Help Me Fix My SSR XF250

[Nicholas R.]

Hey y’all! My name is Nicholas, I got a new bike around 6 months ago and it was perfect when I got it, it was running amazing and a joy to ride. But since around 1 month ago it started to act up. The bike I have is an SSR XF250, an enduro. It started to act up right after I put dirt tires on the bike, the problem I am having with it is it doesn’t rev past 4500 and doesn’t go faster than 50 (which I know is fully capable of doing since I’ve rode around 65 mph before on that bike) so any help would be greatly appreciated, I took the carb apart and didn’t look like clogged jets, then I looked to see if the fuel petcock was messed up and it was releasing more fuel in reserve than in open (which I found very weird). I was also possibly thinking it could be an oil issue since I was tipping the bike forward and backwards but I’m not sure.) I don’t know what is wrong with it and I’m very worried something is wrong really broken on it.

[TxTaoRider]

Did you check the choke to be sure it was opening fully? Also did you check the spark plug? The stock plugs on some of these bikes are of dubious quality.

[CaesarVis]

If you were messing around with changing tires and stuff, did you make sure everything is lined back up properly? Also, have you checked the brakes? When I took my rear tire off and put it back on, I didn't do something properly with the brakes. It was making all kinds of noise and not working. Make sure the wheels spin freely...

[Megadan]

Could be unrelated, but being that you bought it brand new, and I am going to assume it has at least 1000 miles or more on it, have you checked the valve lash recently, or ever? Might be worth to go through and do a proper maintenance service on it if not. The engine yours was based off of has valve checks every 3000 miles after break in.

Hopefully somebody more familiar with these bikes can chime in for you as there may be something specific they are more aware of.

[Nicholas R.]

Alright, I have actually never checked the valve lash. I bought the bike brand new and would give that a check, also I will check the spark plugs, that’s a good idea, I’ve also heard that they’re not good plugs. It also has around 1650 miles.

[Megadan]

Alright, I have actually never checked the valve lash. I bought the bike brand new and would give that a check, also I will check the spark plugs, that’s a good idea, I’ve also heard that they’re not good plugs. It also has around 1650 miles.

Yeah, I would start there. Do a valve lash check and maybe give it a fresh NGK plug. Two things that definitely can't hurt to do.

[dh]

All good advice this far. I'm no expert, but as far as this bike goes I'm betting this is a minor carb/vacuum issue. Was the bike parked for an extended period?

Any exhaust smoke visible? As TXrider says, check to ensure your choke isn't stuck in the 1/2 position.

Pull the seat and check all vacuum lines, vacuum is important with the CV carb. If one has come disconnected from the evap canister this could be the fault.

[dh]

Also, a bit more fuel pressure from the reserve side sounds normal, since the reserve straw is a bit lower in the tank.

[Nicholas R.]

I’m going to go get a new plug today and see if that changes anything, I will check the vacuum lines as well, the bikes once sat for around 3 weeks, I’m not sure if that’s long enough to cause any problems. And the choke is not stuck, working like usual.

[Nicholas R.]

Also, can anyone more familiar with this bike tell me all the vacuum lines on this bike so I can check them, since to be honest, I don’t know a lot about bikes in general and specifically this bike I know close to nothing about.

[franque]

Check the valves first, they might be tight. It will be much easier to do that than hunt down leaks, especially if you don't know what you're looking at for the most part.

[dh]

I disagree about a valve adjustment being much easier than inspecting a couple of vacuum lines. This should only take a few minutes.

There are I believe 2 vacuum lines running between the carb and the evap canister. There is also a tee where 1 line becomes 2. The lines are 1/4" black tubing. It would be easy to pull one loose while wrenching on the bike. I've done it.

Trace each of them and ensure there are no open ends. If you find one, plug it with your finger while the bike is idling. If the idle speed increases, this is likely a disconnected line. Fuel or moisture could be hiding in the lines. If so, ride the bike hard or blow the lines out with a puff of air.

[TxTaoRider]

Not to disagree with anyone, but my experience with vacuum leaks is they usually cause the engines to run the worst at low rpms and lower throttle positions and they seem to get better at higher rpms and more open throttle positions.

[Megadan]

Not to disagree with anyone, but my experience with vacuum leaks is they usually cause the engines to run the worst at low rpms and lower throttle positions and they seem to get better at higher rpms and more open throttle positions.

Not entirely true when it comes to constant velocity style carburetors. They are designed to operate entirely based on vacuum pressure, and at any given condition a leak can completely throw things out of whack, up to an including not actually getting full slide opening or closing. The old Goldwing carbs are a great lesson in this, as even running a freer flowing air filter was enough to toss the entire system out of whack and create several subtle running issues. This does include more wide open scenarios, due to the fact that it can throw the jetting off.

I only suggested the valve check as a generic bit of maintenance, especially since it has never been done and has over 1600 miles. It's one of those things that can't hurt. It also has the side benefit of exposing a lot of things during the process, such as vacuum lines, that can be checked/replaced if needed.

[TxTaoRider]

Not entirely true when it comes to constant velocity style carburetors. They are designed to operate entirely based on vacuum pressure, and at any given condition a leak can completely throw things out of whack, up to an including not actually getting full slide opening or closing. The old Goldwing carbs are a great lesson in this, as even running a freer flowing air filter was enough to toss the entire system out of whack and create several subtle running issues. This does include more wide open scenarios, due to the fact that it can throw the jetting off.

I only suggested the valve check as a generic bit of maintenance, especially since it has never been done and has over 1600 miles. It's one of those things that can't hurt. It also has the side benefit of exposing a lot of things during the process, such as vacuum lines, that can be checked/replaced if needed.

My bad, I didn't notice it had a CV style carb. Yes they can be really finicky about everything being perfect. On my Polaris atvs about all they'll do is idle if the air box lid isn't on tight.

[TxTaoRider]

That reminds me. A few years ago I had a Polaris atv that started not revving and it had a hole in the diaphragm.

It's bad to have a hole in the carburetor diaphragm but not as bad as having one in your wife's diaphragm. Lol

[Nicholas R.]

Yesterday I replaced the spark plug and started the bike up and it seemed much better, quicker startup and seems to have nice throttle response. I didn’t ride it yesterday though, so I’m not sure if it fixed the problem. I have a question, what is a EVAP canister and where is it? The only reason I still didn’t check the valve lash is since I don’t have gap tools to check the tightness. I will ride the bike today and give an update.
.

[franque]

Check the valves, buy the tool. It's a common maintenance item on these engines, and it'll run much worse if the valves are out of spec. Glad to hear it's running a bit better.

[dh]

Youtube has a good maintenance video on valve adjustments for the identical tu250x. The xf250 has room to do valves without removing the tank, but doing so let's you inspect a vacuum line hidden between the tank and frame. That line should be plugged into the bottom of the tank, towards the front.

The Evap canister traps emissions vapors that can later be sucked out and burnt when the bike is running and the vacuum system is pressurized. It's a beer can sized black plastic cylinder with a handful of vacuum lines plugged into it. It's under the seat towards the back of the bike. If any lines come unplugged the bike would run like garbage.

[mtiberio]

That reminds me. A few years ago I had a Polaris atv that started not revving and it had a hole in the diaphragm.
l

only an issue for CV carbs, not pull slide carbs like ours

[TxTaoRider]

only an issue for CV carbs, not pull slide carbs like ours

True, but others in this thread are saying this bike uses a CV type carb and not a slide pull like most of our's use. The CV can develop leaks in the diaphrams.

[dh]

True, but others in this thread are saying this bike uses a CV type carb and not a slide pull like most of our's use. The CV can develop leaks in the diaphrams.
True. This one uses a CV carb. The carb diaphram can also cause problems if it comes unseated from the channels it rests, easy to do during reassembly.