Newby bit off too much?

[timorang]

Just a comment re finding "TDC". Years ago I had two Honda 500 singles (xl and xr) and once the kick start technique was sorted there were no problems, although if I recall correctly it was slightly different cold start vs hot start. With a cold start I would 'push' the kick start through its full rotation a couple of times, but not to start it. No throttle and perhaps a little choke as described by someone previously. TDC was at the point of most resistance. With the compression firming up on TDC I would bring the kick start back up to the top and then down a little to rest on TDC. Then it would be the time to give it the big push down through the complete range of the kick start. Perhaps with a small tweek of the throttle to catch the fire. With hot starting I found it best to pick up TDC straight away without the couple of 'priming' kicks. I have ridden quite a few kick start trailies since and generally this technique has worked with them all.

[warewolf]

A few comments to consider from someone who's BTDT recently.

Kick-starting big 4T singles when cold is about priming the cylinder/carb then trying to kick it into life. Only the latter step requires effort, and can be wasted effort if you didn't do the former. On the KTM 640 I hold the decomp lever in, kick effortlessly for 5-6 kicks to prime, then release decomp, find TDC, ease past, choke & ignition on, one big kick...voila!

It is the speed of the kick at the bottom of the stroke that is important. Slamming the top of the kick doesn't do anything useful, particularly if you are light like me (67kg) in which case you'll bounce off it and have a resultant slow kick and/or not be able to kick it all the way through. Start the kick slow and careful, then accelerate it down once it is moving, slamming into the bottom of the stroke.

Kick it all the way through, as most modern kickstarts disconnect at the top and bottom of the stroke, the latter to avoid kick-back. You'll only get kick-back if you didn't get it all the way down. Kick it down, hold it down, no kick-back.

When hot it often likes just a touch of throttle to help it keep running after firing. We're only talking about one mm on the throttle grip. Open it, hold it steady. Don't wildly pump the throttle, 4Ts don't like that. Just crack it open a smidge and hold it. Don't add choke.

When flooded, you'll need to clear the carb. I'm no expert on this step, but I'm told hold the throttle wide open, pull the decomp, and give it 5-10 kicks to clear it out. Then follow normal hot-start procedure.

The DR-Z250 is auto-decomp only. Priming means kicking it over without trying to start it, a bit harder without the manual decomp. It's much harder to find TDC and to clear when flooded...I cheat & use the button.

btw Flooding means too much fuel (rich), not so full of fuel you'll feel hydraulic lock on compression. That's what breaks conrods & crankcases after water ingestion when the engine is running.

Hope this helps.

[timorang]

Everything that warewolf says which is right is correct! I think we are in effect saying exactly the same things. If this technique does not work then the bike may need a thorough tune (carb, timing, plug, cables etc). Good luck.

[Ixion]

Thing to bear in mind when kickstarting or bumpstarting a big single, is that very few people would be strong enough to kick the engine through TDC fast enough to fire it.

So what you have to do is get the engine turning at a reasonable speed BEFORE it hits compression, and then let the weight of the flywheels bump the engine over TDC.

That's why starting the lick on the right part of the cycle is important. Warewolf and others got the cycle right. Turn over a few times with decompressor to get some fuel in the cylinder. Then find compression ease over it , down to the bottom of the stroke, back up, now you've got a whole cycle to get the engine spinning before it hits compression, and the traditional "long swinging kick" with all your weight and strength . Use you body weight , not your leg muscles. Basically jump on the kickstarter not kick it. And make sure you go all the way through then if it kicks you won't break your leg.

Oh, and if by chance you have manual ignition timing RETARD THE IGNITION.

[warewolf]

Everything that warewolf says which is right is correct! I think we are in effect saying exactly the same things. If this technique does not work then the bike may need a thorough tune (carb, timing, plug, cables etc). Good luck.

yep, you posted while I was writing :-)

[Henk]

No manual decomp on the TTR, it's driven off the kickstart.
Somebody said "Not a good dirt bike". Correct, I have ridden mine in woodhill and the easy bits of riverhead and it is a tad heavy, you can do it but you have to work quite hard. Stunning bike for gravel roads and twisties though. And you can cart camping gear to all sorts of neat places.

[F5 Dave]

Yeah, after I said that I realised it wasn't in the Dirt section but the Adventure one. But I would have thought the KDX would have gotten a 'Hell Yeah' from the likes of you.

Off the subject -oh just a little bit -I spied a DT230 on the last trail ride & thought that would make a cracking Adventure bike. Appeared to cope with the trail all right & should be road reliable enough in a way that I wouldn't ride my GasGas a zillion miles. Must look up Motu's old threads. Ahh heck I just bought a house, it is a silly time to think about another bike. But one day it would be good.

[zooter]

Thankyou one and all. It's nice to have my theoretical suspicions confirmed.
So the priming kicks are akin to a bit of extra "choke" on the very first firing methinks.
This automatic decompression is still a bit of a mystery. I gather it is supposed to make it idiot proof, giving decomp on a kick in the wrong part of the cycle and compression when it might actually catch.
I'll have to figure a way to manually activate it while kicking for clearing flooding. It's easy enough to do from off the bike.

She runs very well and gets 20km/l on the highway so I'm pretty sure it's not a case of tuning.

At the moment the bike is away getting a towbar fitted. The bruises in my shin have just about healed, lucky I didn't catch my kneecap

Starting lukewarm looks like the biggest obstacle now. I guess I'll just have to suffer the flooding until I get used to how cold it has to get to need choke. She needs a fair warm up time on choke before she will idle without. Far more than my 1100 or any two stroke I've had. Last time she cold started on the third kick but I killed her pushing in the choke too much too soon. After that all I could get was a cough before flooding again, and again, and again, choke or no choke. Hopefully I am past that now.

[Motu]

Ahh heck I just bought a house, it is a silly time to think about another bike. .

I bought the DT230 when we bought a house too! I got the DT230 for less than I had accumulated by selling all my other bikes - I was damn lucky to get out of it with the DT!

[Ixion]

Well it's a matter of priorities, isn't it. I mean, you can't ride a house.

[Ixion]

Thankyou one and all. It's nice to have my theoretical suspicions confirmed.
So the priming kicks are akin to a bit of extra "choke" on the very first firing methinks.
This automatic decompression is still a bit of a mystery. I gather it is supposed to make it idiot proof, giving decomp on a kick in the wrong part of the cycle and compression when it might actually catch.
I'll have to figure a way to manually activate it while kicking for clearing flooding. It's easy enough to do from off the bike.

She runs very well and gets 20km/l on the highway so I'm pretty sure it's not a case of tuning.

At the moment the bike is away getting a towbar fitted. The bruises in my shin have just about healed, lucky I didn't catch my kneecap

Starting lukewarm looks like the biggest obstacle now. I guess I'll just have to suffer the flooding until I get used to how cold it has to get to need choke. She needs a fair warm up time on choke before she will idle without. Far more than my 1100 or any two stroke I've had. Last time she cold started on the third kick but I killed her pushing in the choke too much too soon. After that all I could get was a cough before flooding again, and again, and again, choke or no choke. Hopefully I am past that now.

The priming kicks are just to suck a bit of fuel mix into the cylinder before you go for it. Briddish iron , the carbs had a tickler so you could actually let a bit of raw fuel flow down into the inlet. I miss carb ticklers. Blurdy yanks.

The "needs to be hot before it'll idle" is common on big singles.As is the "prick to start when luke warm" thing.

The auto decomp isn't anything clever, it just lifts the exhaust valve a bit at TDC compression stroke (a bit before strcitly) , when the kick starter is being used.

[Motu]

I hate auto decomps,it means you can't find compression.I like to bring it up on comp,ease it over with the valve lifter,then lay into it.I have disconnected the auto decomp on my TLR200,for a small low compression single it gets a tight knot in the lever,but still it's not too hard to get over the top.

Those small Hoda singles have kickstart pinion problems - caused by young guys just fanging into that kicksart like it was a foot pump....smack,smack,smack.Never give a problem if you engage the gears and then give a good bodyweight kick.

I was watching a big multi rider spill at the Nationals in Mercer,they pick those WRf's and CRf's up and just slam into the kickstarter like it was to blame for them crashing,no due care and attention there.Just another cost of the high maintenance 4 stroke...but one that could be avoided.At the cost of winning the race I guess....

[Henk]

With the decomp when flooded thing, don't bother with a manual workaround. Just hold the throttle wide open and kcik through about 6-8 times.
With the choke leave it on until you are on the move. 50 - 100 meters sems enough to warm everything up properly, but then I'm a bit rough.

[Oscar]

Get to TDC.
Decomp to get just past TDC.
Annnndddd jump on the kickstart.
Stay away from the throttle!

If flooded then kick it over a few times with the decomp held in and full throttle.

+1
NordieBoy knows his shit...

[XP@]

As they all said... but also,
When you tart to feel things just ain't going your way take off your jacket and lid, cool down and then have another go.
If you let yourself get too hot it will just get harder and harder.