1982 Seca XJ750, ZRX1200 has company now.

[Bonz]

Thanks for responding. It's perplexing because I'm already down one size on the pilots from stock. Past experience at 7200' elevation says that usually does the trick. The Hitachi carburetors have pilot air jets, figured it would be best to lean out the pilot circuit with smaller fuel jets. Pilot air jets are opposite effect. The larger the number, the leaner the mixture. In any case I'll play with it some more and keep you all posted.

[cajun31]

Instead of making the above post from earlier this morning longer, I would like some thoughts:

This morning, 40°- 45° temperature in the garage here at 7,200' in Palmer Lake. Bike started without any enrichener, almost settled into a steady idle and would take gentle throttle without a problem to steady the idle.

I'm running one size smaller pilot jets than stock and have the screws at two turns out from seated on carbs one through three and one and a half turns on number four because it has a body from an early XJ650 apparently, those had a coarse thread pilot screw that moves further with every turn. Mains are 118 (stock 120), pilots 38 (40 stock), pilot air jets are stock at 225 and 80. Hitachi carbs used some interesting design, but seem to have had a good run of success back in the day.

Question: Screws are in about as far as practical, go down another size on pilots? It shouldn't start that easily at that temperature without the enrichener IMO. For information, with the enrichener off, the plungers are fully seated so there's no unintended enrichening taking place.

Howard, If you think the pilot screws are turned in as far as you want then I don't see any other alternative but to go down a size on the jets. I agree with you that it should not be idling on cold starts and for sure not with the temps you described. Running way rich.

[Bonz]

Put the first mile on it since it was last plated in Illinois in 2007. Front brakes are marginal with respect to feel because of the remote master cylinder behind the headlight that's activated from the lever by a cable, front brake power was average at best. Rear drum brake has good feel and good modulation. Shifted fine, pulled cleanly.

Put fuel screws at 3 turns out after playing with them a bit before the maiden voyage. Idle would stay high, sometimes it would drop back down but still higher than spec. I'll play with the idle adjustment, a synchronization will help as well. Time for a YICS tool of one type or another.

Now it can sit proudly next to it's ZRX 1200 stable mate in the garage.

[Bonz]

Instead of making the above post from earlier this morning longer, I would like some thoughts:

This morning, 40°- 45° temperature in the garage here at 7,200' in Palmer Lake. Bike started without any enrichener, almost settled into a steady idle and would take gentle throttle without a problem to steady the idle.

I'm running one size smaller pilot jets than stock and have the screws at two turns out from seated on carbs one through three and one and a half turns on number four because it has a body from an early XJ650 apparently, those had a coarse thread pilot screw that moves further with every turn. Mains are 118 (stock 120), pilots 38 (40 stock), pilot air jets are stock at 225 and 80. Hitachi carbs used some interesting design, but seem to have had a good run of success back in the day.

Question: Screws are in about as far as practical, go down another size on pilots? It shouldn't start that easily at that temperature without the enrichener IMO. For information, with the enrichener off, the plungers are fully seated so there's no unintended enrichening taking place.

[Bonz]

It's been a minute since I posted on the Seca 750. It has been holed up for the "winter" that we never really had here in Colorado. The ZRX 1200 has gotten all riding which is a little over 2,000 miles since September given how mild the weather has been.

Yesterday I rehabbed the stock float needles by polishing the brass bodies and using 3M label and adhesive remover on a soft cloth to clean the rubber needle tips. Spray a small amount on the cloth, spin the needle tip in the cloth with a relatively light pressure. Amazing the light layer of decomposed rubber for lack of a better term that each tip had. However the tips are all straight and true with no ring where they rest on the seat. They are decently pliable when compared to newer needle tips now that they are all cleaned up.

I had used the 3 mm float bowl fuel level that's in the factory service manual when setting the floats previously and the closer I got to 3 mm, the more the carbs would dump fuel with the aftermarket repair kit needles. Went back to a "set it and forget it" mindset with the rehabbed stock float needles and put them at 17.5mm +/- .5mm. Did a trial run on the bench and the carbs sealed up with no issues.

Got them back on the bike, started right up and I'm really pleased.

Front brakes as I posted last fall are completely rebuilt and that master cylinder behind the light was the biggest pain in the butt.

Today is going to be spent getting the wires back into the headlight housing along with the horns that mount inside of there as well. Had to remove the headlight housing and disconnect a lot of wires to get the clearance to get that master cylinder out.

As well, I noticed yesterday number two cylinder would cut in and out, traced it easily and quickly to a plug wire connecting to the boot on the number two cylinder. Going to trim all the wires back to expose fresh wire which probably should be done anyway even if they were working fine given the age of the bike.

Anyway, it's in the home stretch now that the carbs seem to be good.

[Bonz]

Shinko 230's arrived. Goal is new float needles tomorrow, spin around the block. If all goes well with carbs sealing, wheels off and to local shop next week to get them mounted. Tire mounting is the only thing I don't do, want to give some business to my local guy. IMO, good to have a relationship with at least one motorcycle repair shop. In case you need to borrow a tool such as an impact driver for carb rack screws... Have my own now, didn't when I needed one last fall working on a first generation Vmax carb rack.
.

[Bonz]

Thanks guys. Had Shinko 230's on the 80SG and they were good. Ordered the 230's for the 82 Seca just now.

[bikerphil]

+1 on the 230's, Z rated and much better than the 712's.

[LAB3]

In my experience there's nothing better than the Shinko 230 in the low end of the price range. The Skinko 712 is a couple of bucks cheaper and you'll get about 5-750 more miles out of them but you'll lose a lot of confidence in the rain, on bridge grates and scarred pavement.

Next notch up price wise would be the Bridgestone Battle-axe and they WILL feel better planted all around, expect about the same mileage wear wise as the Shinkos.

[Bonz]

Front brake system back in working order. That remote master cylinder under the gauges next to the steering head operated by 12 or 16-in cable from the lever on the bar that Yamaha designed and used is one of the top 10 most stupid engineering workarounds to then allow plastic covers on the bars to give it a streamlined look. Alas, in the grand scheme it wasn't that difficult to work with. The cable going to the master cylinder takes away some of the direct feel however I doubt it will have any negative effect on overall braking performance in terms of stopping distance.

Float needles I used aren't sealing well. They are maybe a millimeter taller from tip to end of the spring plunger but when getting the fuel level set correctly in the bowls, the floats are at parallel or even a bit tilted downward at the tip of the float opposite the hinge. I think there's some binding going on with the angle.

Ordered some kits off eBay to get float needles, they arrived today. Won't get them on this weekend. However it's coming along. Once I stop the carbs from leaking fuel into air box it'll be ready for its maiden run in Colorado. Last registration was 8/07 so it hasn't seen the road in a while.

While I'm at it, I was happy with Shinko tires on my XS11 when I owned it. Looks like they have tires in the sizes I'll need in one or two of their models. I do not like the D404, they wore quickly and the front end would push in higher speed sweepers on the 80SG. Anyone have something they have had success with to recommend in a reasonable price range other than the Shinko tires?

[Bonz]

Saw that when you posted it on the second page of the thread. If I make one, that's what I'm going with.

[DEEBS11]

Guys, I made up this contraption after a trip to the hardware store and it worked great on mine. I gave it to the guy when I sold the bike.

[Bonz]

You read my mind, I was planning on brushing it out with a bore brush and Hoppes #9. I'll sync them without doing anything to the passages with respect to blocking the ports, and see what I get. From there, decide if seat of the pants and experience tells me it's dramatically off.

[bikerphil]

You know, a gun cleaning brush works excellent for cleaning that tunnel out. There are only four holes in that tunnel that need to be blocked. I don't think anything can get caught on them. I wouldn't be afraid to attempt the oily rag and ramrod method.
Some of these XJ's have the plug on both sides, that may make it easier. I have read of people doing it like this with success.

[Bonz]

Understood on the 3 spots. Thought... If they are blocked individually by the tool, the rest of it is dead air space around the small margin left by the diameter of the tool and would not affect anything, IMO. If it's blocked fully by any means, it would seem to my thinking to be no different with respect to the sync than blocking them with the tool or not having the passageway in the first place, a la the XS1100. Just thinking out loud.