Honda - Africa Twin XRV 750 motorbike - Lean? | Technical matters | Back Room Forum

Sun 16 Dec 2007 16:44

Africa Twin XRV 750 motorbike - Lean? - mss1tw

Not a car question but close enough I hope!

This is a 4 stroke V twin engine fed through 2x36 mil Keihin CV carbs.

I recently replaced the end can of the exhaust (Think 'back box') and want to know how to tell if it's running lean.

I will be checking the spark plug colour and also doing some high rpm shut downs to check the spark plug colour at various points in the rev range.

But for now, are there signs if an engine is running dangerously lean? (Besides dropping a valve or two?!)

Temperature seems to have stayed the same even at motorway speeds.
I think there has been the odd backfire on the overrun.
Tickover rpm has not changed.

Edited by mss1tw on 16/12/2007 at 16:45

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Sun 16 Dec 2007 19:12

Africa Twin XRV 750 motorbike - Lean? - jag

most definitely, to the left for lefthand corners and to the right for righthanders.
seriously, a lean mixture will melt your pistons as it did in my 1968 bsa barracuda. best get it checked but someone with a lot more knowledge will come along and point you in the right direction. jag.

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Sun 16 Dec 2007 19:14

Africa Twin XRV 750 motorbike - Lean? - mss1tw

most definitely to the left for lefthand corners and to the right for righthanders.

Heh :-D

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Sun 16 Dec 2007 19:56

Africa Twin XRV 750 motorbike - Lean? - cheddar

If the new end can(s) is(are) more free flowing the it will probably run a little lean, my ZRX1100 has a full Akrapovic titanium system (as did my ZX7R before it) it is set up to run without the baffle and runs a little rich with it in so conversely if it were to be set up with the baffle it would run lean without it - though the difference is minimal.

Also CV carbs are fairly forgiving in this respect and the XRV is not in a very high state of tune, and if you were to have a problem it would only be if it was very lean at say m/way cruise speeds so was constantly lean for a long time.

All in all I would say dont worry though for piece of mind a dyno run would help, there is a place called MHP in Byfleet, dont have the contact details i'm afraid.

Edited by Pugugly {P} on 16/12/2007 at 20:15

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Mon 17 Dec 2007 00:22

Africa Twin XRV 750 motorbike - Lean? - mss1tw

Thanks cheddar. I know of MHP, they are on the estate near Byfleet train station I believe?

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