I am new to 2 Strokes,(and the forum).The last bike I owned with a kickstart was 20 years ago.I recently bought a 93 MC21 SP and it is an absolute pig to cold start.Once warmed up there is no problem.It recently had a top end rebuild when the engine was split to replace the crankcase oil seal,and this has made no difference.I usually end up bumping it,though this isn't always easy.Once it fires it usually is ok.Why is it so bad?Is it the fuel,the mixture,........ME?
I really would appreciate any advice.Please stop me wishing I had bought another GSX-R.
Cheers.
Craig

I can almost hear the regulars sniggering at me, because they all know this is coming...

I'm sorry to say this Craig, but if you ever make it down to Devon, look me up and we can run up the road in unison as if we were starting a classic push-start GP!!

I've had my MC21SE for nearly 10 years, and it's been a b*tch to start since day two (day one, when I picked it up from the importers, it was fine!!).

On a slightly more helpful note, I hope, a good strong battery is essential for an NSR, and can make a difference - not that it's ever helped me! Sorry again!

In the name of research, I have tried virtually every combination of jetting possible, run open carb's, individual foam filters, HRC needles, all-sorts. The only time it would start reliably was when it had open carbs and huge mains (a la Jha/HRC jetting - which doesn't work on the road), so that was no good!

If you find the secret, I'd love to know! In the mean time, I'll continue to live with it... 'cos it's worth it!! :)

Andy.
NSR-WORLD.COM

This might help, might not. For the last few years ive been racing a CR500 (wonderful bit of kit) The easyest way to start that is turn fuel on, full choak, lean the bike over and wait for a pool of fuel to drain out of the carb overflow... stand the bike up... kick it though a few times then let fly with one good kick! 99 out 100 times she'll fire.
This isnt just my bike and most people with CR500's do it this way. If you leave out the flooding the carb bit they are a b**ch to start. I would seriously try this method.. you never know, it does work

Thanks for your replies.Looks like I am stuck with it.I will try the"CR 500" sugestion...........no harm in trying.Glad I found this site,it has probably saved me pissing about with the carbs and other areas.
Cheers
Craig

A minimum of 9 volts in the battery is required to excite the CDI.

Also, check the air jets in the carbs. Also check the tank vent....these have a tendency to build up with rust and restrict fuel flow, even when partially blocked (a long, small gauge wire inserted down the vent, a guitar string works best). This vent is located under the gas cap.

Float level can also cause hard cold starting as well.

As for the CR 500 starting technique......there is an easier way to start them.
If you slowly kick the lever on a 500, you will notice what feels like two compression strokes.

This is due to the large bore size, as the piston rises to TDC, and closes the exhaust port, there is a rise in compression. Slowly kick the start lever and you will feel resistance ( as the piston closes the exhaust port).
slowly continue to kick the lever past this point, and you will feel a second compression (as the piston reaches TDC). Return the kick start lever at this point, open the thriottle to 1/4 turn and hold it there..... and give it the boot. It will start first time, even when cold.
_________________
Mike

No-one tried rebuilding the choke mechanism then?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Thought about it, but the system's working fine.

A little more insight into my personal experiences...

Sometimes it'll start with the choke from cold, sometimes it will not.

Sometimes it'll start without the choke from cold, sometimes it will not.

Sometimes it'll start without the choke when hot, sometimes it will not.

And yep, you guessed it...

Sometimes it'll start hot, with the choke!

It's always "sometimes" though... if there's a crowd, it won't start!!!! :D

I've just accepted the fact my MC21 has a sense of humour, and will continually embarrass me whenever it can!

Andy.
NSR-WORLD.COM

I know that spark plugs are very very important for starting this engine.
My sugestions :
1. Check spark plugs ( take it out from engine , connect one with cable , put side of it to metal part of engine , turn on moto and try to "kick" by hand and look at spark plug , if there is "electric shoot" in place where it have to be is good, if not buy a new 2 spark plugs.)
2.When engine is cold use choke before kick , and I sugest do not open fuel before first try . If engine start then open fuel . You can open fuel for few seconds and close it and then try to kick( remember of turn on key and start button) , and don`t open the carburator

For good next time
Before you turn off engine , close fuel and wait a moment with workink engine until it RPM start to rise , then turn off.
I have mc 18 and if I forgot about one of this steps, then begins problems
SOrry for my english. ( I hope that will help you)