lower cylinder problems

**Sun Oct 29, 2006 5:57 pm » Post: #1 » Download Post**

my 21 has started only firing on the upper cylinder the lower one is intermittent. done all the regular stuff connecters ect (thanks andy) and it was working fine i parked it up had my tea went back out to go to my mates house and its starting firing on one again i pulled the plug out and its wet with petrol its got good spark and compression and fuel (wet plug) and the electrics are fine any ideas what's up with it ?

**Mon Oct 30, 2006 5:41 am » Post: #2 » Download Post**

Have you put a new plug in?
_________________
james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm

**Mon Oct 30, 2006 8:05 am » Post: #3 » Download Post**

Carb float valve leaking ?
_________________
Poul
"If Life Gets Boring, Risk It!"
MC21SE, KISS box
MC21SP, HRC box, racing loom

**Mon Oct 30, 2006 9:33 am » Post: #4 » Download Post**

j911brick wrote:Have you put a new plug in?

yes i put a new plug in and it lasted all of 10 miles

**Mon Oct 30, 2006 12:05 pm » Post: #5 » Download Post**

I really did have the same thing happen on my race '21 a year or so ago. It drove me nuts for a long time. It ended up being a blackened connector inside the PGM 16 pin connector.

I cant remember what colour wire it was now. Look at your lower coil and find the same two wires at the PGM. Take the pgm off and look at the pins for those colour wires. Mine was very black. I cleaned it up with some contact cleaner and all was well again.
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If I have to take the carbs off once more...

**Mon Oct 30, 2006 1:33 pm » Post: #6 » Download Post**

i will take it out and have one more look just incase i missed it

**Mon Oct 30, 2006 2:18 pm » Post: #7 » Download Post**

when i cleaned it yesterday i cleaned the wrong plug Embarassed

seems to work ok now but not had chance to ride it cos it pissing down Sad

**Mon Oct 30, 2006 2:21 pm » Post: #8 » Download Post**

woohoo, fingers crossed hey.
_________________
If I have to take the carbs off once more...

**Mon Oct 30, 2006 2:40 pm » Post: #9 » Download Post**

i will let you know later on when the rain stops

**Mon Oct 30, 2006 3:47 pm » Post: #10 » Download Post**

If a plug gets fouled, even once, you you need to replace it. It will never be the same again.
_________________
james
Its not how fast you go...Its how you go fast.
MC21 Rothmans
RS250
RC31
CRF250X
748R
Porsche (many)
http://members.rennlist.com/j911brick/rennlist3_002.htm

**Mon Oct 30, 2006 4:49 pm » Post: #11 » Download Post**

no good just took it down the road and it stared to do it again Sad

i have had the carbs off and striped and cleaned them. all connecters cleaned new plug and still no joy

**Mon Oct 30, 2006 5:55 pm » Post: #12 » Download Post**

I had something like this a couple years ago that made me (even more) crazy. It turned out the coil connection (coil blades to wiring harness female connectors) was not as snug as it needed to be. If you've ruled that out, have you also tested the bottom coil itself? Good luck, I feel your pain.
_________________
-Jim
'93 MC21

**Mon Oct 30, 2006 5:59 pm » Post: #13 » Download Post**

yep ruled that out mate that was the first thing i checked

**Tue Oct 31, 2006 2:03 am » Post: #14 » Download Post**

i think i will pull the loom out and give it the once over then in turn all the bits hanging of it as i think its one of those pain in the arse problems that crops up ones in a blue moon. here gos..........................

**Wed Nov 01, 2006 7:52 pm » Post: #15 » Download Post**

turned out to be the coil got it sorted now (thanks steve!)