Jetting a 1300

I took the 1300 out on a group ride yesterday but decided to cut it short because the bike was surging too badly between 3000 and 4000 RPM. It was so bad that I had trouble riding in a staggered formation. Going into a curve the bike would stumble and hesitate and eventually come alive and leap forward.
Here's my setup mains 96 pilots 42.5. Idle screws at 3.5 turns. I called DynaJet a few weeks ago to ask for assistance because I'm using their jet kit. The tech told me to move the clip from #3 to #4 to enrich the transition from idle to main. He insisted that I only move the clip one notch at a time. While I know he's right, I wonder if he knows how much work goes into removing and reinstalling these carbs?

The jet kit also came with a set of 100 mains but I'm not sure they're the answer because at WOT the bikes pulls so hard it's difficult to hold on to the bars. The 100's might just end up wasting fuel.

I pulled the carbs last night and was thinking that I'll move the clips to the sixth notch to see if things smooth out.

Thoughts/Comments?

Bill

Wondering if possibly an ignition issue, such as intermittent firing through one of the secondary loops, which could be fault with coil, plug wire, cap, plug, or connections between any of them? Surges would feel like switching back and forth from normal 6-cyl running to 4-cyl running.

Carbs might have become partially clogged (for whatever reason). A dose of Kroil or other fuel additive might help. But thinking the carbs wouldn't spontaneously fall out of adjustment.


Good Fortune!

Patton wrote: Wondering if possibly an ignition issue, such as intermittent firing through one of the secondary loops, which could be fault with coil, plug wire, cap, plug, or connections between any of them? Surges would feel like switching back and forth from normal 6-cyl running to 4-cyl running.

Carbs might have become partially clogged (for whatever reason). A dose of Kroil or other fuel additive might help. But thinking the carbs wouldn't spontaneously fall out of adjustment.


Good Fortune!

Hi Patton,

No this problem is of my causing. I fitted a DG Six into One exhaust system before I ever fired up the bike so I do not have a base line to start from.

Bill

I was sorry to see you drop out of the ride yesterday, but completely understand. Out of the original 13, we had 7 finish .
I know you said you got the Fuel height right with a clear tube, but I would re check that First. See where that lies compared to the Dry height measurement, it really shouldn't be much difference, maybe a couple of millimeters.
If that is all good, then continue jetting. Lean Mid range, make sure those slide diaphragms are perfect and sealed at the chamber lid. All good I'd go a clip richer. If you need some needle shims I have some for you to try also.
Keep the relay in mind, as Forrest sure does sound eager! KZ all the way!

Thanks Darrell!

While I had the carbs off I did the clear hose thing and found the level near 1/4" below the gasket on all three. Specs call for 5.5 to 8.5 MM. I also dropped the clips to the sixth groove. Did I mention that I'm tired of pulling these carbs? Took it out for a ten or twelve mile ride to see if things changed in the direction I'd hoped.

Bada Bing! It worked!

The engine pulls OK off the line and runs smooth all the way up. Yesterday there was a huge hole in the power curve before the bike got up above 4K. There's still a tiny bit of surge between 3 & 4K but only on steady throttle. If yesterday's problem was a 10 today's surge was a 1. Before I called Tech support at DynaJet I'd turned the idle screws out to five turns in an attempt to richen the bottom end. The tech told me to return the idle screws to 3 1/2 turns and start working with the needles. I've now got the needles as high as they will go. I'm bettin that I could turn the idle screws out another half turn and get rid of the surge completely.

I know that the mains are good because the engine pulls smooth and HARD above 7K. If I was a bit more daring, I think power wheelies might be in there.

One trick I learned when doing the float level check was that any air bubbles in the tube ruin the test. I ended up with 1/8" diameter tubing because the fuel would push all the air out, where with 1/4" tubing it could flow around the bubble. The size of the bubble really makes a difference in the reading.

I'm liking it!

Bill

Boy that sounds like they were way to low. That really makes it lean out, as the fuel is so far down inside the jet wells, it makes it Much harder for it to start pulling up through the jets.
Good to hear its better. Like I said, if you think that it is now correct, and want to use shims to move the needle up farther I got some. You may need a richer needle taper.

Any more then 3.5 turns out and you need to go up one size on your pilot jets