Miker1st

Member
Feb 25, 2022
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Safford, AZ
Howdy folks, I've been lurking here for a good couple of months and have spent a lot of time reading the forum.

tl:dr YFS200 idles great, bogs with any throttle.
Started after replacing OEM ignition with cheap chinese, two day from Amazon parts.

Nitty Gritty deets below.

I recently purchased a 2000 Yamaha Blaster that ran, but not well. It would bog at anything over about a quarter throttle. Previous owner said it was probably due to a cracked reed. I've never owned anything 2-stroke beyond a chainsaw and leaf blower, so this is a new experience for me.

It came with an FMF Fatty pipe and FMF Power Core 2 Silencer. Previous owner said he swapped the carb out to get it to run.

I rode the quad for about two days and had one of the screws in the flywheel back itself out and make contact with the housing stopping me dead in my tracks. I removed the bent screw, tightened the rest down, and continued to ride, sans that screw. (My first thought was to pull all the screws one at a time and lock-tight each one, but...I was in a hurry to enjoy the new toy...) So a day later, I lost a second screw, on the same magnet that I had lost the first screw from, and absolutely seized the motor.

I thought I had burnt it up, but thankfully, as soon as I pulled the flywheel, it turned over great! By this time, I had already pulled the motor and head to check the piston either way and it was in pretty rough shape.

I figured since I lost a magnet and seized the whole kit and kaboodle, I should probably replace the stator in case it was damaged, so I ordered an el-cheapo YFS200 rated ignition kit (Adjustable Stator Plate with Coils, CDI, Ignition Coil, Spark Plug) from Amazon (because I am not a patient man, and boy does that one to two day shipping satisfy my instant gratification). Instead of installing the adjustable plate, I decided to use my handy soldering iron skills to just replace the components on the stock plate with the coils and pickup from the adjustable one. This was to keep from throwing the timing off, or so I thought....

I put everything back together and come to find out, the motor now kicks back every third or fourth kick and tries to break my leg. So I think maybe the plate is off ever so slightly... well, after many hours of adjustment, ordering a second adjustable plate, and trying to adjust timing using the adjustable plate, I find out the pickup on the new plate has a completely different resistance value and is throwing timing ALL out of whack.

So back to original pickup on stock plate with Amazon stator coils. Fires up, but only after many kicks and bogs like a madman outside of idle.

Side note at this point, the threads for the flywheel on the crank are shot so I'm running the nut without washer just to get 4 threads or so onto the nut. I really don't want to split the case to replace the crank....

So I checked compression and found I was around 80 PSI, so off to the Amazon jug and piston store I went thinking this was a compression issue.

One new cylinder and piston later and I have discovered I've got a Vitos +3MM Stroker crank, so I reused the spacer plate with two new gaskets.

While in there, I replaced the reeds, which weren't actually in terrible condition.
I also bought a set of main jets because I wasn't sure what was in there (since the P.O. "just swapped out the carb") and wanted to make sure I wasn't running lean on a new cylinder and piston. Main jet is now a 270. The one that came out looked like it was well under #200.... I am skeptical as to whether or not the pilot jet is the correct size now at this point, but haven't checked....

Built a pressure tester, because they are apparently incredibly important for 2-strokes (especially our blasters) and made sure it held 7PSI for a good 5 minutes or so. Much to my chagrin, it took me a couple of days to figure out it was leaking from the tester and not the motor.....

So now, I have around 150PSI compression, it fires on the first or second kick, idles like a champ, but BOGS with any amount of throttle. LOTS of blue smoke out the back. It also kind of sounds like it's not firing every compression stroke. I have a tiny blue spark that you can hear and see when you crank it with the plug against the case.

I'm starting to think the el-cheapo coils are a terrible idea and I should be looking for OEM replacements or at the very least, the moose kit. The Ignition coil and plug boot only fit the plug if I remove the tip. The one I pulled off the blaster fit the whole tip of the plug.

Unfortunately, the only two parts I didn't save in this whole process were the original charge coil and ignition coil and those are the only two things that could be effecting this mess to the best of my knowledge.

Somewhere in here, I also balked at how much the clutch had been futzed with to compensate for not having the steel ball in between the two rods. I've since replaced the clutch, the steel ball (or added rather) and the outer rod as I couldn't get the inner rod to slide out. Now the clutch is properly aligned and engages/disengages correctly without bending the bracket on the block and adding a bunch of washers (as it had when I originally purchased it).

This little blasty has been awesome so far and I really wanna ride it!

Here is a video of how it runs now.

Here is a video of the spark across the gap @ .030 ± .002. It's in slow mo!

I don't want to spend 150+ on a used OEM eBay stator, may I use the Moose Kit from MotoSport?

Any other thoughts or comments would be greatly appreciated.
 

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Cliff notes would be great.
Have you learned a lesson about cheap parts? Is the TORS deleted properly?
Have you done a leak down test yet?

When I get another cup of coffee maybe I’ll come back and read your book :rolleyes::eek:
 
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Are you back to using a stock carb? Couldn't tell from your write up. Also, is the airbox cover still on? If so, take it off and give it a go.

For a stock carb and your pipe, a 270 main jet is a little on the small side.....especially if the air is real cold where you're at. Once you get it running better, I'd immediately do a "plug chop" to establish the correct main jet size.

If you plan on upgrading to a DC system with LED lights, then suggest getting the Rick's Motorsports (not Ricky Stator) upgrade for your stator. Optionally, I recently did the DC conversion and have my stock lighting and charging coils you can have. Where are you located?
 
Cliff notes would be great.
Have you learned a lesson about cheap parts? Is the TORS deleted properly?
Have you done a leak down test yet?

When I get another cup of coffee maybe I’ll come back and read your book :rolleyes::eek:

That's fair. Now that I have my coffee proper, I'll do notes:

2000 Yamaha Blaster YFS200
FMF Fatty and Power Core II Silencer
Vitos +3MM Stroker Crank

Quad ran poorly when I purchased it. PO had "swapped carbs to get it to run"
(Looks like an Amazon carb) See pics.

Replaced main jet in carb with a 270.

No TORS system whatsoever.

Wouldn't run above 1/4 throttle.

Ran for two days before it dropped a magnet off the flywheel because the screws backed out.

Replaced the Stator coils with Amazon replacements, still using the stock pickup.

Replaced the cylinder, piston, reeds, and all related gaskets.

Leak test held at 7PSI for 10 minutes.

150PSI Compression.

Idles great. Bogs with any amount of throttle given.

I'm thinking the charge coil is not enough to get a hot enough spark reliably and I need a proper replacement.
 

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Are you back to using a stock carb? Couldn't tell from your write up. Also, is the airbox cover still on? If so, take it off and give it a go.

For a stock carb and your pipe, a 270 main jet is a little on the small side.....especially if the air is real cold where you're at. Once you get it running better, I'd immediately do a "plug chop" to establish the correct main jet size.

If you plan on upgrading to a DC system with LED lights, then suggest getting the Rick's Motorsports (not Ricky Stator) upgrade for your stator. Optionally, I recently did the DC conversion and have my stock lighting and charging coils you can have. Where are you located?

Definitely not the stock carb.

It didn't come with an airbox lid.

The 270 I thought would have been around a good starting place since stock is 230, but no harm in swapping up.
I cannot wait until it runs well enough that I can start doing plug chops!

I had planned on putting an LED pod in the front, but wasn't necessary.

I am located in Sunny Safford, Arizona!
 

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Ok, not a stock carb. If it's also not a 26mm (like a stock carb) then disregard my jetting comment and you're on your own lol.

Have you tried it without that fuel filter? Could be restricting your flow.

After looking at your video, appears to be an air/fuel mixture to me.
 
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Ok, not a stock carb. If it's also not a 26mm (like a stock carb) then disregard my jetting comment and you're on your own lol.

Have you tried it without that fuel filter? Could be restricting your flow.

After looking at your video, appears to be an air/fuel mixture to me.

So, that was one of the things the PO mentioned is that the filter may be restrictive. I replaced the tiny stone type filter he had for that paper one, but I may just forgo it altogether.

That would be lovely if it was just a fuel/air issue. I'll pull the filter and go direct and see what that does.
 
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Definitely go direct from tank to carb. Have you removed the OEM oiling system and are now pre-mixing your fuel? 32:1?
 
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Definitely go direct from tank to carb. Have you removed the OEM oiling system and are now pre-mixing your fuel? 32:1?

Filter removed, direct to carb. Still no change.

There was no oiling system when I got the quad. There is a very nice block off plate where I imagine the pump would have been.

Yes to 32:1 ratio.

EDIT: Maybe I should try going back to the jet it had on it when it was working before?
It looks WAY smaller than a 230... Lemme pull the carb and take some pictures.... Should have been taking pictures this whole time. *shame*
 
While it's running and warmed up, what happens when you turn on the choke? If nothing, what happens with the airbox lid back on? Airbox lid & choke?
 
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While it's running and warmed up, what happens when you turn on the choke? If nothing, what happens with the airbox lid back on? Airbox lid & choke?

It didn't come with an airbox lid.

The choke seems to make no difference once it's started.

It had a brand new cylinder and piston and I don't want to let it idle like that for the amount of time it would take to bring it up to operating temp.

I'm afraid I'll Bork the break in procedure per Ken OC without being able to vary the speed of the engine while it heats up.

Gimme a minute to try a couple more things.

I just found my stock ignition coil and charge coil.

I'm gunna try the ignition coil first.

Edit: Also now that I have the carb apart, I actually have a 290 main jet in here... also the barrel on the engine side only measures out to 27.5mm at the widest.

Edit edit: Nope. Stock ignition coil didn't change a thing. Here are pics of the two.
 

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So I rolled back through the jet sizes from the 290, 270, 200, and none of them made any difference. I put the stock jet that came with the carb back in and still no change at idle.

I put it in gear and the RPMs started to raise ever so slight and enough that I can put around at a creep.

Going to swap back up to that 270 jet and try it again and see what happens.

I'm at around 2300' elevation.

Edit: Nope. Same thing as with the tiny jet. It puts a little so long as it has a load, but won't rev at all no matter how much or little throttle you give it. Same with and without the choke.
 
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....so now that I have it apart again and am actually taking a good look at this.... the stock charge coil for the ignition has two wires coming off of it, a black with red and a black with white....

I'm so sick of this dumb electrical stuff and also more frustrated with myself for not noticing that before I cut everything apart....

@piezzi
Is this the correct stator kit from Ricks?
 

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....so now that I have it apart again and am actually taking a good look at this.... the stock charge coil for the ignition has two wires coming off of it, a black with red and a black with white....

I'm so sick of this dumb electrical stuff and also more frustrated with myself for not noticing that before I cut everything apart....

@piezzi
Is this the correct stator kit from Ricks?

Yes, that's the one....PN 22-990H. Bought mine from RM using ebay so I got the free shipping.
 
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Yes, that's the one....PN 22-990H. Bought mine from RM using ebay so I got the free shipping.

Awesome! I next day air'd it direct. I want it WORKING and I want it NOW! I've got a go-kart to flip and I can't flip it until I have a second running toy to go trail ride with the missus!

Thanks for your help on this. I'll keep the thread updated as I swap stuff around.
 
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I would throw that carb in the garbage and atleast get a real stock carb . Good luck jetting that chinese crap .
Start with a 280 genuine mikuni main jet and air screw at 1.5 out on the stock carb.
 
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I would throw that carb in the garbage and atleast get a real stock carb . Good luck jetting that chinese crap .
Start with a 280 genuine mikuni main jet and air screw at 1.5 out on the stock carb.

As much as I would love to do that, I'm already way beyond budget for this quad. That may be an upgrade down the road. For right now I just want it to run properly and then I can start tuning.

I tapped the threads in this carb to accept the Mikuni jets.

The RM stator bits should be in today and I'll get those installed post haste and report back!
 
Alright, Rick's Motorsports Electronics Hot Shot Stator Rebuild Kit installed.
Fires right up and revs like a champ.
Problem absolutely solved.
Lesson learned.
Just because the ($30) ones from Amazon say they are for the YFS200 Blaster does not mean they actually work with it.
$105 quick shipped Rick's parts would have been the way to go from the start.

Now just gotta break in the new cylinder and piston, nice and easy, and start doing plug chops to get jets right.

Thanks for the help, guys!

@Larry's Shee
@piezzi
@82cutty
 
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Well, have you learned anything about Amazon parts ? Instant gratification will get you nowhere quick.
Don’t know what you were reading but surprised you didn’t run across anything about cheap Chi-NA parts.
Does the carb have a name on it?
What does the engine side measure on the inside ?

Blasters don’t work well with the filter directly on the carb. If it were me, I’d look for a stock air box and UNI dual foam filter. The shape and length acts as a velocity stack.

Aftermarket electronics usually are junk. You’ve pretty much proved that.

BBL
 
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Well, have you learned anything about Amazon parts ? Instant gratification will get you nowhere quick.
Don’t know what you were reading but surprised you didn’t run across anything about cheap Chi-NA parts.
Does the carb have a name on it?
What does the engine side measure on the inside ?

Blasters don’t work well with the filter directly on the carb. If it were me, I’d look for a stock air box and UNI dual foam filter. The shape and length acts as a velocity stack.

Aftermarket electronics usually are junk. You’ve pretty much proved that.

BBL

Yeah, I've pretty much learnt that with the Blasty. I'm going to chalk this one up to one of my nicer toys and realize that I have to get it nice parts. Right up there with that BMW I had a few years back....

I read a LOT about chi-nah parts on here and decided to ignore it in the hopes that my prior electrical knowledge would save me. Turns out I now know that the amazon bits don't generate as much electricity as the right bits and I have a box of spares for something else.

The carb is a nameless bastard. Also probably a 15 dollar amazon quickie.
It measures 27.5mm on the engine side side to side and 27.3mm top to bottom.

I'm running the stock intake with a filter in the airbox, but no airbox lid as it didn't come with one.

Pic of Air Filter attached.

So far, it seems to work fine through the first heat cycle for the break in. Took about 15 minutes to get to 200°F revving as suggested by KoC.
 

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