UK Monster Owners Club Forum .: Technical :. Engines, Clutch, Gears » M900 Misfire

Reply
 
Thread Tools Display Modes
Old 02-05-2022, 01:10 PM   #1
Jam911
Registered User
 
Join Date: Jun 2021
Location: Stratford Upon Avon
Bike: Multiple Monsters
Posts: 232
M900 Misfire

I fired up my M900 this morning...took a bit to start but fired up ok...

..after a few minutes, when warmed up a bit, it misfires / backfires when revved.

...now it had not been run for 8 months and during storage I was advised to coat the inside of the tank with a mixture of petrol and two stroke oil...

...I drained the tank and then filled up with super unleaded before starting...

....would the residual two stroke oil be causing the missfire?

Thanks
Jam911 is offline   Reply With Quote
Old 02-05-2022, 03:48 PM   #2
Flip
Registered User
 
Flip's Avatar
 
Join Date: Mar 2010
Location: Beachtown
Bike: M900
Posts: 2,164
It is possible the oil may be giving you a bit of trouble but I would of thought it would blow through relatively quickly as it's so soluble in petrol -did you not flush the tank out before filling it with fresh?

More likely in my opinion though is residue from the old fuel which dried out in the carbs over the time the bike was laid up has gummed up the jets.

These old carburetted bikes were never a fan of long periods of inactivity but that is magnified further as modern fuel has got worse over the years.
__________________
You're perfect, yes, it's true- But without me you're only you!
Flip is offline   Reply With Quote
Old 02-05-2022, 05:23 PM   #3
Jam911
Registered User
 
Join Date: Jun 2021
Location: Stratford Upon Avon
Bike: Multiple Monsters
Posts: 232
No in my haste to get it running I forgot to flush the tank...
Jam911 is offline   Reply With Quote
Old 02-05-2022, 05:24 PM   #4
Jam911
Registered User
 
Join Date: Jun 2021
Location: Stratford Upon Avon
Bike: Multiple Monsters
Posts: 232
It ticks over perfect but when revved misses and backfires...I hope a quick run will sort it out
Jam911 is offline   Reply With Quote
Old 02-05-2022, 06:12 PM   #5
Mr Gazza
Lord of the Rings
 
Mr Gazza's Avatar
 
Join Date: May 2013
Location: Norwich
Bike: M900sie
Posts: 5,083
A little two-stroke in the petrol shouldn't do much harm. If it is that you should be able to smell it in the exhaust. Sloshing the tank about and mixing it up might reduce the effect, but the first thing I would check would be the spark plugs. Changing them is never a bad thing. I give mine 6000 miles and put new ones in. I sometimes notice them going off at slow speed running towards 6000 miles.
You might see some evidence of oil on the old ones or maybe even a wet plug?
An Italian tune up might be the simple answer at the end of the day.
__________________
Mr Gazza is offline   Reply With Quote
Old 02-05-2022, 08:04 PM   #6
Jam911
Registered User
 
Join Date: Jun 2021
Location: Stratford Upon Avon
Bike: Multiple Monsters
Posts: 232
Thanks. The plugs have only done a few hundred miles so I would expect them to be ok.

I will try the Italian tune up ...
Jam911 is offline   Reply With Quote
Old 03-05-2022, 01:12 AM   #7
Darren69
Transmaniacon MOC
 
Darren69's Avatar
 
Join Date: Sep 2013
Location: Sutton In Ashfield
Bike: Multiple Monsters
Posts: 5,696
It's probably gummed up carbs. I run injector/fuel line cleaner periodically in my fuel. It may help or you may have to clean the jets manually if it doesn't clear itself.
__________________
Roast Beef Monster!

Termignoni and Bucci - Italian for pipe and slippers!
Darren69 is offline   Reply With Quote
Old 07-05-2022, 10:17 AM   #8
Jam911
Registered User
 
Join Date: Jun 2021
Location: Stratford Upon Avon
Bike: Multiple Monsters
Posts: 232
So quick Italian tune up and normal service resumed.
Great
Jam911 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT. The time now is 12:11 AM.

vBulletin Skins by vBmode.com. Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.