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RD400 Ignition Timing (stock points)

Started by 2smokenNick, February 23, 2020, 08:36:03 PM

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2smokenNick

Hey all! I need some advice on getting my RD400 ignition timing right. I've heard many say to retard it back a tad to compensate for the crappy pump gas we have now but I'm not sure what to do. Just a little info on what my bike has: DG pipes, bigger jets(obviously), UNI pods with stock "manifolds" and the stock points setup with new points and condenser. Any help would be greatly appreciated!
:help:
Nick

RdsOnly

Stock timing is 2.0mm BTDC
  #1 Run good fuel
       100ll ave gas 60/40 NO ethanol pump 92

Retard = 1.9- 1.8 mm BTDC

Use good fuel and 2.0mm for round town fun. Long high speed runs 1.8mm

JT

2smokenNick

Quote from: RdsOnly on February 23, 2020, 08:54:35 PM
Stock timing is 2.0mm BTDC
  #1 Run good fuel
       100ll ave gas 60/40 NO ethanol pump 92

Retard = 1.9- 1.8 mm BTDC

Use good fuel and 2.0mm for round town fun. Long high speed runs 1.8mm

JT
Thank you for the info. If possible, I would be grateful if anybody that sees this post to share a detailed process of how to set the timing just right.
Nick

RdsOnly

Look in the Library on timing Mark did a video shows how.


RdsOnly

A helpful list
http://www.rdsonly.com/check-list.html
you can find other documents there as well.

Hope that helps


JT

Dvsrd

Quote from: RdsOnly on February 23, 2020, 08:54:35 PM
Stock timing is 2.0mm BTDC
  #1 Run good fuel
       100ll ave gas 60/40 NO ethanol pump 92

Retard = 1.9- 1.8 mm BTDC

Use good fuel and 2.0mm for round town fun. Long high speed runs 1.8mm

JT
2.00 mm BTDC is stock for the 350, I thought the 400 had more like 2.30 mm, due to its longer stroke. That said, 2.00 may well be a good compromise for a 400, running low octane gas.

SoCal250

#7
Stock timing is;
73-75 RD350               2.0mm BTDC
76-78 RD400 (US)       2.3mm BTDC  (+/- 0.15mm)
79 RD400 (US) 2V0     2.4mm BTDC  (+/- 0.15mm)
79 RD400 (CAN) 3J7    2.0mm BTDC
75 Yamaha RD125B   75 Yamaha RD125B (project)
75 Yamaha RD250B   75 Yamaha RD200B (project)
73 Yamaha RD350     77 Yamaha RD400D   79 Yamaha RD400F  
91 Yamaha TZR250R  89 Yamaha FZR400   05 Yamaha FZ6   
05 Yamaha XT225TC  82 Honda MB5  02 Aprilia RS250 Cup (sold)

SUPERTUNE

Quote from: RdsOnly on February 23, 2020, 08:54:35 PM
Stock timing is 2.0mm BTDC
  #1 Run good fuel
       100ll ave gas 60/40 NO ethanol pump 92

Retard = 1.9- 1.8 mm BTDC

Use good fuel and 2.0mm for round town fun. Long high speed runs 1.8mm

JT

I'll stand to correct you JT in a very polite way...Yes 2.0mm BTDC is correct stock timing for a RD350's with a 54mm stroke.
All '76, '77 and 78's RD400 are 2.3mm BTDC stock timing spec's with the US '79 Daytona Special 2V0 @ 2.4mm BTDC.
On modified RD350's I like 1.9mm on stockers or 1.8mm on modified setups for today's fuels.

2.0mm on stock RD400's with just all stock or just with pipes and air filter with proper re-jetting for moder fuels.
1.9mm is a great baseline for modified RD400's.

Chuck
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

SUPERTUNE

Oh, I see that Encyclopedia Russ is here and posted stock spec's! Thanks Russ!
C
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

2t Fan

Lame question   ;D

Do we set both cylinders at the same timing ?

Dvsrd

Quote from: 2t Fan on February 24, 2020, 01:38:12 AM
Lame question   ;D

Do we set both cylinders at the same timing ?
Yes. With "wasted spark" ignition, like stock RD350LC, YPVS, Powerdynamo CDI, etc, both plugs spark at the same time, so 2.0 mm before TDC and BDC. On individual ignitions, like points, Krober (Pietch), etc. the timing is set individually, to 2.0 BTDC, or whatever you prefer.

SUPERTUNE

The Dyna cdi kits in RD setups are 2 pickups also.
I suppose you could do a single pick up with a wasted spark and a dual output coil like for a inline four.
If I were to try that I would use the green race dyna coil (3 ohm) and not the black street coil (5 ohm)
C
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

rd400canuck

#13
dont mean to highjack but I am at this point in my build so thought id poke my head in....

I set my completely stock 1976 RD400c iggy to 1.8mm btd.

Im guessing it's perfectly safe to go to 2mm but 2.3 with modern gas aint a good idea?

m in sc

correct, id not go over 2.0 in a 400 with modern fuel and a static timing setup.