benefit is it does not require as thick of a "spacer" base gasket, so the port-timing is not as affected on a 72cc Corsa kit (designed for the stock-stroke crank). (But it has the little bit of extra torque of a mini-stroke)

Anyways, keep us posted on your progress, Guy. You always do some really accurate, spot-on builds.

Later, jon

[Wheelman-111]

Greetings:

Roger on the quality of the Japanese bearings. The folks from the Land of the Rising Sun have equalled - even surpassed? -Der Fatherland in terms of quality balls. I remember when Made in Japan was synonymous with cheap crappy stuff. Even the early ancestors of your MonkeyBike were not hundred-thousand-mile mounts. My much-abused CT-70 needed a rebuild after only 10K in fact.

But the Japanese learned from their shortcomings, and so will the Chinese once they get beyond their Low-Price-Above-All philosophy. I'll be sure to pic and post the bearings when they arrive next week. Yes that is a threat.

I have ALWAYS heard from the Hawaiian "808" guys about the stock Honda AF16 cranks' reliability / durability. Evidently the stock crank & conrod can handle some high RPM's as well (or would it be those Honda bearings...hmm) My guess is that the Honda crank is absolutely PERFECTLY balanced, they are probably pressed together tighter, use better needle bearings and shims, and are made from a slightly higher quality metal.

Agreed on the materials quality and care taken in assembly as a big factor, but (in bold) you've hit upon the crux of my question. When cheap cranks fail, is it the shaft or the bearings in which it rides? I guess it's a moot point, unless one can improve the reliability of a Taiwanese crankshaft simply by fitting better bearings.
However, the Taiwanese really know their scooter performance. The SEF full-counterweight crank I have looks dead-on a stock Honda crank; it is absolutely a beautiful piece of metalwork.

-The SEF crank is cool because it is not quite a "mini-stroker" crank; it's stroke is between a stock stroke and a 44.4 mini-stroker. No one in Hawaii quite knows the actual stroke of it....

I believe the Ruima is advertised as a 44.1 stroke. You'd think the stroke would be a dead-simple thing to measure, even with primitive Wheelman rock-and-stick toolkit. A couple of v-blocks and the depth gauge on a digital caliper...

Anyways, keep us posted on your progress, Guy. You always do some really accurate, spot-on builds

You do me too much honor. Just havin' fun boltin' up parts in the Boudoir. The poor quality of my pictures hides many flaws...

[Wheelman-111]

Greetings:

Awaiting hardware arrival, here's a pic of the empty crankcase as Honda-san ordains:

Teeny-tiny stock Boost port visible framed in blue.

E4BoostStock.jpg (168.19 KiB) Viewed 4407 times

It may grow a mm or two when the mini-stroker, with it's thick base gasket, arrives.

[Flea_Biskit]

Sorry if I missed it but, whats the monster going in? Or is that a suprise ending?

[odinxxix]

For Wheelman its probably going to be more like a HAPPY ENDING!!!

[Wheelman-111]

Greetings:

Got a passel o' parts from Hither and Yan last night:

E4ToolParts.jpg (264.43 KiB) Viewed 4342 times

Even the cat was excited!

LunaTools.jpg (161.41 KiB) Viewed 4339 times

The Ruima crank stroke measured 44.1, as advertised. The Gasket Stack measured 2.7 compressed, so that should work nicely. Cool detail on the crank:

E4CrankBelt.jpg (176.8 KiB) Viewed 4338 times

Little brass logo. Evidently made with Pride! The whole assembly had a quality look and feel. Shot-peened connecting rod and very little side play by feel. Bearings were not NTN Honda but appeared to be of very high quality nonetheless.

[Wheelman-111]

Greetings:

Bee-Tee's Ruima ministroker crank came with a set of gaskets to raise the cylinder, offsetting the increased piston travel. The gasket provided a template with which to mark the needed boost port matching:

E4BoostScribe.jpg (182.58 KiB) Viewed 4330 times

Man that stock boost port cutout is small! Hmmm, 12mm to 24.3mm wide... that's an awful lot of material to remove, even with a carbide bit in Trusty Roto-Zip. What to do? I used a cutoff wheel, carefully following inside the scribed lines, in order to start a groove large enough to stabilize...

E4HackSaw.jpg (242.1 KiB) Viewed 4325 times

Yes, that's a hacksaw, powered only by Massive Wheelman Muscles. The chunk of metal sitting there represents the material removed. One side took about 40 minutes of patient, cautious work. You can't afford to even scratch anything here or the cases are toast.

E4BoostHalfDone.jpg (180.58 KiB) Viewed 4324 times

I went a little wide toward the front, but had drawn the lines inside the gasket anticipating that near-certainty.
CAUTION: There's not a lot of overlap between the cases at this point around the curve of the mating surfaces. The cases themselves don't use all the room available because of an apparent casting mismatch. Removing material in this area reduces that area even further. Hondabond only goes so far...

Now to address the even-skinnier Left case, then clean up casting flange inside the crankcases here and there.

[Wheelman-111]

Greetings:

I attacked the Left crankcase tonight. Same method with more confidence.

The desired boost port width.

E3Boost24mm.jpg (205.9 KiB) Viewed 4283 times

Here's the chunk of material removed. I had to angle the L case differently to avoid cutting too much of the case mating surfaces away.

E4BoostChunk.jpg (80.5 KiB) Viewed 4255 times

The end result appears below.

The End Result.

E4BoostFinal.jpg (198.47 KiB) Viewed 4283 times

E4BoostF24.jpg (211.38 KiB) Viewed 4255 times

Also assembled the new Ruima 8.4:1 gears from Burnt_Toast. Washer spacing needs to n sorted out, but the Tusk Tool also pulls the clutch shaft nicely! Lucky day

Next to lube and install ministroker crank. I decided to go with Honda main bearings. RUIMA bearings and seals will go on eBay unless I hear from someone here first.

[Wheelman-111]

Greetings:

Assembled the crankshaft with extra HondaBond near the cut-down boost port this evening. I ran an extra bead inside and out for good measure.


The boost port isn't symmetrical. That's all the material I dared remove, because the case junction is very narrow at that point. Hence the extra Hondabond.

The Tusk tool works pretty well, but lacks the seal installation feature.


I also reinstalled the rear brake and alternator assemblies. OK, show of hands: how many of you have gotten the alternator on, only to discover the forgotten right crank seal afterwards? Anyone? Nobody?! Hmm, what a bunch of dirty stinkin' liars!

No matter, my little flywheel puller also works great.

Doesn't disturb the crank bearings. Anyone have access to the depth necessary to drive those seals? It was 9mm for one side on the AF05, but I can't access the specs for the 16 on BB. [Ed: MouseWheels got me the 411: 5mm. Thanks, M!)]

Anyhow, Phase I is done, ready for a bore kit. 51mm makes it an even 90cc, but those thin cylinder skirts make me nervous!

[mousewheels]

Came out real nice - That's a lot of hand sawing

No matter, my little flywheel puller also works great. Doesn't disturb the crank bearings. Anyone have access to the depth necessary to drive those seals? It was 9mm for one side on the AF05, but I can't access the specs for the 16 on BB.

SA50 service manual page 10-5 has is - 'After '93: 5.0mm (0.20 in)'

[Wheelman-111]

Greetings:

Thanks Mouse! As my incredible luck would have it, that's exactly how far I pushed it in. I figured it'd be easier to push it farther than to try pulling it back. Besides, 5mm just looked/felt right. Reminder that the Tusk tool, unlike Honda-san's, does not feature a reversible collar that pushes the seals. However it's less than half the price and you can work around the seal issue, not so much the crank pulling thing.

Adding Wheelman "Pics" (Eeek! ) to last post.