Taking over restoration myself

[JimmyXS11]

It lives

Well, I finally got to hit the start button. After about 5 seconds it roared to life. Unfortunately, I must not have done a good job on the bench sync. I must have had an industrial strength bread tie wire. It reved up to 5-6000 and stayed there. I shut it down and fiddled with the adjustments and it started right up again. I adjusted around and got it to slow down to about 1500, but it is just not right. I am going to pull the carbs and go through the bench sync process again and see if I can do it better. Then it will at least be running enough to sync when my CarbTune comes in.

Happy days are here again.

Thanks for your patience. You have all been a great help.

[JimmyXS11]

I have found one of my problems. I am missing the spring on the master idle adjuster. Don't know if I lost it or if it was never there. Is this something I can replace locally, or is it specific enough to require a Yamaha spring?

[ViperRon]

Spring

I do not see a reason that you would not be able to use a locally purchased spring but it needs to be close to the same size as the original as you do not want it to hang on anything. The original spring was pretty strong for its size but that is mainly to hold the adjustment. Remember that you need one long enough to hold the adjustment even at minimal setting.

I hope the spring is the only issue with the sync. I have used the bread tie method and used a thin tie after stripping the plastic off it and straightening it and had the carbs actually idle between 1500 and 2000 steady. If you still have issues with high idle make sure you do not have a vacume leak.

[jetmechmarty]

Get rid of the bread ties! Do it this way: Easy Bench Sync

You're done!

[JimmyXS11]

@jetmechmarty,
I would, but my carbs do not have the three holes. I guess they are only on newer carbs.

I was tired last night when I wrote about the spring. The spring is there. I had in mind that there should be a spring on the tip. But the spring was still the problem. After going through a lot of postings, I found this one by Pathfinder.
******************************************
PATHFINDER
On my 78 you can't do the bread tie sink without removing the idle screw and spring at the rear of carb bank in the middle pointing up. Then reinstall without the spring, do the bread tie sink and reinstall the spring. Set at loose for a slow idle, it may not want to start, tighten slowly to get started.
******************************************
I took the spring out, went through the setting process, put the spring back and tried to start it. Fired right off, but was set too slow. Turned the master idle adjustment in a bit and it ran pretty good.

NOW I am ready for the Carbtune to come in the mail.

[natemoen]

If you don't have those little holes then you don't have XS carbs. They should and must be there.

No reason you should have to remove the idle adjustment screw and spring to do a bench sync. You are doing something wrong here.

[JimmyXS11]

Carb photos

Natemoen,

I am no expert, I have just followed what I have read here and eventually got them working. You piqued my interest so I pulled the carbs again to check them out. Number two has one small hole, the rest none. All have a larger hole back in the middle.















The only writing on it says:

MIC on one end

MIC
Mikuni Kogyo on the other end

Mikuni Kogyo CO. LTD Japan on the tops.

The interior I saw matched what I have seen here on the forums for 1978 carbs.

As far as the idle adjustment spring goes, all I know is that it did not work with it in place, but did work when I removed it to do the adjustment. It runs pretty well now and I am anxious to get my Carbtune in the mail so I can do the final sync.

If you can tell me what the carbs are from the photos, it would help on future repairs.

[natemoen]

All the holes are going to be in the top side of the engine side of the carb bell.

Yes they do certainly look like the early XS carbs though.

[JimmyXS11]

OK, now I see them. Funny thing, your suggestion is exactly where I ended up setting them by the other method. I guess I did not do it too bad.

Thanks for the clarification.

[JimmyXS11]

Wiring progress

Working on the wiring. I think I have everything working except the low beam on the headlight. It is still way too dim and the headlight warning light is on. New bulb, same problem. I have been reading the posts on this problem and have several things to try, tomorrow. Today is one of those days.

[JimmyXS11]

*%@%*#@%* Rant warning

My new Carbtune came in and I tried to use it. The readings were strange and I could not get anything to work. I adjusted to the point I had no base settings any more. Upon further inspection, the tiny holes in the restrictors were partially plugged by the way I cut them apart. Trimmed the ends and they looked good to go.
I pulled the carbs (again) and redid the bench sync. Put it back together and it started, idled and ran even better than the last time. Then I tried to use the Carbtune and everything went crazy again.
With the bench sync redone and the pilot screws out 2 turns, I am not getting enough vacuum to even move the rods up. They just rattle around on the bottom. I can rev up to 3000 and they will go up, but that's too high to do the tune.
I fiddled around with things and got the vacuum up enough to start the sync, but now I have white smoke and sometimes with the slightest turn of one of the idle adjustment screws it can instantly rev to 4500.
Guess I will go back to the beginning and try again. Good thing I am enjoying this.

[jwhughes3]

Carb expert

Jimmy you are becoming a carb expert.

I hope when I get back in town next weekend I can tool over to Luling and visit or help. And maybe get you going enough to come to the Rally on Memorial weekend.

Sorry I havent had a chance to get out there. I will try harder.

Id like to see how you do with a Carbtune. I havent seen one.

Later

John

[JimmyXS11]

I rode it today!!!!

It is still a long way from right, but I took it out on the street for a bit today. Not very far or very fast because it is not registered or insured. The carbs still have adjusting to be done. As I have heard others say, it did not have a lot of power until it passed 3000, then took off. I believe it is just a matter of finalizing the sync.

I do have one problem with the bike. It seems light and maneuverable while going, but it sure is heavy when you come to a stop. I am getting older and not as strong as I used to be. This makes me question if I can handle this thing. I guess that's a good reason to get back into a training program.

But it sure felt good for a few minutes today.

[DGXSER]

If you do not let these engines warm up well before you take off, they will lack a bit of zip below 3k.

Really, it can take a good warm up period of a mile or so. Even then, you will notice an increase in the power as it hits the mains at about 3k.

If you think that feels good, wait till you hit 5k and the true power band of the bike.

[jwhughes3]

Tire pressure

Jimmy

Did you double check your pressures? They feel heavy when tire pressures are low too...

It will feel better once you are used to it I am sure.

John