A bit frustrated with my 83 Venture

[van avery]

I have an 83 venture that I still can not get running correctly. Looking for ideas and things to check and how.

If I come around corner and accelerate it may “pop” back once or twice and then kick in. Problem seems to gets worse as the bike gets hotter. But is sluggish and “pops” under acceleration then takes off. Notice the problems seem to drop off and the beast has new power at about 3100 RPM. IF you lower the rpms to around 2500 RPM it really loads up.

To start it up I seem to have the best luck choking it and then moving the to the right to almost no choke and it will finally kick in.

Idle is a little unsteady but not too bad.

History

1. Cleaned the carbs a couple of times. Had slider and stuck float this week and there are both fixed. Idle screws are set at 2 turns out, Have also tried 1 ½ turns out. Tried smaller shims and bike run worse so reinstalled original shims in sliders. Rechecked the float levels.

3. Set the valves last year and several were too tight.

4. New plug wires and caps and plugs last year.

6. Have after market TCI using the stock program. about 1 ½ year ago NO MAPP sensor. Basically does the same things with the original TCI in place.

7. Sync;d carbs several times and again last night. Run about 6 inch at 1000RPM .

8. YICS was removed last year.

9. Gas mileage is under 30 MPG.

10. Have spark on all cylinders.

11. Every once in a while running down the road it will stumble but come right back.

Thank in advance for the advice

[bkuhr]

My biggest thought is vacum leaks. Spray ether or start fluid under carb rack while idling and listen for rpm change-then pinpoint spot.

 

Second, running OE or aftermarket ignition really should use some type of load or demand sensor such as the MAP sensor. The basic timing map is fair for normal cruise or slow, steady throttle changes. Sudden changes effecting load on the engine (getting on semi-hard, or quick roll off), are not detected and spark advance can't keep up with what is required, and you get the POP with the late spark. Maybe reason same issue with OE tci is maybe OE sensor is bad, and you have not installed another sensor to wotk with the aftermarket tci.

 

My thoughts:2cents:

[kevin-vic-b.c.]

My very first thought was vacuum as well so yes spray some starter or WD40 works too and see but I would like to back up some......

 

you adjusted the valves some time ago and many were tight..... did this issue start directly there after? Is it possible the valve adjustment was done in an incorrect order or something that may have created this monster. I have never done a valve adjustment on a Venture but I have screwed up more than a few valve adjustments on old VWs in the past.

 

Just thinking out loud

 

K

[bongobobny]

Yup! I'm betting your 30 year old rubber is showing it's age. (Note to self, get mind out of gutter) Also, have you changed your fuel filter? Also, maybe time to service your gas tank, you may have rust flakes floating in there...

[frankd]

6 inches of vacuum is too low---normal is a little under 10 inches. Check for vacuum leaks as suggested above. If you find and repair any leaks, you will have to re-sync the carbs! After you are sure you don't have any leaks, adjust your idle adjustment screws for maximum engine speed which will also be maximum vacuum. All 4 should be able to be adjusted for maximum speed, and this would prove that all 4 carbs have clear pilot jets. Have you checked the float level? Take an ohmeter and measure from each plug wire to ground. They should all read about 24K ohm. This will verify that you don't have an open plug wire to coil connection or a problem at the plug cap.

 

 

If you still havn't fouind the problem by this point, another reason for low idle vacuum could be retarded ignition timing. If your stock TCI gives good spark on all 4 cylinderss, install it. This will eliminate any programing errors with the new TCI. Install the stock boost sensor also. I know you've checked a lot of these things already, but try again and let us know exactly what you find and we can go on from here.

 

Frank D.

[Condor]

On the '83 the vacume for the booster is different than all the rest of the years and the hose comes off a bib on the #2 carb instead of off the manafold. My thought is the hose is toast and leaking, and you're not getting any timing advance as well.....

[greg_in_london]

While we're throwing thoughts out there - when the carbs were apart, did you change the o-ring on the emulsion tube and the two rubber bungs at the bottom of the jet block ?

 

If you're getting real backfires rather than coughing, then it sounds like it is running too weak, rather than what I suggested, which would make it too rich.

[van avery]

I'll go back and check for vacuum leaks again. I replaced the vacuum hose to the original vacumm advance prior to changing the TCI out. I remember previously the vacuum being about 9 inches when I sync'ed the carbs.

I'm confused that the entire system vacuum would be low since each carb is basically it's own system?

The problems existed prior to changing the TCI and adjusting the valves.

The bike had set for about 5 years before I got it running again. Belive I changed the fuel filter back then. Also If it were restricting the fuel then I would think it wouldn't take off at the higher rev's.

I won't have time to check things this weekend. I just stopped by the house between cavalry rides.

I did not change out the o-rings on the emulition tubes and reused the existing rubber plugs, They are a bid hard.

The bike really wakes up over 3100+ rpm. Is the idle circuit active up to that rev?

I'll update with the results when I get then run again.

I'll spray with wd-40 again.

Check plug wires for 24 OHMS each.

Do a compression check.

Check spark with old and new TCI's.

 

Thanks again for the help.

[frankd]

First off, I said the plug wires should read about 24,000 ohms, not 24 ohms!!! Don't get concerned if one reads 26K (26,000), but if one reads 500K ohms or more, you have a problem.

 

The reason that all 4 cylinders have equal low vacuum even though they are 4 completely different systems is that the carbs have been synced and that means they were adjusted to have equal vacuum---so now you have low but equal vacuum in all 4 systems!

 

I just had another thought.....while you have everything apart, do a compression check. Make sure the throttle is open, and if you don't have access to a compression gauge, you can do a poor boys check. Remove all 4 spark plugs, and ground all 4 plug leads (or unplug the TCI if that's easier at the time). Hold a spark plug in a plug hole, but do NOT thread it in. Crank the engine and note how it sounds when it blows the plug out of the hole. Check the other 3 cylinders and see if they are relatively equal. Now don't get shook if one is low, just let us know and we'll go on from there.

 

 

Frank D.

[van avery]

Alright, had a chance to work on the bike this evening.

This is what I found

1.Checked the plug wires to ground and all were about 17K ohms not 24 K, they seem to start at about 19k then drop off to 17K +/- 100 and hold. Checked with different meter and consistantly got 16.5 K, stll started higher then quickly dropped and stayed.

 

2. Ran compression check on cold motor all plugs out and the throttle wide open and reading were #1- 135 ,#2- 130,#3- 138, #4- 140 PSI

 

3. Sprayed starter fluid around the intake boots and the vacumm ports and did not detect any rise in RPM anywhere. Did this with cold motor and again with warmed up motor after quick ride.

 

4. Checked spark on all four plugs with both old and new TCI and had consistant spark on all. All four plugs out when I checked these. The spark does not seem very bright but they are all firing.

 

5. Plugs look like its running rich see picture.

 

Took bike out for quick (about 4 miles) ride and again noticed that the problems "coughing or popping" get worse as the bike warms up. It still takes off after around 3000 RPM. With pop once or twice then kick in and take off.

 

With the looks of the plugs it looks like I should reinstall the thinner shims again.

[bikenut]

Sounds to me it is running lean on the low end. Sure the low speed pilot jets are clean. Main jets are ok if taking off after 3000 rpm. May have to get back into your carbs again.

Hope this helps

[greg_in_london]

Idle circuit could well be in play up to 3,000 rpm - it depends mainly on throttle opening and you could well still be on 1/4 throttle. I'm still not clear about what is happening at lower revs though. Does it feel like the motor is drowning or missing or backfiring. Looking at the plugs I'd suspect too rich, rather than too weak, especially if it gets worse as it warms up. I don't feel that I've heard enough for a firm prognosis though.

 

The emulsion tube o-ring and those rubber bungs will let more fuel through if they are tired, but I know mine has run fairly well with pretty awful ones. I wouldn't tear down the carbs to do them, but they're worth doing while it is apart.

 

 

• Make sure all the choke plungers are returning.
  
• Take the air box off and see how the sliders move at tickover and when you rev the engine.
  
• (I convinced myself I could see petrol flowing down the walls, from the needle/emulsion tube before I changed the o-ring, but I'm not sure what is 'normal', so this might not be reliable.)
  
• Look at the exhaust when it's misfiring - do you get smoke or does it stay clear ?
  
• Other than that it's looking around until you see something that's different on one to the others, or out of spec on all of them.
  
• I presume that you've tried new spark plugs (and maybe caps too).
  

 

Sorry, but I'm not sure that that's much help.

[Dave Dunbar]

I have a 1983 and while i had the carbs apart to clean i changed the rubber plugs on the emulsion tube. What i did is tap the small hole to 1/4 twenty and put a stainless set screw in place, you just have to be very careful not to tap to far in as there is passages for gas that you cannot block up. The bigger plug i used5/16 by 18 and again do not tap to far in. The bike had sat for about 5 years and now runs fine. I am now working on no 4th or 5th gear. Hope this might help Dave

[Venturous Randy]

These old bikes are pretty finicky about the condition of the plugs. With what I am seeing on your plugs, I would put in another set immediately. I use Autolite from Advance Auto and they work fine and they are cheap.

RandyA

[van avery]

Alright, had a chance to work on the bike this evening.

This is what I found

1.Checked the plug wires to ground and all were about 17K ohms not 24 K, they seem to start at about 19k then drop off to 17K +/- 100 and hold. Checked with different meter and consistantly got 16.5 K, stll started higher then quickly dropped and stayed.

 

2. Ran compression check on cold motor all plugs out and the throttle wide open and reading were #1- 135 ,#2- 130,#3- 138, #4- 140 PSI

 

3. Sprayed starter fluid around the intake boots and the vacumm ports and did not detect any rise in RPM anywhere. Did this with cold motor and again with warmed up motor after quick ride.

 

4. Checked spark on all four plugs with both old and new TCI and had consistant spark on all. All four plugs out when I checked these. The spark does not seem very bright but they are all firing.

 

5. Plugs look like its running rich see picture.

 

Took bike out for quick (about 4 miles) ride and again noticed that the problems "coughing or popping" get worse as the bike warms up. It still takes off after around 3000 RPM. With pop once or twice then kick in and take off.

 

With the looks of the plugs it looks like I should reinstall the thinner shims again.

 

Update on progress on the 83 venture. Sorry this is so long.

Purchased new rubber plugs for the carbs jet holders. Pulled carbs and cleaned everything again. Things were in pretty good shape as they were but as long as they were out decided to work them over anyway. Cleaned the jets in the jet holder, checked the “choke plungers”, checked the diaphragms, checked the ports through the carb body. Pulled the idle mixture screws and cleaned including the little o rings.

While I had the carbs off, I also checked the valves clearance and they are within spec.

Put things back together and while I was there I installed new vacuum plugs over the YICS vacuum ports and replaced the fuel filter.

Pulled the original nylon washers on the sliders and replaced them with the two SS washers approximately ½ as thick as original. Looked like I had good action on the sliders When I open the throttle I noticed the vacuum dropped to almost zero.

Sync’ed the carbs and now have a vacuum of approximately 9 ½-10 inches on each cylinder.

Purchased a small digital tach and tried to set each cylinder for the maximum setting with the idle mix screws.

Bike was hard to start but does idle well once warmed up. If I slowly twist throttle the revs will come up. If I twist it quickly it drops off and will die. If I let off quick enough it would regain the original idle. Seemed like it was running to Lean?

So, I reinstalled the original nylon washers in the sliders. Runs better now, resync’ed the carbs and reset the idle mix screws to the fastest idle on each. Put things back together including the air filter .

Seemed to run OK in the garage but when I took it for about a 10 mile run but. Bike stumbled every once in a while running down the road and then immediately recovered.

About an hour later I when back out and it’s running worse . “Coughs and belch’s ” back through carbs during acceleration after a corner , maybe a couple of times then picks up and takes off. It died at an intersection. It starts hard, cranks quite a while before it starts, and then if you give it gas too quickly it will die. Have to start with basically no choke. It seems to help to start it choked and then reduce to no choke for it to start, then open choke to warn it up some.. Again problems seem to get worse as the bike gets warmed up.

While reving the bike in the garage the coughing or belching does not always happen on the same cylinder.

Does not want to start with the original TCI now. I have the Ignitech aftermarket TCI running with the standard program from them and I don’t have a map sensor. The vacuum line is still connected to the original timing advance, and that vacuum line was already replaced and I did check it for leaks while putting things back together.

Could I have bad connectors to the TCI or somewhere else?

Looking for some more things to check?

I have not bought new spark plugs yet, but I know these were all firing, Have not thought aboout buying them when I was in town. :confused07::confused07:

At least my 87 Royale is running good

[bull463]

Hi

Have you checked the floats to make sure that they are working right?

Bull463

[van avery]

The time before that last time I had the carbs out I set all the floats to the spec level on the bench. I also checked the little springs in the float valve to make sure they were OK,

Thanks for the suggestion.

[Marcarl]

I don't think it's your problem, but I would put new plugs in before I would do anything else, it's amazing what a change of plugs will do, and then it eliminates that for sure. And don't buy your plugs from WalMart, go to an auto supply store.

[timgray]

I had no problems at all on my walmart NGK plugs. I don't think that Walmart is buying a sub grade plug and stocking them on the shelves. It's the same plug that my Yamaha Dealer has on his shelf for 20X the price.

 

A bigger problem is the platinum or Iridium plugs. Older bikes want good old standard plugs.