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Attention To Injectors & Throttle Bodies - The Conclusion
Bill Havins:
I'm a bit "fastidious" about some things. And other things? Meh! I could care less about water spots. But I want my Guzzi to run well. I don't want a high performance bike. I just want it to run well.
This '98 EV I have been, er, "restoring," is my first fuel-injected bike. I am very comfortable with carbs and distributors, but it has taken me a while to really wrap my head around this fuel injection thing.
I have been puzzled for many months that I can't get this engine to perform consistently at idle and just above. One day I think I have it. The next day...heavy sigh. Then on our trip to New Mexico a few weeks ago I thought the TPS was acting up. Then the symptom cleared a couple of days later, only to return as we neared home on the last day of the trip. When I pulled the TPS off in the garage there was fuel in it.
I have begun to consider that some of the performance issues with my Guzzi are the seals on the throttle bodies, combined with "tired" injectors. I bought a set of throttle bodies from Pinwall Cycles and am using them as my "guinea pigs." I posted last week that the seals in these throttle bodies were obviously bad (the donor bike had 19K on it). The "rubber" seals used in these throttle bodies just don't hold up to "oxygenated" fuels. So I ordered replacement seals at a cost of $11+ each. The ones I ordered are made with Viton "wipers." I should have the seals early next week. I'll post photos of their installation.
Regarding injectors, I decided to send the "donor" injectors to a Houston-based injector reconditioning shop. Before I mailed them I checked their electrics to ensure they were still patent (they measured 17.2 ohms resistance). Today I received the reconditioned injectors in the mail. The shop that did the work included the report you see below. Before their cleaning, I wonder if these injectors would have caused symptoms similar to what has been frustrating me.
I won't "firm up" my opinion until I install the reconditioned injectors and rebuild the throttle bodies on my Guzzi. But I am beginning to lean toward an opinion that we need to pay more attention to throttle body seals and the condition of injectors as our Guzzis age. Heck, if my EV had carbs on it I would have rebuilt them at least four times by now (assuming I bought the bike in 1998). And I would change the points at least every two years, adjusting them each time I set the valves.
When I swap the reconditioned injectors with the injectors on my EV I will send my originals in for reconditioning. It will be interesting to see how that report reads.
Make sense?
Bill
Bill Hagan:
--- Quote from: Bill Havins on December 06, 2014, 11:25:15 PM --- I'm a bit "fastidious" about some things. And other things? Meh! I could care less about water spots. But I want my Guzzi to run well. I don't want a high performance bike. I just want it to run well.
****
When I swap the reconditioned injectors with the injectors on my EV I will send my originals in for reconditioning. It will be interesting to see how that report reads.
Make sense?
Bill
--- End quote ---
Well, as for "make sense," dunno. I am likely to be way more successful with water spots than with throttle bodies and injectors ::), but I am interested in the results.
Have the EV on the lift awaiting various tasks, and will consider adding that to the list. That said, am reluctant to mess with "success," as when I rode it last week, it was flawless ... or mebbe I am just getting used to flaws!
Seriously, it idles at 11, and doesn't stumble whatever on out to 7+. Did not get to rev limiter, but nary a complaint. Yes, it has some flat spots along the way, but nothing new, I think.
Still, that R&R sounds as if it's in my limited skill set and would be useful PM, so I'm game, especially as it also sounds inexpensive. ;)
Thanks for the report; please do update on completion ... or snags.
Bill
Wayne Orwig:
--- Quote from: Bill Hagan on December 07, 2014, 07:06:58 AM ---Still, that R&R sounds as if it's in my limited skill set and would be useful PM, so I'm game, especially as it also sounds inexpensive. ;)
--- End quote ---
Yes Bill, you need to fix it until it is broken. ;-T
:D
Dean Rose:
--- Quote from: Wayne Orwig on December 07, 2014, 08:49:23 AM ---
Yes Bill, you need to fix it until it is broken. ;-T
:D
--- End quote ---
;-T
Dean
M0T0Geezer:
Rough idle and occasional stumbling can be caused by "non-compliant" (i.e., dirty) injectors that fail to accurately follow instructions from the ECU.
The ECU says "Open to X" but the injector does something a little different, "Opening to X minus delta" because it is dirty.
The tiny valve body ("pintle") can become stiff from contaminant deposits. Each injector also has a tiny fuel filter which can become partially clogged with impurities.
I find a dose of Techron fuel injector cleaner always makes my 2004 Breva 750 (30,000 miles) run smoother.
I suggest everyone try that before spending time and $$ on new or rebuilt injectors.
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