te05

I'm facing a few issues with my '06 model zma.

One, The revs hang on for sometime before they drop between the 3.5k to 4.5k rpm mark. The idle rpm is not constant and varies rapidly. At times in traffic signals, the varying idle rpms drop and the engine shuts down.
I tried in vain with the air-screw mixture. I feel the rpms not dropping might be due to a very lean mixture. Even the richest mixture tuned on the air-screw is not helping.
Just trying to understand if there are other leaks that I should be checking for or I'm altogether missing something big.
(My mech doesn't seem to understand what I tell him and is of no help)

Two, there is a jump in my chain and due to this proper slack adjustment becomes impossible. Parts of the chain are either too tight or too loose.
I want to understand whether new chain/sprocket is the only solution for this. I've done around 30K on the stock chain/sproket set and the sprocket teeth are not bad at all.

All suggestions and advices are most welcome.

Thanks in advance.

sunilg

Query approved.

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vineeth aredath

check the air screw once again and make sure that there is no air leak from your carb, cover the whole air screw part using your finger and feel for any pressure

even check carb insulator

I think 30K for sprocket is a long run dude IIRC my first sprocket set was changed around 18k

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pavanchirmade

Clean the carb thoroughly and install it properly ensuring no air leaks anywhere. The chain is tight and loose at some places is because the sprockets have worn out. You will come to know how they have worn out when you'll compare them with new ones.They wear so uniformly that one really cannot make out if they have worn out or not. The height of the teeth reduces as the tips wear off. I too couldn't understand how my bike's chain sprockets had worn until I compared them with new ones.

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te05

Thanks Vineeth and Pavan for the quick responses!

My air screw was jammed and it had to be removed at the lathe a couple of years ago. But after that there were no issues till recently. I would suspect any air leak from the air screw, however will definitely check upon that.

Oh! now I realize that actually this problem started after my mech opened and cleaned the carb. Maybe he hasn't installed it properly. I should get that checked.

From both the opinions above, I've decided its time to get a new chain and sprocket set.
Any suggestions apart from the stock ones? Reasons would be appreciated.

One more question, is there any proper method to check air leaks from the carb? and any particular area that I should be looking at, I mean the usual areas to suspect leakage.

born2slow

Yes you can try spraying an aerosol like wd40 (try when engine cold to be on the safer side) or any other flammable aerosol near the suspected area the engine rpm should increase. Its most likely leaking from the carb body or the carb outlet manifold to the engine since your carb was recently serviced.
Cheers

pavanchirmade

I switched to the P220Fi chain sprocket kit recently. It is tall. The chain is o ring. The tooth ratio is 14/37 so it is way taller than the ZMA's stock. So if you go for P220 chain sprocket then you'll experience a dip in acceleration but a considerable rise in top speed and a little rise in mileage.

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te05

Pavan, thanks dude, this seems to be interesting. Could you please clarify my questions.

1. Karizma runs on a 14/40T right?
2. Is the P220 Fi's front and rear sprockets(14/37T) a direct fit on the Karizma?
3. Will this drastically affect the way I get to 110-120?
4. I've installed Michellin Sirac 120/80 at the rear. Doesn't this already make my gearing a bit taller?
5. topping this, 37T on the rear, wont it run bit sluggish?

Sorry for asking so many questions together.
I know that there is already a dedicated UT running for sprockets. I just visited to find if I could get anything regarding this, but didn't find specific info. So asking.

Alternatively, If I want to use the stock Karizma sprocket set with the P220 Fi's Chain, will that be a direct fit.
You said o-rings and that hit upon me so that I could remove the chain covers.

Thanks so much!

anmol_1990

Get your carburetor cleaned and adjusted thoroughly.

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pavanchirmade

I really don't know if the sprockets are a direct fit but if the chain pitch matches then you can use the 220 chain on zma sprockets. Sourcing the chain may be an issue as it always comes in a set, ZMA stock sprockets are 13/42. A 14/37 will be too sluggish as compared to stock and yes you can run a o ring chain naked. eliminates the noise of the chain cover

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