Cam timing FXR150

[richban]

You can't just compare jet sizes, every bike will be different, but more carbs will have different air correction jets so a 32mikuni will flow gas differently depending how it is set up.

I am with Dave on this one. All engines are different. even the ones that are the same.

[richban]

running the same jetting on our works FXR's.

How do you get a works FXR?

What's the spec on these things?

[Henk]

How do you get a works FXR?

What's the spec on these things?

Buy an FXR, work on it.
As for the specs, spread lies and mis-information so nobody knows what you are up to.

[richban]

As for the specs, spread lies and mis-information so nobody knows what you are up to.

Worked for me for a while. Not any more.

[koba]

The carb is a Mikuni TM28 flat slide. Off the very bottom(like riding slowly out onto the track) it is perfect and with a slow build up of speed its fine, give it a handleful and then its coughs. Up very top it runs fine, but kinda anything inbetween its pretty average. The largest main jet ive got at the moment its 145 i think, I know I have a 140 and tried these and the bike ran worse than what it was running the 135 main. The clip on the needle is two off the bottom, and have been suggested to drop it down another. The state of tune is more or less standard, just a little grind for the manifold to match up.

The clutching it was the only way to ride around it and have some speed in the weekend. Will have to go order some larger mains and try them out. And the pilot, leave that as it is?

Sounds like its running shit on the bit mostly metered by the needle.

You may have to play with different needles but possibly also the needle jet which is the brass bit the needle runs up and down in. If it's a common setup you should be able to buy alot of different sizes.

[hmurphy]

Wahoo! Just tested with a 115 jet and wow I didn't know the bike had a rev limiter haha. It's still running sliiightly rich I think (it could probably clear out higher revs better) but I'm not too worried and will leave it for now. I do have 1 size smaller main jet too (112) that I bought with the 115.

I do have one question though. Why would my throttle be harder to pull when the motor is running compared to when the motor is off? It's quite noticeable and very, very frustrating. Anyone had this problem?
I am getting a new throttle cable tomorrow hopefully because the one that came with the new throttle is far too long (it's excessive haha).

Other than that, my bike is all good to race and I have tidied up many parts of it. Can't wait to put a few laps in with it on Sunday.

Cheers for all the help

[richban]

The carb is a Mikuni TM28 flat slide. Off the very bottom(like riding slowly out onto the track) it is perfect and with a slow build up of speed its fine, give it a handleful and then its coughs. Up very top it runs fine, but kinda anything inbetween its pretty average. The largest main jet ive got at the moment its 145 i think, I know I have a 140 and tried these and the bike ran worse than what it was running the 135 main. The clip on the needle is two off the bottom, and have been suggested to drop it down another. The state of tune is more or less standard, just a little grind for the manifold to match up.

The clutching it was the only way to ride around it and have some speed in the weekend. Will have to go order some larger mains and try them out. And the pilot, leave that as it is?

I ran with one of these for ages then chucked it. Have lots of jets. It did work great with the standard engine. It should not be the needle Jet unless it has been fecked with. Might want to check if it is a bleed type or primary. Primary would explain the small main jet sizes also meant for a 2 stroke. Are you running a pod or any other filter?. If you have a pod ditch it and see what happens. I hate them. Those jets sizes sound rather small for a Mikuni jet. The standard TM28 comes with a 185 or something. I think my standard FXR used a 270. If you need any bits let me know I need a clean out. I have 3 TM 28s and shit loads of needles etc.

[Shorty_925]

I ran with one of these for ages then chucked it. Have lots of jets. It did work great with the standard engine. It should not be the needle Jet unless it has been fecked with. Might want to check if it is a bleed type or primary. Primary would explain the small main jet sizes also meant for a 2 stroke. Are you running a pod or any other filter?. If you have a pod ditch it and see what happens. I hate them. Those jets sizes sound rather small for a Mikuni jet. The standard TM28 comes with a 185 or something. I think my standard FXR used a 270. If you need any bits let me know I need a clean out. I have 3 TM 28s and shit loads of needles etc.

Yes running a steal pod as a just incase to stop a stone or something else going through. Had a look at it and had a look at the old boys carb which is meant to be the same and his runs perfectly smooth, noticed they were slightly different(both DR250 carbs), so measured it up and mine is actually a 32mm, and his a 28mm. Gone down to a 125 main and going to test and see what that does.

[F5 Dave]

those cheapo pod filters are worse than bad. Better to enclose the carb area with plastic real estate sign or whatever & have a entry out out the way of crud.

[richban]

those cheapo pod filters are worse than bad. Better to enclose the carb area with plastic real estate sign or whatever & have a entry out out the way of crud.

Again I agree with the Dave.

I have made all sorts of air box's most from a cheap $3 plastic containers. If you have the air draw from the top then it should keep out all the dirt and shit. If you can shield it completely from the engine even better. Nice cool air is good.

[timg]

It was suggested to me that I should use an airbox so I'm using the standard FXR airbox on mine. Seems to work well with my cheap chinese flatslide. I enlarged the airbox to carb rubber boot hole to accept a short bell-mouth. Cheers.

[Shorty_925]

Thought id give a quick update. The jet in there at the moment is working a whole lot better, not mint/perfect, but its ALOT better than it was and has been, so progress has been made and got a base to work from.