Yamaha yfm200 Moto-4 bogs with throttle

[@Joseph-ky9ek]

I thank you for the info I was troubleshooting this same problem never thought that my carb repair kit did not have the proper main jet config. I did not buy aftermarket it was from a retail distributor and yet they screwed me. I've been at this for two weeks, went into the carb again put back the old main jet, and BAM it back to the way it was. Thanks,

[@JasonTheMunicipalMechanic]

Glad you got it figured out. It had me running around for a while too.

[@enjoythesho1992]

Those rear tires look awesome

[@fjg2372]

Thanks for posting the jet chart. God bless

[@JasonTheMunicipalMechanic]

No problem. I hope god blesses you as well.

[@AKA.SKITS.N.GIGGLES]

Genius! Your a smart guy. Thanks for the tip!

[@JasonTheMunicipalMechanic]

No problem. It took me a while to figure it out so I though I might be able to save someone some trouble.

[@steptool1]

THANK YOU!!!! Previous owner said ,hey it's got a new carb...bla bla ect.........never thought the jet could be wrong and I should know better....lol Thanks for sharing!!!

[@JasonTheMunicipalMechanic]

It took me a while before I realized the jet could be too small. Like you the previous owner replaced the carburetor in an effort to get it to run right. His original problem was low compression because of a valve that was too tight. I looked on eBay for a new carburetor and everyone I saw said modifications are required for engines above 125cc and that’s what made me think the jet was too small. I squeezed the intake boot down to restrict some air and it ran better. So I measured it as best I could and it was too small. Thank you for watching.

[@frofrobikelife2516]

I'm having problems with the choke in the carb sometimes it works and sometimes it doesn't it like it wanna stay running but it was acting up weird

[@beaucephus6295]

I think issue was probably the cap left out at last min, yup most definitely

[@HectorGarcia-eo1lq]

Thank you for the information 👍🏻👍🏻👍🏻

[@ChrisProvazek]

I've been fighting this same machine with multiple issues (one being this issue) and it also has an aftermarket carb. I will have to check into and see if this may be my issue as well.

[@JasonTheMunicipalMechanic]

I happened to notice all the cheaper aftermarket carbs on eBay said they were for this ATV but in the description stated if over a certain engine cc size would require modification and this engine was over the size. Hope you get it solved. Thanks for watching.

[@ChrisProvazek]

@@JasonTheMunicipalMechanic absolutely, and if you ever happen to need to work on another one of these machines and need to work with the choke cabling, or diagnose and replace any of the stator coils i have videos on my channel for that.

[@JasonTheMunicipalMechanic]

That’s good to know, Thank you.

[@jonathangaliano2617]

@@ChrisProvazek Just opened your channel in another tab to check out your Moto 4 videos! Picked up an 88 YFM350ER a few weeks ago. Can't dump tons of money in it as I just got it to have something to ride for now and be able to take my daughter on rides. Just cleaning it from top to bottom and tidying up some stuff as well as new air filter and brake pads/shoes. Any chance you have a salvageable carb laying around that would fit it haha? The guy I bought it from neglected to mention it and even though I thought of it before hand, when I went to look it over I completely forgot to check if it was a cheap aftermarket carb and sure enough it was.

[@pixel6580]

Luckily my carb was stock but jets where both clogged! after giving it some gas it would slowly come to idle and die one me. after cleaning both jets it ran amazing!

[@JasonTheMunicipalMechanic]

👍 glad you got it figured out. Thank you for watching.

[@daviddesousa3993]

Thanks for your video. I have the same bike with rebuild carb. Have tried everything but still bogs. I have new fuel, new filter,,new plug! Don’t know what to do.

[@JasonTheMunicipalMechanic]

Have you done a compression test. Or checked the valve lash. This bike also had a leaking valve because the valve lash was too tight and had a lot of leakage though it. I almost couldn’t get a reading on a leakdown test at first. That was a problem I fixed before I got to where this video is.

[@benjaminmatejka6182]

I have same issue, been messing with it forever, replaced pretty much everything that could be an issue but doesn't rev up at all. I can ride around and has good compression, but no power or throttle. What should I try next?

[@JasonTheMunicipalMechanic]

Have you checked the valve lash? What are your compression numbers? At sea level 114 psi is minimum and 142 is maximum 128 is standard. Will the spark jump a decent gap? Is is any better hot or cold? What have you replaced so far?

[@benjaminmatejka6182]

I have replaced carb, plug and plug wire, fuel line, cleaned gas lines and tank, replaced fuel petcock, ran fine 30 minutes before it went to crap, and hasn't run good since. Compression was between 110 and 120, but idles fines but doesn't rev up and puffs whitish smoke now and then

[@JasonTheMunicipalMechanic]

I like to verify everything is operating as it should. Basically the cheap or free things first. I’ll clean the carb check or change the spark plug and check for good spark. Then I’d verify the compression and timing, a leak down test if the compression is low. Check the air filter. These are all basically free checks, If all this is good then it could be the cdi box. The cdi box controls the timing advance so if it’s not advancing then you would have low power and may not rev up. They are pretty difficult to diagnose and expensive to replace. I would try and rule everything else out before I went that route. I had a chain saw that operates on a similar ignition system and it would start idle but not rev up at all just bog and it had a bad ignition module on it. The plug would be wet with fuel after running it. You can try blocking off some of the air supply to see if it help or use some starting fluid while running to see if it will rev up with it to check for fuel issues.

[@spacebounduniverse9350]

Thank you👍

[@JasonTheMunicipalMechanic]

Hey no problem. Hope the video can help you.

[@AndrewKellman]

My 85 moto 4 only sputters sometimes and makes a metal clanking noise sometimes but other times it runs fine? Any help would be appreciated!

[@JasonTheMunicipalMechanic]

That would be a hard one to figure out without being there, it could really be anything. If it made the noise when your moving only I’d look for it from the shaft drive back to the axle, if it does it when the engine is running but not moving I’d look at the engine. The speed of the clanking sound can sometimes tell you what it might be by comparing it to the other parts that turn at that speed. The engine will be faster than the drive will be. I would check the timing chain and make sure it’s tight and not slapping around. It could be the clutch or possibly a valve sticking. It’s really hard to tell what it would be without hearing where it’s coming from.

[@jasonjaeger4042]

If the motor is making a "clanking noise"....shut it off til it's fixed

[@crism.r.9688]

I have a Yamaha warrior 350 when I give it gas it dies ..you think it's the carb?

[@JasonTheMunicipalMechanic]

Possibly. If it runs better with the choke on then I would say it has a fuel problem.

[@crism.r.9688]

@@JasonTheMunicipalMechanic fires right up...but when I try going it'll die

[@JasonTheMunicipalMechanic]

I would clean the carb if it was me. Maybe change the spark plug.

[@crism.r.9688]

@@JasonTheMunicipalMechanic thanks

[@crism.r.9688]

Put a new carb and still having the problem

[@MrDesparza]

What year is it ? Have one I just got

[@JasonTheMunicipalMechanic]

I actually don’t remember the year. It belonged to someone else I was just working on it. It was mid 80’s. I want to say 85-86.

[@jasonjaeger4042]

Just don't buy a carb off ebay for $30. Ya get what ya pay for.

[@JasonTheMunicipalMechanic]

I can see that. I would expect a cheap carb to be crappy, but I personally expect to get what I’m told I’m getting. No seller tells you there item is junk, or most likely broken in the box. Everyone says there item is the latest and greatest. If I said I would fix your truck for cheap took your money and didn’t fix it would it be your fault or mine? While I try to personally buy oem or high quality parts, I blame people that lie about what there selling and for selling junk when they say it’s great. Cost should have no bearing on the transaction if they say it’s a great thing or at the least a good functioning part. If they said Im selling this part for cheap and it’s broken I wouldn’t buy it. Giving money for trash bothers me and it’s a waste of my time. But I agree and know better, that a cheap part is probably not a quality part. I didn’t buy this carb it was on there. Thank you for watching I appreciate your time and support.

[@jasonjaeger4042]

@@JasonTheMunicipalMechanic I actually had a customer buy an ebay carb and the venturi was solid aluminum. How is a carb supposed to work if no air can pass through? I didn't believe him til I saw it myself. And I agree, if ya say ur product is a quality part, it should be. That's why I quit working for "Race Driven", their parts were cheap shit and I don't lie to people.

[@JasonTheMunicipalMechanic]

It’s weird that companies produce products that are not right or don’t work and sell them. I wouldn’t feel right about it knowing the truth.

[@GamerNotHere1]

@@JasonTheMunicipalMechanic do u know where I could get a key switch for that for wheeler

[@JasonTheMunicipalMechanic]

I believe I saw one on Yamahapartshouse.com and they are on bikebandit.com. They are under oem parts and in the electrical section.

[@chadhanson382]

That doesn’t fact happen to be the correct carburetor for that machine. FYI.

[@JasonTheMunicipalMechanic]

While it does fit in the machine I believe I proved my point to why the carb was a problem and the jet wasn’t the correct size. I got the 115 jet size spec from the factory service manual.

[@chadhanson382]

@@JasonTheMunicipalMechanic Absolutely I get it. I found your video as I am dealing with the same exact issue on a 1989 just like that one. It ran absolutely perfectly until I let it sit for three years. I used to have one of these when I was a kid so of course I had to buy another one right? I cleaned the whole carb out and it won’t idle. It runs great if you are an actually running it but as soon as you stop it will backfire and sputter and then die. What really gets me is that the idle adjust doesn’t do anything. I swear it’s clean but I’m not a carb guy so not sure what that’s all about. Obviously it’s either not clean or something else is plugged.

[@JasonTheMunicipalMechanic]

I don’t like the carbs myself. I like to use a strand of wire from like a bicycle brake cable to clean out all the little holes and stuff in the carbs. It’s the only thing I’ve found will get into the small holes.