running on one cylinder

09-07-2005, 01:39 PM

Bike is a M750 (carburettor).

It runs on one cylinder (the horizontal front one) until it's been running for about 15 minutes when the other suddenly chimes in. From cold, it again runs on one cylinder. The problem just suddenly appeared one morning on starting.

Sounds like plugs or leads. Any other suggestions? (It seems to be heat related.)

As a further problem, the plug hex seems to be a strange size; neither the box spanner that comes in the toolkit, nor a 16mm plug spanner will fit on them.The plug appears to be 16.5 or 17mm; weird.

TIA
regards
slacker

11-07-2005, 12:53 PM

it's almost definitley plugs.

You may find you've got NGK's in not the 'standard' champions. they are a different size but i forget what, 17mm I think

You need to look at the way you start the bike when it's cold and when it's been stood. I find that mine doesn't like being on half choke. All or nothing - bit like me really.

It's seems to be a fairly common problem with the carbed models. Mine's so bad I always carry spare plugs, but others never have a problem.

Good luck

11-07-2005, 01:08 PM

I had, and occasionally still do, this problem. I use NGK but run a slightly hotter plug than the owners manual suggests, due to the limited milage any rider can do on the island. So i would say that its probably a very good idea to check out plugs. Stick a new set in though as i have found that old ones cleaned up dont always improve the running. Also Mrs Soups comment on starting the bike up is a good point. For mine on a cold start i usually put choke full on, start the bike and let it hit max revs on the choke. Once its done that i shut the choke off and let it warm up on tick over. I found this method didnt foul the plugs as much

Hope this helps

L

spacemonkey · 11-07-2005, 03:11 PM

Also the plug caps are dodgy, so check the connections there too.

12-07-2005, 10:08 PM

Thanks for all your replies.

I'll check it out at the weekend.

regards

09-07-2005, 01:39 PM	#1
slacker Guest Posts: n/a	running on one cylinder Bike is a M750 (carburettor). It runs on one cylinder (the horizontal front one) until it's been running for about 15 minutes when the other suddenly chimes in. From cold, it again runs on one cylinder. The problem just suddenly appeared one morning on starting. Sounds like plugs or leads. Any other suggestions? (It seems to be heat related.) As a further problem, the plug hex seems to be a strange size; neither the box spanner that comes in the toolkit, nor a 16mm plug spanner will fit on them.The plug appears to be 16.5 or 17mm; weird. TIA regards slacker

11-07-2005, 03:11 PM	#4
spacemonkey I see dead people. Join Date: May 2003 Location: Carving a slice thru the braindead masses..(pun intended) Bike: M900 Posts: 1,464	Also the plug caps are dodgy, so check the connections there too. __________________ http://www.jasperfforde.com/swindon/7wonders.html

11-07-2005, 12:53 PM	#2
Mrs Soup Guest Posts: n/a	it's almost definitley plugs. You may find you've got NGK's in not the 'standard' champions. they are a different size but i forget what, 17mm I think You need to look at the way you start the bike when it's cold and when it's been stood. I find that mine doesn't like being on half choke. All or nothing - bit like me really. It's seems to be a fairly common problem with the carbed models. Mine's so bad I always carry spare plugs, but others never have a problem. Good luck

11-07-2005, 01:08 PM	#3
Plum Guest Posts: n/a	I had, and occasionally still do, this problem. I use NGK but run a slightly hotter plug than the owners manual suggests, due to the limited milage any rider can do on the island. So i would say that its probably a very good idea to check out plugs. Stick a new set in though as i have found that old ones cleaned up dont always improve the running. Also Mrs Soups comment on starting the bike up is a good point. For mine on a cold start i usually put choke full on, start the bike and let it hit max revs on the choke. Once its done that i shut the choke off and let it warm up on tick over. I found this method didnt foul the plugs as much Hope this helps L

12-07-2005, 10:08 PM	#5
slacker Guest Posts: n/a	Thanks for all your replies. I'll check it out at the weekend. regards