For those who have done the 1196.. or beyond.

[trbig]

Pat,

By swapping to the earlier heads, you are going to increase your compression and negate anything you lose due to the valve size. I'm going from memory here, but I think Dan mentioned before that the best motor from stock parts on these bikes would be a later motor (Higher domed pistons than earlier models) with an early 78-79 head,(Smaller valve relief area versus later model with big valves = more compression) with the later model cams.

If you're looking for strictly top end, stay with the early cams, but from 0-100, the later model cams are going to be your best bet. Just don't ask me what this is going to do as far as jetting needs in the carbs though.. lol.

Tod

[Dan Hodges]

Head Aches

Now you have me thinking about how my MNS is running.
It has the 1196 kit, K&N filter in the airbox, and a 4 into 1 exhaust with SuperTrapp baffle/discs.
The carbs had 110 or 115 main jets in all 4 carbs. I increased the jets to 125 and it took forever to warm-up and would die at idle unless it was hot outside and the bike was completely warmed-up. I swapped to 120 jets and took some discs out of the SuperTrapp and it got better. I might now try going back to the original jets.
The PO had done some terrible porting to the head. Cylinder #2 has some issues. I have 2 earlier heads, from a 78 and a 79. I know they have the smaller valves (higher velocity / less volume) yet 'hotter' cams. This bike is my 'hot rod' and when I'm in the mood, pushed for accelleration to 100 MPH. Usually I just cruise around town with it (the 78e is for highway cruising).
Does this make sense..... early head (small valve) with later (80) cams equal more torque for my short-burst forays? I do take it to nearly redline in all but 5th gear when I'm feeling frisky.
The only other mod I have planned (eventually) is to make a 'Y' pipe off the exhaust collector to run 2 SuperTraps. Cosmetic reasons only, I don't anticipate any performance differences (able to adjust with discs).

The early head on an 80-81 (using 80-81 pistons) will among other things increase the compression ratio by about 1/4 point which is worth about 1% more power. The late head flows about 10% more air than the early head which equates to about 5% more power all things equal. The late cams will be torqueier below 4,000 rpm than the early ones but from 5,000 rpm up the early cams will make about 2.5 to 3 hp more than the late ones. The torqueiest combination would be the late pistons, early head and the late cams however the big heads with the big cams will win in a drag race or on the top end. You can also use the early intake with the late exhaust which keeps down the overlap and increases torque for better gas mileage while still being better on the top than using both late cams. Decreasing the overlap almost always will increase the gas mileage and emit fewer emissions. Porting a cylinder head haphazardly without knowing what you are doing will generally ruin the head. You can match the intake ports to the carb boots for about one inch up in the port (blending), anything more than that and you need a flow bench to check your work. Some folks have ported and flowed lots of heads and consequently have a good idea what works but even those guys will provide a flow sheet when they port your head. A good flowing small port with lots of velocity at .100 to .250 lift will work better than one with huge ports that only comes on over .400 lift. The port volumn, particully the intake is based on the size of the cylinder and the rpm range in which you are going to run. In our motors, an 1196 will need more port volumn than an 1100 and yada,yada,yada. I have seen some ported heads that were posted on Channel Eleven and they were junk. The main jets have little to no effect on idle and off idle. All 80-81's were notoriously cold natured and will benefit from either a #45 Mikuni pilot jet or a # 180 Mikuni air pilot jet but not both. With this jet combination, the pilot air screws should be turned out 4 turns from lightly seated. An 80-81 Special with stock air box, K&N replacement filter and a Super/Trapp 4 into 1 header using the ST muffler equipped with the mechanical silencer and 15-20 disk will like a 112.5 main jet. Are your carburetors for a Standard or a Special? Before I leave the jet thing I will add that the needles in the 80-81's are too short and have the wrong taper and are not adjustable other than shaving the plastic locating donuts and with these stock needles you will never get it right. The best thing you can do jet wise is to buy a Dyno-Jet kit and install the kit per instructions, it's the best $118.00 I ever spent. The mechanical silencer is very restrictive and should be removed (yanked out) and replaced with a 2 inch straight through glass wrapped core utilizing 20 disk on the end cap. You can order this combo directly from Super/Trapp. You can also use a 2.5 inch core with disk and either a closed end cap or the open competition end cap with 20 disk like I have on mine. If you have one of the original Super/Trapp headers that was designed for the Eleven it would almost be an abomination to tri Y it from the collector back because you can still find dual exhaust for these and you can have them Jet Hotted for a new look and finish. The late head cut .016, late pistons and the early cams installed on the stock marks (102 degree centerline) is the killer combination using stock parts. Cutting the head .016 will increase the compression ratio by .38 of a point and will not be enough to cause cam chain length problems (you won't have to slot the cam sprokets) and will fetch about 1.5% more power. Attached is a nicely ported intake and exhaust port, mine.





1% in five different places is almost five horses, a lot. All of these jet numbers are for sea level to about 3,000 feet, Denver Colorado and the high country would be different.

[Pat Kelly]

I do feel the porting attempted on this 80 head ruined it. They did a so-so job on matching the intake boots/ports but created a lip in the runner . Also, when I removed the carbs #2 boot swivelled down. The upper bolt was missing. It looks like this cylinder has issues as it was quite sooty and that cylinder still seems to be a weak link (plug is always black and sooty).
I think the exhaust is an RC Engeneering system. The collector is directly in the center of the tranny just in front of the centerstand (which was retained). All 4 headpiped come together at the collector. The tailpipe had nothing in it, it was an empty megaphone that sounded cool but WAY too loud. I found a baffle at the local boneyard and slid that inside (wrapped in the appropriate fiberglass). 4" SuperTrapp diffuser discs fit the end. I had 20 discs on it and dropped it to 10 discs and that helped. This header has a 2 1/4" collector. The 2 other SuperTrapp mufflers I have are 1 7/8" inlet and 3" outlet. Like I said in the previous post, the dual mufflers are cosmetic. I just looks naked on the left side with no muffler and I want this bike to look OEM. I do still have the stock MNS exhaust (not for sale) in almost perfect condition. I want to save this item because of it's rarity.
I think my carb tuning will require the DJ kit as most of my riding is under 5,000 RPM so float level and needle setting will be scrutinized. They are the stock LG carbs tho I think a PO changed the jets when they tried porting the head. The LG is my 'quick' bike, the E is my 'fast' bike.

Thanks Dan and others for all the info

[Dan Hodges]

Collector Size

I do feel the porting attempted on this 80 head ruined it. They did a so-so job on matching the intake boots/ports but created a lip in the runner . Also, when I removed the carbs #2 boot swivelled down. The upper bolt was missing. It looks like this cylinder has issues as it was quite sooty and that cylinder still seems to be a weak link (plug is always black and sooty).
I think the exhaust is an RC Engeneering system. The collector is directly in the center of the tranny just in front of the centerstand (which was retained). All 4 headpiped come together at the collector. The tailpipe had nothing in it, it was an empty megaphone that sounded cool but WAY too loud. I found a baffle at the local boneyard and slid that inside (wrapped in the appropriate fiberglass). 4" SuperTrapp diffuser discs fit the end. I had 20 discs on it and dropped it to 10 discs and that helped. This header has a 2 1/4" collector. The 2 other SuperTrapp mufflers I have are 1 7/8" inlet and 3" outlet. Like I said in the previous post, the dual mufflers are cosmetic. I just looks naked on the left side with no muffler and I want this bike to look OEM. I do still have the stock MNS exhaust (not for sale) in almost perfect condition. I want to save this item because of it's rarity.
I think my carb tuning will require the DJ kit as most of my riding is under 5,000 RPM so float level and needle setting will be scrutinized. They are the stock LG carbs tho I think a PO changed the jets when they tried porting the head. The LG is my 'quick' bike, the E is my 'fast' bike.
__________________________________________________ _______________
Thanks Dan and others for all the info

The inside diameter of the collector of the Super/Trapp header is 64 mm and the headpipe is 38 mm. I also have one of the original Kerker pipes for the XS and it has the 2 1/4 collector like the RC. I had an RC pipe on my 79 Honda 750-F way back when and it was a quality piece. The only dual system for the XS you can still get is the one by Mac and from an engineering stand point it's not bad, nice size head pipes with nice bends and the collectors are 2 1/4 each and the megs or the turn outs should flow well enough for a mild motor however the headpipes have to be Jet Hotted because the chrome finish is of poor quality and will blue quickly. Super/Trapp makes some very nice brushed stainless steel universal megs with the 2 1/4 inlet that taper to the desired 4 inch outlet that can either be used with mechanical silencers with disk or 3 different sizes of glass wrapped straight through cores with disk with the Mac head pipes. With a little fiddling and the Jet Hot process this Mac & S/T combination makes a very sanitary piece with good looks, longevity, power and what ever sound level you prefer. I too still have my stock pipes but when I rebuilt my motor in search of horsepower I used the S/T header because I wanted that 8% to 15% more power that the 4 into 1 system provides. On a mildly modified motor, an empty megaphone (no baffle at all) will make less horsepower than one with the correct baffle, even the mechanical one. A high rpm drag bike is a different story. If you use the DJ kit that was designed for your application and install it correctly, you set the floats per the shop manual and you are good to go. There is more BS regarding carburetor tuning than any other mechanical thing I can think of. Attached is a picture of the S/T system I am presently using. Good luck on keeping an XS under five grand............it ain't gonna happen. Dan

[Pat Kelly]

That does look alot like the system I have for the MNS. it is black and I tried to sand it to paint it. Sanding didn't seem ot phase it so I think it already may be/ have been ceramic coated.
The muffler sticks out too far and goes too far back for my tastes. The 2 mufflers I will be using will sit about where the OEM mufflers are/were.

[Dan Hodges]

Form vs Function

That does look alot like the system I have for the MNS. it is black and I tried to sand it to paint it. Sanding didn't seem ot phase it so I think it already may be/ have been ceramic coated.
The muffler sticks out too far and goes too far back for my tastes. The 2 mufflers I will be using will sit about where the OEM mufflers are/were.

The muffler/megaphone of the spec made XS/XJ S/T header terminates in the same place in relation to the rear axle nut as the stock pipe/pipes but it is more upswept or higher than the stock pipe/pipes. If the muffler were longer in this application it would require removal to get the rear axle nut out to remove the rear wheel which would be bogus. This header was made in two choices, one was in brushed/polished stainless steel and the other was chrome plated double walled steel. A naked Eleven looks good with a 4 into 1 header however an Eleven decked out as a baby Gold Wing looks better with the dual arrangement. I chose the combination I'm using for the extra horsepower it makes vs the stock pipes. I also like the sound and the ability to change the core from 1.5 inches in diameter to 2.75 inches in increments of 1/4 inch. I also like the looks however I generally prefer function over form unless function becomes hideous because nobody likes ugly no matter how sweet she is or how good her biscuits are..........!!!!!

[aussixs11G]

bored motor/carbs?

great reading the above comments from those who have tried it.....
My machine is bored to 1130 balanced and head flowed (by a professional), and
a hot cam.
the carbs are the ones that were on the machine when i aquired it and have 132.5 mains - the only fiddle i have made is to drop them to the top (lean) circlip
the bike goes well (108hp) but some diaphrams have a couple of pin holes - i am now considering a) new diaphrams b) new (different) carbs c) fuel injection
suggestions please anyone