81' Special re-hab

[bikerphil]

Have you checked for broken P/U coil wires under the left side ignition cover?

[SNDSLGR]

Have not, good suggestion I'll do that in the morning. Thanks

[TopCatGr58]

Hey there,

Like Skids said, you can run the bike until it starts acting up and then stop it and recheck the secondary resistance. The primary resistance is a bit harder to check on the side of the road, especially having to take the tank off and such to get to the harness connectors. It's possible the windings/coils could develop a short or break when they heat up. Also as stated, they are 35+ y/o wires and could be shorting thru the insulation to the frame also.

The Accel # you have is correct, and the DYNATEK # is the DC1-1 3 ohm style. Both are the 3 ohm type for older ignitions, you do NOT want any type for CDI type ignitions.

The 81 had 42.5 stock pilot and 110 mains, so you've gone up 1 size pilot and 3 sizes mains already, don't think you need to go up another pilot size? Your description of "BOGGING/Surging" almost sounds like too rich to begin with and it only picking up once the rpms get high enough to catch enough air to handle the excess fuel!!?

The 81's are a lot less prone to the pickup coil problem than the earlier models due to only the vac. adv. causing the wires to flex, no mech cent. adv. rotating the plate, it's programmed into the TCI, but you can still check them to rule them out.

It's still possible that your carbs are having ignition problems.

T.C.

[SNDSLGR]

Hey there,



The 81 had 42.5 stock pilot and 110 mains, so you've gone up 1 size pilot and 3 sizes mains already, don't think you need to go up another pilot size? Your description of "BOGGING/Surging" almost sounds like too rich to begin with and it only picking up once the rpms get high enough to catch enough air to handle the excess fuel!!?


It's still possible that your carbs are having ignition problems.

T.C.

Agree about the jetting.. its strange, it feels and sounds too rich but backing out the screws improves the problem, but never goes away once warm. Im very familiar with Keihn slide carbs w/fixed float, not much time with these Mikuni CV carbs.

Plan of action is 1) go over electrical real good and 2) lower fuel level 1mm. This quote from factorypro.com is exactly what im experiencing.

"a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. / FUEL LEVEL IS EXTREMELY IMPORTANT!!!"

Weather here is terrible and my work cycle starts tomorrow night so Ill have the new tires I ordered by the time I have any time to really get into it.

Thanks all.

[motoman]

Agree about the jetting.. its strange, it feels and sounds too rich but backing out the screws improves the problem, but never goes away once warm. Im very familiar with Keihn slide carbs w/fixed float, not much time with these Mikuni CV carbs.

Plan of action is 1) go over electrical real good and 2) lower fuel level 1mm. This quote from factorypro.com is exactly what im experiencing.

"a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. / FUEL LEVEL IS EXTREMELY IMPORTANT!!!"

Weather here is terrible and my work cycle starts tomorrow night so Ill have the new tires I ordered by the time I have any time to really get into it.

Thanks all.

Since your scoot has the drain-screw seats on sides of float bowls, slide a piece of see-thru fuel line on nipple on bottom of fuel bowl. Start bike, and at idle unscrew the seat screw while holding fuel line up beside fuel bowl. Fuel in that line will be the actual fuel level in fuel bowl. That actual level with bike idling is 3mm down from carb body casting where fuel bowl attaches. All four carbs need to measure the SAME 3mm. So, with that, just lowering float bowls the 1mm as per your statement IS incorrect. FWIW, 1mm of actual float change equals 3mm of fuel level change. If your insistant on just changing float level settings, I suggest not changing them more than a 1/2mm at the most. The actual fuel level setting procedure as previously stated IS also the required method for 81-82 XS and XJ's, as stated in the original Yamaha shop manual. Having this advantage with these later model carbs makes for getting float levels set so that all four carbs fuel levels are the SAME. Also, this procedure, with several carb bank removals and installations makes one cut that removal time down to approx. 12min., starting with seat and tank.

[SNDSLGR]

Only 1 day off to work in garage but got a lot done today. Took it for a ride this morning and checked coils while hot, no trouble found. I pulled the carb bank and adjusted the float height then put in 47.5 pilots. Im fairly sure my main is 1 lean and im compensating it with too big of pilot but at least its running smooth now.

Took the wheels off and got them cleaned up then had the old rotten tires removed. Ill refinsh the wheels next week.





Also ran up to a local hose shop and had some custom brake lines made I can install when new tires and refinished wheels go back on.

[spectra]

What hose shop? Am local to Portland and need a set also.

Thanks!

[SNDSLGR]

It's called "oil filter service shop" downtown Portland on market Street. Great place, makes your parts while you wait.

[spectra]

It's called "oil filter service shop" downtown Portland on market Street. Great place, makes your parts while you wait.

Thanks and have used them before for fuel lines for my diesel. Thought maybe there was another game in town.....

I was just actually next door to them last week and should have went in but didn't even think about it.....

[SNDSLGR]

Took the front end down and cleaned some of the chrome up. Soaked it in the same phosphoric solution I used on the tank.

[SNDSLGR]

Cleaned and re-finished the rotors and lower fork legs then got the new tire mounted up and installed new brake lines and MC. Its starting to look pretty nice.

[SNDSLGR]

Been a while. I got it running close to right, I'll wait to do a final tune until I get the exhaust back from ceramic coating.

Headers where nice and strong metal through out but the mufflers where getting soft. I've read enough about good headers being hard to find and wanted to preserve mine so I decided to cut the mufflers off and rework them for aftermarket mufflers.

Some of this has been covered by others but here is a step by step for anyone considering the same.

Cut the mufflers just rear of the dimple about 4" behind the smallest part of cone.
(I'll have to pick this back up when I get home... Having a hard time posting pics from phone.

[SNDSLGR]

Next if you look close there is a slight bulge 1/2" behind the weld. I marked it with a sharpie to use as a guide once I break thru first tube. The exhaust is double walled here, the inner tube reduces and the outer tube expands at this point.
s


Use a cutoff wheel and carefully cut off the outer ring only, leave the inner tube in tact to sleeve over later.

[SNDSLGR]

Clean it up and prep for mock up and welding.



Put the headers back on bike and figure out mounting etc for mufflers. For the Supertrapp mufflers I chose (443-1717) I need a 5" extension to make it work.



The inner tube is 1-5/8" OD. A piece of 1-3/4" exhaust pipe is a near perfect fit to slide over the stub left being. Weld it up and grind it down smooth.



Mock up shot. I cannot weld SS so will have to get the bike over to my buddies house. I plan to make a SS mount tab like the stocker and get ride of the strap at a later date.

[SNDSLGR]

2 of 3 bolts snapped on each header when I removed the heat shields. I used a dremel cutoff wheel to cut what I could of the weld and then a chisel and hammer to remove old threaded bung so I could weld new nuts into place.