MHR backfiring through carbs

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Trevor
Cucciolo - the Lil Pup
Posts: 10
Joined: Mon Jan 22, 2007 10:52 am
Location: Durban, South Africa

MHR backfiring through carbs

Post by Trevor »

Hi All,
I was in the process of taking my MHR to a local classic bike meeting and whilst riding there a I passed a car missed a gear and revved it a bit nothing serious and the bike starting missing and back firing through the carbs. I turned around and headed for home and when I got home I checked the plugs, the compression (1050kpa on both cylinders), the ignition pick ups were tight, swopped the plug caps over, checked the carbs where clean. Everything seems to be ok but the bike does not like to run below 3000rpm and spits flames out the carbs every now and then. The bike was running perfectly yesterday when I rode it. It has a Rita ignition, NGK BHS 7 plugs and had a carb overhaul 6 months ago when rebuilt.
Any ideas to solve.
thanks Trevor :lol:
Trevor
Durban, South Africa
1982 MHR,2007 BMW GS1200Adv, 2000 Yamaha WR 250

wdietz186
Cagiva Alazzura
Posts: 703
Joined: Sun Sep 10, 2006 5:40 pm

Post by wdietz186 »

Trevor, I had a similar problem on my 77 900SS. I assume the Rita you have is mounted on the vertical cylinder. The ignition rotor is not keyed to the shaft it bolts to, so it is possible the rotor has come loose on the shaft and the timing is retarded. Or the cam nut has loosened and has altered the timing. Both are pretty easy to check and rectify. Hope this helps,Bill

Trevor
Cucciolo - the Lil Pup
Posts: 10
Joined: Mon Jan 22, 2007 10:52 am
Location: Durban, South Africa

Post by Trevor »

Thanks Bill, will check it out. Unfortunately I am working 600km from home so it will only be in a couple of weeks before I can get to it again.
regards
Trevor
Trevor
Durban, South Africa
1982 MHR,2007 BMW GS1200Adv, 2000 Yamaha WR 250

Trevor
Cucciolo - the Lil Pup
Posts: 10
Joined: Mon Jan 22, 2007 10:52 am
Location: Durban, South Africa

MHR backfiring through carbs

Post by Trevor »

Just to say that it was exactly as Bill suggested, the timing rotor has shifted, I stripped it out set the timing carefully again and it is now running better than ever before.
Thanks Bill
regards
Trevor
Durban, South Africa
1982 MHR,2007 BMW GS1200Adv, 2000 Yamaha WR 250

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