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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Westone on April 27, 2013, 05:11:01 PM
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Today I installed these upgraded, Bosch Type II injectors, which have four tiny holes to disperse fuel versus one for the originals, and I believe I read they have a slightly higher flow rate than the originals:
http://motors.shop.ebay.com/osidetiger/m.html?_nkw=k75&_sacat=&_odkw=&_osacat=0&bkBtn=&_trksid=p3911.m270.l1313 (http://motors.shop.ebay.com/osidetiger/m.html?_nkw=k75&_sacat=&_odkw=&_osacat=0&bkBtn=&_trksid=p3911.m270.l1313)
The motivation was to attempt to address a knock I was concerned about, which from what I have read may have been due to a rough idle and rough acceleration until beyond 3,000 RPM. Initially I was thinking of sending the originals off for cleaning, and it was not much more money to purchase the rebuilt upgrades.
Immediately on startup after the installation the idle was noticeably smoother. At operating temperature the idle is now 1,200 rpm versus 1,000 before. And where previously the bike smoothed out over 3,000 rpm, it is now smooth at all rpms. I was cruising through a parking lot in 1st at 1200rpm, completely smooth. I cruised in 4th gear in city traffic on a slight incline at 2,000 rpm, completely smooth, though power loaded.
DISCLAIMER: YMMV. I have owned this bike, my only K bike, for all of 400 miles. While I recommend this upgrade, I also think one of the original injectors on this bike may have some issues. The electrical connector for the injector on the #1 cylinder was slightly discolored, and in general the area around that injector looked like it may have experienced some over heating or a small fire or something at one point in the past. And, the grommet for the fuel rail mount in that location was seriously degraded compared to the one by cylinder #3. In any event it's possible some occurrence negatively affected that injector. Or maybe they did just need cleaning. I do know the rebuilt injectors are a significant improvement all by themselves, and the knock that had me concerned at idle is gone.
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My only concern with those would be the different flow rates and opening times. I considered using those with my megasquirt system, as I could address the incorrect fueling that they would introduce.
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Well, honestly I wasn't aware there were those things to be considered. I should look into it more and try to learn about it. However, the bike runs much better and I'm thinking that's a good thing. I will try to find out the differences from stock on the parameters you mentioned.
ETA: The Bosch Type II are stated to flow 17lbs (180cc) @ 43.5psi. According to my Clymer's, the pressure in the K Bike system is 36lbs. How does that compare to the stock injector? And is there a method to calculate what they will flow at the reduced pressure of 36lbs?
ETA: Just found the thread on K75 injectors. Reading through that now. Thanks!
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Well, honestly I wasn't aware there were those things to be considered. I should look into it more and try to learn about it. However, the bike runs much better and I'm thinking that's a good thing. I will try to find out the differences from stock on the parameters you mentioned.
ETA: The Bosch Type II are stated to flow 17lbs (180cc) @ 43.5psi. According to my Clymer's, the pressure in the K Bike system is 36lbs. How does that compare to the stock injector? And is there a method to calculate what they will flow at the reduced pressure of 36lbs?
ETA: Just found the thread on K75 injectors. Reading through that now. Thanks!
That might be right then.
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As I posted in the injector thread recently, I found an automotive site with beaucoup injector info. It indicated that an injector rated at 17lbs/hr at 43.5lbs pressure would flow 15.465lbs at 36lbs pressure.
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As I posted in the injector thread recently, I found an automotive site with beaucoup injector info. It indicated that an injector rated at 17lbs/hr at 43.5lbs pressure would flow 15.465lbs at 36lbs pressure.
You mentioned Stan Weiss's site, which is a good one, but I would recommend cross referencing that info with the info at Witch Hunters site. I have found a few "irregularities". YMMV
Here are some links.
Stan's:http://users.erols.com/srweiss/tableifc.htm (http://users.erols.com/srweiss/tableifc.htm)
Witch hunter:http://witchhunter.com/injectordata1.php (http://witchhunter.com/injectordata1.php) Witch Hunter has pics too.