OMG! This much fun has to be illegal! But how do I start my bike?

[Meekey_Mouse]

Hey sorry I can't help you out at all mechanically... I'm just learning myself Welcome to KB and the 2 wheels of freedom

Jaz

[xwhatsit]

Thanks for the welcome Meekey_Mouse ^_^!

No toolkit by the looks, it's been flogged somewhere along the line of 8 owners; I don't have a spark-plug socket myself so I can't get the spark-plug out yet to look at it. As soon as I get my learners (I did BHS test this morning -- easy! GN125s are like scooters!) I'll get the bike over to my uncles and raid his toolshed.

I put my multimeter over the battery, and read about 12.10v, so that seems OK. However as soon as I switched the headlight on highbeam the voltage started dropping slowly but quickly, down to about 11.5v within 5 seconds and continuing to fall (normal headlight a little less strong effect, but still there). I know the headlight pulls a fair few amps, but is this normal? Seems excessive voltage drop. Maybe the battery just can't give enough current for the sparkplug until the magneto/alternator/whatever is backing it up?

One last thing, when push the kickstart lever down it automatically triggers the decompression lever through a cable. Would it be more likely to start if I disconnected the lever, or would I break my calf as it kicked back lol? One thing to note is that when I bump start it, the decompression lever is obviously not being triggered. However, I'm also getting a fair bit more RPM out of it when I bump start it (as I'm in first gear, second gear hasn't worked for me yet when starting it), so this may be the reason instead.

Thanks everybody,

-Tom

P.S. T.W.R when you mentioned how it probably just needs a `tune-up', were you meaning just change of plug, oilfilter et al, or were you talking of more arcane things that I don't have a hope in hell of doing such as valve clearances and such frightening things? Thanks.

[Ixion]

Hm

How are you trying to start it on the kickstart?

There's a technique to starting a single , though usuallyu you don't need to worry too much with a 250. But just pushing the kick start lever down wont do it.

I wrote it up once, hang on

Yes, here it is, from this link..http://www.kiwibiker.co.nz/forums/sh...ad.php?t=11041

ep. Separates the men from the boys.

Full drill for those too young to have done it

Retard ignition
Tickle the carb
Free the clutch
Stand on kickstart lever and take it down until it hits compression.
Let kickstart come back up to top
Lift exhaust valve
Take kickstart through one complete stroke with valve open
Allow kickstart to come back up
Kick start **HARD** . With **ALL** your weight on the lever (one foot on kick start other off the ground, kicking with all the strength of your back and leg. And whatever you do don't let the bike fall over at this point because you have no foot on the ground, so you ahve to balance it)
Absorb impact when kickstart hits compresion (like kicking a brick wall)
Repeat until it starts
*REMEMBER TO ADVANCE THE IGNITION*

Bah. Electric starts, just push a wussy button. Wusses. See what you miss out on nowadays. Bet half of you don't even understand half the above process. (PT). Though the guys with big trailies I guess still have to do the full drill

Yeah, I've still got a kick start bike.

[SwanTiger]

Well done on passing your BHS dude

P.S. T.W.R when you mentioned how it probably just needs a `tune-up', were you meaning just change of plug, oilfilter et al, or were you talking of more arcane things that I don't have a hope in hell of doing such as valve clearances and such frightening things? Thanks.

If you have the cash it would be reasonably cheap to give the bike a complete service from a dealership, which would include valve clearances. The cost would be between $200 and $250 or cheaper as you've only got on cylinder.

[xwhatsit]

Ixion:
Cor I didn't know it was that involved lol! I don't know if my bike has all those controls; by tickle the carb, are you talking the choke or something? I get take it down to compression; you mean run the kickstart through til it goes hard -- but will this still work with the automatic decompression lever? I suppose so. I tried doing that, it didn't help much. I don't know how to lift the exhaust valve. I am kicking pretty hard I think -- at least towards the limits of my weedy frame haha. Should I retard/advance ignition as well, or will my bike be too new and have automatic ignition setting? I don't remember seeing that many levers and knobs on the engine lol. Thanks for the tips though, and sorry for asking all these n00b questions!

SwanTiger:
Heheh yeah need to look at the cash situation lol. Will see how far I can get first but if I still have no options I'll get it serviced. It was supposedly serviced in July in Tauranga, but obviously not much was fixed. Hope the engine is not shagged in a big way that's not immediately apparent. Goes all right when it's running though!

Cheers, thanks everybody for their patience with me!

-Tom

[Ixion]

Um Sorry, yeah, you can ignore the advance and retard stuff , it'll be automatic on your bike.

And the cable from the kick start should work the exhaust valve lifter at the right moment, that's what a decompressor is, and exhaust valve lifter.

The trick is not too kick hard so much as at the right time.

[T.W.R]

Well done on the BHS.

Don't worry about the tool kit, about the most useful item is/was the pouch the tools were in, the tools themselves are putty metal best to make up your own selection of basic emergency tools.

The decompressor hardly ever works properly on the CB, once the cable stretches a bit it doesn't work the internal cam through the full arc of motion anyhow. It only partially lifts the R/H side exhaust valve only not both exhaust valves.
Best to roll the Kickstart through one full swing & let it return under your foot then on the 2nd start the swing again slowly till you feel it firm up on compression rest it there then push it firmly (kick for the better use of the word) through the rest of the stroke.

Basic tune-up is just oil & oil filter, cleaning the air filter and a new plug seeing your starting out with the bike. The tappets aren't a major problem to adjust (they're screw & locknut not bucket & shim) and the two alloy caps on the L/H side engine case are for timing marks (large centre one is for turning the motor over & the smaller one at the top of the casing is the timing marks) it would take under half an hour to do if needed. Don't worry about adjusting the valves unless they're noisey. Generally the motor is very quiet and smooth (twin counter rotating balancers)

[xwhatsit]

Thanks all for the kickstart advice. As I know it's startable, I'll try all those things you listed in hope of abandoning the bump-start method lol. It would look a bit dick to do it on campus ^_^.

The seller mentioned quite a few of those things (oil + filter, air filter etc) but I do it anyway, and definitely change the plug. As I'm not totally sure what tappets are, and how timing exactly works, I think I will pick up a Haynes manual for the bike (now out of print, but will see if I can get one second-hand. Manuals.co.nz doesn't list it but encourages you to email them to see if they have one anyway, but about $80 for other Haynes on the site seems a bit steep). My manual-requesting thread doesn't seem to have been too successful lol. Yeah, the motor is very nice and smooth, it's not much louder and seems to vibrate about the same as the GN125 I rode.

Hmm one thing I just thought of... when I do get it started, if I give it any gas it stalls straight away, so I leave it to idle for a good while before I even touch the accelerator. My uncle adjusted the idle speed, set it quite high, just to help me out when learning with the clutch. Could it be that the idle is set so high it's having the same effect that squeezing the throttle does when first started? Then again it was a bitch to start before the adjustment... arghhh!

Thanks

[Ixion]

Was that engine based on a Honda off roader? A lot of those 80s little Jap enigles were, and it's often much easier to get a manual for the off road version.

Try Auckland Public Library, the main one in Lorne St. They have a shit load of manuals, but you have to look at them there, can't take them out.

Go to the first floor, up the escalator, and turn right at the top, go to the far right and there's a service desk with helpful ladies

You do have to be a member I think.

[T.W.R]

Try a few 2nd book shops for a manual too, it may be worth a try.

Idle speed should be around 1000rpm give or take a wee bit (width of the needle).

Ixion : yeah base engine is from the XL250SA, higher comp, bigger carb with accelerator pump etc

[xwhatsit]

Yeah, the XL250SA. Same engine, I learned from reading some article on the net that the valve inlets are larger on the CB250RS plus what T.W.R said as well.

Auckland Public Library! Wah! Why didn't I think of that? I'll go there tomorrow after uni... great! If they don't let me become member (I live Manukau City), I'll just photocopy the relevant bits .

Scweet, libraries. Forgot they existed. Just went to the Lorne St one the other day with girlfriend, looking for information on Wonder Woman

Set idle speed to 1000rpm? Next time I get it started and warm I'll adjust it to that, see if anything changes. I really, _really_ don't want to stall it though for obvious reasons hahaha, so I'll give it a lot of revs and really be careful with the clutch. Gah. 2nd hand book shops? I love those places... an excuse to have a look around then.

Cheers

[xwhatsit]

Sorry for double post. Went to library, they had to bring up the manual from the basement. It's not for loan so I took notes on it in the library. Not too many surprises there; listed spark/ignition as usual problems for starting. Mentioned the tappet covers as a common point for leaking oil, so that just confirmed what T.W.R. said.

Will replace spark plug (Haynes mentioned different plug comes as standard but to use the DR8ES-L if bike is consistently being run at temps below 5 degrees -- probably not necessary but sure it won't cause any problems), and get spark plug removal thingy ASAP.

Also, how about carburettor? Haynes didn't mention starting issues particularly relating to carb, but might adjust the pilot mixture anyway. Would carb issues like blocked jets affect starting without necessarily making a big effect on the bike once it's running? Might disassemble it and check it out.

Heheh. Getting my hands dirty. I feel like less of a bookish uni student now and more like a proper male lol. Girlfriend isn't so keen on the smell of oil on my hands but I suppose she'll just have to live with it hahaha.

Cheers,

-Tom

[WINJA]

Heheh. Getting my hands dirty. I feel like less of a bookish uni student now and more like a proper male lol. Girlfriend isn't so keen on the smell of oil on my hands but I suppose she'll just have to live with it hahaha.

Cheers,

-Tom

DONT YOU MEAN BOYFRIEND FAG

[xwhatsit]

__________

[xwhatsit]

Wo0o0o0o0!

Popped out existing sparkplug -- turned out to be a D7xxxx something, which I haven't seen at all as a recommended sparkplug for my bike. Put in new plug, DR8ES-L, bike started second kick! ^_^! So that seems to have been the problem. Fixed!!! Very happy. So now just the WOF remains, and insurance and then I'm a very happy lad. Bike still leaks oil -- looks like the tappet covers, will take a look, and misses occasionally at low rpm and when I back off the throttle -- I think I need to change the mixture. But I'll have a fiddle around, it's 100% easier to use now I can start it and aren't worried about stalling.

Thanks everybody for their help in this thread (sans WINJA of course :P)! You have all been very very helpful and I appreciate the time you've given a n00b.

Cheers,

-Tom