running lean

[prime]

Ive just bought some new stock jets ie. 45 pilot and 150 main with needle in middle and the bike is running on the lean side as im getting this metallic clattering sound when im riding which I think is pre ignition. I moved the needle up 1 to richen it up and thr clattering noise stops. Ive gone through the bike to check for air leaks and there aren't any at all which makes me think the crank seals are gone? The bike has a full dep exhaust by the way. Help

[knackeredMk1]

It really does depend on how bad the kicking is . The MD24 CRM engine is basically 24 years old and they never ran like today's bikes.

Have you checked the power valve setting? That can have an effect when not closing enough.

Moving the needle up one stop won't make much difference so I'm sceptical that this has stopped the clattering. Mk2s in particular make a noise that is very much like pinking that seems to depend on the bike and even the barrel but when it happens they seem to run fine otherwise with no problems.

I assume you have the Mk1/2 version of the DEP on the way as the AR/Mk3 seems to only fit the AR without modification (though this is variable ) (see FAQs. LT use Mk1/2 on Mk3s that they fit with DEPs). Running a DEP probably will not change your jetting needs.

It is really difficult to diagnose these kind of problems without standing next to the bike and playing around a bit.

[prime]

Yeah sorry I forgot to mention the bike is a mk3 and the dep exhaust on there is the old type that LT are selling. I checked the alignment marks and they are bang on and it moves freely and opens and closes as it should. I have put the bike back to standard settings as per the manual but if I try to put the airscrew back to the 1 1/4 the clattering/pinking gets worse and the plug looks very light likes its getting really hot and not the light tan colour it should be

[knackeredMk1]

What air screw settings do you have?

[prime]

I tried it this morning at 1 turn out

[knackeredMk1]

The suggestion is that you go up on the pilot jet then. Although changing the crank seals is not a big job and would be worth the effort as well.

[prime]

Thanks for the help will try these

[fallenmikethebike]

Welcome, what position was the clip in when you moved it?
Running a tad richer will aid longevity, though absolute peak power will suffer a smidge
Is the filter clean and oiled?
What plug are you running?
Mike

[prime]

Hi mike the needle was in 1 up before but is now back to the middle. Im running a br9egv plug and filter is a brand new twin air filter oiled.

[prime]

Correction the plug is a b8egv

[fallenmikethebike]

Correction the plug is a b8egv

That sounds better. As an exercise, you could lift of the magneto cover off, and liberally spray some WD type oil in there, covering the seals contact area to the shaft, this would temporarily seal the mating surfaces.
Check for any goo, leaking from around the seal area.
Also spray around the intake manifold, as a separate exercise, they are known to perish, and leak air.
Just do one test at a time, so as to monitor any effects.
Mike

[prime]

Thanks for that mike gives me something to do over the weekend

[prime]

Well ive had a good look around for air leaks and the intake rubber has no splits or cracking so I just took the carb out to install the slightly larger pilot jet I got from LT and im a bit confused. I took off the float bowl and one of the floats is wet with fuel and the other is bone dry?

[fishtail]

u prob tried this already? but I'd go thru give the carb a good clean, check float height etc - make sure the airfilter is clean an lightly oiled etc.

can also try richening the main jet a bit?

[prime]

Hi fishtail the carb was stripped and thoroughly cleaned a few weeks back and its also had a new air filter. I put a new pilot jet and main jet back in which are the standard 45 and 150 and mixture screw set as per the manual and the bike is running on the lean side ive also checked for are leaks are the manifold and there aren't any. Just a bit confused on when I drained the carb and took of the float bowl one side of the float was completely dry and the other is wet as normal. When my mate cleaned my carb a few weeks back he asked me what the float height should be and I told him its 16mm and he thinks at 16mm it wouldn't be letting enough fuel into the carb and running lean?. But he set it to 16mm anyway to the same as the manual, now im really confused