1984 XT 600 high rpm "miss"
 

Hi All,

My 84 Xt 600 misses around 5-6000 RPM. The bike only has 5900 miles and is clean. I purchased a new CDI from Wayne Gum on Ebay. Swapped ignition coil and carb from another 84 Xt 600. Purchased new plug, ignition key switch and on/off switch and battery. Bypassed kick stand switch. Should I swap the stator assembly now?... help!

Thanks, Baron

Assuming your valve clearances are all set correctly.

I had a similar problem recently - after troubleshooting with electrics, spark, etc. Finally found it was my fuel pump. Not sure if your model also has vacuum pump, but my vacuum hose was kinked, causing 'missing' at higher revs.

It was accompanied by loss of power as well though - so perhaps not exactly your problem?

Easy enough to test your stator and charging system before you make drastic (& costly) changes!!

I had a similar problem with the SZR660 (an xtz660 in drag) after i kinked the vac hose under the tank. The problem manifests itself as a misfire which goes away at lower revs. It's caused by fuel starvation, casued by the fuel pump not working properly.

A split or poorly attached vac hose would manifest similar symptoms and would probably get progressively worse.

XT 600 miss
 

Thanks for the suggestions, but mine is a 34L so, no vacuum hoses and fuel pump. I will check the OHMs on my stator assembly before swapping. I wonder if metal flakes/debris could be on the rotor magnets, causing an intermitant spark?
All ideas/thoughts welcome. I want to enjoy this bike while summer days are still here!

It might still be worth checking for fuel starvation at high rpm; if it's a 34L then it's few years old and there could be all sorts of goop floating about in the fuel system. One wonders about float heights and so on too

What are you doing to that pooor bike, riding at thoose rpms =)

You could check the carb'

Check volt feed to low tension side of coil... make sure theres a good 12volts getting to it.

Tried a new plug - always worth doing & dead cheap :thumbup1:

other checks
 

The volts going to the coil are not 12 V - this is CDI ignition, independent of the battery.

The rest of the above suggetions I´d certainly do, but your airfilter could also be a bit clogged. Just remove and try without. Or clean thoroughly.

I would not think of an ignition problem; that would manifest itself at lower revs (second part of advance kicks in before).

So that leaves air intake, carb, exhaust (not clogged?) or spark plug.

Success!

Xt 600 miss
 

Thanks.... all great suggestions, but all checked out good. I checked the ohms on the stator assembly and pick up coil. Both read WAY below the specifications in my manual. So....., I need to replace the stator assembly. Where do I find one. The dealer wants about $800 for one! The bike isn't worth that much!.... Help!