By the sounds of it the TT600 has a handlebar mounted decompression lever? The TT model must have been a Europe version of the XT or something like that, none of my OEM parts sources lists a TT600. I found a picture of a TT head and it has the same decomp. lever and bracket as mine so the handlebar perch and cable from a TT should be a direct bolt on.

I did rotate the kick start lever by hand slowly till it hit tdc and just barely went passed it, my brother gave it a good kick and on the second try it fired up and ran smooth, no squirting gas down the sparkplug hole first. It idled smooth with no miss or stumble for about a minute then slowly started to do its normal uneven firing.

We went for a 15mile ride and it ran fine with just the stumbling at 2600 to 3200rpm range, above that it didn't miss. Once warmed up, at idle it sounds like it fires only every other compression stroke instead of each one. Doesn't die or seem to even want to die but just has that slow and steady pattern of firing. Motor is dead quite as far as ticks or knocking.
I did notice that my headlight dims each time the turn signal blinks( engine at or just above idle rpm), I think it's normal for that age of electronics. I'm going to switch all bulbs out with LED's if possible.

I'm hoping to get a spare cdi and coil to swap out as a possible cure to the missing(unless this is the normal way these engines run, as I said, this line of bikes is new to me). I doubt it though.
Thanks for all the help and suggestions , it saves lots of hours of guessing and parts changing(when they are not needed).

An update, after a week or so, I had been running the bike, it started good in about 2 kicks on full choke, it always ran perfect for about 1 minute, didn't matter if choke was on or off(high idling). then it would start to do its stumbling, never acting like it wanted to die but just nothing will stop the miss. Going down the road, under acceleration, it ran perfect, steady throttle=miss. Filled up with premium(it had 87octane in it), ran it 2 miles home, missed the same. Next morning started up first kick, ran for 5seconds, quit and won't start, even dumped some gas down the sparkplug hole, it just backfired at messed up my ankle again and actually broke a buckle on my motocross boot plus broke the kickstarter stop bolts inside the motor.

This is the last straw for me and this setup. If I can't make it electric start( I can't find "E" model parts here in the US, only kickstart years, except brand new$$$$, I wonder why?? Since I will not ever attempt to kick it again, I won't be able to even try to fix it unless there is some mechanical way to turn it over soooo

I'm ripping it apart to
1) put in a Honda motor I have that Will not kill me
2)recoup my money by ebaying as much of the parts and say good riddens.

The sad part is the bike is in mint shape, never tipped over, never run offroad, adult owned, it looks like it is maybe a couple months old!! It just does no good if it can break bones at any moment or be impossible to keep running. Ya for another $500-600 I can buy every electrical component and "hope" it works, nobody can say what is failing, so all that can be done is to buy, buy, buy and hope! I bought this bike to save money on gas,

jjrider,
No, the decomp system is automatic on the TTR600, much as you have been dealing with I guess; a cam system that lifts the valve as the engine is turned over.

Anyway, sorry to read about your ongoing issues with your own kicker.
I got into the habit of kicking over the TTR600 engine while standing next to the bike - on the RHS and kicking with the right leg. This was partly because of the height of saddle but also because when it did backfire I did very little damage to my foot/ankle because I used the forward (toe) part of my boot rather than the instep. When it did backfire, my foot was more flexible and would just fly off the kicker instead of taking a "rebound" via the length of my leg.
It's also an easier kicking stance when you are fiddling with the carb at the same time (I had float valve problems).

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Dave

My XT600 has never injured me. Actually I can kickstart it with slippers! It probably only backfired once, when I had a broken decompression cable, and had to start the bike without it for a few days in a row... I don't really know why but it's really easy kicking.

I had a Suzuki DR600 before Yamaha, and the Suzuki was a pain in the ass to kick! It had both manual (with hand-lever) and automatic (with kickstart lever) decompression systems. I was fiddling with both cable tensions, and nothing worked. I got some backfires, but they only threw my leg in the air so my boot sole scraped the top of the tank. But one time it backfired so bad it really injured my ankle, and I almost passed out from pain. I ended up selling the bike and getting an XT600 with kick and electric start (back then I did not know how easy XT600 starts... At least the ones I looked at and took for a spin before buying).

Maybe it's because of it's age (different model I mean). Your Yamaha is '88, my Suzuki was '86 or '87 I can't remember now. And my Yamaha is '93 with '97 engine. Maybe they improved something over time?

I'd say don't do quick decisions, heal up, let it sit a while, and if it doesn't kick over EASILY with ignition off, then don't try it with ignition on... Or it will hurt you again. I was limping for a few months when I injured myself.

Don't know what advice to give right now... Just heal and think. It will come to you.

P.S. maybe your ignition timing is too early?

Zergman, I had a '91 Suzuki DS650 and it kicked easier than this one, plus never backfired on me, though I bought it new and owned it for 3 years so it wasn't to that "aged" point where things act up. I regret selling it to this day!!
In 1990 quite a bit changed on the Xt's bikes(now looking how to add electric). The carbs are different to a point, then totally change in '95-'96ish, after 1990, non here the states as far as can tell had kick, that is also the cutoff year for used parts on ebay, very few parts after '89, I think that says that once the electric comes out, most people keep them going rather than scrapping them.
I'm quite sure it is firing early, and that's the backfire. I spun the motor over by electric drill yesterday on the stator nut and it was sparking like crazy, so spark+gas+air = running, unless timing is bad. No adjustment for timing though and $125-$200 for a used cdi that "may" work, or another $125+ for the used pulse pickup and stator, which is the other likely culprit.

I'm trying to picture how Walkabout started his, by standing on the right, I'd have to kick with my left, and then a backfire would likely put my knee into my chin. Right now to kick mine, I have to push down on that kick lever like I'm tring to drive it 2 feet into the ground, it's that speed that it takes to fire it up, slower results in these backfires usually.

I was hoping to do some traveling up north this summer, possibly into Canada, but I need a bike that I can rely on, my '83 Honda isn't a long distance runner anymore, though reliable, just getting worn out.

TTR600s are/were rarer than the XT in the UK and I don't think they would be imported to the States, but they look like this, which shows the height of the saddle:-
ttr600 in Motorcycles & Scooters | eBay
Hence, with short legs, my starting technique was to stand next to the bike and kick it over using the right leg - kind of reaching across with that leg & with the body weight on the left leg and close to the bike for overall balance.

Here's another earlier thread about kicking over the TTR, but it applies to the XT as well, IMO (but your use of the throttle on start up might vary):-
http://www.horizonsunlimited.com/hub...00-r-how-32814

ps The search in here works quite well nowadays (it didn't always). You can see more threads about kicking over your bike in here:-
Search | Horizons Unlimited

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Dave

Before this last "episode" I attempted the procedure listed above for turning it over 2 or 3 times then going till the decompression lever clicked, then let the kick lever up to top and then gave it the almighty startup kick. It backfired every single time I did that, so I quit it. Up till this it didn't backfire at all since the last bad one and it was starting reliable 1 or 2 kicks, just had that constant stumble/miss. Also the last time it did this I had just filled up with super unleade 91octane, then by draining and switching to 87 from another station, it started up again. I was running on that gas all the while till I filled up again with 91super, but at the same station that I got the 87 from.It wouldn't start after that. It couldn't possibly be that it HATES 91 octane (no ethanol), and will only run on 87(with ethanol)???? I do know the bike is running rich, black sooty plug, but I put in an iradium plug the morning before.
Is there any chance the regulator could cause the miss, due to it not missing for the first minute, then the miss starts. Also when I rode to work at 40F, it ran better(less missing/stumbling) than when the temp was warmer later in the day. Something was staying cooler and allowing it to run better.
The rich running condition wouldn't cause that much missing could it? Smaller pilot? lower the needle in the primary carb? Out of sinc carbs? It ran great under acceleration!

I'm pretty clueless with the "black box" technology of CDIs etc, but the heat issue does point that way, as per earlier posts in here - the usual advice is to obtain a replacement part and do a one-for-one swop, but I guess these things for your year are quite rare nowadays.
Buying one is the obvious way, but swopping out, temporarily, with a buddies bike is an alternative.
The prices you mentioned earlier are in the same ball park as those asked in the UK, if that is of any consolation.

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Dave