first road test

[dpj]

I've been working on this bike [79 XS1100SF] in my spare time for two months. Took it out for its first road test today. SWEEET [ at least a little sweet].

A ten minute ride lasted over an hour. It has plenty of power in the low end , but falls on it's face above 4K. Guess the carbs need a third cleaning,but it will probably be a week before I can get to it. Also the speedometer will slowly go up to 30, but no higher. The odometer and trip meter work fine. I did a search on the speedo, but don't know whether to open it up and clean it , or ride for a while and see if it loosens up.

[webbcraft2150]

Try cleaning your speedo cable before taking apart the speedo.

[dpj]

Already cleaned it. I put a light coat of white lithium on it before I put it back together ,but it didn't seem to help it any.

[DiverRay]

Check your float level on the carbs. If they are off, and too low, you may be lean at the higher RPM range.
Just a quick thought...
Ray

[dpj]

I'll do that. Its running fine in the low range. While I've got them off, I think I'll give them another cleaning in case I missed something or they picked up some crud from the new fuel lines, the petcock rebuild, or the auxillary tank I used when I tried to tune them. Thanks, David.

[John]

Originally posted by dpj
Already cleaned it. I put a light coat of white lithium on it before I put it back together ,but it didn't seem to help it any.

Try checking the tabs on the speedo drive clutch that sits in the hub of the front wheel. These tabs engage with the slots in speedo drive, and turn it. It is possible that the tabs have been bent down a little, and aren't engaging the drive properly, and are just rubbing against the drive, and then slipping once the rpm of the wheel increases.

[TopCatGr58]

Hey David,

How about a better description of your work. The last thread I can find you stated that you can cleaned and lined the tank, was doing work on the brakes, and was hesitant to tackle the carbs, but that's it!?

If it falls on it's face around 4K, that's right where the mains are starting to kick in with the vacuum slides. What did you find when you got into the carbs? Did you remove the needle jet, the main emulsion tube that runs down the middle of the carb body thru the bottom? If Not, they are probably still very clogged!

More info on what you've done will help us to steer you in the right direction for how to try to fix it! Are you sure your upper "T" fittings on the carbs are well vented?
T.C.

[dpj]

When I cleaned the carbs I took everything off except the emulsion tubes. I soaked them, cleaned with a small brush, and blew them out with a compressor, but they're probably still dirty. I was afraid of damaging them if I tried to force them out. My main goal from this cleaning was to find out if the motor would even run. Iwas pretty sure I would have to take them apart again to change some jets.
All 4 carbs have 137.5 mains. It has a Jardine 4 into 1 exhaust and I replaced the 4 foam Unifilters with 4 EMGO filters. If I understand all the search information I found, with that set up I need to increase the mains by 4 sizes and the pilots by 1. I'm not real familiar with jet sizing, but I think that means I need 147.5 mains. Somebody let me know if thats not right.
I thought I might find out how to remove the emulsion tubes before I take the carbs apart again to replace the jets. Other than that, so far I've Cleaned and lined the tank, gone completely thru the brakes, changed all the fluids, rebuilt the petcocks, new fuel lines, resoldered the wires on the turn signal switch, put on 1 of TC's fuse blocks [ thanks TC it looks good and cured the headlight woes], and found 2 seats for it. It came without a seat.
I was a little concerned about the motor because the PO said it had been sitting for 7 or 8 years, but when I was cleaning the grime off, I noticed the last safety inspection was 1986. Don't know if he just didn't get it inspected or what, but sitting for 20 I guess is possible. Want to thank all who've helped out. So far I've found the search feature here to be way more valuable than my Clymers.
David

[John]

The easiest way to extract the emulsion tubes is to loosen the main jets a few turns, but don't fully unscrew them. Using the screw driver that you just used to loosen the mains, place it back in the slot of the main jet, and tap on the end of the handle with a hammer to break the tubes loose. Then remove the main jets, and use a small wooden dowel, or something similar as not to damage the threads in the tube, and the hammer to drive the tubes UP through the air horn and into the diaphragm cavity. Now you can get to the holes in the tubes to clean them out. Make note of the small notch in the end of the tube, where the main jet threads in. There is a small peg in the body of the carb that aligns with the notch. It all there, and it's easy, you'll see. As far as jetting goes, I have a 1179cc big bore, Uni foam air cleaner, and Jardine 4-2 Spaghetti pipes. I am running a set of 78 carbs, and I only had to increase the jet size up from 137.5 to 140's., and the pilot jets are stock. I have had to turn thr pilot screws out to about 2 1/2 turns, and that's all I have had to do to the carbs.

[TopCatGr58]

Hey David,

John's tips are very good!! Remember you have to take off the vacuum diaphragm/slide to get the needle jet out.

As for rejetting, the guide states 4 sizes -1 when combining mods like 4-1 AND Indy Filters. So..either 142.5 or 145 would probably more than adequate, and you might not need to bump up the pilot jet. I remember Skids(IIRC) saying that the pilots should only be turned out 1.5 turns or so, and more means you need a bigger jet, but if you can get the affect you want with a few more turns out, then why get the larger jet??

When I put 4-1's on my stock 81SH, it would easily rev to and beyond redline. I drove it like that for many a year without any rejetting! That's where the MAIN size kicks in under full throttle. Mine came with 110 mains, I went to 117.5's when I did my big bore and added Indy Filters(3 sizes), and it performs quite well, had good plug color, etc.! I was told after my DYNO run that I could probably go up one more size in main jet, but haven't bothered. In the later years, Yamaha jetted these things fairly lean for emissions control. Also remember, the later year carbs have separate supply for pilot and mains so that's why my main is so much smaller, the 78-79 pilot gets its supply THRU the main, that's why it's so much larger. Also, your carbs are a bit more tunable with the slide needle clip for the midrange tweeking. If it'll run up to redline NOW, then probably just a couple sizes would be sufficient.
T.C.

[dpj]

Thanks for all the help guys. I'll check with the local Yamaha shop tomorrow to see whats available. I don't expect to find much. The last couple of times I tried, the kid at the parts counter was no help. Said the bike was too old for them to get parts, and he wouldn't try to look anything up. So I'll probably order from an internet store. Will keep you posted.
David

[LoserShoes]

When you get that kind of bs, go to the yamaha site and print out the parts list and diagrams for the pieces you want, and just tell the kid to look up the part numbers.

Steve