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had my innova carb cleaned because it had stood for 18 months or more, bike starts and runs fine, no choke required.
only problem i have is that when decelerating i get a loud popping noise/ backfire.
i have checked the spark plug and it was very dark, almost black but not oily. the plug is a ngk cpr6ea-9.
i put a new plug in but still have the same problem. the air filter was changed about 6 months ago.
i have read that my fuel air mixture is probably too rich. is this an easy thing to cure or do i need to take it to a mechanic.
i can do basic maintenance like oil changes,air filter change, brake pads etc, but never had anything to do with carburettors.
don't want to make things worse.
any advice appreciated.

I have the same problem with my '07 carb Innova, hopefully someone has a fix for this .

The Innova has a PAIR valve, which could be the cause as it adds Air to the combustion on deceleration for emissions, in the Haynes Manual it explains how to test it, i would start looking for air leaks around the chrome pipe were it enters the head as these pipes do rot and the gasket can fail.

Check the exhaust sealing washer that seals between the exhaust pipe and cylinder head.
It's cheap to buy. Old one may need prising out of head with a screwdriver or picking tool if flattened.
Careful with exhaust head nuts, 12mm spanner if Honda or 13mm if replacement.

Diddly

thanks for the replies onittion3 and diddly,
interesting that you think it may be something other than a carb problem. i just assumed a carb problem. i will take a look at the exhaust gasket.
hopefully a cheap and easy fix.
forgot to mention in previous posts, is 70 miles per tank full about average or is this low because of the backfire problem?

thanks
chris

Can't remember per tank, but at least 120mpg.

The problem I found with an Innova is holding your nerve.

It's that point when you look down at the fuel gauge and see that little last bar flashing away; and you think "How long has that been flashing"?

It's usually 3 seconds later when the motor cuts out.

I rarely got 100 miles out of a tankful on my carbed version and ALWAYS kept half a litre in a bottle under the seat. (At least I did after the first 3 times I ran out).

I ended up refuelling at home daily from a 20 litre jerry can daily - the problem was I had a 33 mile journey to work - each way! ATEOD a CG125 made much more sense with a near 300 mile tank range.

hi guys,

i have changed the exhaust sealing washer but unfortunately this did not cure the problem. i have read as much as i can find on the net and watched a load of videos and i think the problem is the carburettor.
the plug is almost black, very poor mpg and still getting backfire / load popping noise on deceleration.
are there any screws on the carb i can try to adjust? or does the carb have to come off to see if the problem is internal?

thanks
chris

got the innova running better now, took it for a long run, adjusted the idle screw down as low as possible without cutting out then adjusted the brass screw to the left of the idle screw until i got a high idle, then went back to the idle screw and adjusted it until i got a nice sounding tick over.
went back out on the road and gave the bike a good run, closed the throttle and braked to slow down and had no more backfire/popping.
hopefully it is now cured.

On carbs you have an idle screw and an air screw, you set the idle to a fast tick over then start adjusting the air screw, screw in makes it richer and out makes it leaner. in the middle of it running rich and lean is the sweet spot, having got that, very slightly screw out until the engine speed very slightly slows. Check the throttle pick up and set back the tick over to slow idle.
You should always make adjustments when spark plug, air filter and tappets are set correct.
See a Haynes manual for spark plug colour pictures. If the air screw has been fully screwed in in the past it may be damaged as it is a tapered rod.
Always worth checking the main needle location, held by a small circlip, this can get displaced or wrongly set, usually when the throttle slide/cable is fitted.