Project: Tumblr (1984 Yamaha TriMoto 200 Rebuild)

[StarFury]

So, 3 weeks ago I picked up this beast, it was in rough shape cosmetically. Needed the carb rebuilt, rubbers and just some love. Yes, that's faux bear fur as a seat cover.
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Spent the last few weeks tearing down...
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Sanded and Rhino'd the chassis...
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Put a Wiseco 68mm HighCompression Piston, Enameled the Engine and Exhaust
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New Rubbers from Duro
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My buddies at work called this the 50/50 Gears of War inspired paint job...Looks kick ass in my opinion.
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Got that hideous seat upholstered with marine grade leather.
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Installed a rear rack and started putting everything back together this past weekend...
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After 3 weeks, I think I've got a winner. Been tweaking the carb the past couple of days. Jetted the carb with a Sigma 6 carb kit. The blue healight tint is from Lamin-X.com for about $7.
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...and here's my dilemma. Finally got the thing to start w/ and w/out the choke. My needle is on the 2nd from top position, mixture screw is @ 2 1/4 turns, and fuel stop is just about 2 turns from being all the way in...and I'm still running rich. I've looked, searched, asked, downloaded the service manual, and I'm exhausted. Couple of questions...how does turning the mixture screw affect it (e.i. screwing in allows more air or the opposite), same with the fuel stop. I'm frickin' stuck...

Wheelie's like a beast!!!

[barnett468]

Hello


Jetted the carb with a Sigma 6 carb kit.


What jets are currently in it?

Did you modify the slide or carb body as they recommend?

xxxxx

Finally got the thing to start w/ and w/out the choke.


How cold was it when it started without choke?

Did it start easily without choke ie 2 or 3 tries?

If it starts easily with no choke and it is 60 degrees or less air tewmp it is slightly rich on start circuit.

Pilot jet slightly rich or idle mix screw too rich.

Xxxxx

My needle is on the 2nd from top position, mixture screw is @ 2 1/4 turns,


Good

xxxxx

fuel stop is just about 2 turns from being all the way in.


What do you mean by fuel stop?

Are you talking about the screw used to set the height of the carb slide?

Do you know which screw is which?

The screw closest to the motor is the idle mix screw not the slide screw.

xxxxx

I'm still running rich.


Please explain EXACTLY in detail what causes you to say this?

If it “burbles/stutters” under acceleration from a stop or cruising speed it is rich.

If it simply hesitates and doesn’t go under acceleration then it is lean

What color is your plug?

White is lean, med tan is good, DRY black is rich, moist gooey black is burning oil.

Xxxxx

I've looked, searched, asked, downloaded the service manual,


Here’s a Clymer’s manual, takes 5 minutes to load..

http://www.oscarmayer.net/atc/manuals/Yamaha/ytm200-225-fm200l.pdf

xxxxx

how does turning the mixture screw affect it (e.i. screwing in allows more air or the opposite), same with the fuel stop. I'm frickin' stuck...

xxxxx

Wheelie's like a beast!!!


If it runs this good your carb must not be off by much.

Xxxxx

Does it smoke?

Can you do compression test, not necessary just curious?

Xxxxx

What are your jet sizes?

Std settings

Main 102.5
Pilot 35
Starter jet 65
Needle 4l25-3
Mix screw 2 1/4 - 2 ½
Float level 21.5 mm

XXXXX

CLYMERS MANUAL CARB PG 177-178

http://www.oscarmayer.net/atc/manuals/Yamaha/ytm200-225-fm200l.pdf

[dougspcs]

Great looking build..the best kind in my opinion!! The rideable kind!!

They don't have to look showroom when they're done, but if the inspiration and thought behind it is sound it'll turn heads..

Good job..


Couple of questions...how does turning the mixture screw affect it (e.i. screwing in allows more air or the opposite), same with the fuel stop. I'm frickin' stuck...

Wheelie's like a beast!!!

In answer to your question..

1/ if the mix screw is before the throttle plate/slide then it's an air mix screw.

2/ if after the throttle (which yours is) it's a fuel mixture screw.

So if you close the screw in theory it will lean, screw it out will richen..for the 1st type the opposite.

Check your choke plunger and make sure it's seating all the way when the choke is off..if it's stuck part way open you have uncontrolled amounts of fuel dumping into the intake..you'll never get it to dial it.

And your 'fuel stop'..do I assume you are talking about the idle speed adjuster??

[Woodsrider]

What a transformation! Looks awesome !!

[JasonB]

wow man that looks great! and that fur seat was awesome lmao


what coating is that on the fenders, did i miss that? I like the rhon'd frame too. Bet that's durable as heck

[Fink]

looks good brother

[StarFury]

Fuel stop...idle screw. A friend of mine kept calling it while he was over, must've lingered. Yes, the idle adjustment screw on the side. With his help, got it a little more dialed in. Mostly adjustments to the fuel mixture screw (Thanks Dougpcs), idle adjustment, and choke plunger.

Main jet and pilot jet were all swapped out with the replacements from Sigma6. I did however follow those install instructions to the "T" and wasn't too complicated. The tuning gave me run for my $$$.

Clymer's Manual helped alot as well, Thanks Barnett468

Jason B, What I did with the fenders: 1, sprayed with Krylon Fusion....2, Rustoleum Bedliner Spray (same stuff as Rhino-lining, used it on the chassis as well)

[Adrenaline]

Really Nice Job! Use it well!