Bad crank seal = Melt down on left cylinder
1) Fuel system clean- tank rusty?Phosphoric acid treatment.
Cross over tube clean -pipe cleaners
Petcock clean replace gasket @ fuel selector
2) Carburetor clean
Clean all passageways compressed air, Pilot, choke, nozzle, air, fuel
Inspect needle and seats -if visible x5 eye loop wear mark replace
Remove air screw, clean with steel wool tip
Remove needle Jet [Nozzle] clean all debris off shaft, clear holes, hone cavity.
Set float height as manual stated RD350 = 15mm +/- 1mm RD400 = 23mm +/- 1mm
Remove Jet Needle from slides -clean with steel wool -note type and clip position
Clean pilot jet -guitar wire to clean all holes -shoot with air
3) Compression - test both cylinders [dry] must be a minimum of 100psi both sides
Both sides should be within 5% of each other.
4) Timing- NOTE: Battery must have at least 11 VDC
Inspect points -pitted (R&R) replace or repair file down if in limits
Set gap to 0.012" - 0.016" [0.014']
Using a dial indicator [metric preferred] set timing to 2.0mmBTDC
If motor work and pipes, big carbs 1.8mmBTDC -Retarded
5) Install new plugs as recommended R5-RD350 B8hs, RD400 B8es
gap to 0.022" - 0.026"
6) Start that mother up!!!!
If all was done correctly 1-2 kick should bring it to life.
7) If Right pipe [sitting on bike] smokes more than left crank seals will need to be replaced
For GOD sake this is a 35-39 year old bike rubber parts wear out due to many years of exposure.
If seals need to be replaced Jetting will be a bitch -left side FAT jetting right side LEAN jetting. If the labyrinth seal is weak both sides will smoke.
8) Noise in the engine - Slappy pistons will make noise- Ride the Bitch.
When you are riding and it slows down and will not start. Wait for 10 minutes then start and go home you have just experienced a seizure. Medication for this is a new top end! YEY!!
Off you and your wallet go, new tires, chain and sprockets, brake rebuilds, rubber parts, new odds and ends. YourWifehas to love you a lot or the bike for this to work... Once you ride a well tuned RD you will find it is not the fastest bike out there. But is sure is fun, power band is an addicting thing on these bikes
Shop Phone: 512-575-7018