Motorbike expert? Suzuki gn125 question Page 1 / 3

kiwigrl2, Jun 9, 4:31pm
Hi, hoping someone might have some insight. I am new to riding and wanted to get my Learners, so bought a 2020 Suzuki GN125 as I heard it’s an easy bike to learn on. With the plan on upgrading when I get a bit more confident. I bought it from a trusted dealership in Auckland, pre owned but only about 2 months old. 300kms on the clock so basically new. My issue is with the bike starting. I have to have the choke out, and even then it takes 5 or more attempts to actually start. Then I have to stand there as it revs itself like crazy, so that it warms up, sometimes more than 5 mins of standing there waiting. When I try to get on and ride away too soon, it loses power and doesn’t go anywhere. It’s extremely frustrating! Once it’s eventually going, it’s absolutely fine. But is this normal? I wasn’t expecting issues from a new bike. I was thinking of getting it looked at, but thought I’d ask around first in case this is a common issue with this sort of bike. Thanks

kazbanz, Jun 9, 4:57pm
A choke isn't all or nothing. You might find you actually need half choke rather than full choke to start the bike the easiest. You also don't slam the choke shut after a couple of minutes for example. Shut it off by increments.
THAt said--if the bike is as you say all but brand new it may be in need of its first service. Those little suzuki125's have been around forever so its unlikely to be faulty.

kiwigrl2, Jun 9, 5:25pm
Thanks for that, yeah I definitely do shut the choke off in increments (after 5 or more minutes of standing around waiting), if I slam it shut the bike does completely. Just seems very strange to have these issues on a new bike. Will probably take it for a service then

kazbanz, Jun 9, 5:53pm
There are a range of small adjustments made to a simple motorcycle at its first service. So im betting it will start far better after that is done

gblack, Jun 9, 7:28pm
Very simple little bikes, and very old school; been many years since I had a bike with a manual choke and carbs.

I believe that during run in, they run them a bit rich so in theory, even in the current cold mornings you may not need that much choke. I would only let the bike warm while pulling on gear, and try and reduce choke down a notch or two then start riding, taking off the choke fully once running. 5 minutes sounds like too much for a wee engine.

The bike shop should be able to confirm. Only downside I used to find was that a bike that was iffy when starting from cold, by the time to got to the bike shop the bike was nice and warm so always start sweet when demonstrating the issue. You might want to get the first service done early, and leave it at the bike shop overnight so they can tune it from cold.

You will be looking forward to getting your full license and upsizing to something a bit more modern with EFI.

kiwigrl2, Jun 9, 8:41pm
That’s a good point, after a few minutes of normal riding the bike always seem fine - so will probably seem like nothing is wrong with it by the time I ride it there. Might see if they can hang onto it for a couple of days, then try it. Can I ask what is an EFI?

pettal, Jun 9, 8:45pm
Is the bike garaged or left outside overnight ? , Cold damp winter mornings will cause a longer warm up time .

kiwigrl2, Jun 9, 10:53pm
Unfortunately don’t have a garage so it’s outside under a cover. So that’s probably not helping but I don’t have anywhere else to store it sadly

muppet_slayer, Jun 9, 11:16pm
Give it full choke until it fires then back to half choke after it fires. Try that.

gpg58, Jun 9, 11:28pm
Wondering if you are using 91 octane or 95? does handbook recommend which one, or just say 91 or higher. personally i think 91 is only useful for starting a bonfire.
How many km's on it now, sounds like it may just be still very tight, and just need some mileage on it to free it up. a good long ride varying your speed/revs up and down a lot, and slowly increasing maximum revs you go too, usually works for me. (but read what handbook recommends for running it in). Both my current brand new cars, are slowly feeling much more willing, now they have 800- 1000+kms on them. Constantly treating new motors with kid gloves and lugging along at low revs, often ruins them permanently, if done long term. (getting close to red line for brief bursts, in both my cars now).
I did read one owner report for your bike, that said start on full choke, with no throttle, then immediately move to half way once started.

kiwigrl2, Jun 10, 12:02am
I’ve ridden it so little that I’ve only filled it up twice since I got it (95 both times). I start it on full choke, and even then it takes about 6 or more attempts until it finally splutters to life. I’ve tried reducing down the choke to halfway after that, but then the bike immediately dies. It essentially forces me to have the choke all the way out, and if I try riding it too soon it wont take off - I go to accelerate and it just loses power - it’s really weird.

saxman99, Jun 10, 4:58am
Electronic Fuel Injection. Came along in the 50s as an alternative system to chokes and carburettors.

gblack, Jun 10, 8:20am
If you get some decent weather over the weekend, try and clock a few km on the bike; even on a 125cc, should be possible to get some hours on the bike which you will need, as well as the bike getting some km. My record was 1100km in bit over 24 hours one weekend 😎

The GN125 is a cheap learner's bike as it has been made largely unchanged for something like 40 years, so the technology is old school drum brakes and carbs that need a manual choke. Hence a bit more fiddling to get the bike running and keep it running. Once you move up in the bike world to something more modern - something like the little BMW 310 that my bike shop uses as a loaner when my Triumph is being serviced, then they have electronic fuel injection (EFI) so no choke and instant start, smooth running as well as features like ABS braking.

The GN series are classic, but do think time for Suzuki or some other motorbike brand to bring in a better low cost LAM bike or fewer people will learn to ride or end up disappointed by their first bike

desmodave, Jun 10, 8:44am
I agree , take it for a good run . With bikes it seems to be the case of the more you use it the nicer it starts and runs . I would be running it by the shop you bought it from . Keeping motorcycles on a battery tender is a good thing also . Small batterys doing a big job from cold (in the case on my 1000cc twins any way ) turn the key on , head lights are on and you still need a good power supply for starter motor and ignition . Ride it ride it and ride it some more . Don't forget to check ya tyre pressures and lube the chain . Have fun .

kiwigrl2, Jun 10, 9:58am
Thanks for all the advice, will try and get some more riding time in and see what happens.

gary06, Jun 10, 2:24pm
If it was my bike I'd be pulling the spark plug out see what colour it is . Sounds to me like the Carby needs cleaning,you might get lucky with a quick blast down a motorway or as above a good run might do it.

kazbanz, Jun 10, 4:08pm
Sorry but in this specific instance I disagree with the advice you are getting from other posters.
Although a used bike given its age it will be covered by manufacturers warranty.
THAT means the bike needs to have its servicing carried out "by the book"
And any issues need to be addressed by the dealership.
So I stand totally behind my recommendation to take it back to the dealer and have them carry out that first service which is due.
Once that is done I agree wholeheartedly with their advice.
My genuine concern is that there are settings made when an engine is new that are often changed once the engine has a few k's on the clock. or settings that just change as the components settle in. Especially with the made in china engines.

muzz67, Jun 10, 5:03pm
Agree. Most new bikes are jetted ridiculously lean for greenness etc, which makes them really cold-blooded until warmed up.
dealer may richen at first service.
OP,, try twisting the throttle a couple of times before starting from cold.
If it has a accelerator pump it may start better, (if it hasn't it wont make it worse. ).

slarty45, Jun 10, 7:27pm
I would expect it to start first kick and idle with no choke in less than a minute.
While it is new, it may have been assembled many years ago.
Carb strip/clean and a damn good thrashing should sort it.

kiwigrl2, Jun 10, 8:25pm
Update - I managed to speak to the dealership that sold me the bike, and they got me to drop it at my local service shop to take a look at it. He said they’ll keep it overnight so that they can start it from cold (as obviously by the time I’d ridden it to them it seemed fine). He did say that it’s very unusual for a Suzuki with only 400kms on it, and said he might try cleaning out the carb - I think that’s what he said anyway. But agreed that it is still under warranty so should be covered if something is wrong.

gblack, Jun 10, 8:46pm
Totally agree, and I didn't mean to say that the OP should not get the bike checked by the dealer, as a 2020 vehicle (even if early 1980s tech) should start and run without a 5 minutes warm up.

I think though the OP is just wanting to check what was expected, so they didn't look stupid taking a bike to the dealer that was running fine.

My first bike many years ago was a 50cc scooter that would get a clogged up carb jets and run like a dog if not used on a regular basis.

Given that OP only done two tanks of gas since new, still think it would be worth going for a decent ride and get a few km on the odo with the bike hot, then if bike still not idling well within a minute of starting cold, then back to dealer for a look

I assume Suzuki have first scheduled service at 1000km? Challenge to OP would be to add a few hundred km this weekend 🙂. Though long distance ride as a newbie on a 125 single cylinder bike with 12hp.

Reading online and others reports similar issue when cold; so not just you.

tamarillo, Jun 10, 10:14pm
This and what kaz says. Likely set lean and often dealer service will richen it up away from factory spec designed for emissions. Insist it’s sorted but don’t muck about yourself.
I didn’t know japs even made things with carbs anymore!
Hope you’re doing ride forever

richynuts, Jun 10, 10:57pm
gn125 are made in china

desmodave, Jun 11, 2:29am
https://www.bikechatforums.com/viewtopic.php?t=222869
Interesting little read . I would not be surprised if the shop opens the fuel mixture screw a tad . Glad your going to run it by the shop . Older bikes or older designs is where forums rock as its all been done before so the info and experiences are all in black and white .

desmodave, Jun 11, 2:40am
Even Royal Enfeild seen the light and have efi now days . Take Suzuki ag bikes for example , still the same basic bike since forever . Ltf300 kingquad has used the same basic design for around 30 years. They did move from drum to disc brakes along the way and the carb may have changed but bugger all else . If its not broke , no need to fix it .

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