85 venture dies at 5200

[MiCarl]

THAT's interesting - I would have never guessed that. But it just highlights how many strange things you can find with a TCI. Simple lack of advance is not going to cause misfire or sputtering, just loss of power, but if the TCI is getting an erratic or incorrect timing signal at a particular RPM (or vacuum level, in this case), then it can go all wonky with unpredictable results.

Goose

 

Starting in 90 and in the 2nd gens they went to a computerized ignition with a single pick up coil. They don't have TCIs. The processor calculates the ignition timing and controls each coil. I wouldn't think there is a way the different sparks would have different advances.

 

The TCIs have a separate functional unit for each coil, and I wouldn't be surprised if it's analog. The net is the 89 and earlier Ventures have four ignition modules in one box.

 

Where I saw one spark not advancing was on ... DRUM ROLL ... a Virago. Sure seems like Yamaha managed to cram just about every problem they ever had into them. Second gear does seem to hold up on them though - perhaps it's because they rarely run.

[GaryZ]

Did this problem get solved?

 

Today my VR started doing about the same thing!

 

Seems to start and run OK. Idles fine. Runs through all the gears good.

Runs right up to around 5k and stops accelerating!

Gray smoke and gas smell from pipes.

[GaryZ]

It appears my boost/pressure sensor is not working. I sucked on it with the engine idling and no increase in RPM. Now I am trying to take it off to get a good look at the little devil . . . and verify the hose isn't stopped up.

Edited August 1, 2011 by GaryZ

[GaryZ]

3:00pm:

The hose is OK. Any way to verify the pressure sensor is bad versus the TCI?

:(

 

5:20pm:

I figured out how to test the Pressure Sensor and I have attached a .pdf showing my method.

At this point it looks like the TCI. However, I will try cleaning the contacts/connectors.

:(

Edited August 4, 2011 by GaryZ

[85 venture]

It's going back in on Friday or so, to check if the timing advances. ***Gary Z., Can I remove the pressure / boost sensor and replace it or check it if I remove the battery box or is it a huge job to get to it ?

[Squidley]

Can I remove the pressure / boost sensor and replace it or check it if I remove the battery box or is it a huge job to get to it ?

 

Yes it can be removed/replaced, it can be a bear to get at and is easier if the left side plastic is off the bike.

[GaryZ]

It's going back in on Friday or so, to check if the timing advances. ***Gary Z., Can I remove the pressure / boost sensor and replace it or check it if I remove the battery box or is it a huge job to get to it ?

 

How big the job seems is dependent on your mechanical ability. I removed the top and side panels (the side panels can be removed without pulling the seat. Lift the edge of the seat for clearance), removed the air box (it usually comes right off by simply lifting it up), then the battery and battery box (two 9mm bolts on the bottom and 10mm on the front). The pressure sensor is beside the TCI and held on with two cross-tip screws that must be accessed from below. I used a 1/4" ratchet and cross-tip apex to remove the screws and the pressure sensor was out. Re-assembly is straight-forward. Loosen the clamps on the carb boots, set the air box in position and stab the breather hose. I now successfully use a long-handle needle-nose to install the breather hoses on the bottom of the air box. Make sure the air box boots are all the way down on the carbs before tightening the clamps.

[GaryZ]

8/3/2011 @ 3:00pm:

The hose is OK. Any way to verify the pressure sensor is bad versus the TCI?

:(

 

8/3/2011 @ 5:20pm:

I figured out how to test the Pressure Sensor and I have attached a .pdf showing my method.

At this point it looks like the TCI. However, I will try cleaning the contacts/connectors.

:(

 

8/4/2011 @ 12:30pm:

Cleaned connectors, checked timing advance, shot carb cleaner in all throats and verified diaphragm action.

Still same symptom . . . will not drive past 5000 - 5500 rpm

Any other ideas out there?

:(:(

[motorcycle.jockey]

I'm having similar problems. Did any of you find out what was causing it for you?

[85 venture]

Tci and booster or Pressure sensor tested all ok, the timing advances like it supposed to. Yesterday they checked for a restriction in the exhaust - disconnected the pipes, still died at 5200, so, no exhaust restriction. I'll stop in again on Wed.

[jurob]

I would bite the bullet and pull the carbs. Clean the heck out of them and then see what happens.

 

When I bought my bike 2 weeks ago it wasn't running quite right. I trusted the previous owner that the carbs were removed and cleaned. Come to find out all 4 diaphragm caps were removed and new diaphragms, air jets, etc were installed, but nothing was done on the inner fuel side.

[bkuhr]

I have not seen anyone mention to check for carb linkage obstructions.

Are all the butterflies opening completly?

 

When I put may carbs back together, I had a bent link arm that prevented doing a good sync as butteflies could not be made the same, but suspect bent/jammed link or throttle cables could prevent full throttle.

 

Suggest hold sliders back and check response of each butterfly.

[GaryZ]

I have not seen anyone mention to check for carb linkage obstructions.

Are all the butterflies opening completly?

 

When I put may carbs back together, I had a bent link arm that prevented doing a good sync as butteflies could not be made the same, but suspect bent/jammed link or throttle cables could prevent full throttle.

 

Suggest hold sliders back and check response of each butterfly.

 

At this time I tend to agree that it is a carb problem. I rode the beast about 60 miles today. It starts and runs in the low and mid circuits.

 

My symptoms are:

1) Will not run above 5k in any gear

2) will not take WOT in any gear, chokes out

3) blubbers off idle when hot

4) harder to start when hot

5) smells of gas

 

A friend on another forum thinks my problem is clogged or stuck main jets. This is supported by a chart I found that shows the main jets of a CV carb do not come into play until about 5k rpm. I guess the carb rack will be coming off . . .

[dingy]

At this time I tend to agree that it is a carb problem. I rode the beast about 60 miles today. It starts and runs in the low and mid circuits.

 

My symptoms are:

1) Will not run above 5k in any gear

2) will not take WOT in any gear, chokes out

3) blubbers off idle when hot

4) harder to start when hot

5) smells of gas

 

A friend on another forum thinks my problem is clogged or stuck main jets. This is supported by a chart I found that shows the main jets of a CV carb do not come into play until about 5k rpm. I guess the carb rack will be coming off . . .

 

If your going into carbs, check with MiCarl. I think he is carrying a basic rebuild kit for the carbs that has the O-rings & few other things in it.

 

Gary

[motorcycle.jockey]

If your going into carbs, check with MiCarl. I think he is carrying a basic rebuild kit for the carbs that has the O-rings & few other things in it.

 

Gary

 

Isn't that rebuild kit (the one pictured) for a V-max, or will it also work for a venture?

It would be awesome if it worked for a venture.

[bkuhr]

At this time I tend to agree that it is a carb problem. I rode the beast about 60 miles today. It starts and runs in the low and mid circuits.

 

My symptoms are:

1) Will not run above 5k in any gear

2) will not take WOT in any gear, chokes out

3) blubbers off idle when hot

4) harder to start when hot

5) smells of gas

 

A friend on another forum thinks my problem is clogged or stuck main jets. This is supported by a chart I found that shows the main jets of a CV carb do not come into play until about 5k rpm. I guess the carb rack will be coming off . . .

It just hit me as I read this. I suspect your choke is open/ not closing. First suggest close look at choke(enrichers:witch_brew:) plungers bottom out completely, actually push on them to see if more play inward.

Second look at plugs to find rich cylinder/s.

Third-not sure easy way to test for defective plunger short of bank removal, and even then not sure how to prove plunger will not close- maybe someone has idea, but rich test of plugs should indicate which carb may have defective plunger.

[dingy]

Isn't that rebuild kit (the one pictured) for a V-max, or will it also work for a venture?

It would be awesome if it worked for a venture.

 

 

I tried it & it works for a Venture. It doesn't have any jets, just gaskets and fuel level valve.

 

Gary

[Condor]

Don't see any mention of syncing the carbs after the cleaning. Might also consider changing the plugs.....

[rjg1985]

I have been watching this thread because I am having a similer problem. Poor mpg (29) no power at WOT spark plugs are black. It is a 1985 with an 87 1300 motor carbs from the 1200 with 125 main jets, pilot screws 2 1/2 turns and new diaphrams last year. I took the carbs off to give them a good cleaning and found the the rubber plugs in the bottom of the jet block fit very sloppy and are hard. I'm thinking that fuel is getting sucked by them creating a rich condition. I never have to use the choke to start it. The bike runs fine under normal conditions and stumbles at WOT. Last year it ran great when I twisted the throttle I had better be holding on tight and I miss that. It had the problem when I took it out of storage this spring. I'm going order new rubber plugs and gaskets tomorrow. I will post the results after I have it back together.

[dingy]

I have been watching this thread because I am having a similer problem. Poor mpg (29) no power at WOT spark plugs are black. It is a 1985 with an 87 1300 motor carbs from the 1200 with 125 main jets, pilot screws 2 1/2 turns and new diaphrams last year. I took the carbs off to give them a good cleaning and found the the rubber plugs in the bottom of the jet block fit very sloppy and are hard. I'm thinking that fuel is getting sucked by them creating a rich condition. I never have to use the choke to start it. The bike runs fine under normal conditions and stumbles at WOT. Last year it ran great when I twisted the throttle I had better be holding on tight and I miss that. It had the problem when I took it out of storage this spring. I'm going order new rubber plugs and gaskets tomorrow. I will post the results after I have it back together.

 

 

Another thing you might want to get is the 37.5 pilot jet in the jet block. It clogs very easily and is very hard to clean well, less than $5 each. Remember jet block gasket, these almost always get destroyed when block is removed.

 

Gary

[CrazyHorse]

At this time I tend to agree that it is a carb problem. I rode the beast about 60 miles today. It starts and runs in the low and mid circuits.

 

My symptoms are:

1) Will not run above 5k in any gear

2) will not take WOT in any gear, chokes out

3) blubbers off idle when hot

4) harder to start when hot

5) smells of gas

 

A friend on another forum thinks my problem is clogged or stuck main jets. This is supported by a chart I found that shows the main jets of a CV carb do not come into play until about 5k rpm. I guess the carb rack will be coming off . . .

Will it go over 5k without load like sitting on center stand not in gear?

[GaryZ]

Will it go over 5k without load like sitting on center stand not in gear?

 

yes

[rjg1985]

All I can say is WOW. WOT is back. I cleaned the carbs replaced the rubber plugs in the jet bodies the jet body gasket and main tube o-rings and the bowl cover o-rings. Put it back together and went for a ride. It ran great no stumble or hesitation. I synced the carbs and now it is good to go. I'm going to monitor the spark plug color to make sure the mixture is good and hopefully the mpg goes up. Total parts $160.00.

[GaryZ]

I have been running heavy doses of Sea Foam for the last two tanks with no change. A week ago the beast was still messed up.

 

Took her out for a ride today and it is running perfect. After about ten miles I tried running past 5k RPM and got to 6500 without trouble. Found a clear stretch of road and stretched my Vmax cams to 9,000 RPM and was still pulling like a train . . . What's the deal???

 

[Yammer Dan]

Sea-Foam:think:

 

One of the ones that claim to know it all on here claims it will not unplug a completely plugged jet. I don't agree with him on much. Could have been something somewhere that just had to soak loose??

 

It sometimes takes a while.

 

Hope it stays that way.:clap2: