Front cylinders are dead

[Lil Venturous]

Going back tomorrow night I hope. About to start our taxes.

 

I know the wiring, there is a huge wiring schematic hanging on my cabinet SGN gave dad and we have both been wearing it out. I just never looked at the pickup area as the problem because I never thought of it til I was away from the bike.

 

Hopefully I will be back over there tomorrow night. I will probably swap the carbs for the fun of it to rule that out. I feel in my heart they are not the problem, but right now that is the easiest thing I can do and not have to think.

 

Yes I have the right cdi box.

 

Shane my son brought me the good compression tester but of course it was for the big plug.

[Lil Venturous]

WELL?????????

 

Carbs made a huge difference, But I still had some spitting back through the carbs on cylinder one. Each cylinder did produce heat now. Reved fairly crisp and strong. Pulled the wire on number two and it did not appear to make much difference but it was shooting fire real good. Still no tach or fan. Let it get up near the red and they did not kick on. Fixed what little bit of wiring I could find that they cut and taped back together. Checked risistance on the pick ups and they all showed the same at about 115.

 

Really feels now like it is out of time? may also need a rad cap. Right after fire up it starts dripping a little out of the overflow tube. Head gaskets ever go on these things?

 

One good thing about the bike is that it has not been rigged up really any that I seen so far.

 

So I guess I will check these carbs yet again or try and keep dads carbs til the other issues are figured out.

[dingy]

Really feels now like it is out of time? may also need a rad cap. Right after fire up it starts dripping a little out of the overflow tube. Head gaskets ever go on these things?

 

 

 

So I guess I will check these carbs yet again or try and keep dads carbs til the other issues are figured out.

 

 

There is no way to adjust the timing on these bikes with a stock TCI. With the Ignitech TCI a few of us are using, you can change it.

 

How bad do you want a set of carbs? I have a very good set I am taking off my 83. Diaphragms are good, I will put stock jets back in them. Actually 125 mains instead of the 117.5's. I have 150's in them now.

 

I am also going to take the powder coated parts off the and put them on the set I am rebuilding. (diaphragm cover and outside cross brace). I can put the mains back in without splitting rack apart, so they should stay close to being synched. Float levels are correct.

 

These would be a direct replacement for your 85. Only tweak from the 83 is blocking of the TCI port. I have had it blocked all last year. It is a rubber cap that fits over the port. The 84 & up didn't have this port.

 

Gary

[Lil Venturous]

Right now Im not going to worry about another set. Actually believe dad has a spare parts set. With so many issues this thing is still having I just cant justify throwing much money at yet. Been a lil poor lately. I might ask about the V-max motor in your avator pic though.

 

Hopefully by sunday dad and I can get some stuff figured on it.

[Lil Venturous]

Well the other carbs made a big difference.

 

But felt it was still not right. The number two cylinder was still off. It was producing heat but pulling the plug wire made little difference. So, I started doing some ohm tests. nothing really odd showed.

 

Finally started doing some volt tests. Power on and not runnig had 12 volts or so coming out for each coil at the tci, good. Fire it up and start checking again, All have around 11 or 12 except number two. Only had 7 volts. UGH!!!!

 

Tryed the spare tci box off a 83 and fixed the volt deal. Bike appeared to run pretty good. But still no tach. Going to pull cover and check that it is not just stuck.

 

Ok now todays question, Why the voltage drop through the tci?

[dingy]

There are several threads on here about failures in the 1st gen TCI's. Especially MKI's.

 

There are 8 barrel diodes that die an early death due to corrosion of the lead where it meets the body of the diode.

 

If these are replaced in time, the TCI can be saved. If the cylinder output is still showing signs of live, I would guess it could be saved.

 

It is moderately difficult to do. The TCI needs to be opened up. The diodes need to be unsoldered & replaced. This is a 25 year old electronic component that has spent its life in a somewhat hostile environment. The traces on the circuit board are fragile.

 

I have seen where a couple of people have cut the back of the box open, rather than unsoldering the front pin connectors. They make the diode repair then reseal the case together with RTV or some other sealant. It does seem to make sense to go in this way. The front pins are a pain to unsolder then resolder.

 

Gary

[bkuhr]

Ok now todays question, Why the voltage drop through the tci?

 

Keeping in mind that #2 coil feed is also feed for the tach, and I think maybe the fuel pump control on the 85, there may be partial (high resistance) short to ground-likely thru a component.(wire shorts are typically hard shorts)

 

Fuel pump seems to work, but tach does not, may suspect defective tach circuitry. Since you seem willing to dismantle the dash-"to check for stuck needle", I would disconnect the grey wire from the rear of the dash tach, isolate with tape, and do your voltage checks again at the TCI

[Lil Venturous]

Tach was a stuck needle. Seen that a few times from stuff that has sat for awhile.

 

Running real good now. Just now I dont want to give dad his carbs, spare tci, and radiator cap back.

 

So, so far I found that my carbs are still bad, my 2nd tci has issues and the tach had a stuck needle.

 

It is fun trying to bring back one that was not running when you got it.

[Venturous Randy]

Yes, the bike is running better every day that Brian is working on it. With my carbs, it is still not smooth at idle and given I synced the carbs recently, I don't think that is it. Power feels pretty good at low rpm pull and don't feel bad when opening it up. He did not move the boost sensor pick up point to match the 83 carbs and TCI,so I am sure it would run even better.

The best thing is that the bike does have some potiental and I think will become a good driver, but it will take a while.

RandyA