How hard is it to kick start a 72 750 Roadster?

Hi all, I am new here and very impressed with the site and forum.

I have a 1972 750 Roadster (not Combat) and find it very hard to kickstart.
Assuming it gets a good kick, it will fire readily, works beautifully, no operational problems, pulls like a hog.
It's just so hard to give it a good kick (I weigh 76 Kg) and on occasion will kick back which frankly, is scary.

So I wonder if compression may be at fault here .

Is there an easy way to ascertain whether my compression ratio is way out? I do have a compression gauge but not sure what values to look for cold / and at operating temperature ...

Thanks a lot for any help, this is my main complaint from an otherwise great bike.

Aris

It can be a bear to push over the first compression stroke, what I do is get up on the pegs (I know lots of people don't like this, but my wimpy 69 side stand is still good) and use my weight and what little muscle I have to just get it through compression and then give it what for.

Dave
69S

All about technique.

[video]http://www.youtube.com/watch?v=6886wWeh8UQ[/video]

When I got my first Commando back in 1971 I weighed all of 125 pounds, and I was as intimidated to start it as you are

There are a couple things you have to know and do

1) Realized that you gotta "man up", there is no secret to the fact that you are going to have to brace yourself mentally and physically for the effort.

2) I assume you have a centerstand, if so put the bike on it.

Turn on gas and ignition switch and tickle carbs until a little gas comes out from ticklers
Then open the throttle a quarter turn or so with your right hand and move the kick start lever so it is in the 10pm
position, any higher as in 11pm and the effort is even harder and there is no benefit to trying it.

Then, you are straddling the bike on the center stand, get your right foot on the kicker with your knee bent,
lift your entire body up and then down together on the kicker, do not ever "jab" at it or you can break the pawl inside the cover (this is not a jab dirt bike kicker).

Yes, if you do not come down with your right knee straightening to a locked straight position at the same moment supporting all your weight then it can kick back.

Practice starting it with gas and ignition off, it will get easier, you will get more confidence over time.

We ALL went through what you are going through now, the learning curve.

Thanks, all this is very helpful and I am planning to practice!
I am a bit surprised no one has mentioned the choke?
Also COULD I have a case of overly high compression, which could appreciably increase effort? Yes or no?
Thanks again, Aris

If the bike has not been started for several days the engine oil may have drained down from the oil tank and filled the crankcase. This will cause extra kick starting resistance especially if the oil is cold.

Spark plug condition and priming the carb idle circuit just right with the tickler also aids in an easy first start of the day.

I doubt very very much you have a case of "over compression", in fact the actual compression ratio goes down over the years as the rings and valves lose their sealing through wear.

No, it just feels very high compression because you are new to this.
You are attempting to turn over 750 cc's spilt between two big pistons, that requires a lot of effort, from all of us.

Choke? Now others may disagree, but if you flood your amals so a little gas leaks past the ticklers then you have insured that your float bowls are full of gas above the normal level.

If you then open the throttle a good quarter turn while giving it a manly thrust, you are drawing that gas in to the combustion chambers, all set to ignite.

In fact, many of us removed the entire choke mechanism as we did not find it necessary if given the above procedure

The choke thing goes not give it more gas but it lessens the amount of air so the air to fuel mixture is richer.

You can pretty much do this yourself by flooding the ticklers and opening the throttle with a good kick.

Try it this way for a while without fooling around with the choke, but if you must, then turn the choke off almost right away after starting so you don't load up and foul your plugs with an overly rich mixture.

And remember, we all went through what you are going through.

You have chosen a Norton Commando, practice and it will get easier and easier.

And before long you may not need the center stand, simple straddle it and balance as you come down.

And remember, you cannot do this with your knee bent, it must be straight so all your weight feels like it is above your knee and coming down together on your feeling strong entire right leg.

Keep us posted

The kick back may be to poor timing or low battery.

If your compression is too good then celebrate it and practice. What ever you do, never jab at it ala 2 stroke Suszki 80. Once kickstart is brought to bear on top, do not separate the contact and push it through. Repeat as needed.

Tough kicking due to compression is like saying a hard to pull clutch is due to a warn out cable.

1up3down said:

When I got my first Commando back in 1971 I weighed all of 125 pounds, and I was as intimidated to start it as you are

Click to expand...

Mine is easy to kick. Of course, my right leg weights 125lbs

Oil in the sump makes it a bear to kick at first.
Just kick it with key off and throttle open a couple of times, then tickle it, choke it and push the kicker to just to the top of the compression stroke and stand on the kicker and kick through it. Turn the key of course.
Pretty soon you be saying, "My bike starts on the first or second kick".

As pvisseriii said, it kicking back at you could mean the timing is too advanced, can you check it with a partner and a stobe light. But being new to all this, this may be beyond you at this point.

More likely, make sure battery is fully charged, and if so the kicking back is really because you are not being strongly physical enough while downstroking, all the way down and holding leg straight at the very bottom.

IF you kind of let off toward the bottom, it can kick back.

So you have to feel as you are accelerating through the kick all the way, like hitting a golf ball.

The kicking back might just mean you're not kicking it like you mean it.

Initial throttle position varies with different bikes and carbs and people. Most all of my bikes like to start best with no throttle or very very little. (All Amals.) There is more vacuum pull on the idle circuit with the throttle closed so it does what it is supposed to do. If flooded it does help to clear it out with some added throttle though.

My bikes all like the chokes too.

Kool_Biker said:

Thanks, all this is very helpful and I am planning to practice!
I am a bit surprised no one has mentioned the choke?
Also COULD I have a case of overly high compression, which could appreciably increase effort? Yes or no?
Thanks again, Aris

Click to expand...

I like the site here. Easy to determine what your cranking compression should be at your altitude. Look up the information for filling in the variables in the service manual. If you don't have a combat, then it has standard cam...you need to know camhshaft duration. My combat was cranking 182psi which was definitely too high. Cause was a previous owner had put a std camshaft in the combat engine. You should not have that issue unless the head has been milled to increase compression or there are domed pistons inside such as powermax type.

http://www.not2fast.com/turbo/compressi ... sure.shtml

I have only noticed one time when my bike was harder than normal to push over and that is when it was about 40° out with my SAE50. I don't find the sump being full any different than not, but if it's been sitting a while I drain the sump mainly so it doesn't smoke. I do use the choke and flood the carbs until I see gas, having previously cleared the clutch and make sure it's in N, I just go for it with some throttle and 80% of the time it starts right up. You do have to give it both barrels and follow through. Don't go into it thinking it's not going to start, show it who's boss.

Dave
69S

Try the suggestion if you still have trouble the 850 kickstart lever is about an inch longer giving better leverage or there is aftermarket ones that are longer again goodluck

It's about technique more than anything. If it has compression, fuel and spark at the proper time, it will start. Usually on the first kick, hardly ever more than two kicks. I doubt your bike has too much compression. Probably more likely not enough oomph in your kick. The advice about the center stand is definitely the way to go. Once you get the hang of it they are relatively easy to start.

I have a 1972 combat that I was able to start by hand after a little warm up and a one kick first start. Once all the cards fall into place it's pretty easy.

Want to see how to start a Norton Commando with ONE ARM?

Here is our own Jim Commoz starting his bike.

Pretty scary strong in my opinion, WOW
http://s658.photobucket.com/albums/uu31 ... art001.mp4

All that been said plus the fact Norton have about the worse ks leverage of any bike ever sold beside being a big size engine for the ks era. Jim's a big dud, look at them arms. I'm Icakbod skinny but still can hand start a brand new tight full Combat. But it must be in peak tune to do so. Btw, its wasted effort to kick over even once with key off, they should fire off one kick most the time and conditions. The tickler only fills the pilot mixing chamber and what's seen dripping off is excess that will only flood floor as a fire hazard. A Norton Commando is a real man's bike both in athletics and mature spending habits.

[video]http://www.youtube.com/watch?v=cmM5emTXK-g&feature=player_embedded[/video]

Hey, Wolfie, I hope you've tied down that tach cable, put some air filter on and slowed down that idle. I've given up on the starting with the hand, not for me, I tried it about 3 times. I was starting mine with my crocks on last winter, but got a slight sprain, so enough of that at my age. Anyhow, here's me as a geezer starting mine first day on the centre stand last year, as long as we're showing off. It's even better now, as long as the coil wires don't fall off.

Plus Jim has his bike set up with fuel injection to start easy, he even says so.



Dave
69S