I cut the exhaust half off, Is that the problem??

[whoride76]

I have a 1980 XS1100G. I have installed pod filters, and rejetted the carbs. I did take the carbs off and did a general cleaning of the. They seem to be in good condition. The bike shows a little over 61,XXX miles on it. Here is what I did I cut off about 6-8 inches of the back to put on a solo seat, after I did that the exhaust didn’t look really good sticking off of the sides, so I cut them off. Just below the foot pegs.

The problem is the bike is missing all around but really noticeable around 4-500 rpms. Reading through some other threads There was a comment that the engines needs the back pressure of the muffler/exhaust to make it runs properly. I do not mind how loud it is or that it back fires like a shot gun every now and then. but do i need to have that back pressure to run smooth.

It does idle and starts ups with no problems.

I have replaced the coils, wires and put in new plugs—good spark
Redone the timing wires
Replaced the all the hoses.
Did a compression test with a warm engine with throttle wide open and
1-160psi 2-130psi 3-160psi 4- 155psi

I have also sync the carbs, I have the dial type not the mercury. I sync to the 3rd carb witch was just over 20 (psi?) now all the carbs are now sync to 20 when I raise the throttle to 4 -500 rpms the dials all move and stay together.

I am missing something or do I need to get another exhaust or should I retry to clean the carbs and take out everything and clean it and put it back together??

SIDE NOTE::
I was having problems with my head light not turning on and when I open the “ignition box” someone had done some modifications to it. So I ordered one off ebay and right when I plugged it in I started the bike and the headlight came on.

For what ever reason I still can get the turn signals to work. They have never work since I have owned the bike. The come on but will not blink. The funny thing is when I turn off the bike and then turn on the hazard switch they all blink and I can hear the relay switch. If you have ideas on that I would a appreciate it.

I will post some pictures when I get everything back together, (everything is black, everything)

[Korr]

For the turn signal lights are they stock or aftermarket? I had the same problem with my turn signals when i changed them to aftermarket ones. They turned on, but did not blink, but did only when i used the hazard light. Somebody on the forums told me to get an electronic flasher for cars. It worked. The only problem i have is that they only start blinking at 2.5k rpms

Cutting the exhaust is probably like running straight pipes i think? You might have to re-jet. That's what i think, but i am still a newbie diy. Please don't kill me if i get it wrong

[cywelchjr]

For what ever reason I still can get the turn signals to work. They have never work since I have owned the bike. The come on but will not blink. The funny thing is when I turn off the bike and then turn on the hazard switch they all blink and I can hear the relay switch. If you have ideas on that I would a appreciate it.

Have you tried an electronic auto flasher? Use the two prong type and I forget which way works but just try both. I picked mine up at Auto Zone for about $4 and it works great. You lose auto cancel, but since they don't blink now that would be no great loss anyways (plus I hate auto cancel because it cancels too quick for my taste).

[whoride76]

Yeah, the blinkers are not stock. But the are not LED lights either, They just have a smaller bulb.
I did try an auto flasher and it did not do anything, But that was before i changed out the I.U./computer. So i guess i will try it agian to see if it works

[trbig]

Since you talked a couple times of raising the rpm to "4-500 rpm", I'm assuming you meant 4-5 thousand rpm.

If you went to straight pipes and have pods, you're probably running really lean right now. If it's lean popping you hear with a lot of it on a hard deceleration..(Wide open then chop the throttle) that's carbs. If it's actually missing.. I'd look at the pickup coil wires as the first subject.

Just to remove one aspect of it... it did do this with both ignition boxes.. correct?

Tod

[whoride76]

Yes 4000-5000 rpms. I only cut off the pipes on the 2nd ignition box. I replaced the box when i replaced the coils and did all the other work.
Ok... if i am running lean, isnt that what rejetting the carbs should fix? IT does back fire on hard deceleration.
I did replace the pick up wires with the "fix" that is found on this site.
I also replaced the fuse box with the blade type fuses.

[Crazcnuk]

Not sure which 'ignition' box you opened, but there isn't one that has anything to do with the headlights!

The TCI (real ignition) is a large flat square module under the seat.

There is a reserve lighting unit under the gas tank, towards the rear of center and a headlight relay under the tank near the front.

The signals will not work with smaller bulbs/stock flasher. You need an ELECTRONIC flasher, not just any auto (car) flasher. It will say 'electronic' right on it. (watch out for electro-mechanical masquerading as an electronic!) An electronic flasher will cycle with no lights plugged into it.

The hazard flashers have thier own flasher under the seat, and so have nothing to do with the signal lights. I assume, though, since they will work, that that flasher has likely been replaced at some point or it would have the same difficulty with the smaller bulbs.

[oldyam80sg]

Hello-i looked at your profile-did you check the motor vehicle laws regarding exhaust modification?I know from talking to several persons from other message boards CA is pretty strict as far as modifications to the exhaust/emissions area goes!Why it might sound good just don't want you to get hassled by Motor Vehicles.

[skids]

Congratulations. You are in carb hell and you will not get out with those pipes the way you cut them off...at least I have not heard of any satisfactory "carb adjustments" to compenstate for that. If you have stock headers and pipes up to that point, you might consider harley muffs, jardine slip-ons or something else.

[79XS11F]

Yes 4000-5000 rpms. I only cut off the pipes on the 2nd ignition box. I replaced the box when i replaced the coils and did all the other work.
Ok... if i am running lean, isnt that what rejetting the carbs should fix? IT does back fire on hard deceleration.
I did replace the pick up wires with the "fix" that is found on this site.
I also replaced the fuse box with the blade type fuses.

Backfiring if heard in the pipes is an exhaust system leak in most cases. As was stated in an earlier post you are also likely running lean now that you opened up the exhaust so check the plugs and re-jet as necessary. Start by upping the main jets ..
Rob

[Ivan]

When I put the cherry bomb on my exhaust, it ran great on the top end. Pulls hard all the way to redline. I had to go back to stock main jets or it was soggy on the top end. Personally I don't think the back pressure has much to do with proper running. I do think the airbox is critical on stock tuning. The resistance of the small snorkel will aid in fuel draw in low rpm ranges. After many beers, I have come to the conclusion that the carbs simply can't draw enough fuel in the 1500-3000 range to get rid of the dead spot without some finessing (like a dyno jet kit).

With the pod filters, you will definately have to open up the jets a bit and possibly mess with the needle. I am not saying it is impossible to make it run well in that config, but it will take some dialing in.

Here is a good tuning guide

[Bigfoot]

Sorta reminds me of that post where the guy drilled holes in his tci.

[BigDick]

something I've seen done to increase back-pressure is drill a hole in your pipe from the top, drop a bolt in that, then weld a washer to the end of the bolt. see the ms paint fancy pictures

whether or not it works, or how well it works is anyone's guess.

[Crazcnuk]

That is the poor man's Supertrapp.

You can actually dial-in your backpressure with that method, although it's a bit crude.

If you weld a nut onto the muffler, then screw a long bolt through, with a 2nd locknut, you can turn the washer to play with your backpressure then lock it in place.

[whoride76]

answering some of your questions---Thanks for the ideas-more ideas are always welcome

Not sure which 'ignition' box you opened, but there isn't one that has anything to do with the headlights!

The TCI (real ignition) is a large flat square module under the seat.

Yeah, that is the one I replaced under the seat, and with my new unit my headlight come on. For those who remember me I tried everything to get my headlight to work and nothing. I had to hard wire it in to the battery with a switch to turn it off and on. So when i replaced the "black box" I thought I would just try to hook up the head light again and it worked. AT that point the only thing that I did was to change over the box. so if it did not really play apart, Then God just felt sorry for me and decided to let me have one thing go right with my bike

I am running the stock headers. CA might be strict on the modifications but there are so many Harleys in Fresno that sound like a F-16 taking off, you can even hear what my bike sounds like when i am near one.

""The signals will not work with smaller bulbs/stock flasher. You need an ELECTRONIC flasher, not just any auto (car) flasher. It will say 'electronic' right on it. (watch out for electro-mechanical masquerading as an electronic!) An electronic flasher will cycle with no lights plugged into it.""

--I will look for that electronic flasher, Thanks

I looked at the segment that talked about using LED blinkers --It seems that running LED blinkers all the way around would take a load of the charging system and improve it. --So I just can’t put on LED blinkers?? Would they not even work? The way they showed it in segment looked like a pain to have to cut and modify stock blinkers, cant you just buy the LED blinkers?

I am running a LED tail light and it is doing ok. I had a Tail light with 2 bulbs and it worked, it was just too big. So I replaced it with LED. I don’t know if the blinkers have anything to do with the taillight circuit but in either case they didn’t work.