New member with a "new" '79 Special and a to-do list

[DouglasVB]

I traced the source of leaking fluid to the forks that I just rebuilt. Seems that either I did something wrong with the rebuild (maybe flipped seals?) or the K&L seals I got aren't particularly good. The Yamaha part number appears to be 3H3-23163-00-00 which also appears to be discontinued. Is there another source or a newer part number that I should be tracking down?

I took the bike out for a spin again today. The 1100 feels much more refined than my 850. It also feels like it has a bit less power. Perhaps a re-jetting is in my future?

I adjusted the idle up to where it will not stall out. Still seems not quite right though. I suspect that I have some clogged slow jets. With time, seafoam, and more riding I expect that they will open up.

The rattling/buzzing noise is definitely from the exhaust. Seems to be around the area of the center stand on the left side of the bike. I only notice it when stopped and revving the engine. No big deal. :-) My shopmate is eager to weld me up a new exhaust for the bike. Maybe I'll cut him loose to do his magic here in another few weeks to give it a more throaty note.

Thanks everyone!

[fredintoon]

- - - I took the bike out for a spin again today. The 1100 feels much more refined than my 850. It also feels like it has a bit less power. Perhaps a re-jetting is in my future? - - -

>
Hi Doug,
if your XS11 has a bit less power than your XS850 either your XS850 was race-tuned by experts or your XS11 is only running on 3 cylinders.

[DouglasVB]

>
Hi Doug,
if your XS11 has a bit less power than your XS850 either your XS850 was race-tuned by experts or your XS11 is only running on 3 cylinders.

That is very possible on both counts. Before I got the 850, someone else had done some serious work to the carbs. Transitioning between sub-4000 rpms and above 4100 rpms is like riding on a 2 stroke. It goes from normal (what my 1100 feels like) to stuttering (4000-4100 rpm) to someone kicking me in the seat of the pants.

On the 1100 I know that several of the spark plug boots are cracked. For how long it sat, one of the carbs could be completely gummed up, too. Is there a quick test to see if I am losing a cylinder?

Thanks!

[jwhughes3]

Quick test is to remove one spark plug wire at a time. If there is no change when one is removed that is the suspect cylinder.

John

Also I think there are different part number on standard vs special fork seals (someone correct me if i am remembering wrong) so maybe you got standard seals by mistake?

[DouglasVB]

Ah perfect test! I'll give it a shot tomorrow after work.

Thanks!

[Shacknasty]

It's SOP to remove, completely disassemble, and thoroughly clean the carbs. Seafoam is no substitute for a proper cleaning. Period. Wouldn't hurt to clean the tank and replace the fuel lines, if ya haven't already. Then synchronize the carbs, adjust the idle mixture screws, and synch again.

These steps, common with any old motorcycle that has sat for some time, will prolly reveal a newfound power. Good luck.

[Yard Dogg]

You can also feel the exhaust pipes to see which ones are not firing. Do it as the bike warms up, and don't just grab them.

[DGXSER]

I would certainly pull the carbs and go through them thoroughly based upon your recent descriptions.

Best way I know to tell if one cylinder is missing, ride the bike in the miss range for a mile or there abouts, keep it in that miss range. Now spray each header with water. The one that was missing will not steam up as much, and cool to water dripping off it pretty quickly.

As to the fork seals, you may have the wrong ones, they are different from Special to Standard. However, as BikerPhil pointed out to me, when you reassemble the forks the end on the stantion tube can tear the lip on the seal. A couple ways to avoid this, first is to reassemble the fork before you put the new seal in. The other is to put a wrap of plastic like form an empty soda bottle around seal to protect it from the tube till the tube end is past the seal.

[Yard Dogg]

I've always just greased the seals, then use finesse. I've tried the sandwich bag trick recommended in quite a few SM's, but I always grease em anyway.

[WMarshy]

Quick test is to remove one spark plug wire at a time. If there is no change when one is removed that is the suspect cylinder.

John

Also I think there are different part number on standard vs special fork seals (someone correct me if i am remembering wrong) so maybe you got standard seals by mistake?

Ive been saying that since his first post... make sure you get the right ones as the specials are different than the standards...

Sounds like a a full carb clean is in store for you my friend. If you have no desire to get shocked or burnt by a hot cylinder head then we usually recommend using a squirt bottle to mist on the down tube of the exhaust. If you do it within the first 2 minutes of start up then you will find your dead cylinder as they heat up. Just dont let your bike sit idle for xsessive amounts of time without putting a fan on it.

[DouglasVB]

The parts I got for the fork seals were from GeorgeFix. I purchased the "79-81 XS1100 SPECIAL & MIDNIGHT SPECIAL FORK SEALS @ $11.00 = $11.00." which according to http://www.georgefixs.com/servlet/the-14/79-dsh-81-XS1100-SPECIAL-%26/Detail seem to fit my bike. Perhaps I tore them when I reassembled the forks. Should I try buying the same seals again or get something different? The ones from GeorgeFix were K&L brand.

It appears that the spark plug wire boot on cylinder #4 wasn't pushed down all the way. Now it runs much better. Also the idle is getting better and I have been able to adjust it back out in slow increments. I plan to rebuild the carbs in the next month or so but when I do, I will probably also go to pod air filters and a custom exhaust. I need to spend some time poking around the forum to see what other people are doing for jet sizes and for exhaust setups.

I took my girlfriend out on a 50 mile spin this evening. She loved it! Here is a photo that she took of me in my shop with the bike:



The Pirelli Sport Demon tires I put on the bike sure make it corner well. :-)

[natemoen]

You will regret getting rid if that stock exhaust if you swap it. The stock exhaust is the best option for these bikes. Yamaha put a lot of time and effort into getting the pipes tuned to these engines and made the power band nice and consistent and smooth throughout. If you change to a different exhausts you will either loose the top it the bottom.end.

[DGXSER]

You customize that exhaust all you want, lots of folks have modified exhaust on their bikes and tuned them to run quite well. In fact, you can just send that crappy stock POS exhaust system to me, I'll even pay the shipping fees, just to get it out of your way of course.

[DouglasVB]

If I keep the stock exhaust, will it adversely impact re-jetting or unipods? I was under the impression from working with other bikes that if you derestrict the intake and up the jet size, you will also have to derestrict the exhaust system.

[Yard Dogg]

You will only need to re-jet if you start changing things like the exhaust, intake, cams etc... Carbs are vacuum actuated, so anything that effects vacuum effects carbs and jet sizes. Lower vacuum means bigger jets.