Diagnosing a Missfiring 2 Stroke! (Yamaha RD350 Twin)
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- čas přidán 26. 09. 2021
- The RD started missfiring and totally lost a cylinder on the way home from work. Spent the evening tearing it down and checking everything to no avail....then I realized one of the spark plugs were fouled :) facepalm
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I remember when my plugs would foul in my R5 350.
It’s good to know all of the tune up is correct anyway
I ran with K&N open air filters and standard automotive large black ignition coils stamped on the down tubes up front.
I sold that bike over 20 years ago but picked up another (71) to do it all over again!
Have fun and be safe.
:-)
A little advice. Don't leave the ignition on any longer than you have to. It can burn the coils out. Nice bike.
Love the sound rd make it bring back memories when i was a teenager
Loving your RD content.👍
Thank you!
* strapped to the frame (standard auto ignition coils had more punch than stock 1971).
Good Idea to use Dielectric Grease on all connections since the bikes are pushing 50 years old! Yamahas are some of the Most Reliable 2 strokes out there I own 5 RD'S Nice 350! Last year!
I am watching your video so still don’t know the conclusion. However, the RD350’s were notorious for fouling plugs. They don’t like to loaf around but rather prefer to rev. Yamaha solved the fouling problem with the introduction of the RD400 (I owned both). If your problem is plug fouling (well, done now 2 years later), maybe changes in oil pump and carb jets. Small changes make a big difference.
The problem ended up being fouled plugs all along, but it gave me a chance to verify timing before I put on the HVC performance heads afterwards, so I didn't mind checking over everything. The plugs were older and went through a variety of jetting tweaks before I got it right, so must have just fouled out during that period of time.
Nice custom RD! I just recently bought a ground up restored '75 RD350 but haven't had a chance to get to know it yet. But on my '75 Zuki GT185, it's really picky on plug types. It misfires like crazy with anything but an NGK BR7ES, even though the Haynes manual called for a B8HS.
buying an RD from a friend, your videos helping me learn a ton!! keep it going! The one I'm looking at needs a good going through lol
Love to hear it, thank you! Don't worry, this RD was also a barn find sitting for at least a decade when I picked it up in 2018. Just takes some time and dedication to get them back on the road!
points and plugs my friend! i used to own one!
Yeah I always carried tools and a spare set of NGK's when I had mine lol
Drop the points and replace with something electronic like a Zeel. Well worth it. Don’t forget to put a drop of oil on the felts!
There’s a lot of sparking at the points so definitely time for a new points condenser (the cylinder at the bottom). That will slow the points erosion and give a stronger spark at the plugs. CDI conversion best though.
Quick disconnect on the crossover is nice. Such a pain with a full tank. Remember that problem from the 80s!! And catching the throttle cables so having to do it all again. More petrol everywhere….. Good times!
It needed a plug because it fouled, it fouled because the spark was weak, it was weak because the gap wasn’t right. It told you what was needed and you nailed it. No bummer there, all sorted. 👍👏
Very nice
Great video and nice running RD Enginerded. I have a very stock rd350b and enjoy the he'll out of it. Was wondering if you timed the right cylinder the same as the left? Also have you installed the new heads? I know they require re torqueing after each heat cycle. The last thing I wanted to say is a change of plugs stuffed in the tool kit is a must on a lot of 2 stroke bikes. Just in case! Good luck to you Enginerded.
Thanks, and that 350B has got to be sweet! I believe I got the timing right. Bike starts and runs like a top and I put a few hundred miles on it after this video as well as with the new heads on it. The video i posted after this one is where I installed the heads, check it out if you're curious!
Top man for using JIS driver's you can get impact bits as well
Vape electronic ignition although expensive it is worth the money far stronger spark and maintenance free
That is on the list for later on down the road!
Hi, can you tell me where to buy screw drivers for your Rd? Thanks!
I bought mine from amazon! Highly recommend them, get the fullest set you can find (Vessel brand JIS screwdrivers). Worth every penny
Any video of the front end swap? What was the cost?
Haven't made anything specific to the front end swap, but i can make a video sometime going over what was involved! I designed in CAD and had machined multiple parts to adapt the front end to the bike. Was a really fun learning process for me and made something unique. Using 2017 honda grom forks with racetech springs suited for my weight and the bikes weight
Second that, would also like to see a video of the conversion.
It seems when they are hard to start or one cylinder craps out, it;s usually a bad plug
That's true, gotta check for the big 3. Compression, fuel, spark!
Instal a cdi and be done with it.
way too expensive
I love stock RD's, I have a 77 RD400 but the one thing I splurged on was a VAPE and I can not believe how much nicer the bike feels. It might just be the added flywheel weight effect but the engine defo feels better, I noticed it instantly. I also tried an HPI ign but there is basically no flywheel effect at all and I hated how the bike behaved at lower rpm and needing a higher idle just to keep it ticking over turned me off. Be fine if I was tracking the bike but around town all my time is spent in lower/mid rpm.