still having idleing problem

[motorhead704]

Hello I am back, on my 88vr I am still having idleing problem when you first start it and when it reaches operating temp. It will idle for a second and then the tack will drop to 0 the engine will still idle but it very low and it will start backfireing thru the tail pipe. when you throttle up it will pop a little and then smooth out when you let go of the throttle it will drop back to 1000 rpm for a second and then drop to 0 and start backfiring. Squeese told me to check for vac. leak around base of carb. I checked this with brake cleaner srayed around each one but it seemed ok no rev. The hoses from the top of the carbs into the air box two of them are a little loose where they go into the box should I seal them will they cause any problem? running down the highway it runs fine. I checked the diaphrams in all 4 carbs no holes they looked new. I have only had the bike for 3 weeks when I first got it, it idled fine iI ran sea foam thru it when I first got it. when I pulled the cover to check the diph. it looked like ther was some oil on the diphrams. I think theres to much oil in it on the sight glass it is all the way to the top is it suppose to be that full? Its been about20 years since i have had A bike I have to learn how to work on them agine. can anyone tell me where I can order a service Manual for this bike. I will be asking a lot of question on here I hope you all dont get tired of me. thanks alot motorhead 704

[CrazyHorse]

Hello I am back, on my 88vr I am still having idleing problem when you first start it and when it reaches operating temp. It will idle for a second and then the tack will drop to 0 the engine will still idle but it very low and it will start backfireing thru the tail pipe. when you throttle up it will pop a little and then smooth out when you let go of the throttle it will drop back to 1000 rpm for a second and then drop to 0 and start backfiring. Squeese told me to check for vac. leak around base of carb. I checked this with brake cleaner srayed around each one but it seemed ok no rev. The hoses from the top of the carbs into the air box two of them are a little loose where they go into the box should I seal them will they cause any problem? running down the highway it runs fine. I checked the diaphrams in all 4 carbs no holes they looked new. I have only had the bike for 3 weeks when I first got it, it idled fine iI ran sea foam thru it when I first got it. when I pulled the cover to check the diph. it looked like ther was some oil on the diphrams. I think theres to much oil in it on the sight glass it is all the way to the top is it suppose to be that full? Its been about20 years since i have had A bike I have to learn how to work on them agine. can anyone tell me where I can order a service Manual for this bike. I will be asking a lot of question on here I hope you all dont get tired of me. thanks alot motorhead 704

 

 

Will it idle with choke on? Skydoc has a small filter for sale to replace the emmisions breather hoses. It works well plus no oil sucked up into the air filter.

[GeorgeS]

Check the " IGNITION FUSE " holder, pins might be corroded, or loose, or cracked, causeing high resistance contact to the fuse itself.

 

Give the Ignition Switch a bath with WD-40 and Electrical Contact Cleaner, you might have High Resistance across the Main Contacts of the Ignition Switch.

 

Open up the " Run-Stop " Red switch on the right handle bar. If you have High Resistance across the contacts of this switch, this will cause LOWERED VOLTAGE, to the TCI Ignition Unit. Low voltge to the TCI , will cause th unit to " NOT Fire " the plugs properly. ( I know of at least TWO 1st Gens, that quit running due to a faulty , --- Run Stop---- Switch !!! )

This switch, corrodes, turns into a High Resistance, Series Resistor, in series with the voltage to the TCI, thus Lowereing the voltage to the TCI. Result, TCI no work right.

 

Remove the TWO Plugs from the TCI Unit, ( 6 pin, and 8 pin ) and CLEAN the contacts, here, and apply contact cleaner,

 

You have a 5 pin cable running from the " Pickup Coils " going to the 6 pin plug of the TCI unit. About 1/2 way, located just about under you left knee as you sit on the bike , there is a Pull apart plug. Open this plug, and Clean the contacts, Carefully inspect the Male and Female Pins inside this plug, make sure the are makeing good contact. Any high resistance across the pins in this plug, will cause problems with the TCI Unit.

 

You might have to " REMOVE the TCI Unit " ( not easy to to ) Now remove the top cover of the unit. Put the Unit in OVEN, at about 110 deg. F for about an hour to Dry Out the MOISTURE-- That IS PRESENT , inside this unit. ( Yes, it does have moisture inside of it ) ---

Then from each of the two plugs, ( 6 pin and 8 pin ) follow the connections going to the Circuit Board. RESOLDER, the connections to the Circuit board. They are notorious for developing cracks, and cold solder joints at the board. This might be your problem.

 

Check the Main 40 amp fuse holder, open the holder, and clean the fuse element, and make sure the two small #1 phillips head screws that hold the element in place are tight.

 

Clean Both Ends, of Both Battery Cables, and consider Resoldering the Studs to the cables.

 

And, of course, charge your battery, consider possibility of an intermittant "internal short in the battery " . Maby replace plugs, and Carefull Inspect all 4 plug wires, ( remove them at caps, and coils, nip off 1/4 inch of wire, and re-install the wires ) ( plug wire is 7MM solid core copper plug wire, avialable at most any auto parts dealer )

 

Also, consider draining the fuel tank and replaceing ALL of the fuel, you might have water and crud in the tank.

Also, find the Drain on Each Carb bowl. Drain them seperatly, and let the fuel pump run fuel thru each bowl drain seperatly.

 

And, of course, add a good dose of " SEA - FOAM " to the tank, maby thats all you need !!

 

Consider this a " Witch Hunt " in no particular order, ( but start with the Run Stop Switch )

Edited June 29, 2010 by GeorgeS