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Have had a 83 VR for two years now and have been working on an overheating problem. The 83 VR has an 86 (1300) motor because the PO had a second gear problem and replaced the whole engine. Anyway, the bike has been running hot since I bought it (right up at the red/green line). When the weather is in the high 80's low 90's it boils over when stopped at a light or in traffic, etc.. (See my posts from earlier this year) I have changed everything trying to correct the problem. I was going to sell the bike for parts and have bought a 89 VR from a member on this forum and am in the process of fixing it up and getting it ready to ride next season. I took the 89VR to Earl to have some mechanical work done on it and spoke to him about the overheating on the 83 VR. He said that he thought the TCI was the original one from the 83 and that the timing curve was different from the 86 engine that was currently in the bike. He thinks that that is what is creating the overheating problem. I stumbled across the article about the foreign made TCI and it said in the thread that the 83 had a different timing mode than the later engines.

So, I think my overheating problems may be because I have a 1200 TCI in the bike and not a 1300 TCI. I don't think the original PO changed the TCI but cannot confirm that with the previous PO. I do not want to teardown the bike to get the TCI out, instead I just want to try a 1300 TCI and put it on top of the airbox and see if that corrects the problem. I will be selling this bike in the spring if it solves the problem , otherwise I will part it out as I don't want to sell this bike with this problem. I now own a 89 VR, which is being worked on by Earl (Skydoc) and don't need two bikes.

 

Does anyone have a TCI for an 86 1300 engine they would like to sell?

 

Thanks

 

Jim

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Sent you a PM regarding 86 TCI.

 

If it is still the TCI from the 83, and the bike has 86 thru 93 carbs on it, there is not an easy way to reconfigure the vacuum line.

 

I t is doable, but would require drilling the #2 carb body for a fitting to receive the vacuum line. Carbs would probably need to be removed from bike.

 

The 83 TCI in effect is possibly retarding the ignition, or at least, not advancing it when engine is under higher power demand. This would result in the air/fuel mixture being ignited later than optimal in the power stroke of the piston.

 

Are your tail pipe tips covered with soot? This would be an indication of running rich, which could be a result of incorrect timing.

 

Gary

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Sent you a PM regarding 86 TCI.

 

If it is still the TCI from the 83, and the bike has 86 thru 93 carbs on it, there is not an easy way to reconfigure the vacuum line.

 

I t is doable, but would require drilling the #2 carb body for a fitting to receive the vacuum line. Carbs would probably need to be removed from bike.

 

The 83 TCI in effect is possibly retarding the ignition, or at least, not advancing it when engine is under higher power demand. This would result in the air/fuel mixture being ignited later than optimal in the power stroke of the piston.

 

Are your tail pipe tips covered with soot? This would be an indication of running rich, which could be a result of incorrect timing.

 

Gary

 

I doubt running rich would cause an overheating problem.

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I doubt running rich would cause an overheating problem.

 

You are correct Gunny.

 

From what I know about rich/lean conditions, lean will run hotter than rich. This is due to the heat from the combustion process will be expelled through the tailpipes in the form of unburnt, but heated fuel molecules. The unburnt fuel is a direct path out of the engine for the heat.

 

I was just asking about the soot on the tail pipes as this is an easy way to tell the difference for someone as to if the bike is running rich. If it is rich, there is probably another system fault in the cooling system that is causing the overheating.

 

Possibly incorrect thermostat bypass valve setting, low coolant level, malfunctioning thermostat are some possibilities.

 

If it is running lean, then this could be the source of extra heat.

 

I am not really sure which way the rich/lean condition would swing, if at all, due to a timing issue.

 

Gary

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Dingy:

 

To answer some of your questions:

 

!. New radiator which was cleaned and pressure tested.

 

2. New auto thermostat installed - no difference - replaced with original Yama thermostat which was temperature tested to make sure it opens and also screw on top of thermostat screwed down to lower opening temperature.

 

3. drain valve in correct position. "Off" at 2 o'clock position.

 

4. Bypass tube not plugged.

 

5. Coolant level correct.

 

6. Water pump impeller OK - checked bearing for wear - no play.

 

7. Checked for fluid flow thru radiator when thermostat opens.

 

8. Checked all hoses for collapse @ 4000 RPM and engine hot.

 

9. Fan rewired to operate manually.

 

10. No soot to speak of on the exhaust pipes.

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Gary:

 

As far as what you posted above about the carbs and vacuum line, I was lost at the second sentence. Sorry, I am not a mechanic. All I can tell you is that the PO replaced the complete engine and I assume that they have the 86 carbs on it. I don't know what TCI is in the bike, I just assumed that the original 83 TCI is in there. I will have to look in the tech library to find out how to get to the TCI and take it out and look at it. Although, I wouldn't know an 83 from an 86 TCI. Do they have a part number on them or is there some other way to distinguish an 83 from an 86 unit? I just thought it would be easier to just plug in a 86 unit and see if it makes difference.

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Look at the #2 carb, if the vacuum line to the boost sensor comes from the intake boot, they are 84 and up carbs. If the vacuum line comes off of the upper throat (above the butterfly) of the carb, then they're 83 carbs.

 

On the TCI, 26H is 83, 41R is 84 and up.

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Hey Dano,

The engine that was swapped into his 83'VR is from an 86'VR. The #2 Carb. draws vacuum for the Boost Sensor from the tube in the intake boot. (Like a regular MKII VR, NOT The 83'VR) I believe that the timing is retarded, which causes the spark plug to ignite the air/fuel mixture BEFORE the piston reaches top dead center. Which in my opinion, would cause this motor to run HOT. Jim is trying to find an MKII VR TCI to plug into his harness to see if the different TCI will advance the timing enough to solve the overheating problem. He has been thru the entire coolant system and the TCI is pretty much the only Item we have not swapped out yet. If I had one, we would have checked it out, but alas, I don't.

Hey Gary, (Dingy) is there any reason that you can think of why the MKII VR TCI would not plug into the MKI VR wiring harness? I can't think of any, but you dealt with the MKII motor in your MKI bike. Aren't you using an MKII TCI on your "Monster MAX" bike?

I would be personally grateful for any help anyone could give Jim in regards to finding an MKII VR TCI for his bike.:thumbsup2:

Earl

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Go ahead and pull the battery and battery box now, you will have to anyway to get to the TCI connectors to swap in another.

Then you can use an inspection mirror, and read your TCI part number, which is mounted upside down (label facing down) on the bottom of the coil mounting bracket.

 

At this point I was able to go ahead and remove the TCI for the relocate mod with the fairings on, but be advised, it is very, very difficult. I took about 3 hours to unscrew 4 bolts holding coil bracket. Some state they have been able to unscrew tci directly from underneath the coil bracket, I could not. It was too tight and I had to pull the complete bracket and flip the bottom up to reach the TCI. Not sure, but may have been easier and faster to go ahead and remove fairings. Prior to disconnecting, somehow mark both halves of each of the 4 yellow coil connectors, to prevent mixing them up.

 

While I has my coil bracket out, I modified it for future removal from the battery area, and replaced my coil leads/caps.

The mod consisted of

1. Reinstall forward coil bracket screws from inside-out

2. Cut forward facing slots in forward coil bracket screw ears. This allows coil bracket to slide from rear to front, camming onto front screws, locking coil bracket down in up/down direction. Also required grinding of unnecessary tab to allow forward/rear mounting action.

3. Welded 'L' brackets to both coil bracket and frame to allow rear bolts of coil bracket to bolt in from the rear vs the side, although the orginal side mount could still be used without to much difficulty, skiping this step

4.Chassis ground wire was attached to forward left coil bracket screw. Extended wire and attached to new rear left coil bracket screw. Also steel wire welded to coil bracket which helps holds throttle junction block in fairing removed, and junction block held with tie-wrap to near wires.

5. I also modified the battery box bracket by removing the nutplate from the frame, and welded a nut the bracket so the bolts would work from inside out.

 

PS. I have pics, but I used a cheap camera and they are badly out of focus.

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Hey Dano,

The engine that was swapped into his 83'VR is from an 86'VR.

 

Hey Gary, (Dingy) is there any reason that you can think of why the MKII VR TCI would not plug into the MKI VR wiring harness? I

Earl

 

I knew that Earl, which is why I stated the differences between the two in order for anybody to see and understand the difference. As I understood it, he did not know if the carbs were off the 83 or the 86.

 

I can swap any 41r TCI into the 84 without any changes, you'd have to look specifically at the 83 wiring diagram to see if there are any differences in the wiring to an 84-89 TCI.

 

Me

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Hey Dano,

The engine that was swapped into his 83'VR is from an 86'VR. The #2 Carb. draws vacuum for the Boost Sensor from the tube in the intake boot. (Like a regular MKII VR, NOT The 83'VR) I believe that the timing is retarded, which causes the spark plug to ignite the air/fuel mixture BEFORE the piston reaches top dead center. Which in my opinion, would cause this motor to run HOT. Jim is trying to find an MKII VR TCI to plug into his harness to see if the different TCI will advance the timing enough to solve the overheating problem. He has been thru the entire coolant system and the TCI is pretty much the only Item we have not swapped out yet. If I had one, we would have checked it out, but alas, I don't.

Hey Gary, (Dingy) is there any reason that you can think of why the MKII VR TCI would not plug into the MKI VR wiring harness? I can't think of any, but you dealt with the MKII motor in your MKI bike. Aren't you using an MKII TCI on your "Monster MAX" bike?

I would be personally grateful for any help anyone could give Jim in regards to finding an MKII VR TCI for his bike.:thumbsup2:

Earl

 

I knew that Earl, which is why I stated the differences between the two in order for anybody to see and understand the difference. As I understood it, he did not know if the carbs were off the 83 or the 86.

 

I can swap any 41r TCI into the 84 without any changes, you'd have to look specifically at the 83 wiring diagram to see if there are any differences in the wiring to an 84-89 TCI.

 

Me

 

 

The 83 wiring hookup is identical to the 84-89 units.

 

The 86 TCI will be a plug & play replacement, no other changes needed.

 

Jayceefolly, PM me with your address and I will get the 86 unit sent out to you.

 

Gary

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Hey Dano,

I believe that the timing is retarded, which causes the spark plug to ignite the air/fuel mixture BEFORE the piston reaches top dead center. Which in my opinion, would cause this motor to run HOT.

Earl

 

 

I may be wrong, but I believe the motor runs counter-clockwise as viewed from the left, which puts the firing sequence BEFORE TDC, as is with most motors I know of (RE: Chevy small block, which is anywhere from 10d BTDC to 4d BTDC), therefore, as the piston reaches TDC, the explosion is then pushing down on the piston as it comes around, providing maximum force or torque to be applied. If you waited till after TDC, the piston is already traveling downward, which would be wasting some of that torque.

 

I WAS wrong once before, tho........

Edited by Dano
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Gary:

 

Sent you a PM. Thanks

 

Brian:

 

I am just going to unplug the wires and then put the 86 TCI temporarily on top of the airbox to see if that solves the problem. If it does, then I will probably leave it on top of the airbox permanently. I really don't want to remove the fairings and go thru all that work. I am going to sell the bike (in one piece, if I can fix this problem or part it out) in the spring. I understand that the top of the airbox is the best place to put it anyway.

Thanks for your help.

 

 

Jim

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I may be wrong, but I believe the motor runs counter-clockwise as viewed from the left, which puts the firing sequence BEFORE TDC, as is with most motors I know of (RE: Chevy small block, which is anywhere from 10d BTDC to 4d BTDC), therefore, as the piston reaches TDC, the explosion is then pushing down on the piston as it comes around, providing maximum force or torque to be applied. If you waited till after TDC, the piston is already traveling downward, which would be wasting some of that torque.

 

I WAS wrong once before, tho........

 

 

This is correct but there is another factor or two to consider.

 

This is somewhat long, and is based on my experience, other peoples opinions may differ. Most of the text refers to the 84-93 (and RSV) motors. There is an explanation of the 83 difference.

 

Static timing is the amount of advance that is hard coded into the system at the crankshaft/rotor connection. This setting is not adjustable on the Venture motor. The setting is determined by the relationship between the journals on the crankshaft and the positioning of the pickup coil trigger magnet on the rotor in conjunction with the placement of the pickup coils in the stator housing. The rotor to crankshaft connection is fixed with a woodruff key. This setting determines the static spark advance for the motor.

The second system is an electronic advance based on engine RPM's. In the case of the Venture motor this is determined by the pulse coming from the #2 coil that is input into the TCI. The equivalent setting on a auto engine that was pre electronic ignition system would be the set of mechanical weights in the distributor. As engine RPM's increased the weights would be forced outward by the spinning of the distributor shaft. This advance was controlled by the size of the weights and the stiffness of the springs. Normally, the mechanical advance would be at full advance in the 2,500 to 3,000 RPM range. The change of the timing is done by moving the plate that the points are mounted to rotationally around the distributor shaft.

 

The third system is the vacuum advance. On the Ventures, other than the 83, this is 'Manifold Vacuum'. As the carb butterfly's are opened, manifold vacuum reading rises to closer to atmospheric reading (14.7 PSI). This is due to the positioning of the vacuum source. It is between the carb butterfly plates and the cylinder heads. When the motor is idling, the piston creates a closer to zero vacuum reading as it moves downward on the intake stroke, since the vacuum source is connected below the butterfly plates, the sensor reads this lower than atmospheric vacuum. The manifold vacuum reading rises to nearer atmospheric pressure as the butterfly's are opened.This is due to the vacuum sensor now being exposed to the higher atmospheric pressure source. Once the motor RPM's level off in relationship to the butterfly opening, the vacuum reading will will return to a somewhat lower reading but still closer to atmospheric than at an idle condition. This is useful in determining load demand that the motor is responding to.

 

The Ventures use an electronic sensor that is attached to the #2 intake manifold between the cylinder head and the carb. This sensor uses an electronic strain gauge that senses the vacuum, then translates this into an electronic signal that is input to the TCI. The equivalent setting on a auto engine that was pre electronic ignition system would be the vacuum advance unit that is attached to the distributor. This unit functions by pulling on a rubber bellows in response to vacuum change, this unit is very similar to the cruise control bellows on the venture. This bellows movement is hooked to the plate on the distributor that controls the advance setting.

 

The 83 Venture is basically identical to the 84-93 engines (and the RSV's) except it used 'Ported Vacuum'. This vacuum source is above the throttle plates in the carbs. When this source of vacuum is used, the vacuum is nearest atmospheric reading when the butterfly's are closed. When the butterfly's are opened the suction from the piston moving downward on the intake stroke lowers the vacuum reading above the butterfly's. This difference is what makes the 83 TCI unique. It must interpret the vacuum signal opposite that of the 84-93 (and RSV) motors.

 

Mechanically the 83 motor is identical to the 84-93 motors as far as the mechanical ignition timing is concerned. The crank, pistons, stator and pickups are basically the same. The 90-93 motors differ from the 83-89 motors in that these motors use a single coil pickup system. This also entails a change in the magnet located on the rotor. The 90-93 TCI's cannot be used on an 83-89 motor due to this difference.

 

The 83 TCI cannot be used on an 84-89 motor without modifying the #2 carb to provide a ported vacuum source above the butterfly's. A TCI from an 84-89 motor can be used on an 83 motor by plugging the port above the butterfly's and connecting the vacuum sensor hose to the port on the #2 intake boot.

 

The TCI receives three signals, one from the pickup coils, one sensing the motor's RPM's and one from the vacuum boost sensor. It uses these three signals to determine the amount of ignition timing required.

 

All timing starts from the same place. On the Venture motor, this starting point is fixed. It is set at a static advance of 5 degrees before the number one cylinder reaches top dead center on the compression stroke. The four stroke engine, the type of engine the Venture uses, has the crankshaft rotate two times for each time the engine fires. The downwards movement of the piston begins and the intake valve opens, allowing the fuel/air mixture to be drawn into the cylinder as the downward movement of the piston creates a vacuum. This is called the “intake stroke” and fills the cylinder with fuel/air. About the time the piston reaches the bottom of its stroke, the intake valve will close, making a seal and the cylinder is now a closed system full of air/fuel mix. The piston then begins to move upwards compressing this mixture, hence, the term “compression stroke”. When the piston reaches near top of the stroke, the spark plug fires, igniting the fuel/air mixture which burns in a rapid manner forcing the piston downwards. This is where the power comes from and is called the “firing stroke” or “power stroke”. As the piston nears its bottom point, all of the air/fuel should be burned and needs to be forced out, or exhausted, to make room for a fresh charge of air/fuel. Thus, the exhaust valve opens as the piston travels upwards and the rising piston forces the burned residue out of the cylinder on the “exhaust stroke”. Near the top of the exhaust stroke, the exhaust valve closes and the intake valve opens so the whole process can begin again.

 

In first glance, the spark plug would fire as the piston just begins its downward cycle on the firing stroke. But, the air/fuel mixture is a controlled burning, not a violent explosion. The burning begins near the triggering device, the spark plug, and moves across the top of the piston and the combustion chamber until the entire air/fuel mixture is burning. Ideally complete full burn should take place when the cylinder has moved slightly downwards, or at about 20 degrees after Top Dead Center (TDC). This is the point at which the crankshaft journal is at the apex of its rotation and any further rotation of the crank initiates the downward movement of the piston. The burning process of the air/fuel mixture causes a chemical change to the gasoline molecules. As they change from a liquid state to a gaseous state, the volume of the molecules increases, thus causing the piston to be forced downward to allow for this increased volume. Also involved in the need for advance is the very slight delay involved in the firing of the plug. If the mixture were signaled to be ignited at TDC the piston would be traveling downward by the time the spark plug reacts to the coils collapsing field which generate the arc across the spark plug. This seems like an instantaneous reaction but is not. There is millisecond or two for this reaction to occur.

 

When an engine is running at 1,000 RPM's the crankshaft completes a full revolution 16.6 times a second. In a four stroke engine, every other revolution is a power stroke, so each piston is firing once every .12 seconds (120 milliseconds). When the RPM's are at 7,000, the piston is firing every .017 seconds (17 milliseconds).

 

If the timing is advanced too much, pre-detonation (pinging) occurs. This is a condition that happens when the expanding air/fuel mixture happens too soon and forces the piston downward while the crankshaft is still moving it up during the compression stroke.

 

The Venture TCI will advance the ignition timing by about 48 degrees at 2,800 RPM's with a nearer to atmospheric vacuum reading (open butterfly's). This timing curve is shown below which is from the VMax service manual and does vary somewhat from the Venture., it is shown because I believe the Venture nomenclature is wrong that identify the curves in the service manual. The format of this curve is in a 2D format, it does not show the 3 three factors that control timing fully.

 

http://i1007.photobucket.com/albums/af193/gdingy101/VMaxtimingcurvefrommanul.jpg

 

The next picture is taken from the software that is supplied with the Ignitech ignition module that several of use are using on our Ventures. By looking at the timing advance in a 3 dimensional format, it is more apparent as to the relationships between the 3 inputs controlling timing.

 

The lower left corner is the 0,0,0 point. Zero RPM's, Zero advance and lowest vacuum reading. Vacuum on this chart is indicated by the symbol 'TP' on the lower right side. This is due to the Ignitech unit is shown as using a Throttle position sensor to supply the unit with the somewhat equivalent input as Vacuum. The Throttle position input is used with most modern fuel injected systems. It is not however, an indication of engine load that is more useful in carburated engines. The reason for this is that if the throttle is half power position, the optimum timing advance is different while the engine is under load as it accelerates. I think that all of us that are using the Ignitech unit are using a vacuum sensor in place of the throttle position sensor.

 

As can be seen more apparently from this depiction of the timing curve is that the advance is at a larger amount when the engine is at a higher RPM with with either the closest to atmospheric vacuum, or at high RPM with somewhat low vacuum reading. When the motor is operating at mid range RPM's and mid range throttle position at steady RPM's , the advance is in the somewhat flat area, towards the center of the graph.

 

http://i1007.photobucket.com/albums/af193/gdingy101/Ignition3Dmap.jpg

 

 

The same timing curve as shown in the 3D graph above is displayed below in a data input format. The Throttle Position (Vacuum) is on the left side of the chart. The vacuum is depicted in a range of 0-100%. 0% being the idle condition and 100% being the closest to atmospheric reading the vacuum the sensor detects when the throttle is snapped open. RPM's are shown across the top. The boxes in the middle are the advance settings at each intersection of a given TPS (vacuum) and RPM point.

 

http://i1007.photobucket.com/albums/af193/gdingy101/Ignition3Dflatmap.jpg

 

A link to the best thread detailing the Ignitech unit is at:

 

http://www.venturerider.org/forum/showthread.php?t=40414

 

Gary

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OK the abreviated version of Gary's write up, on the '83 the vacuum is 180 degrees out of phase from the '84 up, so your ignition advance is going to be wrong. It will run but won't respond correctly to accdeleration. Yes, this timing error can cause the engine to run hotter...

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Thanks a bunch everyone, for taking time out to help Jim, (JC'SFOLLY) get his bike running properly! You gents that are Electrical Geniuses are the best!

Gary, a special thanks to you for helping Jim with an MKII VR TCI.:clap2:

And to you Don, All I can say is.......Don't you have some leaves to rake!!:rotfl::crackup::rotf:

Earl

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Gary:

 

Thanks for the description of the timing. I was doing OK, following the details, until I got to the graphs and then my eyes started to glaze over! Anyway, I will read the explanation again in the morning when I am more wide awake than I am now.

Thanks for your help.

 

 

Jim

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  • 3 weeks later...

To all of you who took the time to help we with this TCI swap, I thank you because I think the swap has solved the problem. WOO HOO!!!! Bottom line is it made a big difference.

 

I put the TCI on top of the airbox and just left it there.The bike started up and ran fine, so I let it get good and warm and when the gauge got near the red line the fan kicked on and the gauge started to go down after a minute or so. The fan then shut off and the temp started to creep up after a few minutes and the fan came on and then cycled off again. This is the first time I have been able to let the bike idle this long without it boiling over. I let it idle for almost a half hour with the fan cycling on and off. The temperature gauge never did go up in the red. It would come very close but when the fan came on it would drop down from the red/green line and then the fan would shut off. So, I think the TCI swap is a success just for the idling. But, there is more! Took it out for a ride and discovered that the new TCI was just like adding two more cylinders to the bike! Much more power and the bike ran much smoother. It ran really well when the RPMs were over 3000-3500. The power increase was remarkable. And the acceleration from 55 to 80 mph in top gear was awesome. I actually had to hang on the handgrips. The engine felt like it was running very smooth at 3500 RPM, much more so than with the old TCI.

 

The temp in city riding would creep up and the fan would come on while sitting at a light. Once moving again the fan would go off. Before the TCI swap, I would have to have the fan running all the time I was in city traffic. (I have a manual override switch installed) There is one caveat though and that is the outside ambient temperature. I have ridden the bike twice and both times the temp was in the low 60's, so this may not be a fair test. Although the overheating problem has been evident at any ambient temp. I ran the bike on the local x-ways at sustained speeds of 70 to 75 MPH for at least 10 miles and the temp gauge never got over 3/4 of the way thru the green. When I transitioned onto the surface roads, the temp would creep up on the gauge but at no time would it go in the red. I feel that this new TCI has solved the problem. I put about 125 miles on the bike on each trip and it combined city travel as well as highway. I also think the temperature gauge is reading high. My 89 temp gauge only goes halfway up before the fan kicks on and then falls back to the 1/4 mark. The gauge on the 83 has always been running up near the red line.

 

So, to sum it up, I think the TCI change has made a big difference, but the proof will be on those 90 degree days. So, now I think I may keep the bike and see what will happen next spring when the temps start to go up. We are now into the late fall weather here in western NY and the temps are now generally in the 40's and 50's during the day.

 

I am going to take the bike to Earl (Skydoc) in the Spring and have him do a tune up and check the timing, etc.. I feel much more comfortable about selling the bike now and not parting it out.

 

A big thank you to Bongobob and Skydoc and Dingy. They were all instrumental in solving this problem. Thanks for all the help and support. There are great people on this site!!

 

 

Jim

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