ONE CYLINDER RUNNING PROBLEM

MATTT · Jul 23, 2013

Hi all
just got the bike back together and got it motd but its running poorly on 1 cylinder
Basically it starts and idles ,the poor side runs much cooler,
when riding you puill awayt its chugging and misfiring,if you get going and open it right up the 2nd cylinder will fire up and you shoot off,mid throttle theres nothing
Its a 750 non combat,standard , apart from Pazon altair
2 new amal premiers fitted a few months ago, not ridden until now.I did sych the carbs and will have to recheck them , ive also taken the carb off and carb cleaned the jets and pilot circuit just in case.the mixture and throttel stop adjustment on the back side are also way less sensitive to adjuments than the good side
swapped the coils this morning
cant think of what else to check at the moment

cheers
matt

Bernhard · Jul 23, 2013

Try a commpression check.

JimC · Jul 23, 2013

Boyer?

MATTT · Jul 23, 2013

have had another look at the carb and took the slider out as its the only thing i didnt check yesterday
found the copper clip that holds the needle in place had cracked and the needle had slid out of the groove and was sitting about 2 inches out of its correct position

LUckily I just rang them and the are posting me one out.Its wierd that cracked as ive never actually ridden it until yesterday,unless i managed to break it somehow fitting the cables.

JimC · Jul 23, 2013

Sorry, I missed the Pazon part.

CanukNortonNut · Jul 23, 2013

MATTT said:
have had another look at the carb and took the slider out as its the only thing i didnt check yesterday
found the copper clip that holds the needle in place had cracked and the needle had slid out of the groove and was sitting about 2 inches out of its correct position

LUckily I just rang them and the are posting me one out.Its wierd that cracked as ive never actually ridden it until yesterday,unless i managed to break it somehow fitting the cables.

Mattt
If you are referring to the small cut just where the needle lives then this is normal for the clip. You must be careful when inserting the slide back into the body. Watch that the needle doesn't jam up while you are aligning it to go into the needle jet. If things are lined up properly then there is very little pressure on the needle when it slides up and down through the needle jet and the clip will hold it always.
Regards,
Thomas
CNN

batrider · Jul 23, 2013

The needle clip is not cracked. There is a split right where the needle goes. Normal. When you install the slide, do it with the air filter off so you can guide the needle into the needle jet.

Russ

john robert bould · Jul 23, 2013

+ 1 Russ, it's not so easy to dislodge the needle and push it up out of it's clip, but can happen. Normaly the slide will not drop in.

MATTT · Jul 27, 2013

well at least ive got a couple of spare needle clips now

the new ones are , as you all said, the same as my "cracked" one !
well its back together and im going out later for a ride to test it out
its idling fine and revs up ok
its still cooler on 1 cylinder so i might have to recheck the carb sync ?
i did set it up at full throttle openings but i didnt synch the idle stop screws ,so ive got them set visually from the outside of the carb not really sure if thats an ok way to do it though.

MATTT · Jul 27, 2013

Just to add
ive run it for 5 mins and compression test,open throttle ,one side ( the cooler one ) is 120 and the other 150

Nortiboy · Jul 27, 2013

MATTT said:
Just to add
ive run it for 5 mins and compression test,open throttle ,one side ( the cooler one ) is 120 and the other 150

Mate, you got a problem. The differential between the pots is too much. Check tappet clearance is ok first.

Then stick about a quarter cup of engine oil in the weak pot and try again. If the compression goes up, then the rings and or bore need attention. If nothing changes then the valve seats are the problem.

Good luck.

MATTT · Jul 27, 2013

Ive also noticed theres a bit of a dark stain on the barrel between the fins sticky oil like,so Im assuming the head gasket could be leaking

I may well ride it though as before you know it the summer will be over !

MATTT · Sep 25, 2013

Well it running cool still on the lower comp cylinder.
So I need to check the valve clearances but if they are ok,what type of head gasket should I use,I've seen copper,flame ring and composite ones all listed for sale
Confused now!

Any particular brand better than others.?

MATTT · Sep 25, 2013

Well it running cool still on the lower comp cylinder.
So I need to check the valve clearances but if they are ok,what type of head gasket should I use,I've seen copper,flame ring and composite ones all listed for sale
Confused now!

Any particular brand better than others.?

ScottMDMC · Sep 26, 2013

Make sure the floats are not hung up.

Stillreel · Sep 26, 2013

I had a similar issue with a Honda years ago. It was a cracked spark plug. Take out both plugs. Reattach high tension leads. Turn over engine and ensure there's a good spark at both plugs.

BC

Torontonian · Sep 26, 2013

Always good to change sparkplugs when those symptoms appear. Battery voltage low can do these thingys too. Loose wires too.

ONE CYLINDER RUNNING PROBLEM

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