Attention To Injectors & Throttle Bodies - The Conclusion

[Bill Havins]

Hi, John.

This particular injector shop charges $18 per injector.  In that price they do their testing, cleaning, re-cleaning if the first run wasn't enough, and then their after testing.  They also replace the o-rings (there are 2 per injector).

I ordered a couple of small tubes of "O-Ring Grease" at $1 per.  Then there was state tax since I'm also in Texas ($3.19) and $6 for priority mail.  Total bill $47.19.  In my book that was "Okie-Dokie Fine."  Figure what a couple of carburetor kits would cost, or a pair of new injectors.  To me it was a no-brainer.

Bill

[Bill Havins]

I am setting up my Smithy to cut the plug to go in the bottom of my right side throttle body.  Remember, there is an aluminum plug that has to be removed to get to the bottom throttle body shaft seal and replacements plugs are not available.

Would anyone else like me to machine a plug for them?  Since I will be set up to do the lathe work I might as well cut several if other Wild Guzzi members think they will eventually change the seals on their throttle bodies.

Send me a PM even if you post a response here - I can keep track of the PMs in Outlook on my computer.

Bill

[Bill Havins]

Here is a photo of the plug I machined yesterday.  The nickel in the image offers a comparison to the plug's actual size.  The plug fits in the bore of the right hand throttle body (the hole in the middle of the photo.



When I cleaned this throttle body the carburetor cleaner I used caused the old seal to swell.  This put drag on the pivot shaft.  After a couple of days the drag was still there so I decided to replace the seal.  That made it necessary to machine the plug.

I am going back together with everything this afternoon (unless it is too cold to "think" in the garage).  It will be a few more days before I start the engine to see how well all of this works.

Bill

[balvenie]

             Hope it turns out to be a good, early Christmas present for you Bill ;-T

[Bill Havins]

I have received several PMs about the seal and aluminum plug in the bottom of the right throttle body.  "When and why do you replace that seal?"  Here are my thoughts.  Remember, no one appears to have ever paid any attention to this issue with Guzzis, so I may be a crazy man off in the woods attempting to change the growth habits of centuries-old trees.  And I may be known to the forest animals as "Nuts!"  So take this with a grain of salt.

I said early in the above that it may not be necessary to replace the seal in the bottom of the right hand throttle body because the aluminum plug that covers it makes the seal "redundant."  I still believe that is true.  But, and it's a big but, I used carburetor cleaner on my throttle bodies and this appears to have made that seal swell and "bind" on the pivot shaft.  When the binding was still present after two days I decided it was time to pull the plug (literally) and replace the seal.  I didn't want to leave that seal exposed to the elements so I made a replacement plug to cover it - the plug is a simple "press fit" in a vise.

Regarding this whole seals and throttle bodies thing, I have been asked, "Why do it?"  When I bought this scooter several years ago it had had "stuff" added to it (specifically, Bub mufflers and a Power Commander).  And I'm not sure it has a "stock" microcontroller in the ECU (the label is torn off).  So I set myself to taking the bike back to "baseline" so I might get it to run closer to "stock" (if such is possible).  When I had all of the "stuff" removed/replaced the bike still did not run consistently at low revs from one day to the next.  So I began to question what might be involved.  Using my experience with carburetors as an analogue, I finally arrived at the thought that the problem might be seals on the throttle body pivot shafts.  That's where I am now.

1Sourdough indicated he is waiting for me to finish this process to see if replacing the seals really helps.  He's not the only one!  So, for the next few days I will turn my attention to putting all of this back together.  And as soon as I'm done I'll report the results.  http://wildguzzi.com/forum/index.php?topic=73861.0

Cheers!

[Bill Havins]

Today my goal was to get the EV back together to the point where I could start it and ensure it would run given the fact that I had just rebuilt the throttle bodies.  The short version is, "Yes, it runs very nicely, thank you."

I have contaminated these data something fierce.  I did replace the seals in the throttle bodies.  And I did have the injectors cleaned and flow-tested.  But, I have done so many other things that have the potential to affect performance that the only conclusion I can draw from all of this will develop when I remove the TPS after a ride of a hundred miles or so.  If there is no fuel in the TPS then I can conclude that replacing the seal on the bottom of the left hand throttle body "stopped the blow-by," or drip or leak or whatever it has been.

While I have had my EV apart I cleaned and lubed the ignition switch.  I also cleaned and "doxit-ed" the starter switch and the kill switch.  I replaced the sheathing on the wiring harnesses that exit out from the front of the tank and go to all of the controls on the steering head (so all of the connectors were taken apart and treated with doxit).  I rebuilt the mounts for the ignition coils (one had been rubbing on the frame) and applied a little paint.  I replaced both spark plug wires (Dawg knows how old the others were).  I greased the steering head bearings (won't affect engine performance) and replaced the clutch cable (well...).

When I tried to start the bike a few minutes ago it...did...not...wa nt...to...run...  And then I remembered the bypass screw on the bottom of each throttle body...  This time it was ready to run, so I let it warm just a bit, tuned the idle "by ear," synched the throttle bodies "by ear,"  and revved the engine.  Our neighbors across the street have two pit bulls - the garage door points right at them...  ;D

Our Albuquerque daughter is due in here in a few minutes.  Tomorrow I'll attach the vacuum gauges and AFR meter and do a careful tuning.  Then when I have a chance I'll take the bike for a quick hundred mile ride.  I'm hopeful.

Bill

[creaky99]

I will be giving my '98 EV a good going over soon and I've been following this thread with great interest, good job Bill.  Bottom plug on the TB............I have several small plugs of various sizes and would like to know what the correct diameter is.

[Bill Havins]

The bore measures right at 15.20mm.  I made my plug with a 15.18mm diameter (Dawg knows what the actual diameter was - it's to the point of splitting hairs).  It seemed to be an "easy" press fit; sure won't move now.

The diameter of the plug can only go in about 2.5mm.  Any further and it hits the throttle body shaft.

[Bill Havins]

It's raining; the prediction is for snow and sleet with a high near 39°.  I'm putting off the big test ride until tomorrow.  Frtzlfraken!

[creaky99]

Thanks for the info Bill. 

[Bill Havins]

An update:

I have my EV back together and running well.  I have not been out on the road with it, though, so I can't say if this repair has really been worth the effort.  Seems like it has.  The engine starts easily from cold, idles well, revs well, and seems fine with all of the testing one can get done with the bike sitting on its center stand.  As soon as I can break free and the weather cooperates I'll do the road test.

Now, would I recommend that others perform this same maintenance task?  If you are confident in your mechanical skills, and if you have the necessary test equipment to set the TPS, set idle/synch the throttle bodies, and set the higher speed synch of the throttle bodies and CO level of the exhaust then, yes.  I'd recommend doing it.

But, if you are not confident in your mechanical and tuning skills, either get an "expert type" to help you, or pay a skilled Guzzi wrench to do it.  This task is a fiddly pain in the keester!  The throttle bodies have to be removed and disassembled (but the butterflies do not have to be removed from the throttle body shafts).  When you go back together you have to rebuild the throttle bodies assembly, reattach the throttle cable and "warm up lever" cable, and then adjust, adjust, adjust.  It is a task that takes patience and the luxury of being able to walk away when you get tired of working on the bike.  I believe it can be done in a weekend, but I would allow more time than that.  And, if you have even the least bit of arthritis in your hands/fingers, get a fresh bottle of ibuprofen before you start.  You end up working in tight spaces, trying to get fuel injection hose securely attached and many other tasks that want to rub the flesh from your fingers.  Lovely!

When I can find the time I'll attach my data logging stuff and go do a 100 mile run.  I don't need the data, I just want to see it.  Then I'll pull the TPS and look to see if fuel has found its way inside.  If the bike runs well and there's no fuel in the TPS I'll call this a worthwhile effort.

[wildduck]

This was a great series of posts and has got me thinking along the same lines. Thanks for documenting the many steps along the way,

thank you,

John

[Bill Havins]

One more quick update and I'll drop this for several days - freezing temps and frozen precipitation are setting in here.  Dawg!

Late yesterday afternoon I had enough time to do a twenty mile run, about half at highway speeds.  With the TPS set at 375 milliVolts and idle set at 1100 RPM I did have the old popping and backfiring stuff; it was especially noticeable when rapidly decelerating from >5500 RPM.  Otherwise the engine ran very well once warmed up (but the ambient air temp was just 56°).  I pulled the plugs when I got home and they looked "normal" for a '98 EV (white on one side of the ceramic insulator and brown on the other).

We are due for about four days of yucky weather.  I'll reset the TPS to about 420 milliVolts at idle and reset the idle to 1100 RPM at that TPS setting.  I'll then attach my data logging stuff and, when roads are passable, I'll get in a 100 mile run.  I'll check gas mileage at the end of the run.

Winter.  Ugh...

EDIT:  Setting the TPS to 420 milliVolts was an absolute waste of time.  Back to 375mV.

[Bill Havins]

We finally had a bit of a break in the weather today so I wanted to get out on the highway with my EV and determine if the work described in this thread was worth it.  My conclusion is it was just the thing for me to do.

To review, I bought this '98 EV several years ago.  It was fitted with Bub mufflers, a crossover of an unknown brand, and a Power Commander III USB.  It was said to have been dyno-tuned to MAP the PCIII; I have a copy of that report.  I don't know if the microcontroller in the ECU is stock - the label is torn off.

The Bub mufflers were not installed well; they leaked where they met the crossover, in part, because the crossover was too short.  Shimming the joints and attempting to seal the joints with high-temp gasket sealer did not fix the problems.

Fuel was leaking into the throttle position sensor on the bottom of the left throttle body.

I did not care for the way the bike ran - I had a sense it could run more reliably from one day to the next.  That included variations when idling, and "dead spots" that came and went when revving the engine.  I attributed these "dead spots" to wear on the throttle position sensor.  When they appeared at cruising RPMs (around 3800 RPM) they were really annoying.

The purpose of this thread was to document attempting to get the bike back to a "baseline" of sorts.  So, I went through the ignition switch and kill switch and cleaned, lubed, and "doxit-ed" as appropriate.  I replaced the spark plug wires and plug caps.  I installed a new stainless steel crossover and stainless steel mufflers made by Keihan Systems in the U.K.  While installing these components I installed new exhaust gaskets on the heads, and ensured that each slip-joint was carefully clamped after sealing them with high-temp gasket sealer (Permatex Ultra Copper).

I sent my injectors off for testing and cleaning.  I installed new Viton gaskets on the top and bottom of both throttle body butterfly shafts after carefully cleaning the throttle bodies.  I set the TPS to 375 milliVolts (per Guzziology).  I performed other maintenance tasks as I waited for a break in the winter weather we have been having (lubed the steering head bearings, adjusted the positions of the coils in the frame so the right one didn't rub the frame, replaced the Y-shaped high pressure oil delivery tube on top of the block, replaced other sealing washers to stem oil weeping, and on the list goes).

It has been sunny here today and the temperature made it up to 50°.  So I put on all of my riding gear layers and headed out for a mix of spirited riding, including both stop-and-go in-town riding, and highway travel at speeds in excess of..., well, let's say in excess.  What an absolutely wonderful ride!  Once the engine warmed up it ran perfectly!  If I didn't have obligations in just a few minutes I would have stayed gone all afternoon.

Coming back into town the idle seemed to be a bit fast, but I'm not going to worry about it for now - I'll wait until the weather warms and I have an entire Saturday to get the engine up to temperature and then pull it into the garage to do that fine-tuning.

When I got home I let the engine cool a bit and then pulled the right spark plug.  Almost perfect.  I need to install a new set of plugs and repeat the "read" - the plugs that are in the bike are old so any conclusions I might draw are potentially contaminated by "old news."

I then pulled the throttle position sensor to see if gas had dripped into it from the throttle body.  It was bone dry!  Yippee!

So, here is my conclusion: if you buy an older fuel-injected Guzzi and it is a bit tough to tune "just right," consider having the injectors tested and cleaned, and consider cleaning the throttle bodies and replacing the old rubber seals with Viton seals.  Then consider if there is a need to clean and "doxit" the TPS and those switches/connectors that supply power to the ignition.  And decide if you need to attend to the spark plug wires/caps and the exhaust system.  In the case of my '98 EV this all seems to have been worth the effort.

Now I get to do all of the driveline periodic maintenance.  Then we're off to Big Bend and the Gila Wilderness in the spring and early summer.

Cheers!

Bill

[RinkRat II]

 :bike Thanks for all the great info ;-T There's nothing like real world validation for all your efforts and the old injector cleaning and testing seems to be in my future ~;

     Paul B. :BEER:

[balvenie]

              Thanks Bill. This has been an enthralling topic ;-T

[AMGeneral]

This is the sort of thread that needs to be pinned to the top forever!

 Great info and addresses to those with the parts and services needed. ;-T

Now how does the engine behave when going through town. Example when you are just trolling along not really accelerating or coasting. Your in that limbo area in between, that is where my Jackal really throws a fit. Now wondering if this fix will cure that. Guess it is worth a shot.

Nice work, keep us posted!

Rod

[Bill Havins]

...how does the engine behave when going through town. Example when you are just trolling along not really accelerating or coasting. Your in that limbo area in between, that is where my Jackal really throws a fit. Now wondering if this fix will cure that. Guess it is worth a shot....

Rod,

I purposefully got into some traffic that required tooling along at a constant speed (appx. 3000 RPM) both on the highway (5th gear) and in town (2nd or 3rd).  Wherever I set the throttle the engine speed stayed generally constant.  There was no bucking or surging or whatever you want to call it.  The throttle and engine seemed to be "hard-wired" (or maybe it was pure "placebo effect"  ;) ).

Now, this was not an exhaustive sample.  So I don't have any idea how this performance will continue "days on end."  But this first sample shows promise.

Bill