Re: The Official Yamaha Chappy (LB50) Thread!!!

getting close to the payoff now... final challenge, retain the nut in the arrestor housing.

pilot hole in housing (first attempt on left was too "high" to catch the meat of the nut):

20190709_161918.jpg

marked and drilled the nut:

20190709_161907.jpg

found a roll of fiberglass house insulation, peeled off a bit, wrapped the perf tube tightly, eased/packed it into the arrestor housing, threw in a self-tapping screw and went for a spin!

20190709_211213.jpg

initial reactions:

definitely less restrictive than the arrestor. had to richen up a bit, picked up 2-3 mph on the flats, but more noticeable in the midrange. all well and good, but the best part is IT'S QUIETER. that makes me happy since i'm free to open up the muffler chamber restrictions a bit more.

Re: The Official Yamaha Chappy (LB50) Thread!!!

midrange was puffing so much that i had to do some needle surgery!

20190708_210927.jpg

Re: The Official Yamaha Chappy (LB50) Thread!!!

Kenneth,

Very cool! Love the dedication, detail, and resourcefulness. You have taken the stock appearing performance exhaust to the next level! Awesome to see both performance gains as well as a reduction in sound with your homemade "baffle" system. Just to confirm, your bike is a stock carb, stock cylinder LB50?

Re: The Official Yamaha Chappy (LB50) Thread!!!

not stock, no. lb50pj with a polini "70cc" kit. i shaved about 1mm off the stock head with some sandpaper on tempered glass (still gotta test compression, probably around 10-11:1). intake manifold is MLM, carb is vm20, 15 pilot, adjustable main (probably around 150), stock needle (now on position 6.5). i found a way to reuse stock airbox/resonator with the vm20/MLM:

20190708_204500.jpg

aluminum tube is an old "carb manifold preheat" hose i picked up on amazon, shaped carefully by hand and hose-clamped on.

https://www.amazon.com/dp/B000C5G8Y0/

i drilled four more 1/2" vent holes in the back of the oem airbox and snipped off a bit of plastic from the back of the box, and wedged in a cheap filter that fit just right.

https://www.amazon.com/dp/B00SQNJTZ0/

20190708_202921.jpg

Re: The Official Yamaha Chappy (LB50) Thread!!!

MLM People's Pipe arrived yesterday for my LB50. Got right to installing it. Pipe bolted right up and required no modifications, unlike when installed on my LB80. It seems they have changed the mounting brackets just slight to aid in installation.

However, the bike is an absolute turd with the MLM. Almost as slow as stock. The bike struggles to get up to 20 mph. I was able to get it up a hill and run downwards to which it was able to get up to speed and maintain once the hill leveled out. It hits a power band but its wayyy up there. I suspect the tiny cylinder combined with the extremely short header length is to blame. My quick questimation puts the MLM header about 6 inches shorter than the stock header (the stock header has an S bend which adds length). My next plan of attack is going to be lengthening the MLM header, probably my mimicking the stock header shape, less an inch or two.

I put the stock modified exhaust back on because I couldn't believe it, and the bike zoomed right to 36-37mph. So its the pipe and not something transient. I will post findings here (edited)

IMG_1357.jpg

Re: The Official Yamaha Chappy (LB50) Thread!!!

Dirty30 Dillon /

Did you rejet when you put the MLM pipe on?

Re: The Official Yamaha Chappy (LB50) Thread!!!

The bike had a 115 jet in before with the stock modified pipe, and it was running rich. Cylinder head temperatures on my last 30 mile cruise at mid 30mph, never exceeded 300*F. As such, I left the 115 jet in since it seemed to have some overhead. After installing the MLM I messed with needle and it seemed to be less forgiving going down, than up, so if anything it wants a smaller main jet. I highly suspect header length is to blame for the huge drop in low end performance. I remember when doing hack and welds on older projects, even an inch change one way or another in header length had dramatic effects on acceleration / top end.

Re: The Official Yamaha Chappy (LB50) Thread!!!

hunter, you have the same MLM PP on your lb80? and it didn't react the same way at all?

ken

Re: The Official Yamaha Chappy (LB50) Thread!!!

Ken,

Yea totally different experience with the MLM Peoples pipe on my LB80. On the LB80, the pipe softened the bottom end a little, but gave a general increase in power everywhere else. Acceleration at higher speeds was drastically improved with the pipe. I will tackle the header length this weekend on the LB50. I already made the cut! there's no going back now lol

~Hunter

Re: The Official Yamaha Chappy (LB50) Thread!!!

grabbed one of these off Amazon a few weeks ago...

Ailavi DC-DC Buck Converter...

https://www.amazon.com/dp/B00XPZ7I4I/

last night i soldered a couple of bullets on it, (begrudgingly) used a vampire tap to snag switched 6v battery voltage in the headlight housing (dark brown to speedo cluster) , wrapped it with electric tape, and stuffed it all back together.

cheap and works a treat to keep my phone charged on longer trips when I bust out the ram mount.

Re: The Official Yamaha Chappy (LB50) Thread!!!

That’s pretty slick

Re: The Official Yamaha Chappy (LB50) Thread!!!

had a nice long ride with a decent downhill today...

20190714_154914.jpg

flats are slightly shy of 40.

note: this is with a 16t front sprocket, oem 32 on rear, and shinko white walls (slightly taller than stock). this nets almost exactly 5mph/1k rpm.

Re: The Official Yamaha Chappy (LB50) Thread!!!

This is the rough markup of the MLM Header extension I made. It has since been fully welded and ill get a video up in a couple days. Added approx 6 inches to the header length. The "bends" weren't really planned, I thought I was going to have a harder time fitting extra length of pipe in the small space under the header but I didnt. Also, factory bracket cut and moved forward (moves pipe back) an inch. Low end power has been restored to that of the modified stock exhaust. Powerband kicks in around 20-22 mph, and pulls smooth to 40. Video soon with more details. Hope to see how it stacks up to Ken's ^

IMG_1408.jpg
IMG_1409.jpg
IMG_1410.jpg

Re: The Official Yamaha Chappy (LB50) Thread!!!

Brandon Weiss (Detective brandon to you) /

Wow, very nice pie cuts

Re: The Official Yamaha Chappy (LB50) Thread!!!

> Brandon Weiss (Detective brandon to you) Wrote:

> -------------------------------------------------------

> Wow, very nice pie cuts

Thank you! Lots of pie was had

Re: The Official Yamaha Chappy (LB50) Thread!!!

finally had a few hours to revisit oem exhaust and remove the silly restrictor/pipe/whatever.

a little touch with a cutoff wheel and the tab at the "top" was free. then a little wiggling and the couple of spot welds at the "bottom" popped off too.

beforeafter1.jpg_resized_17.jpg

so it wasn't really sealed at the bottom, but the circumferential gap was so small (~1mm or so) that for exhaust flow purposes it was.

looking up the inlet, before and after:

beforeafter2.jpg

now that's a good deal better!

while i had it opened i popped two more "shunt" holes from front chamber to the exit:

20190717_165128.jpg

took it into work this morning and initial impressions:

a bit louder, but nothing obnoxious. i think it's perfect actually, draws a little attention but it's not HEY LOOK AT ME loud. got a little more raspy, likely due to the shunt holes, on decel with the pops and burbles.

had to open up the main jet a bit. no hard numbers, but dialed out the adjustable needle 1/4 turn.

i BLEW up a steep hill that normally bogs me down to around 25mph. engine really held rpms up throughout the pull a lot better than before, probably sustained 30. was surprised.

top speed change is currently unknown... roads were wet this morning and i was taking it easy while dialing in fuel. acceleration is improved for sure.

so far, so good.

ken

Re: The Official Yamaha Chappy (LB50) Thread!!!

> Hunter Skiff Wrote:

> Thank you! Lots of pie was had

hunter, am i correct that even with your mods the MLM PP is a no-go with pedals?

ken

Re: The Official Yamaha Chappy (LB50) Thread!!!

Ken,

Love the detail and explanation. I will make the same changes you've outlined above to my stock modified exhaust. Thanks for the further improvement!

The mlm peoples pipe does work with the pedals. Even before modification to lengthen header.

Re: The Official Yamaha Chappy (LB50) Thread!!!

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> After trying every combo of spring in the Chappy clutches, I am pretty

> frustrated.

dillon, i know you tried shortening the 1st gear spring by ~3/4". what other mods/combos did you try?

> No matter how stiff the spring I put in there is, I barely see an

> increase in stall. Combined with pipe, kit and carb, it means I have

> port stalling at low rpms which kinda makes the bike unfun.

agreed on this. the 0-5mph hole shot is underwhelming.

i'm wondering if we have to start lightening clutches?

ken

Re: The Official Yamaha Chappy (LB50) Thread!!!

> Hunter Skiff Wrote:

> The mlm peoples pipe does work with the pedals. Even before modification

> to lengthen header.

oh SWEET. for some reason i thought it didn't work with them. i ain't takin' off my pedals.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Dirty30 Dillon /

> ken gilbert Wrote:

> -------------------------------------------------------

> > Dirty30 Dillon Wrote:

>

> > -------------------------------------------------------

>

> > After trying every combo of spring in the Chappy clutches, I am pretty

>

> > frustrated.

>

> dillon, i know you tried shortening the 1st gear spring by ~3/4". what

> other mods/combos did you try?

>

> > No matter how stiff the spring I put in there is, I barely see an

>

> > increase in stall. Combined with pipe, kit and carb, it means I have

>

> > port stalling at low rpms which kinda makes the bike unfun.

>

> agreed on this. the 0-5mph hole shot is underwhelming.

>

> i'm wondering if we have to start lightening clutches?

>

> ken

I shortened the stock spring to no avail, but it did kind of help the sticking I had coming to a stop. The first gear clutch arms are braced via riveted guides that keep the clutch from arcing out of plane. Where the arms are touched by the guides, they are rubberized which causes a bunch of friction. I eased the tension on these guides of the arms so that the sticking stopped.

The tightest spring I used was a Stihl 100cc chainsaw clutch spring. This thing took me and a bud's entire musculature to wrestle on and i maybe saw a 500 rpm increase from stock... Very underwhelming.

The 0-5 is the worst part about what is otherwise a punchy 35mph bike. The one-way bearings in the first gear clutch bell and in the second gear main assembly give it really good coasting characteristic and also really good "pop" when you hit the throttle. But I just can really stomach the slow take off from a light, especially driving my Chappy through Manhattan.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /
chappy.jpg

Chappy spotted in South of France. Thought it might be a 3 speed but I can't tell.

Re: The Official Yamaha Chappy (LB50) Thread!!!

I spot the gear selector, and rear passenger pegs!?!?!?! How much $$$ would it take for you to commit grand theft and ship that puppy back lmao.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Dirty30 Dillon /

There is no foot shift on that, so it is the 2 speed w/o hi/lo that was offered in france.

Both the three speed semi and four speed full manual had LH foot shift. The chappy was never offered with a twist shift option.

Re: The Official Yamaha Chappy (LB50) Thread!!!

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> There is no foot shift on that, so it is the 2 speed w/o hi/lo that was

> offered in france.

>

> Both the three speed semi and four speed full manual had LH foot shift.

> The chappy was never offered with a twist shift option.

My mistake, at quick glance and zoomed out on my phone the right hand center stand foot appeared to be a left hand shift lever

Re: The Official Yamaha Chappy (LB50) Thread!!!

Jack Rutherford /

anyone catch the chrome fenders? yeah I searched in vain for a gear shifter. the buddy pegs rock

Re: The Official Yamaha Chappy (LB50) Thread!!!

wait, the buddy pegs aren't/weren't standard on every chappy??

Re: The Official Yamaha Chappy (LB50) Thread!!!

Eric Migliorino /

Also notice it has a double seat! Anyone know where to get one of those? Don’t think they ever made them from the factory with foot pegs for the US.

Re: The Official Yamaha Chappy (LB50) Thread!!!

Dirty30 Dillon /

That's the same seat as the US models it just has the leather grab handle across it

Re: The Official Yamaha Chappy (LB50) Thread!!!

anyone ever do a port map on the chappy polini kit?

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