Adjustments after adding new mufflers

[ultra6xlt]

Hello,

I needed to replace my original megaphone style exhaust on my 1980 XS1100 Special. I had to replace it where the headers come together and enter the mufflers. I wanted a new look, and purchased some 16" turnout mufflers. I like the look, but it really dogs on the low end. I took off the air filter to get more airflow going in, and it ran a little better. What is the best solution when approaching this re-calibration? Should I start by buying a more hi-performance air filter? Should I adjust the carbs first? Any insight on where to start and how to do it would be appreciated. I would like to do it myself, but am willing to take it to someone if it is better to have a professional do it. Thank you all for your ideas! This is the best resource I have ever used for any vehicle.
- Matt

[TopCatGr58]

Hey Matt,

Okay, putting on any aftermarket pipes lets the XS11 breath better, but usually does affect the bottom end a bit. The bike gets leaned out a bit since more air is flowing out, and with NO filter, or putting Indy Filters vs. a K&N style OEM filter box insert also provides a leaning affect! It's interesting that removing your air filter actually improved it's performance....could be that your filter was very dirty choking down the engine?

So....jetting guide recommends adding 2 main jet sizes for each breathing mod, ie. pipes! So....would suggest getting a set of mains 2 sizes larger to start with! Also, IF you haven't removed the brass plugs on the top front of the carbs, then you can't get to the Pilot Screws to adjust them....turning them out a turn or two to further richen up the pilot circuit which may also help the bottom end a bit!

Manual says your mains should be 110-120-120-110, but you may be surprised when pulling them, they may be all 110's across? Depending on if you find the staggered setup and want to maintain it, will determine what jets you order, so you'll have to pull the carbs and check them before ordering! They go up 2.5 increments, so 110; 112.5; 115, etc! HTH?
T.C.

[DeanR]

TC, Do guys generally remove those four plugs on the carbs? Mechanic suggested I do it at some point but it kinda sounded like unnecessary surgery. Do you just drill them out? They must have some purpose?

[prometheus578]

The purpose of the plugs is to stop people like us from clowning around in there. When the bikes are set up at the factory, the screws are set for the bike to run best... according to the emissions people. (new triumphs are set so lean from the factory that they almost instantly blue the pipes!)
also... it's almost impossable to insure, when cleaning, that you've got the pilot circuit cleaned without removing the plugs and taking out the screw and spring, etc.
Get a small drill bit and a sheet metal screw. Slowly drill a hole in the center of the plug. I say go slowly, as it's not to thick, and you don't want to go plunging through it into the pilot screw. Anyway.. after making the hole, screw the sheet metal screw a little way into it. Twist the screw back and forth with a pliers, and the plug will come out.

[Ken Talbot]

Those plugs were put there to keep you from adjusting the screws under them - keeps them at their "set at the factory" setting. I can't see how anything that was "set at the factory" 25 years ago can possibly still be correct. Wear and tear on the engine, different fuels, deposits in the fine orifices and passages, changing riding altitude, etc, etc. There are just way too many things that can and have changed. Read up on it here, then drill those puppies out and give your bike its first proper tune-up in a quarter of a century!

[ultra6xlt]

Thanks for the input. The XS1100 is the first motorcycle that I have ever owned, and I am learning as I go. I don't mind getting my hands dirty, but I am not always sure what I am doing. I have a manual for it, and a decent understanding of automotives. Enough to get me in trouble I guess. Where is a good place to find the main jets in the sizes that you recommend? How do I know what sizes I have in there now and what size should I ask for? The bike is almost all original. I had to replace the exhaust when it rusted out, but I believe the engine is all original. Do I need to remove the carbs to replace the main jets? I will take a look to see if I have brass plugs still installed or not. Thanks again for teaching a rookie the ropes!

[TopCatGr58]

Hey Matt,

Yes, it's best to pull the carbs to work on them in this way. Once you pull the bottoms off, you will be looking at the main jets, they are on the tallest stalk in there! They may be gummed up, or just very dirty, but once you clean them, you can see the number values stamped on them as to their size. Mike's XS supplies 650 parts, but the LARGE head mains for Mikuni BS carbs fit, are the same, and relatively cheap....but you will possibly want to replace the gaskets as well, to help bring your order to over $35.00 so you get free shipping! I pretty sure I posted a message about what the Model #'s were on MikesXS in a reply to another XSive looking for main jets, can't recall which one!? If you do a search for MikesXS and look for carb jetting threads, you should find it!

Note to self...make a tech tip with ordering info for cross referencing parts for the XS11!
T.C.

[ultra6xlt]

Hello TopCat,

It has been a while since I asked about re-jetting the carbs. I am finally getting around to it. I want to buy the new jets, but I am having trouble locating MikesXS in the forum. Is this a member or a store? What do I specifically need to ask for when I am looking for the LARGE head mains for Mikuni BS carbs? Thank you, again!

- Matt

[John]

Just type Mikesxs.com in the address bar, and you'll be there.

[chevy45412001]

or

if your in the mood to do it now,go to the dealer and get a set they are about3-4 bucks a pieace. And usually have all sizes,because you might have to do it a few times to get it perfect
And waiting 20 weeks for the mailman can suck.

[tommystinson]

fwiw

Go to your local Parts Unlimited dealer and look at their catalog. Genuine Mikuni N100/604 "large round" main jets are $10 per set of 4, of the same size. I started a thread regarding aftermarket main jets because I had such poor luck with them, and the genuine article was actually cheaper!

[xs650mike]

and waiting 20 weeks for the mailman can suck

You won't be waiting 20 weeks for the mailman if you order from Mike's XS, every time I've ordered the order came the second day following even though Mike is in Florida and I'm in California. Besides free shipping on orders over $35 he throws in a beautiful print catalog free. Bear in mind that the business is really for XS650 parts but there's a lot of stuff that is common between the two models. I hear from the micapeak XS650 list that he's retiring (well-deserved!) but the business will continue as an internet entity and there are new products in development. I'm really going to miss talking to him on the phone.

[Winterhawk]

TC, or anybody else. I have the criss-cross Jardines on my XS1100E. My old pipes had a crossover tube on it. The new ones off of Ebay doesn't. It really affected my power band. It used to be a rocket down low and able to short shift it for quick acceleration.

Now with the new ones as I sold the old ones to a member on here. I did need to readjust the mixture and Synced them again.

It hits real hard at 6,000 rpm all the way to red line. It feels though that it doesn't pull hard down low anymore. Brady from Merriam Cycle said it was the best running XS1100E down low that he ever rode.

Any ideas as to jetting changes that I might need to do to get back my low end power. All that was changed was the Jardine mufflers. The new ones sound louder also.

[pggg]

Hawk, slot your cam sprockets and advance the inlet cam by 2 degrees for more bottom end torque. Was told that by a post-classic racer. DONT tell merriam cycle - no FREE advice to them!!

[TopCatGr58]

Hey Pggg,

Not everyone here(me included:P) has the know-how or equipment to "slot the cam sprockets", or be able to measure "2" degrees of cam timing!

Hawk,
What adjustments did you make to your carbs?? What jets are you running, both pilot and mains? How many turns out are your pilot screws. Remember, I'm no GURU, just like to type and talk, and have a "little" experience with these machines....I defer to the real Carb Gurus!!

Also, have you checked your ignition timing lately? I know it can affect the power/performance if off.
T.C.