# Yamaha TTR 225 no power under load



## happysaws (Aug 25, 2018)

Super off topic here, but here goes.

I got a 1999 Yamaha TTR225 a few months back, and I cannot get it to have power under load. So far, I've rebuilt the carb, replaced the fuel shut off valve, installed an E3 plug, and replaced the battery. I've even tried oversized carb jets, but those didn't help either. 

It starts up, idles and revs up fine in neutral, but when I put a load on it, it has no power whatsoever. For example, on a straight away, if I bump it into 4th gear and give it full throttle, it'll just sit at the same RPM and not gain any speed at all. 

I'd like to try to avoid paying a repair shop if at all possible. 

Thanks for any help or advice!


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## cuinrearview (Aug 25, 2018)

Is there some kind of screen in the tank? Sounds like a fuel obstruction to me. You didn't mention a filter.


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## happysaws (Aug 25, 2018)

The fuel shut off valve has filters on it, and I replaced the valve because the handle was broken off the old one, so it does have new fuel filters...


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## cuinrearview (Aug 25, 2018)

Blow some compressed air back through the valve and line into the tank.


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## happysaws (Aug 25, 2018)

Got it running (said this before, knock on wood), kept switching carb parts until it had power. Now it doesn't idle very well, but at least it runs for now LOL


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## cuinrearview (Aug 25, 2018)

Is a rebuilt or new carb that cost prohibitive?


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## happysaws (Aug 25, 2018)

Well, maybe a little.
I did rebuild the carb, as mentioned in my original post. It really started acting up after the carb rebuild, so I put some of the old parts back into the carb, specifically the jets. With the old, original jets reinstalled in the carb, along with a new needle and seat, it runs with plenty of power... Just doesn't idle all that well. If I get the time and/or ambition, I may reinstall the oversize pilot jet to see if that will help with the idle issue.


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## Bwildered (Aug 26, 2018)

happysaws said:


> Well, maybe a little.
> I did rebuild the carb, as mentioned in my original post. It really started acting up after the carb rebuild, so I put some of the old parts back into the carb, specifically the jets. With the old, original jets reinstalled in the carb, along with a new needle and seat, it runs with plenty of power... Just doesn't idle all that well. If I get the time and/or ambition, I may reinstall the oversize pilot jet to see if that will help with the idle issue.


Check the valve timing .


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## s sidewall (Aug 26, 2018)

Are you running it without the air filter?

Steve


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## happysaws (Aug 26, 2018)

s sidewall said:


> Are you running it without the air filter?
> 
> Steve


Ya, why?


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## s sidewall (Aug 26, 2018)

We had a problem trying to fix a carb problem on a Polaris, had no power after fixing carb. We put the air filter back on and fix the problem. Original problem was the needle had worn in half at the retainer clip.

Steve


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## s sidewall (Aug 26, 2018)

Brother had a TTR225, fun bike on the woods trail, but I like my son inlaw's Kawasaki KDX 220R a little bit better, a lot more power and zip when you want it, hard to bet that 2stroke. Brother also had a Yamaha YZ 250, that was too much power.
Had to edit.
Steve


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## 1Alpha1 (Aug 28, 2018)

If there is a baffle or a spark arrestor in the muffler, pull it out and inspect it. It may be all plugged up. 

I'm not familiar with the TTR225, so it's just a thought.


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## s sidewall (Aug 28, 2018)

I thought of that also but, don't remember those having one, spark resistor that is.

Steve


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## 1Alpha1 (Aug 28, 2018)

s sidewall said:


> I thought of that also but, don't remember those having one, spark resistor that is.
> 
> Steve




If it didn't, I'd be surprised. It will have a baffle of some kind though.


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## s sidewall (Aug 29, 2018)

I know my brothers bike didn't have a spark resistor in his, unless it's was welded around the baffle, that part was unremoveable on his.

Steve


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## s sidewall (Aug 29, 2018)

How's the bike coming along?

Steve


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## 1Alpha1 (Aug 29, 2018)

I forget what year it was, but back then, all dual-purpose m/c's imported into the USA had to have a USFA spark arrestor. 

Mid 1970's maybe?


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## s sidewall (Sep 1, 2018)

Bro's was a 2014, YZ 250 ws also a 2014. Like I said, don't remember seeing one on his TTR.

Steve


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## 1Alpha1 (Sep 2, 2018)

A mystery wrapped inside an enigma perhaps? 

I did find this exhaust parts schematic. If you look at part #8, you'll see some "fins" on the muffler insert. Those act as a spark arrestor.
You can - / + to enlarge the screen. If the holes in that insert are plugged, the bike will not run properly, if at all.

https://www.yamahapartspro.com/oemparts/a/yam/50044ae9f8700209bc7909eb/exhaust


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## BusyBeaver (Sep 2, 2018)

If it's like my '07, it has a vacuum operated, diaphragm slide throttle. Check that the diaphragm is intact and drill out the hole that sends the vacuum signal up top.
Also be sure to gut the muffler out as suggested. Then get your jets sorted out. The pilot jet screw is EPA non adjustable similar to a chainsaw's jets. You have to drill off the jet access cover to expose the slotted screw and then adjust the screw out to richen it up. Stock is 1 1/4 out, set it at 2.5 -3 turns out. Makes all the difference in the world.
BB


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## happysaws (Sep 3, 2018)

s sidewall said:


> How's the bike coming along?
> 
> Steve


Running good, but it starts hard and idles rough when cold.


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## happysaws (Sep 3, 2018)

Where is this jet access cover?


BusyBeaver said:


> If it's like my '07, it has a vacuum operated, diaphragm slide throttle. Check that the diaphragm is intact and drill out the hole that sends the vacuum signal up top.
> Also be sure to gut the muffler out as suggested. Then get your jets sorted out. The pilot jet screw is EPA non adjustable similar to a chainsaw's jets. You have to drill off the jet access cover to expose the slotted screw and then adjust the screw out to richen it up. Stock is 1 1/4 out, set it at 2.5 -3 turns out. Makes all the difference in the world.
> BB


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## s sidewall (Sep 3, 2018)

Should be cut out around the float bowl, will be a hole with a plug in it, it's covers the mixture screw. 

Steve


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## sb47 (Sep 8, 2018)

As said before check for any in line filters or screens. DI box may be going out or the stater is going out. If the stater is not putting out enough currant it will bog at high RPM's


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## s sidewall (Sep 9, 2018)

Lot easier to work on if looking at it.

Steve


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## s sidewall (Oct 5, 2018)

Get that bike going?

Steve


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## happysaws (Oct 7, 2018)

s sidewall said:


> Get that bike going?
> 
> Steve


Ya, starts really well now, and runs well without the air filter. The float height was incorrect, it was letting too much fuel into the carb, causing it to constantly run rich and foul the plug.


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## s sidewall (Oct 7, 2018)

Glad to hear that.

Steve


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