1968 Yamaha YAS1C 125 Twin will it run
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- čas přidán 12. 09. 2024
- In this video I introduce the Yamaha AS1C, discuss some of the problems we are looking to solve. This is a very nice bike for its age and deserves to be repaired and rode. It seems the engine is misfiring on the right bank. I cleaned the carburetors it seemed to help some, but the misfire is still present. More troubleshooting to come.
Good evening Dale, checking in to watch the shop fun.
From the sound of it you have quite the stash of bikes in your barn.
How about a walk through some time?
Hey Don, glad to see you here, I doubt that I would ever do a walk thru, although bikes will emerge as I need them for projects and videos.
@@montana2strokeracer most people doing restorations seem focused on one bike or a certain model. It’s cool you try and save em all. Climate must be helpful there. Nice and dry I’ll bet.
With that low off idle bog maybe raise the metering rod on the slide up a notch and see if that helps.....Good video...Thanks!
great lookin bike dale i dont no if its pulling gearbox oil through crankseal seems to be smokin more on that cylinder and the slight bog on throttle im sure ul check it and sort it out keep up the great work next video please
About to get it figured out Mark. Stay tuned buddy.
Great video. Love how you walk us through the diagnostic process. I thought for sure it was a plugged carb jet, but that what was only part of the problem. Using a thermometer was a great idea!
Thanks Jim, the temp can tell you a lot. Yep, pilot jet on this is tiny, easy to get plugged.
I had this bike when I was 18 years old in Hawaii. Sole transport, rode it everywhere. Thank you for this!
What a great story, they are fantastic bikes in both appearance and performance. These bikes would be perfect on Hawaii, wonder if guys are restoring them out there.
Thanks Dale. Lovely little bike and you'll soon sort it out.
Sorry to hear about the bushfires. We're all too familiar with them down here. A group of Australian firefighters have not long gone to Canada to help out.
Cheers, Peter.
Thanks Peter, this is a cool bike for sure, I am positive a solution will be found. I know you folks have those terrible fires too. The heat and the smoke are just an annual thing here. Depends on the wind if it's effecting you today or not. I sure thank your firefighters for their support here. I am only a hundred miles from Canada, so it affects us too.
is it possible for the crank seal to leak into the crank on the right side of the engine on this bike just a lot more smoke from the right side than the left side.
Yes, it is possible, I did find in the second video of this series that the seal had been replaced 10 years ago. That certainly doesn't mean it can't leak though.
What a sweet sound these twins make Dale !!
Regards, Ard
No argument from me Ard.
What a great looking bike Dale. This one was not left out in a shed to rust away. Several "aha" moments there that didn't pan out. The fluctuating temps on the right cylinder clearly shows the miss-fire. It will be interesting to see what the root cause turns out to be. I appreciate your commitment to creating these informative and well-produced videos.
@@douglasmeeker360 it’s super helpful for people who don’t know how or don’t have the tools. I’ve picked up a lot watching these videos over the past couple years. Good informative content is like a gem or precious mineral. You usually have to dig to find it
Thanks Doug, you are clearly on the right track, you will enjoy the solutions in the next video.
Carbs may need syncing Dale. Remove one spark plug and and run the engine on one cylinder, check the RPM at idle on this cylinder and adjust it if needed, now repeat on the other side ensuring the RPM remains the same on both cylinders.
I’m sure you already know this trick. Great video again Dale, take care friend
You are right on my friend. Stay tuned for the 2nd video, syncing is part of the solution.
I'm sure you'll get it running right Dale, it's a great little bike, amazing how clean the tank is for a 1968 bike. The city hipster crowd would love this little vintage Yamaha. Down to freezing overnight here, not sure what's worse, too hot or too cold!
Hey thanks Darren, I just watched your video on the cam chain roller, I did that once......I pulled that bolt out. What a turd I was and created a lot of work for my dad. I know man, the temp extremes are the worst. We are 60 days away from winter weather here, so that means you're coming out of it soon. Take care buddy.
@@montana2strokeracer thanks Dale, hopefully my video will stop someone making the same mistake.
First thing I did on my stroker twins when running lop sided was to swap plugs over, to see if the fault moved over with the plug. But the oily exhaust on the drive/clutch side looks like it could be a failing crankshaft oil seal (first had that on a Suzuki 250 twin - 54 yrs ago!). Enjoyed the vid. Keep at it.
I did that in a roundabout way, I swapped coils side to side, no change. Both crank seals have been replaced, the RH cylinder has been cold so long that the excess oil is just standing in the up pipe. Running right as it is now the smoke is decreasing with every ride. Thanks for spending time with me in the shop.
If a 2 stroke runs lean it is hotter so I would not think a bad crank seal would cause a low temperature. Perhaps the carb adjustment or partial clogging in the exhaust is keeping the one cylinder at a lower temperature. Or point dwell throwing off the timing. I will be interested to see if the coils time independently. I saw you feel the exhaust flow so I would guess they are similar. Does it have reed valves? All of these will be answered in the next video I am sure. Can't wait to see.
Thanks for watching, all those suggestions are for sure possible, I think you will enjoy the next video, it seems there were many variables to consider in repairing this engine. Not one thing would have done it. No reeds on this engine.
I had one of these that had a misfire on one cylinder. It turned out to be a crack in the coil. I used epoxy to seal up the crack and it ran perfect. That is a beautiful example. Good luck.
I have had coils crack like that, humidity plays havoc with them. You are spot on. I fill them with epoxy also. Good fix in my opinion.
70's for daytime highs?? in August ??? Geez! Here in Alabama we're 90's til late September! I have to have my garage air conditioned, or I'd never get anything done. High temps, high humidity, just saps the strength out of you. Around here, air conditioning is worth whatever it costs! I'll be looking forward to going riding with you (vicariously thru YouYube) on that bike, hopefully soon. BTW, Brad's Triumph in my garage right now, hopefully will be running this week. He's coming over this evening for us to start reassembly.
Yes sir, 70 for a high today, rain coming in tonight. What a nice cool down. I think every year about putting AC in the shop, then winter gets here. I do have two heaters, just in case one breaks down. I am enjoying your Triumph series, good job Johnnie.
That is a really clean looking little bike for a 1968 !
We have been in the 100+ temps here in Tucson and it definitely does a number on us older folks. When it comes to your projects, all you can do is what you can when you can. Like you said in one of your earlier videos, it all depends on getting the parts you need.😊
I see the temps there David, I could not function like that. It beats me down when it happens here for just a few days. I really don't mind the cold weather, just the extremes, either way for that matter.
I insulated and installed a mini split system to the shop to make working on my projects more tolerable.
My wife's friend has one of them. They do work pretty well. Will need a big one for the shop.
Enjoyed this a lot Dale. It always amazes me how something as small as a pilot jet can cause a big machine to fail. 😮
Thanks Graham, these little twins are enjoyed by lot of folks, so the videos with this subject matter do well. The hole in these pilot jets are some of the smallest I have ever seen. Very easy to plug up.
@@montana2strokeracer Glad to hear they do well Dale. Your videos are very well done we all learn a lot. For example, I didn't know how to properly measure the float height before this video. Thanks for all your effort and time.
Thanks for the video, that's a stunning bike you have there! Looks like a points adjustment/condenser. Hope you guys get some rain to stop the fires. Here is S Hemisphere it's a brutal winter, massive cold fronts from Antarctica blasting through, but the days have started getting longer. Can't warm up fast enough for me. This morning as I was watching this a new front hit with gale force, snow in the mountains.
I am sure most of the problem will be ignition. It has been so hot and dry here for way too many years. You folks are in winter now, so we know it's coming here in a couple months, I really don't mind, I just dislike extreme temps either way.
I agree with you Dale, that is a sweet looking bike! I'm sure you will have it running like a top in no time.
Replace or change the condensers around ,from side to side first to see if the problem follows your actions .But I believe it's the sealing pressure difference between both of the bottom halves of both crankcases
Great video Dale. Your thought process is very helpful.
Love those old ring dings..
Reminds of a Suzuki 125 Wolf that my brother Had in New Zealand ,
Back in the Day !!
It was probably made to compete with it. I remember them, was it the Stinger in the US? with the laid down twin cylinders.
Good show Dale. The blue Ford is missing in the background.
Hey Cliff, it's still here, just moved it out for a while, got to get another car on the lift to take pictures before I list it for sale.
Well yeah, I would go after points, condensors, and timing; standard tune up stuff.
But anytime a two stroke gives me much grief, I am all over doing a pressure/vacuum test right away. I'm worried about a leaky right side crank seal on this one.
Best to not do much carb adjusting without the air cleaners on. No air cleaners makes it run lean.
Oh man, 125+ here today. The heat is rough. I can't get anything done. It's 115 at night here!! Does it cool off at night there??
Good luck with the Yamaha. Love those 2t twins! Nice production as always. I just love how clean you get your parts, and how fastidious you are...
Robert
I hear ya, just got to check all the systems, obvious ones first. The problem will be found.
Re: Unknown compression value, an easy formula is 13 x engine compression ratio.
For example, with a 1:8.5 compression ratio engine, 13x8.5=110 psi, which is very close to factory specs.
If you are interested in where the 13 comes from, 14.7 is the atmospheric pressure in psi, but you must also account for a few factors such as compression heating, air not being an ideal gas, the impossibility of perfect sealing even on a factory spec engine, and a few others. The actual value to use is 13.23, but 13 is easier to remember.
Holy cow, that's great, I had no idea there was a formula, that is great stuff to know. In these early manuals they never give a reading for a compression test. But generally, they do give the compression ratio, but again I generally just kick it through and can tell if there is enough to make it run. I have already tried it, and have made a note, and I thank you so much Mariano.
My brother had one. Great bike
2 or more carbs can be a challenge for sure at least for a shade tree mechanic like myself. ✌
They can be a challenge for anyone John. Twice the cleaning and adjustment, then Sycro too.
Yea it's crazy here to,take care again.
Right hand crank seal i had the same problem with my RD400 👍👍👍
Crank seals have been replaced.
@@montana2strokeracer ok man 👍
Crank seals will make your problem,The end ones and the 2:centers,you got two different pressures that are different from each other,in each of the crankcase halfs,,as the left side is working correctly Dale,,, I've been there and I had the same running issues on a Kawasaki 400 free air sled engine ,,I tour the engine down and replaced all the seals on athev400 free air Kawasaki snowmobile engine ,and my issues quit,,esp the sound of both sides hitting correctly after I first restarted the engine after doing so ,,no more dragging rpm's for sure,,just a crisp hit on both cylinders was the sound after and a very quick rpm increase when throttling up,,it was much quicker for sure
Hey Lynn, the outer crank seals have been replaced (just found out that when researching the point gap) the center one on these bikes is a labyrinth seal, it's made from aluminum and is not really a seal at all, not like a rubber seal, it does not seal that good, it controls oil flow but not really vacuum or pressure. Normally you are correct in your thinking though. You will be amazed what I find in part 2.
My guess would be a bad crank seal on the right side causing extra build up in the pipe restricting flow.
If you run it in the road Dale ,the left side will destroy itself cause of the extra load or drag on it pulling the right side along
Nope, bike will not be on the road till a solution is found.
Slides synched? a couple spoons will do
I adjust my points and then I use a timing light I got at Home Depot that has a 2 stroke setting and a degree setting I put at zero. Sync your timing it might make a difference
Good looking bike
I like them too, new bikes just don't look right to me.
Great Video Dale: What was the brand of battery you found favor in? Needing a stout one for my XT225.
Hey John, I like the Motobatt jell battery's. I have some still in service that are over 10 years old.
@@montana2strokeracer Was able to track one down at Amazon and was on sale. Will be here this afternoon. Thanks Dale.
Looks unique/obscure. Good condition 👀
Its cool Vinny! Nice old bike.
@@montana2strokeracer some of these really belong in a museum. For posterity
Cool bike
made it, had a grand daughter birthday party is my excuse.
Always something with you Frank, LOL, Sure glad to see you stop by any time though.
Hi Dale, new to the channel and found it to be most interesting. Would it be worth checking the output of the oil feeds to make sure they are the same, I had one in the past with a slight blockage in one of the pipes and caused it to run similar to yours, also I would fit the air filters to test. Just my opinion but I know how frustrating it can be being so close.
Just did it Rob on the Oil pump adjustment and output verification video just released.
I would check the the fuel cock some times one side will get restricted. I notice that the stingers are in on the exhaust try removing them to see if that makes a difference. I have a friend that had newer bike it had a vent problem and when he ran the bike with the fuel cap off it would run better. Cheers
I think we think a lot the same Carl, stay tuned for part 2.
Sweet Machine Dale! I am of the same opinion you are..... the miss and temperature differential would most likely indicate ignition issue in the cooler cylinder. Thats the logical place to start.
Thanks Jeff, think you will enjoy the next video. You are most correct, with some other problems needing help too.
Thanks Dale , Man that girl is a real Beauty . Such amazing nice all there condition . It sounds like one Cylinder is trying to pull the other along . Are the carbs sinked ? Im sure you checked that . I just always start at the ignition my self . Thanks allot Dale . I understand the heat Dale I have not touched my Yami XS 500 . Still hot here in Georgia .
Hey Murray, yeah, I like this bike a lot, it deserves to be running. Yes, you are spot on, I think all your suggestions will be part of the solution. The only reason I started with fuel was because of the inability for it to move from idle to 1/4 throttle, that is normally a pilot jet clogged. But yes, ignition is a good place to start and will cure a lot of the problems along with syncing carbs. I know man, I just can't function in the heat. I didn't do anything in the shop for over a week, it was just disgusting. 70 for the high today, life is good. Snow is about 60 days away.
Dale, if the crank seal was
Leaking just a tad, would that cause the right cylinder to smoke a bit more and run cooler?
It sure would Don. I think this cylinder has been dead so long that a lot of oil is in the pipe, I think it will clear in time. Just my thought.
Try putting the factory air filters back on and run and then take a pipe temp test again
in the next video I do.
sounds like 2 me that the left side is in perfect time and the right side is firing a little bit late, if thats possible, i know that if anybody can fix it its you dale, im into a pickle myself, im doing a top end on an old 550 honda thats ben sitting in a corn crib for 34 years and was stuck real tite, i got it loose by soaking in diesel fuel for a few days then welded a 3/4 drive socket on to the engine sprocket and put in 5th gear, with a big strong arm and some mussel i broke it lose but had 2 do some dis-assembly at that point because a valve was stuck down and would not let me rotate all the way over,, wow iv got a mess, but there's always the scrap yard, catch u on the next one...
I think you're on the right track there James. Man, I never would have thought to unstick by using the transmission as a lever. That is cleaver my friend.
I am curious to see what the two installed condensors measure in farads. You must have a meter. Do you have one of those adjustable spark gaps? It would be interesting to basically measure the generated spark voltage. thank for the video.
Hey Rowland, I think there is a dedicated tester for micro farads, but you can check using an ohm meter, probably not as accurate. Condensers are so problematic on these old bikes that I just routinely replace them. A sure sign of a bad one is lots of, more than normal sparking at the points and lots of burning of the points. Most run about 22 micro farads or their bouts. If I can't get one, I just use an automotive one if I can fit it in there.
Another Yamaha that I longed for as a teenager! One friend had the low pipe 68 model with the chrome tank panels, another had the orange 69, was that the AS2C? And WHY do I even remember that?😳
Seriously, is it possible it is sucking trans oil thru the RH cyl crank seal? I remember my Campus 60 did that, emptying the transmission, performing poorly, and smoking heavily.
Of course, at the time, I was unaware of the existence of crank seals, let alone theirfunction!
Wayne you are so right, I always wanted one too, my buddy had the 180 Scrambler, CS3C I think or maybe that is the 200. Nice bike regardless and has that fantastic two stroke, two-cylinder sound..........wow. Yes, I think that was the AS2C. Think its the same color as my HS1 that I am rebuilding, the 90cc twin. You will love what I find out in the next video, you probably have already seen it since I am so far behind on comments and emails.
Check check the timing with a dial indicator. Perhaps 1.8 mm btdc ?😊
Spot on William.
"A lot of oil here", ...you might want to check whether the right cylinder outlet or the right exhaust is free of carbon and oil deposits, as this side hasn't been working properly for a while...
By the way, these problems of yours are the reason for me to install single-cylinder engines and, if it cannot be avoided, to only use one carburettor on two-cylinder engines...
Well,... just my two cents...
Btw., great Vids ...
Got her running much better in the follow up video.
... yup, already seen ...,@@montana2strokeracer
My engine smoked the same , differently from both sides,,as it takes pressure to move the fuel thru those little ports ,evenly ,and if you don't have the same pressure moving fuel pressure and flow correctly,,you'll get a engine running ,but not running evenly as a match , the one working correct cylinder sort of drags the bad side along creating your issues,,that's why you have 2 different running temps,side to side,,you are not getting even fuel flow pressures
Lots of good info there Lynn, thanks
Is the cold side 'pulling its weight' on idle? In other words maybe the slide needs lifting slightly on the cold side by turning the idle screw in and on the hot side it needs turning out a small amount.
As you will see in the next video......syncing the carbs is part of the solution.
Does it have a reed valve ? If so, it could be bad. Bad condenser ? Bad coil ?
I had a 1970 yamaha 125 it was fast compared to the 125 Honda and 125 Suzuki. I wish I had it today, thanks for the memories. Cheers
They are great bikes Carl, always wanted one when I was young. Yeah, much faster than the Honda, but I would guess pretty similar to the Suzuki twin.... was it the Stinger? It was a cool looking machine with that laid down twin and the carbs sticking straight up, .............and those pipes........pretty cool Suzuki if I remember, never saw one in the wild though, just magazines.
@montana2strokeracer I had the Yamaha 125 with my girlfriend on the back and my friend was on his 125 Suzuki and he could not keep up. We worked in the same motorcycle shop. ( Suzuki dealer )They wouldn't give me a good price for my Honda 90 scrambler for a trade in . I went with Yamaha and never looked back. Cheers
If your using pump gas with ethanol you need a little more jet to compensate
I only use non ethanol premium; we are lucky to not have to use ethanol products here if we choose.
@@montana2strokeracer nice you have non ethanol. I doubt them engines have the compression to need premium though. On the other hand extra octane wont hurt anything either
Well Earle, the only way you can get the no ethanol is in premium, otherwise ethanol you get. But your probably right, it sure doesn't need it. Two strokes just don't like any kind of water in their fuel, think they say ethanol is hydroscopic........absorbs water? Thats bad for them.
Did you sync the slides. I use pop cycle sticks. The left cylinder just seems a little leaner
I did, in the follow up video on troubleshooting. I used tongue depressors cut in half.
@@montana2strokeracer I pulled my 73 RD350 out of the garage yesterday. A quick points adjust and timing light and she’s screamin’! Weather cooled off enough for a nice ride.
@@montana2strokeracer do you think a worn out ballast resistor on the voltage regulator would cause surging headlight. It burns out quick. Also getting charging voltage at headlight plug. 14.5 volts when throttling up. Shouldn’t it just be regulated at 12 volts? 73 Rd350.
Did you check the slides were pulling the same?
Yes sir, get her done in the next video.
Synchronize the slides. I used to have to do a similar adjustment on my Corvairs.
Right on Jack, this is actually a 2 or 3 stage solution, syncing carbs is part of it. Oh, those Corvairs, haven't thought of them in years. The factory made a hot version of that car too, the name escapes me.
@@montana2strokeracer It was the “Corsa”. Yup, had to go back and forth between linkage and carb until everything came out right. I’ve got a tool called UniSync that you put over the intake to measure vacuum. The goal was to get it running smoothly and vacuum identical.
Oh yes, Ralph Nader didn't like these cars if I remember. That sounds like a cool tool, vacuum was our code reader back in the day.
Hi Dale, did you do any work to this engine?
It turns out I had replaced the crank seals. In the next video you will see what I had done, and the solution.
Check the timing then move the needle clip down one notch
Lots of variables to consider, stay tuned.
Are the inlet rubbers ok with no cracks or air leaks ,crank seals ?
No rubbers on this model Vincent. These have the bake-o-lite phenolic inserts in the carb mount, they seem to be intact and functional. If all else fails, I will perform a leak down check......easy stuff first. The crank seals have already been replaced.
@@montana2strokeracer I reckon you are there with that ignition system Dale.
Needs a good ride out in that great country and a plug chop on the roadside.
I agree Vincent, think I am going to enjoy a nice ride in the country on this old bike. Look for that video soon, the music out of those twin high pipes is going to be outstanding.
Crank seal?
Yeah. Just because it's rare for a crank seal to go bad does not mean it never happens.
This one has all the signs.
Needs a pressure/vacuum test.
Here