550 J cylinder misfire solved

User avatar
barney01
Posts: 2080
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

550 J cylinder misfire solved

Postby barney01 » Tue Oct 02, 2018 6:15 pm

Just want to share my experience when my right hand cylinder began misfiring.
Went out yesterday after about a mile bike felt down on power and was making that funny sound when I cracked the throttle. Bike wouldn't idle. Did the licked finger test on the downpipes right one was lukewarm. Went back home changed plug no change. Did the unscrew plug cap and nip off the end of HT lead thing. On test ride seemed okay to start but then began spluttering. Checked timing with strobe light which confirmed coils were firing okay.
Plug was wet so fuel was getting through so removed choke piston from right carb found that it had stuck mid bore and was therefore flooding cylinder and killing the spark. Gave the choke piston a quick clean with carb cleaner a smidgen of grease and problem solved bike restored to full power!
Last edited by barney01 on Wed Oct 03, 2018 9:28 am, edited 1 time in total.

User avatar
JOHNJENKS66
Posts: 1207
Joined: Mon Apr 11, 2011 8:38 pm
Location: Cork City Ireland

Re: 550 J cylinder misfire solved

Postby JOHNJENKS66 » Tue Oct 02, 2018 10:17 pm

Good save Barney, and a cheap fix too :D 8-)
what the fuck was that ????

If you can read this, thank a Teacher.. If you are reading this in English, then thank our Soldiers..

User avatar
Roger Ackery
Posts: 3293
Joined: Wed Jul 20, 2011 3:40 am
Location: Sydney NSW Australia

Re: 550 J cylinder misfire solved

Postby Roger Ackery » Tue Oct 02, 2018 10:41 pm

Just read your PM Barney, good you fixed the problem ;)
Cheers.
Roger
GT750A.

teazer
Posts: 472
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: 550 J cylinder misfire solved

Postby teazer » Wed Oct 03, 2018 1:32 am

Good catch. Another thing to check on our old bikes is to see if the choke plunger is sealing. I have found quite a few that go down and appear to seat but still leak past the hardened rubber insert. A MityVac or similar is an easy tool to use to check for leaks

User avatar
Alan H
Posts: 8524
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Re: 550 J cylinder misfire solved

Postby Alan H » Wed Oct 03, 2018 9:03 am

I had exactly the same back in about 1974 with my 550J. Started well and 'lost' a cylinder after a few seconds as the engine got warm. A bit of tarnishing in the choke plunger tube was soon cleaned and ran fine afterwards. I don't think it would happen on a linked carb set up as they have solid connections, where the separate carbs have individual cables of course.
Proof that four strokes are over complicated

es2GT550
Posts: 99
Joined: Tue Jul 11, 2017 10:08 pm

Re: 550 J cylinder misfire solved

Postby es2GT550 » Thu Oct 04, 2018 5:33 pm

Good stuff -thanks for sharing the info :)


Return to “STOCK FAULTS AND CURES”

Who is online

Users browsing this forum: No registered users and 4 guests