LTR needle wear

[mattmax]

I just went to raise the clip on my needle from the LTR kit in my 05 MC250 and noticed wear that I've never seen before on a needle, even an old one. On two of the tapers, the first being the straight section at top, and then the second one down from that. It looks almost like scuffing and has a rough looking finish. It has very little time on it.

I raised the clip, and power was definitely increased, but it stuck the needle lower in the bore, so this concerns me. Is the LTR needle made out of softer metal than a Keihin?

Also, unless I'm mistaken, my kit came with a 48 pilot, and I think stock was a 40 or 42. The air screw tunes in just fine, so I know the 48 is working, but I think it's only because the needle is very snug at the top. I know you can go with a bigger pilot if you run a fatter needle because fuel leaks past the needle even when the slide is closed. I'm afraid my needle is too fat and causing wear.

Anybody's kit come with a 48 and anyone see wear?

 

[GMP]

Matt,

What you describe is a classic case of dirt being caught between the needle and the needle jet, causing scratches and wear. Sometimes it can cause the needle to jam and then you go for a real thrill ride. The dirt makes its way in through the vent hoses and settles in the float bowl. Split them and run the little filters. I've also had the stock GG throttle cable let water in that collected in the top of the slide. If for some reason the needle cannot "float" in the slide there will be a side load on the needle jet and cause wear, it must float. The LTR needles are made exactly like a standard Keihin needle.

 

[Eric K]

I have had the LTR needle wear slightly and the nozzle jet (where the needle goes in) wear as well on my '01 XC300. I expect it was the result of a lot of use.

As GMP said, the LTR needle is just like Keihin.

If the nozzle jet is worn, you need a new carb or someone to replace the nozzle jet (good luck). A short term, marginally effective solution is to experiment with different needles to compensate for wear.

 

[iancp5]

Pretty sure the LTR is just a needle and shouldn't wear any different.
Yes LTR ship big pilots - I couldn't get them to work but many can. I run a 35 in my 300!
Vagaries of environment, production tolerances, pipe & fuel??

I just went to raise the clip on my needle from the LTR kit in my 05 MC250 and noticed wear that I've never seen before on a needle, even an old one. On two of the tapers, the first being the straight section at top, and then the second one down from that. It looks almost like scuffing and has a rough looking finish. It has very little time on it.

I raised the clip, and power was definitely increased, but it stuck the needle lower in the bore, so this concerns me. Is the LTR needle made out of softer metal than a Keihin?

Also, unless I'm mistaken, my kit came with a 48 pilot, and I think stock was a 40 or 42. The air screw tunes in just fine, so I know the 48 is working, but I think it's only because the needle is very snug at the top. I know you can go with a bigger pilot if you run a fatter needle because fuel leaks past the needle even when the slide is closed. I'm afraid my needle is too fat and causing wear.

Anybody's kit come with a 48 and anyone see wear?

 

[mattmax]

needle wear

I inspected the needle closely and found the place it is really worn is were it is inside the slide and goes up to the clip and never touches the bore.

It has circular rings grooved into the needle and it's has no more than 3 hours on it, and no more than 8 hours on the bike.

The taper is not really worn, just the shininess worn off it. I've never seen a needle do this.

 

[GMP]

Post a photo. Does it fit/float in the slide normally?

 

[jeffd]

Hey Matt,
The LTR needles are made by keihin for the keihin pwk carb that you have in your bike. The part number is machined off to protect it from being copied; This accounts for the wear marks you see near the grooves for the clip. By the way, JD jetting machines the numbers off all their needles as well...

So, to answer your original question, no the LTR needle isn't softer than a keihin needle; It is a keihin needle!

The keihin pwk carb doesn't have a replaceable nozzle jet (where the needle fits into the carb body) - this is machined into the body of the carb. It could be this was a little rough causing some initial break-in wear on both the carb body and the needle; Or as Glenn said, you had some ingestion of dirt which caused some wear.


jeff

 

[Eric K]

Measure the straight diameter of the needle and check with LTR on what the straight diameter of your needle should be. That way you can determine how much the needle is actually worn.

As a note, my needle wore about 0.0005" over about 5 years.

 

[RBD]

JD jetting machines the numbers off all their needles as well...

JD makes his own needles....

Ron

 

[jeffd]

My bad - I assumed he did. I stand corrected. Thanks Ron.


jeff

 

[mattmax]

needle wear

I took the slide out and had some grit in the needle hole. I examined the needle under good light, and it's not that bad.

I'm disappointed with the LTR kit though. I took out my digital caliper and examined all my needles and the LTR needle. The LTR is exactly the same measurements as stock until the last 15mm, where the stock has a sharp second taper

Also, my kit came with a 48 pilot and 178 main. 40 and 180 was stock. 48 was way too rich and a 42 dialed in perfect. The 178 is close, but I'm running lean at the last part of the throttle opening. Could be two other things besides main.

I know guys swear by the kit and it must work for most people, but it wasn't a cure all for me. I still have to jet the carb and will try the stock needle.

Oh, I know what the letters are on the needle, but won't divulge out of respect for the kit maker

 

[Eric K]

The stock needle is a triple taper needle. The LTR needle is a single taper.

I have run various triple taper needles and various single taper needles. For trail riding, I prefer the single taper needles, with the LTR needle working very well for me.