autoteach

So, here is the deal. I have had some issues (as some of you know) over the last year. Last year I had a slight rich problem (carbon'd the cylinders to a nice 30psi compression), the needle jets were oval from wear. Anywho, new carbs...still rich. some idiot accidentally pulled the choke "yoke" out of its rubber. Fixed. Rear cylinder not running at idle after install. Missing spring in throttle mechanism. fixed. Now I can't get the bike to take throttle nicely off the bottom. yes the petcock is on, tps hooked up... but it turns it off like a switch if opened to quickly, then it will rev. I know that there were a few of you with this problem, and I will go through a list of the items checked already.

slides (definitely sucking)
petcock - on and hosed properly
airbox properly assembled
chokes installed properly


I have had the tank off 6 times today f-ing with this. this is what i changed:
Coil on plug conversion
one clip down on needles


I am going to go back in to the carbs tomorrow (just to re,re,re,recheck slide diaphragms and that there is nothing above the inlet needle), but for those of you who have had this problem, what was your answer.

superh1998

Fuel petcock diaphragm?

autoteach

no, it isn't like that. It is getting fuel, it just wont take large amounts of throttle off bottom.

superh1998

If you didn't open the petcock and check, I would recommend it.
I also got fuel most of the time, but it would cut out when cruising at 2-3k rpm, and also if I would try to give it a lot of throttle.
It felt like a cylinder was shutting down...I was convinced I had a carb, electrical, or engine problem.
I figure its worth a shot if you haven't looked at it...it doesnt take long if the tank is already off.

autoteach

I just replaced it with a new one 2 years ago, and I am talking about stationary in the garage.

residentg

did this occur before you did the coil mod?

autoteach

no, but I did end up changing too many things. I am going back to all the same minus coil change and giving that a shot. I will see if that helps (I am also going to ride it this time to see if it is just me. I also have extra coils, so I will swap in others. They were giving solid spark, though. I went through the carbs today and couldn't find anything. I will update the group when I find the answer. as for now, grad school work calls (friday is my last day).

Hotbrakes

First get a plug reading.

Then adjust the airscrews accordingly. If the airscrew adjustment doesn't sort it go to the needles. I'm assuming you have the recommended jets installed and they are clean and all your vacuum hoses are properly routed.

Take it for a spin and make sure you have good power throughout the rpm range. Unfortunately it's a tedious process but at least it's only 2 carburetors!

Make sure the carbs are in sync as well.

autoteach

I was hoping for a problem that I recently caused, as it has been with these jets and settings for some time (yrs).

revhead1957

In your first post you mention new carbs - were they 2nd hand? If so, I would suggest going over them meticulously, working on the assumption that everything is wrong - float level, jets, etc etc. Also check very carefully for air leaks on the inlet rubbers.
Keep it simple and systematic. It sounds like you have a lean condition at the lower end - what is the plug colour like?

autoteach

So, got the verdict. Front marker light unplugged. Fixed!

No, seriously. I would have to account my problems to the following.
My jetting was on and I shouldn't have touched it (choke was my rich issue) and the spring in the carb linkage was definitely shutting down the rear cylinder. I just took it around the block, so it is not a solid verdict yet. I will let you know after my afternoon ride. By the by, I have no idea how I knocked that little spring out of there.

autoteach

Up to 36 mpg with country road riding. looks like I am doing alright, still have some work to do with the idle.

autoteach

Well, Huge update here. I ended up having to clean the carbon off the rings 2 years ago after Denver CO trip. Everything seemed to be fine (after I fixed my choke issue). Well, recently fuel mileage has been lackluster, and now oil consumption seems to be a predominate issue. .5qt in 120miles, all unaccounted for (airbox is oily).

8541Hawk

Well I can comment on the oil consumption.

My bike does the same thing from time to time. At first I though it went with high RPM riding, as that is when it "normally" seemed to happen but by keeping records of when it has happened I have found there is no set conditions that it happens. It just does it once in a while and then all of a sudden it will stop.

So even though I really don't have a answer, I can say it is not that uncommon. Just another joy of a big twin.

In fact, a few months ago, I though the engine was telling me it was time for a rebuild as I had about the same or a little more oil "loss" than you are seeing. Then after about a month, it just stopped.

It tends to happen (as per my notes) more often than not after the bike has sat for a little while. Though I don't have enough data to really stand behind that conclusion.

So IMHO, just keep an eye on it but don't let it bother you too much....


Now for the fuel mileage, has the weather changed recently? or have you changed the type of fuel you have been running?

I don't think they change the fuel too much where you are at but here in CA I have had a few issues when they switch from "summer blend" to "winter blend" or vice versa.

autoteach

The fuel consumption loss was marked by the F-up in the choke getting stuck before my denver trip. It never has come back. I am expecting to tear down the engine this week, as I dont accept .5 qt/120 miles. That means on my longer trips I need to carry almost as much oil as gas.

msethhunter

My bike has been using a little oil lately as well. But from the sounds of it, with you having so much compression increase from carbon build up, I would say that you probably have stuck oil rings, and you might try and run something through the engine to get it out. When I was working foro Chrysler, we used to use this stuff that came in an aerosol can that you would spray into the carb/throttle body while the engine was running, and literally let it bog the engine out till it quit from a high idle. Let it sit for about 15 minutes, the fire it up, and "blow it out." It worked wonders. Let me search around real quick and see if it's still availible.


Found it. Similar to SeaFoam, but IMO, it works WAY better. You can head down to the local Dodge/Chrysler/Jeep dealership to get it. Follow the directions. Basically, get the bike to operating temp, then spray the stuff down into the carbs and keep it running. I have used it on a few cars that had high oil consumption in the past with decent results (per "Star Techline," Chryslers technician assistance phone number). The bottle might look a little different now, but the product should be the same inside. Just be prepared for some huge billows of smoke when you're done and fire it back up. It could be a fix instead of doing a complete rebuild. I'd use about 1/4 of the can per cylinder.

VTRsurfer

As for the oil consumption issue, I'm sure you've checked the crankcase breather (PCV system).

autoteach

Yep, and the airbox had oil in it. It was the only place that showed any signs of oil (as in no external leaks)

comedo

I just returned from a 7,800 km. trip. The bike used 2 l. of oil in total. I had to add one full litre of oil at the end of the second day of a 10 day trip after travelling approximately 1,800 km. The rate of oil consumption decreased significantly after that. I have no explanation for the change. I used the same kind and brand of oil throughout.