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Author Topic: jetting for rd350 no baffles  (Read 1800 times)

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Offline SCHMITZ

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jetting for rd350 no baffles
« on: June 28, 2011, 08:09:45 PM »
Hey guys. Couple o' noob questions. '73 RD 350

1: can you adjust the amount of oil the autolube imports?
2: given the following parameters and assuming clean fuel delivery  and spark why am i oil fouling the plugs?

NO BAFFLES
Injector= Yes, working
Pilot jet=  stock
Air jet= Stock
Air screw = 1.5
Needle jet= Stock (Mikuni VM28)
Jet Needle / clip = need help
Main jet= 160 (need help)
Filter type= Y-boot / K&N

also the brass main jets (as gentle as i was) had some threads shear off. i am 'mostly' sure that i got the tiny bit of metal out of the main jet housing...how bad is that? :sigh:
Thanks! and any austinites two stroke mentors who wanna grab a beer and share the knowledge...i'm buying.
1973 RD 350

Offline Makin Treehugrs Mad

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Re: jetting for rd350 no baffles
« Reply #1 on: June 28, 2011, 09:39:50 PM »
You can adjust oil delivery at idle with shims - thicker ones reduce oil, while thinner ones increase oiling .. but only at closed-throttle. Clearance specs are in the service manual. I suppose you could get creative with gear sizes on the oil pump, but that would be going way overboard with this IMHO.

When my bike was stock except for the Y boot/ K&N, I ran a 260 main & 27.5 pilot. It was still lean with the 260. YMMV. I had the stock pipes with the baffles removed, & some home-made metal "baffles" bolted in their place - presumably to pass the "rod-in-the-pipe" baffle check by the cops.

You could be fouling plugs due to a weak battery/spark. Or could be as simple as a plug change.

As for the brass threads, you could just do the Dave F. mod which requires replacing the needle jet anyway, thus fixing the thread issue. But if you can get the main snug enough  I wouldn't worry too much about it for now.
« Last Edit: June 28, 2011, 09:40:35 PM by Makin Treehugrs Mad »
RD350A with B cosmetics
RD200 (in need of lots of my time)
Several '86 Yamaha BW80S 's
'01 KDX220R (sold ...to pay for RD rebuild!)

Offline SCHMITZ

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Re: jetting for rd350 no baffles
« Reply #2 on: June 29, 2011, 09:37:48 AM »
cool. I checked my charging system and it appears that it is putting out  around 14v. the point s/condensors and plugwires were just done at the shop. new plugs today and i'll go with the 260 jets if these  oil foul. thanks for the help!
1973 RD 350

Offline snorkelfork

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Re: jetting for rd350 no baffles
« Reply #3 on: June 29, 2011, 11:30:18 AM »
I think I saw your bike over at Limey's shop yes?

I'd be careful about tinkering with the pump shims till I had addressed all my other options.

you might for one check to make sure that the left and right carb slides have not been swapped. the cut away should face the air filter. that will make your bike foul plugs regularly.

I'd also track down some baffles to eliminate that variable. I have a buddy who just pick up a parts lot and might have some spares locally.
-{connoisseur of slack}-

74' rd350
75' G3ss
85'RZ350

Offline SCHMITZ

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Re: jetting for rd350 no baffles
« Reply #4 on: June 29, 2011, 12:49:30 PM »
that's the bike! i spoke with him a bit today. didn't realize that he had not changed the points on the bike (!!!!)  before i ran out of money. so i 'll order the tune up kit (30 bucks?) and start there. i get paid wed and am looking for baffles so if you run across any on the cheap i'd be most appreciative. :bowdown:

Cutaway towrds air filter...hmmm I'm afraid i might need a visual for that. i see a cut away that looks like it's for the air screw clearance.

and i think i'll leave the autolube alone....babysteps..
thanks for all the help!
1973 RD 350

Offline RLloyd

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Re: jetting for rd350 no baffles
« Reply #5 on: June 29, 2011, 01:45:29 PM »
I'm in Austin and have some stock baffles you can have.  They're off the massively neglected '73 350 I'm cleaning up, so they're kind of messy, but they're yours for free if you want 'em.  Shoot me a PM.
'73 RD350, Spec II F1 chambers, K&N filter w/ Y-boot, TDR Hypertension reeds w/ modified cages, Banshee manifolds w/ crossover, Dave F. carb mod, Pre-mix, Vintage Smoke electronic ignition, etc.

Offline snorkelfork

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Re: jetting for rd350 no baffles
« Reply #6 on: June 30, 2011, 08:37:34 AM »
see below

the slide is essentially a cylinder with a wedge cut away. you can't really get them turned around if they are in the correct carb but you can swap them from left to right. If that happens the bike will run like a dog smoke like mad and foul plugs a lot but it will start first kick. kinda like riding with the choke on all the time.

-{connoisseur of slack}-

74' rd350
75' G3ss
85'RZ350

Offline SCHMITZ

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Re: jetting for rd350 no baffles
« Reply #7 on: June 30, 2011, 03:29:49 PM »
ahh. thanks for the diagram. checked it out and looks good. new plugs and i got her to start up and idle a bit. took her down the block and same booggy at low rpm a backfire and then it screaming fast for gear 2 into 3 then pull clutch in and she dies. ordered a ignition tune up kit. not real handy with points or timing. but i gotta start somewhere right?   :confused:
1973 RD 350

Offline snorkelfork

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Re: jetting for rd350 no baffles
« Reply #8 on: June 30, 2011, 03:56:25 PM »
doing it really is the only way to become proficient at it. the first few times might take you half an hour but once you have it down you can do the same points adjustments in five or ten minutes

-{connoisseur of slack}-

74' rd350
75' G3ss
85'RZ350

Offline RLloyd

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Re: jetting for rd350 no baffles
« Reply #9 on: July 01, 2011, 02:45:00 AM »
You still want those baffles or are you going to give it a go without them?  I'm about to go pile up a bunch of rusty bike shit next to the trash can, but I'll hold off on tossing the pipes just in case.
'73 RD350, Spec II F1 chambers, K&N filter w/ Y-boot, TDR Hypertension reeds w/ modified cages, Banshee manifolds w/ crossover, Dave F. carb mod, Pre-mix, Vintage Smoke electronic ignition, etc.

Offline SCHMITZ

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Re: jetting for rd350 no baffles
« Reply #10 on: July 05, 2011, 01:15:51 PM »
was pretty sure i sent my ph number to ya. i'll try that again.
1973 RD 350