Have done 2500km's since rebuild of my 43f with 34L engine (replaced piston, crankshaft, oil pump, gears, rebuild cylinder head, new seals, bearings, gaskets, everything) and it is riding great. Goes well to 150km/h, haven't had to top up oil at all, did a 1500km ride through Germany last week but after replacing the old, rusted out and full with holes BSM exhaust it has been blowing a bit of black? smoke. It might have also done this before, but there was a hole in the exhaust where it mounts to the header, blowing on to my boot where i never noticed it. I think the bike is running a bit too rich, starts very easily but also smells quite nasty (not like oil, kind of sour smell).

Here a little video of the smoke:

https://youtu.be/MOxjVHhZJgg

What could this be? Too rich? Or could it be burning a bit of oil anyway? Did a small ride today (35 degrees celsius weather) and the bike did get very hot. Checked with bbq thermometer, went above 120 degrees celsius. After checking oil it was a bit below max, while it has been at max for the last 2 weeks. I check after every ride (at least 50km's), let bike idle for a bit, shut down, take off helmet, take out dipstick, put back in without screwing it in and then check.



Another problem is this sound that i think is coming from the valves:

https://youtu.be/sjs-FT83DuE

A ticking noise, most noticably at idle and low speeds, kind of dissapears in to the sound of the engine when revving. I think you can also hear it in the video of the exhaust. Have checked valves couple of times, no need to adjust. Thinking about taking off valve cover tomorrow to check the timing, maybe i have reassembled it and put it off a tooth? I think it's normal to have some valve sounds on these bikes, but it is quite loud and noticable when waiting in traffic. This is my only XT and have nothing else to compare it to except an bmw f650 which is totally different engine.

For the rest, bike runs very good, starts very easily with one kick, no sputtering or hesitation when accellerating to 150kms/h.

I think you’re correct to think it is rich. A cheap diagnostic test is to put in a new plug and let the bike idle for five minutes, cut the engine, and pull the plug and look at plug color. If it is dark it is running rich. Tan coffee colored is ideal. You can do the same test while riding the bike and holding the throttle locked open at different positions (1/4 throttle, half, 3/4).

http://www.dansmc.com/carb10.htm

As for the sound, it sounds good to me. Mine have always sounded a bit ticky like a sewing machine.

Yep agree its to rich, go for a run (nice & hot) then pull the clutch & kill the engine (known as a plug chop) then have a look at the plug colour.

Mezo.

Few things to check..........

Does the bike start very easily when engine is cold and not using any starter/ choke? If it does it is rich.

You say in your other post that the original cable style choke/ starter plunger has been replaced with a knob type? Does it have the correct type of plunger? When you remove it there should NOT be a pin on the end like this......

https://www.partspak.com/productcart/pc ... 220296.htm

The end of the plunger should be flat and I think has a rubber seal on the end if the bike has the original 43F carb?

Is the needle clipped on the 3rd clip from the top on the primary venturi? Is the pilot jet stock, should be about a 46. Is the pilot air screw wound out approx 2.5 turns from bottom?

The idle speed seems very high? Should be about 1300 rpm if you have tacho when engine is hot. Doesnt sound like any bad noises going on with engine although my lappy has poor sound. Have heard a lot worse than that! Lower your idle and lets hear it then.

Not sure if it has been replaced with knob style or if the carb is actually a 34L or other model carb, will pull out choke plunger today and check. Bike does indeed start very easily when cold, agree that idle is a bit high, will adjust a bit. Also floods very fast if I don't kick it the right way. Think i'm just gonna order a carb rebuild set, clean it out and check it next week to see, need the bike this week.

Tacho is broken so i have removed it, still searching for a new one but seem impossible to find for a normal price.

Have had multiple xt people listen to the bike, sounds seem okay for an old XT so i'll get the carb sorted and then see what happens. Air filter is cleaned, engine rebuild but didn't touch the carb at all since it was running okay before the rebuild but I guess I should've done that too.

Thanks for the reply's, will update when it's fixed.

Back on the ticking noise, some people say it's normal for an XT but still not sure. No sound when cold, starts after riding it a minute or so. Checked valves again, nothing there. Also took off clutch cover to check counterbalance nut and crank nut, both are tight (loctited them too when assembling) but there was a bit of play in the counterbalance gear. Not much, but still there. Since i've read many threads about the nuts coming loose, keys shearing etc. i was wondering if a small amount of play is normal or if i should replace the key (could this be worn after 5000km's?) Nuts all tight, just a tad bit of play in the gear of the counterbalance gear.

Cheers

Edit: just read some more, bit of play between balance shaft gear and crank gear seem normal, both nuts are tight and when assembled (5000km ago) the key was good. Seems i'm just chasing normal air cooled bike noises. Gonna go out and ride tomorrow, bike runs good with fresh oil, pulls strong without any strange sounds except the valves ticking a bit.

I´m quite new to old XT´s since I´ve had mine for only one year. But mine does also that sound and rides perfectly, so I guess it should be all fine in yours also.

Once someone told me that the valvenoise is due to the automatic decompression system, so...perfectly normal and typical for the bike!
I´m sure anyone else in this forum can help you out better than I, but still that´s my perception.

Cheers, Ibai

Hi, maybe your decomp wire is to tight. Its important to set it correctly by the book.

Kindly regards Brage