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**Noor** · 10-30-2011, 03:38 PM

Query approved

**atulgupta230489** · 10-31-2011, 01:44 PM

No replies yet! come on fellow xhbpians, just pour in something

**The Mountain** · 10-31-2011, 02:41 PM

Here's a link that does a decent job of explaining how CDI ignition works:
Dan's Motorcycle "Electronic Ignition"

Adjusting it would presumably be as simple as removing the timing cover (usually the cover over the crank end on the right side of the bike) and adjusting the trigger ring. You'd need a timing light to make sure the spark is advancing properly as the engine RPMs rise. However, as noted on that webpage, CDI ignition normally doesn't need adjustment.

What prompted you to ask about it? That might be a better place to start. Explain what's going on with your bike, assuming there is something and you're not just curious.

**atulgupta230489** · 10-31-2011, 05:31 PM

Thanks buddy

well I recently replaced my Apache 150's bore and head to that of rtr..... And ever since then I've been facing some timing issues.

initially i used to get some tappet noise from the head and the engine used to go off at low RPMs so just got it opened and got the tappet clearance adjusted.. But then it was too tight i guess cos I used to get some noise while accelerating and rpm used to fluctuate or dip a few times...

So I want to know how it could be adjusted and what exactly is meant by advanced and retarded timing and which would suit my bike Better...

**atulgupta230489** · 10-31-2011, 05:33 PM

And am curious to understand the Mechanism as well

**sambha_yamaha** · 10-31-2011, 06:13 PM

ignition timing

Originally posted by atulgupta230489 View Post

And am curious to understand the Mechanism as well

ignition timing mens exact timing at the tip of spark.
as per engines requirment its changed by cdi unit.
when u axcelarate more airfuel mixture go to engine thru carburator ,to burn that mixture need more spark ,that time cdi advanced ignition timing .
u made some modification on ur engine like change bore and cyl head of rtr.that means increase engine cc. it needs more air fuel miture to ur engine.so replase jet and tune ur engine.

**atulgupta230489** · 10-31-2011, 08:32 PM

Thanks bro. An panning to go for BS 29 carb. Well that be fine?

**itssaurabh.negi** · 10-31-2011, 09:48 PM

Originally posted by atulgupta230489 View Post

initially i used to get some tappet noise from the head and the engine used to go off at low RPMs

hi atul, sorry to bother u but me getting the same problem from past few days. IDLE RPM is set to 1.5K when HOT,Airfilter also checked.
IDLE RPM decreases slowly by itself and engine stalls after 10-15 sec even on main stand.like there is loss of fuel or something choking fuel supply.it doesnt matter wheter engine is cold or hot(happens even after 20-30 km's of riding) CHOKE is also off.
please let me know what was the reason in ur case.

**atulgupta230489** · 11-01-2011, 01:19 AM

Bro in my case the engine never stalls but the rpm just fluctuates for a moment.. Out happened after paying with the timings.

I think there might be some problem with your inlet valve

**The Mountain** · 11-01-2011, 12:22 PM

I would recommend checking the current ignition timing first before you start messing with it. The way you describe it, it sounds like you're experiencing a loss of vacuum, rather than an ignition problem. I'd bet that one of the gaskets on the intake manifold (the pipe between the carburetor and the engine) is cracked/dried out. That, or the carb itself has a leak somewhere. As a result, fuel isn't being pulled through the idle jet strongly enough, and the engine is gradually being starved.

You state that you've replaced the head, which means you've had to disconnect the carb/intake, so do check for leaks. Also, the RTR head no doubt flows better than the old Apache head, so your current carb may not be up to the task of feeding the new head/valves. Try enriching the idle circuit on the carb a bit and see if that helps.

**atulgupta230489** · 11-01-2011, 02:38 PM

I have tried bigger jets bro but the thing is that even with rtr main jet the mixture seems to be going rich... With 105 Martin jet, my rpm doesn't cross the 7000 mark

**kb100** · 11-01-2011, 07:20 PM

Originally posted by atulgupta230489 View Post

I have tried bigger jets bro but the thing is that even with rtr main jet the mixture seems to be going rich... With 105 Martin jet, my rpm doesn't cross the 7000 mark

i thought rtr had a larger main jet

**The Mountain** · 11-02-2011, 03:07 PM

Originally posted by atulgupta230489 View Post

I have tried bigger jets bro but the thing is that even with rtr main jet the mixture seems to be going rich... With 105 Martin jet, my rpm doesn't cross the 7000 mark

What about the idle jet? The main doesn't sound like a problem, just the idle. Also, how many turns out are you on both jets? My experience has been that the best operation is to close the jets until the engine starts to stumble, then back them out a half-turn. That might cure the richness problem on your main. In any case, check for leaks, not just gaskets but loose/cracked vacuum lines.

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ignition timing mechanism

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