CDI or what else

[55W1985]

On 34L standart is 15-39

[itchywheels]

I had a problem like that for a year or so because I couldn't find it !! I also changed my cdi with a friends and it didn't cure It. It turned out to be a loose connection from my wiring loom to the cdi. It would only miss fire at certain revs due to the vibration.

[nop]

Out of the two I would lean towards carb, in my experiance a CDI will work. Or it won't at all.

[xtjoe]

getting back to this after reading Mcgoos and various others, stripped the carb again now everything that had a screw in was taken apart. Can i get a picture of a xt carb with the names next to individual parts, this is a needle, this is a jet etc. stealing pics from mcgoo



filter taken out, suck blown clean, the hexagon thingy (jet) behind it in picture, unscrewed cleaned put back



on the choke side i opened another small cover(didnt take pics at the time) with a diaphram inside, all in tack closed again, for not a better word i oppened the second carb, seems clean inside, had to helicoil the rear screw as it stripped, when turning the throttle needle thingy is moving up and down as in the main carb. All looks ok. Actionman send a link years back with detail on mikuni carbs "Ian Williams Tuning" which i scratched out again but as it does not have pics showing throttle valve/jetneedle etc i scratching in the dark and words carbjetting is determined by throttle position. As the problem is on three quater throttle and up according to "Ian W Tune" its the main jet, which one's that and what do i do withit, is it the hexagon thingy. Unfortunatly the mixed reponses received here makes it difficult to decide. Put the carb back together, 6 kicks later she's idling, again in lower gears we can rev past 4 and higher up no go.

Managed to f--ck it up a bit in that i replaced the 2 throttle cables and as per normal could not get them smooth again, throttle not returning to idle position unless you help it by hand, loosen the screws at the carb but only marginal better, in this process and refitting carb i must have opened a positive wire and within a few kays when testing the bike around the block saw smoke coming out, just about whole wire loom melted together, faacck. Just what i love the most about this bike, simplicity, with a friend we had it sorted about 4 hrs later with a couple of milkshakes, new wires fitted, i just need to fit a cover tube to protect the whole bunch

I'm planning to strip neighbours same bike this winter and fit his carb to compare ride it and maybe then strip the 2 side by side to see diffs. What do you get in a carb kit?
Any carb assistance appreciated

[Eric66]

Joe look in the hot links section under manuals,diagrams etc, there is a carb diagram there. The hexagon thing is the main jet, the one in front is the needle and seat for the float, directly behind the main jet down a hole you will see a screw, this is the pilot jet,undo it and make sure it is clean, mine was blocked and ran lean and popped real bad on deceleration.
Regards Eric

[Mezo]

The small cover you took off with the diaphragm is to stop the bike popping on decel.

Mezo.

[xtjoe]

As a friends tenere went down with a 2nd gear broken we took off his carb and fitted to mine and went for a test ride only to find out no difference.( I know his Tenere performs well as its the one that leaves mine behind) Came back took his CDI and fitted that and again it made no difference. It seemed to sound a bit different but mayb that was all in the head. After the carb change it it does the normal clean pull 1st to 3rd revs easily going past 4000 but in 4 and 5 it runs out here by 4 ish. Bottom line was performance more or less the same after all the changes. I'm sure its something small but where what

Someone suggested timing 180 out, any ideas

[ActionManMelb]

The solution must be close.....
Spark or fuel, that is the question?

Make sure you have a good high volume flow of fuel to the carb. Put a drain hose on the float bowl drain nipple. Place the hose in a litre measuring container.
Open the drain plug screw (3 turns) and time the flow with a stop watch. You should get a minimum rate of about 500ml/min.
Try a run without the aircleaner, you may have an unseen restriction.

Spark. You cant time the engine 180 out as it uses a waste spark and fires the plug every revolution.
Is the coil up to strength? You might want to swap out the ignition coil to check it.
More difficult to check are the timing pickup coils. One pickup is for starting and idle and the other is for full advance. If the second pickup is not functioning then you would never get full advance (and full power). A timing strobe light and an oscilliscope are best used for checking this.

[Eric66]

Also fuel tap may be clogged up, they have a straw like filter. Pull tap out and check.
Regards Eric

[ActionManMelb]

Also fuel tap may be clogged up, they have a straw like filter. Pull tap out and check.
Regards Eric

The fuel flow test I described above covers everything from the tank vent, fuel tap through to the internal filter and needle and seat. Simple, non-invasive test.