What did you do to your bike today?

[Wildkat]

Finally got around to doing a proper carb synch on the XS.
She purrs like a kitten... with a LOT of attitude.


Actually pulled the FJ out of mothballs yesterday and will be cleaning the carbs (and apparently everything else) today (and over the next month)
lol

[jjz28]

FINALLY got my filters on and gas lines ran. I ran them the way in the tech tips under "inline filters". They fill all the way with gas and no crimping. Took it for a ride and still dont have the clutch adjusted right or probably need springs.

[trbig]

FINALLY got my XJ running decent again. It was running terrible, so I pulled the carbs and found the slide diaphragm on #4 had a pinhole. Changed that out, and it ran better, but not good. Took them apart again and found the #2 also had a pinhole. Replaced that, having to drill out each one for the Dynojet kit, and it still ran terrible. Checked the petcocks, and had good flow and no water in the fuel. Swapped out the TCI, no change. Changed the spark plugs, and it was still terrible. Took the air filters off (Pods) and saw that the #1 carb's slide was not rising like the others. Assumed a pinhole in it also, so took it back apart.. no pinholes. Put it back together and decided to swap the #1 and #4 spark plugs, and the miss went to #4. Looked, and I had 3 resistor plugs and one non-resistor. The coil was throwing all the spark to the non-resistor plug.

Went and got the right plug, but still not running right on #1. It kind of idled OK and wide open was ok. Anything in the middle was aweful. Took the carbs out yet again to swap slides from #1 to #2 and see if the miss moved also and noticed the slide needle was not springy on the #1. On the later carbs, there is a small plastic washer that sits under the circlip with a little protruding piece that goes into a notch on the slide. This protrusion was not in the notch and the slide needle was raised up. I have the Dynojet kit circlip at the top notch on the needles, so the slide needle moves up and down quite a bit.. enough to let that protrusion come out of that notch.

So.. seems to be running much better. Does anyone know why this protrusion is there? Why can't I just file those off to make sure it always comes down fully? Why would it matter if the needle possible spun a bit?

Also, I've seen replacement skirts for these slides. How do you get the old ones off and the new ones on? I did a little prying on an old one, but couldn't figure out how/if they do come apart? I'm out of spare slide diaphragms now unless I start robbing from a complete set of carbs I have on a parts bike.

[BA80]

I don't have a clue what your talking about with the needle. How about a pic?

The diaphragms just pull out of the slides. It's a little bit tough to get them started but then they get real easy. Then just lube the new ones, I used silicone grease, and push them in.

Practice on one of the bad ones and you'll see.

[trbig]

Slide needle plastic washer with protrusion (Tab?)









And the hole in the slide that goes into.









If I ground that little tab off, I would need to fill that hole since that was letting air get up into the top of the diaphragm and letting the slide drop. But... is there any reason they wanted the needle postioned so that it came down with the slide situated the same every time?

[BA80]

Hmmm......I don't know Tod. On the early carbs there is a spring that goes between that piece and the slide the HOLDS the needle up and there isn't a nipple on there, or a hole.

When you pull down on the needle and let go the spring pressure snaps it back up.

That's an interesting fact I was unaware of.

I would have to say that grinding that off and sealing that hole might affect the performance in a detramental way. Is there any way of adjusting or shimming the needle so it doesn't go up as far?

Possibly the plastic washer or the slide itself is worn allowing this to happen. I would think that the dynojet engineers would have allowed fo this.

OR, maybe the needle is slightly bent and is catching in the main jet somehow.

[jwhughes3]

Got carbs on Rising Sun again

That forlorn yellow bike has been sitting with its tank and seat off in the drive since the MOM Rally when I decided to dump the Kawi carbs the PO had on there and start over with proper matching carbs.

I had an early set of carbs from someone here I bought ages ago (when you see parts cheap, strike!) and started cleaning them at the Rally but found I needed some parts that were buggered up.

Richard (rpgoerlich) kindly sent me the replacement mixture needle and emulsion tubes to replace a broken tipped needle and tube that had cross threaded threads in it.

I ordered all new allen screws and patched a pinhole in the diaphragm, bench synched, got everything back installed and hooked up gauges with the new airflow restrictors in place.

One carb needed to be adjusted 1mm. They all matched. And it started right up too

This 78 engine always pulled hardest and I am anxious to try riding it. Got to finish rebuilding front caliper tomorrow so I have front brakes always a good thing.

John

[BA80]

Cool!

I wish I could have gotten there earlier and helped you put that head back on the SG. Don't let that engine get water in it. It's pretty low mileage.

I personally would have it in the garage.

But, that's just me.

[trbig]

On the early carbs there is a spring that goes between that piece and the slide the HOLDS the needle up and there isn't a nipple on there, or a hole.

These are the opposite. There's a spring over the top of everything with a plate holding that down that forces pressure to push down on that slide needle.



When that tab is in the hole on the slide, the plastic washer just sits down flush. If that tab were removed, it'd still just sit down flush.

[jwhughes3]

A different carb?

Tod,

Could the diaphragm slide be from another mikuni carb thats the same size and is setup different?

John

@Greg - got plenty of tarps over that engine. It may make the garage eventually

[trbig]

No, they're all like that stock.

[BA80]

These are the opposite. There's a spring over the top of everything with a plate holding that down that forces pressure to push down on that slide needle.



When that tab is in the hole on the slide, the plastic washer just sits down flush. If that tab were removed, it'd still just sit down flush.

I see that. I went to the parts fiche and looked.

I'm just wondering if that little titty and the hole have something to do with the operation of the slide is the only thing. Do they ALL pop out and get stuck or is it just that one?

[trbig]

If you pop them up and spin them at all, they'll all do that. BUT, with the stock needles in there (These are Dynojet) you only had one slot available for the circlip. They aren't adjustable like the early model needles. I don't remember if I could get them to spring up high enough with stock needles in there to get that tit out of the hole enough to be able to rotate the needle.

Sorry about this to all.. Probably should have asked this stuff in the regular forum under its own heading. .

[BA80]

Ok, I wonder if you just put another washer ON TOP of the clip so it couldn't travel so far if that would solve the problem.

That way the needle would be in the same postion and you wouldn't have to irreversably alter anything.

See what I'm saying?

[Boothman]

Carbs, what else?

When we had a warm streak a few months ago I rebuilt my master cylinders, calipers, new brake pads, installed ss brake lines but this post is about what I did today... After taking for a spin had terrible throttle response and was not smooth, so out come the carbs. After cleaning, cleaning, and of course, cleaning, put them all back together. This is not fun anymore. I suppose it never was. Anyhow, lost my sync tool to a bitter x. Waiting now for my new sync tool to arrive so I can do a proper sync. Got it close but that only gets it to warm up and move around the property but I am now waiting for the UPS guy. Can't wait to scare the crap out of him as I throw open my door just before he rings the bell. Can you tell I am anxious?
Should be riding next weekend but that will be in next week's post about what I did today.