Tuneup problem

[Guest DAZ]

Hi All,

 

I am trying to get my 90 working right. I do not think the owner before me did anything yet ride this bike and he did not even do much of that.

 

I pulled the plugs and they were rusted on the outside. Also they looked as if they were burning right not black etc.

 

I got my carb tune today and hooked it up to sync the carbs. I can bearly get them to move at an idle. when burping the bike they do jump up yet then settle down to the bottom of the scale. I can get the readings to change as one would expect with the balancing screws yet all at the bottom of the scales. Right now I am thinking a big vacumn leak what do you all think.

 

Thanks

DAZ

[BuddyRich]

Be sure your holding the cartune straight up and down also. But I would say a leak. Use some carb cleaner to spray around hoses and stuff till you hear the engine change.

[Gearhead]

My plugs were rusty too. Water can get in the plug wells, but is supposed to drain off through a hole that drains behind the little rectangular cylinder side covers. Remove one (1 screw) and see if it's plugged (no pun intended : )

 

What speed is it idling at? It should be about 1000 rpm. Pull one of your carb slides and check the diaphragm for holes and cracks, although mine have holes (new ones on order) and I could still sync the carbs. I think bad coasting enrichment diaphragms will cause a vac leak internal to the carb.

[CrazyHorse]

I had a problem with some sort of fluid in the restrictors but I blew it out and then it worked.

[Guest DAZ]

More stuff after dinner. I went out and was doing the carb cleaner and when I hit the intake on carb 1 the idle went from 1000 to 3000. I pulled the seal cleaned and reinstalled and then hooked CardTune (great tool) back up. The vacumn is much better yet still low. I am reading around 12 on the carbtune.

 

I am holding it straight up and down (found that one by trail and error).

 

I am thinking I may have a diaphragm problem just not sure yet. I am getting about 45 MPG yet the bike just does not feel right. So thanks so far and I will keep looking.

 

The UPS man just showed up with new wires and cap so I will not have time this weekend yet after the 4th I want to look this problem over and get to the end of it.

[GeorgeS]

Have you been useing Sea Foam. ??

 

Did you drain the bowls ?? Also, you might Drain the Gas tank, and run some HEET, just in case water in gas tank.

 

Give it some run time with sea foam, then Re Try the Sync proceedure.

 

I have read where some folks have had problems with the Intake manifold gaskets, makeing a good seal. One guy said he puts Sealant on them. I don't know if I would do that, but check the Clamps holding the Carbs to the Manifolds for leaks, and the bolts holding the manifolds to the Engine intake ports.

[Gearhead]

"I have read where some folks have had problems with the Intake manifold gaskets, makeing a good seal. One guy said he puts Sealant on them."

 

 

 

Is this problem reported to be on the carb side or the engine side? If it's the engine side, I would just replace the o-rings!

 

Jeremy

[Rocket]

"I have read where some folks have had problems with the Intake manifold gaskets, makeing a good seal. One guy said he puts Sealant on them."

 

Is this problem reported to be on the carb side or the engine side? If it's the engine side, I would just replace the o-rings!

 

Jeremy

 

I read in the tech bulletins for my 83, to seal the intake boots to the airbox, had used a semi-drying gasket sealer for this.

[Gearhead]

"I read in the tech bulletins for my 83, to seal the intake boots to the airbox, had used a semi-drying gasket sealer for this."

 

 

 

This makes sense, as when the air box accumulates a little blow-by-oil on my 87 it leaks out those joints and down on to the carbs.

 

Jeremy

[GeorgeS]

The black rubber intake manifolds have an O-Ring where they bolt onto the Heads. Also, the Clamps that hold the Carbs to the intake ports are very light metal, and Stretch with time.

 

Also I have had the Rt. Forward intake manifold " Crack " and you could hear it " sucking " I noticed this sound a 70 MPH on I-5 half way between Eugene Ore, and Portland on return trip from Los Angeles. ( Just threw that in for Effect !! )

 

Anyway after you get the fuel tank cleaned, out, and the carbs cleaned, be sure you don't have any Intake leaks between carbs and Intake valves.

 

Also, the Rubber Caps, that cover, and seal the Vaccume test port on each Intake manifold, may look good, but pull them off and check for cracks and rotten rubber. You might be driveing with a Hole in the Intake manifold !!

Just recently, sombody said he found a couple of these rubber caps that was leaking . This would lower the Intake Vaccume pressure.

 

Just something to check

[Guest DAZ]

Thanks guys. I hope to get to this next week. it has been raining for the last two days in St Louis so I have not been able to see if the bike is running any better.

 

I have run a couple of tanks of Sea Foam and that helped. I did not drain the bowls yet sounds like a great idea.

 

The leaking problem looks to be on teh carb intake side. After messing with carb 1 things did look better, yet I still have what looks to be low vacumn, and I am hearing some missing.

 

I will replace the wires and caps and clean all teh connectors I can get to and then try again.

 

Thanks for all the help as I do need it

 

I also ordered a repair man. today as being a 17 year old bike I think I will be spending some time working on it.

 

DAZ

[Scudrunner]

I realize this is an older thread but has anyone else had a similar experience of very low vacumn readings in the carbs while doing a sync job? It seems like my rear cylinders fire first and then after about 20 seconds or more the front cyls come online. This 84 sat for awhile but I cleaned it up and it ran last year ok except for needing to raise the rpms up to get all cyls firing, then it screams well. Thought syncing the carbs would work but can't get a reading on the gauges. (older dial type)

[GeorgeS]

Well there has to be something wrong with the Tool.

 

What tool are you useing ??

 

If the engine is running, there is vaccume--

[Scudrunner]

The gauges are a new older set of 4 vac gauges with hoses and simple valves on each. I put another gauge I have on one of the hoses and it acted the same way. I could feel vacumn at the hose end when I disconnected it from the gauge but it wasn't very much. Since thinking about it today I'm going to pull the hose off the carb and see what kind of pressure I get there. Perhaps the diameter of the hoses are too small and being older they may be collapsing. Also, according to the manual it calls for about 9 in of mg. which is much less than an auto would pull.

 

Reading this thread about drilling hole in the filter cover makes me curious. When I first start the beast I have to use full choke and let it run for awhile. if I ease off on the choke or try to give it a little gas she will die. It's not that cold out but it will do this all the time. Is this normal for this gen 1 bike?

[Squeeze]

I'm sorry to say but your Carbs may need a intense claaning Job.

[mbrood]

My bike always needed about 1/2 choke to start and after about 30 seconds I could back it off to about 1/4 and another 30 seconds or so I could remove all choke.

 

A different problem made me pull the carbs and do a full cleaning. The FINE gas jets (in the jet block) looked fully clogged but I guess there was SOME fuel flow... but after a complete cleaning it REALLY doesn't want any choke unless it's a real cold morning.

 

The lower manifold boots are odd, they ALL crack in the lower section, but that lower half of the rubber has a metal housing inside and only the top half is just rubber and that part seldom shows cracking, but CAN be sealed with several sealants. And yeah, the lower manifold clamp rings stretch and after... oh... 20 years or so... could stand to be replaced.

 

I bought new clamp rings mainly because I was "in there" and didn't want to be in there for many years to come.

 

Although I would swear the previous owner did nothing but put in gas and oil... it must have been the guy before that rounded off all the bolts and screws!

 

Although Seafoam is regularly recommended, I REALLY think it's mainly for the cleaning effect it has on the fine gas jet and that thing needs all the help it can get.

[Dragonslayer]

I realize this is an older thread but has anyone else had a similar experience of very low vacumn readings in the carbs while doing a sync job? It seems like my rear cylinders fire first and then after about 20 seconds or more the front cyls come online. This 84 sat for awhile but I cleaned it up and it ran last year ok except for needing to raise the rpms up to get all cyls firing, then it screams well. Thought syncing the carbs would work but can't get a reading on the gauges. (older dial type)

I had a heck of a time with carb vacume pressure, mostly the lips around the air box rubber throats to carb throats. I could not get them to seal properly. I finally changed out the air box and finally got them to seal. I also had problems with the clamps on the airbox side and the intake boot side and went through several sets before I found some good ones before I could get enough vacumn pressure to sync carbs. Tight seals are critical and the proper air flow thru carbs.

[Scudrunner]

I sprayed carb cleaner around the base of the carb to hose area without any change but I haven't tried the top by the airbox yet. As a comment, I have to really crank in full choke to get this bike started and have to hold it there for awhile before I even think of releasing any choke. The low end get up and go is not good but once you get up to about 3000 rpms she runs fine and cruises highway speed well. Lately it has a tendency to idle too low and even die out which I was thinking due to the ethanol blend we have in the gas. Will check the upper hose areas for leakage next although the battery is now petering out and will have to be replaced also.

[Squeeze]

I sprayed carb cleaner around the base of the carb to hose area without any change but I haven't tried the top by the airbox yet. As a comment, I have to really crank in full choke to get this bike started and have to hold it there for awhile before I even think of releasing any choke. The low end get up and go is not good but once you get up to about 3000 rpms she runs fine and cruises highway speed well. Lately it has a tendency to idle too low and even die out which I was thinking due to the ethanol blend we have in the gas. Will check the upper hose areas for leakage next although the battery is now petering out and will have to be replaced also.

 

Your Carbs need a complete and thorough Cleanning Job. Working aorund them will not help in any Way. Just tackle the Job and clean them, especially all Jets inside the Floater Bowls.

[MiCarl]

Collapsed vacuum hoses will cause this problem.

 

Also, these engines run pretty well on two cylinders. If you have a cylinder or two not firing it will cause extremely low vacuum.

 

Also, valve lash too tight can cause vacuum problems.