The Journey of a wrench and his first motorcycle

Excessive idle time is not good for the motor. You need to take the bike for a long highway speed ride to know what jets to use/tune. I don't even start a bike unless I can ride it for at least 20-30 miles. It loads up the motor with carbon.
I really appreciate the info xschris. I'll be sure to be very attentive to the sound and feel of the motor whilst logging smile miles. In your opinion, is seafoam worth anything?
Non-ethanol fuel and a good LONG ride will do wonders for cleaning. If your carbs are clean and your running a good fuel filter in the bike your good. The only thing I ever run in my bikes is a bit of lucas fuel treatment. It lubes and cleans everything fuel contacts.
So I disassembled the points but left the majority of the timing plate on. Points weren't looking to good so I got out the Swiss file and dressed em like the manual suggests. Gapped perfectly to .013 and set the timing with a multimeter looking for needle swing on gap. Spent all day yesterday triple checking these adjustments. Briefly fired the bike over but only for about 15 seconds. Decided to wait and triple check my adjustments this morning. I don't think I could have done better but of course now the bike sounds different nothing excessive but a lil "ticky-er". I also triple checked valve clearences. Everything is per manual. Here's the question. Where should I begin to look after finding a small amount gas in the carb boots. Float height? Triple checked to 26mm with gasket removed. Utilizing the + or - 1mm which way should I lean towards to close the needle a little sooner. Suppose its a 50/50 shot but no covered garage here in Arizona means a large chunk of daylight is just too hot and dry.
The float and needle valve regulate fuel delivery, they are not meant to stop it completely.
Check your petcock. If it's leaky it'll let fuel through and will overflow the carbs.
If gas is blowing out the carb while the bike is running you could have a bad seal on an intake valve.
Would it be safe to run the engine very briefly without the air filter pod to visually observe for gas? Will try petcock very soon, either replacement or rebuild.
Last edited:
Allrighty checking in.
Decided to take my time with a really good tear down and clean basically about 2-3 hours on the weekend and that's it. Button it up and repeat next weekend. Replaced all the torn up cruciform hardware with beautiful crisp button and socket head caps on the carburetors and timing plates. I meant to post pics of the carbs cause i think the level of cleanliness would make ya'll proud but i was so excited to get 50 bucks worth of bolts on it I didn't stop to get the camera. Decided to pull the petcock and found a few chewed up seals inside so i'm very excited to rebuild that once the kit is ordered. Honestly to keep my sanity though i won't be ordering till a few more weekends of deep through cleaning. I just wish it had come with the thousand missing parts i see in the manual that aren't on my bike. Whats pictured is what i got. I also think my needle was put together incorrectly. I put it back the way i took it out but after some research i think the flat washer and the thick plastic washer might have been in the wrong spot as well as the e clip was not stock. it was on position 2.

I had let the bike sit for a week to take my mind off it. When tearing down the carbs i didn't find any gas in the left boot to cyclinder so that was nice unless its the intake seal in which cases gosh darnit! but honestly i found about a teaspoon of gas in the left bowl. the right dumped when i removed the bowl screw but very very little trickled out of the left. I don't see how it could have left the bowl, its below the boot and wouldn't wiggle upwards and down into the cylinder. I suspect fuel starvation.
Last edited:
Update with a question
Fallowing the manual i can get the timing and points gap pretty spot on, but playing with it obsessively for the last weekend got me to thinking. Is there any sort of factory timing plate position that will get me the full usable range of adjustment on the gaps. At the moment i get needle swing right at the LF/RF line on the compression stroke but the RF has been a pain to set as it seems to be less then a millimeter away from the furthest i could even move the points plate. Is there any trick out there? i noticed 3 lines etched into the lobe.
Update with a question
Fallowing the manual i can get the timing and points gap pretty spot on, but playing with it obsessively for the last weekend got me to thinking. Is there any sort of factory timing plate position that will get me the full usable range of adjustment on the gaps. At the moment i get needle swing right at the LF/RF line on the compression stroke but the RF has been a pain to set as it seems to be less then a millimeter away from the furthest i could even move the points plate. Is there any trick out there? i noticed 3 lines etched into the lobe.
Post pics of what you are seeing.
Not exactly sure what the problem is from the description.

Gap the points first before trying to set the timing. I had the same problem when I first got my 360 where the timing plate would not move far enough.
Thought I'd set the gaps properly.
Apparently not.
Once I reset the gaps the timing was much easier to set.
I'll be taking some pictures this weekend, probably Sunday morning. I'll try and describe exactly what i'm doing in the mean time. First i gap to manufacturer specification. Left then right. Then i loosen the timing plate bolts and hook up a multi meter to the left cylinder wire and a good ground. Then i fallow the books recommendation on setting the left first while turning the engine clockwise after the adjustment to pick up the slack in the chain. I can get the left cylinder amazingly spot on. As soon as the etched line crosses/hits the case pointer i get needle swing/ separation at the points. I'll tighten the timing plate bolts and loosing the smaller right cylinder timing plate. This is where i go back and forth for an hour, trying to estimate which way the plate will move as i tighten the bolts while messing up my adjustment. A diagram of what the final adjustment looks like.

( -----B-)

The parenthesis are the manufactured range of possible bolt adjustment area and the B is the bolt. This is usually the spot i'll get the plate while getting me needle swing on right gap separation. I wish i could use the entirety of the adjustment area, somehow moving or "resetting" the timing plate to get point separation at LF/RF as well as manufacturer spec on gaps. I have the manual but as a favor, what are you guys setting your gaps at? Purely out of curiosity since the printed float height in my book was wrong.
Last edited:

13 mins of your time but any info is appreciated. Perhaps ya'll will notice a fumble in technique or something im misinterpreting. I don't show gaping the right points since i had done both left and right prior to filming before any other adjustments per the list of steps in the manual i.e gap then timing.
I've decided this weekend i'll be doing a better test of the ignition electrical. i think in my video is a huge clue. i haven't confirmed with the manual but i suspect what ever is being inherently resistance tested by using a multi meter, set to resistance to help make gap separation more apparent, is telling me that my left coil might be toast. I did notice some sparking at the gaps a couple months ago when the bike ran a little better. Might be in for coils and a condenser on the next shopping cart.
I confess I haven't watched the video but if you're concerned about the coils you can do resistance tests of the coil primary and secondary windings.
If you're testing the resistance/continuity from ground the the other side the contact breaker, ie across one of the two points, you're not testing the coil too.
Update : its alive but not 100% yet
As far as i can tell I'm experiencing lean symptoms in the pilot circuit. I don't think i'm getting far enough into the mains while experiencing the latest problem but i might try putting in the 147.5 main jets that the bike came with. Any who's. Been taking care of other things in the last few weeks and i let the bike sit after getting stranded 3mi away from home after a petcock rebuild and deep carb clean. Decided to come back to the bike and thought i would start with gaps and timing again. Popped off the Yamaha cover and had to keep from losing my mind as all the gas that had leaked apparently from a crap petcock job that i did guzzled out. Found some in depth threads fallowed all the instructions to the letter, polished all the gasket mating surfaces took apart slowly in a clean environment and reassembled. Found some chewed up seals in the petcock and was excited to potentially improve it. Not the case. So w/e going to measure the mounting holes and grab a manual petcock. Redid the gaps, and dialed in the timing as best as i can, more on what i mean by that soon. Button it all up and its driving! Took it out for a few trips and that's when i noticed it. Back firing and sputtering pretty much exactly at the 40 mph mark. So this weekend rolls around and i pop the carbs back out, bring them to work crank up the ultrasonic and run em a few times. Compressed air in all the holes and the carbs look a lil cleaner, I did a hell of a job 2 cleans ago and i think they rival brand new. Thought i had some 45 pilot jets lying around but couldn't find em so i went from what my manual says is stock 42.5 to 47.5 and went back to the original needle i took out when i first started getting into the carbs. I noticed the "new" needle is slightly longer by like 1mm or less but thats enough i would think to do weird stuff. Also replaced the "new" idle mix screws with the originals that I took out cause they also looked "a little" different. Set the c clip to 1 position richer then stock and buttoned them all back together and its driving! Synced the carbs and dialed in the tick over screw to get me close to 1200 rpm, was pulling the plugs repeatedly during all this and had to turn my idle mix screws in about a turn from 3.5 to not get completely sooted plugs. Right side is starting to become tan and left is still a tad rich i suspect. This morning i rigged up the timing light that the book suggests after seeing how easy it was to make in a youtube video and redid the timing. Left side - spot on. Right side - as good as it gets but pretty damn close. What i mean by this is I've noticed that my points plate is warped or mishapen or something. As i tighten my adjustment down i can see the edge that contacts the lobe move, it pulls up slightly making my right adjustment incredibly difficult but with the light set up and a good nights rest i got it "good enough" i feel. This evened out my acceleration immensely no popping in 1st from 1200 to 5-6k, no popping from 2nd gear 3000-5ish000 no popping in 3rd from 3000-6ishk, but this is right around the time i get to about 40mph and get into 4th gear. In 4th gear doing 40mph and 5-6k rpms if i give it any additional throttle its popping and sputtering the whole time. I'm stumped. I driving this thing super light and i would described my normal throttle usage to be basically always under half throttle, I just don't think i'm getting into the mains according to my mikuni chart. This weekend i'll be returning the carbs to exactly how i got them. original needles slightly richer by 1 clip position, the original idle mix screws, 42.5 pilot and 147.5 mains. O yea, butterfly shaft seals? Could these be symptoms of this? One of the screws holding one of my butterfly valves in place is not so much a tool surface and more of a pit so i didn't take them out or apart for any of the cleaning i did since i've owned the bike. I did break loose the other carbs butterfly valve screws yesterday with my ultrasonic clean but since i couldn't get any purchase on the other i left them both assembled.
I would start with stock jetting and needle settings and three turns out on the pilot mix screws. Carbs where synced with a manometer with bike at idle, right?