K11 Owners Group

k11gaz · Joined: 31 Mar 2009 Posts: 22

Hi guys

I need some help...

I went with a mate to pick up his K75 (1993, 103k miles) and it backfires on the over run. Any ideas?? It was like sitting behind a WW II rear gunner firing at me LOL

Thanks in advance Smile

_________________
1984 CX650 Turbo 48k miles
1993 K1100LT 63k miles

Ride it like ya stole it !!

Scott_Anderson · Posted: Mon Jun 08, 2009 7:37 am Post subject:

TPS sensor would be the first thing I would check.
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1997 K1100LT 0302488(R.I.P.)
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Flying Duck · Posted: Mon Jun 08, 2009 8:25 am Post subject:

To some extent it's normal on a K75 for them to backfire when you chop the throttle. MY K75RT did it a fair amount when I first bought it. However, the longer I owned the bike, the less it happened. I suppose that over time it eventually taught me how it wanted to be ridden. On subsequent K75s I've ridden it's never happened so my bike must have trained me well.

Things to check:

TPS

Header bolts are secure

That there is still a gasket between the headers and exhaust can

Air leaks on the intake side:
Crankcase breather hose
The little rubber vacuum clamps
Also spray some startter fluid around the TB's to see if there are any air leaks. If there's an air leak then the bike will idle a bit faster.

Synch the throttlebodies.
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93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
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Al. · Posted: Wed Jun 10, 2009 7:56 pm Post subject:

Yea - they do that !

Jim · Posted: Wed Jun 10, 2009 10:22 pm Post subject:

When the throttle position switch is adjusted to factory specs it'll backfire like a big truck. Mine used backfire like crazy until they adjusted it at Gina's. You have to adjust it so it cuts the fuel just a tad sooner.

Seems like I just read somewhere (forget where) that the older bikes have a switch, the newer bikes have a sensor.
_________________
Jim
1997 K1100LTSE 94,000 - still has gremlins!
1995 R100RT Classic 16,650 crashed - repaired!
1992 K75RTP 46,000

"We shall not all die, but we shall all be changed."

k11gaz · Joined: 31 Mar 2009 Posts: 22

Thanks for all the answers. They are really useful and gives us a good starting point to attack the issue.

Thanks again

Gaz
_________________
1984 CX650 Turbo 48k miles
1993 K1100LT 63k miles

Ride it like ya stole it !!

Phil Marvin · Posted: Sun Jun 14, 2009 4:41 pm Post subject:

Jim · Posted: Sun Jun 14, 2009 5:42 pm Post subject: TPS

Hi Phil - thanks - that's what I thought.

When my K75 was backfiring like crazy, the tech adjusted the TPS to cut off a little earlier - took care of the problem.
_________________
Jim
1997 K1100LTSE 94,000 - still has gremlins!
1995 R100RT Classic 16,650 crashed - repaired!
1992 K75RTP 46,000

"We shall not all die, but we shall all be changed."