korider.com | Hyosung Motorcycle Owners Forum

korider.com | Hyosung Motorcycle Owners Forum

  • October 22, 2018, 12:24:11 AM
  • Welcome, Guest
Please login or register.

Login with username, password and session length
Advanced search

News:

Welcome to Korider.com!

Pages: [1]

Author Topic: 125 Single Cylinder upgrades  (Read 8291 times)

s-m

  • Learner rider
  • **
  • Offline Offline
  • Posts: 35
125 Single Cylinder upgrades
« on: March 23, 2013, 01:17:18 PM »

Hi, my bikes engine is what i would consider noisy, now i cant seam to remember if it was always like this or not  :o the problem in my head is that i know the manner in which the bike has been used is not really what its designed for.

The bike is a 2005 Karion/RT125

It regularly sits at 55mph+ for around 10 mins on a dual carrigeway, for example last night i saw 60-65 depending on if i was on the flat or going up a slight incline (finished work after a friday late shift and i am not hanging about!), the bike rides well, it makes good power, no smoke, it has been modified in that it has been upjetted and a much better exhaust system fitted, its currently on the stock gearing and i know this is probably getting very close to maxing out its RPMs in 5th gear.

FWIW i do have a larger front pinion (although no longer fitted) and did use to use this for 3 months when i moved away and had to spend 30+ mins per trip on a dual carrigeway instead and managed 75mph once! i was like "holy **** i am catching CARS!!" lmfao

Anyway, my head says i am screwing this engines tits off, therefore its probably noisy because of this :D

I am looking into repair/upgrade options as i am due to take my full bike test this summer, this bike is used as a commuter, although i plan on taking it to some offroad stuff when the weather is nicer.

I know people will always say "sell and get a bigger bike when you pass your test" but i am not so sure its sell-able if the engine is noisy.

I have spent the morning searching for Suzuki 125 engine noises on youtube, DR125s can sound quite noisy, rattly etc etc, mine sounds a bit whiney (i think, maybe bearings)

My current ideas are....

1. Strip down and rebuild.

2. Swap out motor.

I am trying to research things like the DR200 engine, or the GN250 engine, it looks like they will almost drop in without too much trouble, but i am also looking at a simple "big bore 150 kit" which costs a lot less, i can rebuild the bottom end myself with new bearings and should be a significant cost saving, but this option has me a bit confused.

The 150cc kit should bolt up, but will the supplied pistons work with the Hyo head/valves ?

I have read a hell of a lot on another website about using Suzuki quadbike heads/cylinders/pistons on a DR125 and ended up even more confused.

Ideally i just want this bike to hold 70mph for 10 mins so i can get to work in the cheapest manner possible, i do feel going back to the 14tooth front pinion and a more torquey 150 kit might help with this, the bike is great now since i removed the stock Hyo exhaust, really impressed with it, but it needs that bit more oomph.

Looking to start this work in the summer, so i am planning ahead.

I know i could get a "faster" 125, but i like the RT125 styling, you never see them about, it gets a lot of looks/stares and thumbs up, and the 250cc version is probably not going to be sold in the UK (i bet it uses a GN250 engine!)
I did look at Yamaha tw200`s but they are slower than what i have now lol
Logged
2005 - RT125D (Karion)

Register and log in and the Ads below will be gone! :D


s-m

  • Learner rider
  • **
  • Offline Offline
  • Posts: 35
Re: 125 Single Cylinder upgrades
« Reply #1 on: March 23, 2013, 01:26:31 PM »

Couple of proper photos taken showing the new exhaust.





Cheers.
Logged
2005 - RT125D (Karion)

Cloud

  • Korider's Fastest GT125R.
  • Forum Addict
  • *****
  • Offline Offline
  • Posts: 2571
  • Head removal specialist.
Re: 125 Single Cylinder upgrades
« Reply #2 on: April 06, 2013, 12:21:20 AM »

What kind of noise?

There are established categories: whirring, clicking, vibrating, grinding, and hissing. Noises can be combinations of these.

FWIW my Hyosung has the noisiest engine of any bike I've owned. Quietest exhaust, but, the engine itself makes a racket. I too spank my bike at 65+ up and down major roads on a regular basis. My "fix" is going to be to pad the fairing out with some soundproof matting to cut down on both engine and wind noise. Not having that option yourself, you need to find out what's making the noise. I can't suggest anything until I've got an idea what kind of noise. There's a lot of moving parts on a bike.

As for upgrades, start with a damn good service. New filters, new oil, lube chain, new everything else it says to do in the service manual. Firm-up suspension and drop it if possible, and make sure you're running correct tyre pressures. Bouncing slows you down more than you might think.

Camshafts are better than bore kits. Bore kits put a bigger piston on a standard crank, thus making it unbalanced. It'll bring about vibration and increase engine wear considerably. They work for some but I certainly would not recommend one especially if you need dependability.

Before that though, I'd be looking in the direction of the carb.
« Last Edit: April 06, 2013, 12:29:55 AM by Cloud »
Logged

s-m

  • Learner rider
  • **
  • Offline Offline
  • Posts: 35
Re: 125 Single Cylinder upgrades
« Reply #3 on: April 07, 2013, 10:40:43 PM »

The best way to describe the noise, would be to say that it sounds like a knackered old diesel !  :o  ;D

Slappy and rattly.

It does not seam to be getting worse, so i am currently trying to research a complete engine swap with a suzuki gn250 engine.

A 150cc big bore kit on this bike would probably be more hassle then bolting in the bigger engine by the looks of things.

Doubftfull a new chain would do anything, the current one is only about 2 weeks old :D
Logged
2005 - RT125D (Karion)

s-m

  • Learner rider
  • **
  • Offline Offline
  • Posts: 35
Re: 125 Single Cylinder upgrades
« Reply #4 on: April 19, 2013, 09:54:08 PM »

Still looking into this, I found a GN250 engine/carb/exhaust bundle on ebay yesterday, i looked into the seller and it appears he bought them to fit into a GN125 frame and they did not fit, so i can assume they would not just drop into my RT125 frame, this closed this avenue down for me as i wanted a plug and play setup so i could change it back to a 125cc machine to sell, ohh well. my current engine appears to be getting more and more noisy, today i looked into this further, i have had the top cylinder cover off, the cam shaft bearings are silky smooth, the camshaft looks unworn.

I have not had the head/piston off yet.

I also looked into the starter motor, now this had me a bit confused, i removed the starter and used the kickstarter to start the bike, inside the hole that the starter goes into, i see a spinning cog, this is the cog the starter motor engages with (why is it spinning all the time?) i stop the bike and have a feel of this cog, it has a fair amount of play.

I strip the stator cover off and investigate further, the cog has play because it can slide up and down a shaft, no problem, but this cog is an intermediate cog and drives the magneto/flywheel cog.

This magneto/flywheel cog is attached to the starter clutch, it spins freely one way, but spinning it the other way turns the flywheel (as it should) the flywheel cog also has a lot of play, but it appears this one actually sits on a proper bearing, and its damn noisy for a bearing  coated in fresh oil (it sounds like a buggered bearing to me to be fair!), i don't have a flywheel puller at the moment, so i removed the intermediate cog and tried to start it again, the bike still sounds rough, not sure it sounds any better, bahhhh!!

The crank does not appear to have any play when i try and wiggle the crank, this engine is going to need stripped and rebuilt, its DEFIANTLY getting worse day by day (now just under 17000kms)

Feck it, lets look on ebay, brand new K157fmi Chinese engine for around 500, various second hand Pulse Adrenaline/Sinnis Apache engines around 2-300.

And a second hand Superbyke RMR125 engine for 140 delivered  ;D

For those that dont know, they are all pretty much the same Suzuki GN/DR/RV125 engine thats fitted to my RT125, except Hyosung fitted a 4 valve head to there version (also it looks like a better carb with a acceleration pump), it also needs its own piston with cutouts for the valves, not sure what improvement the 4 valve head actually gives, but it makes source spares a PITA as everything else seams to be for the 2valve version fitted to the other bikes.

Alas, this engine should be here by next weekend, all going well i will bolt it up, then i can take my time stripping the Hyosung engine down and looking at rebuilding it, if i do pickup a 150cc kit, then at least i will now have a proper 2 valve head and parts to fit it.

Then i can have a spare engine in the man-cave for emergencies, every month i keep this bike on the road saves me 80ish in toll road fees to start with (toll tunnel is free for bikes) hence why i don't really like using my car (and the car only does 33mpg lol)

Really had my heart set on a 300cc RT though! would have preferred one of them over a Suzuki DRZ400 (second choice)
Logged
2005 - RT125D (Karion)

s-m

  • Learner rider
  • **
  • Offline Offline
  • Posts: 35
Re: 125 Single Cylinder upgrades
« Reply #5 on: April 20, 2013, 05:48:37 PM »

Ok, well the bugger actually cut out on me around 100 meters from work this morning, i pulled over, restarted it but it was not happy, pulled away and it cut out again, tried to restart but the starter was having trouble turning it over, and then it stopped, tried the kickstart and it was seized solid LOL

Pushed it to work and had it recovered afterwards back home, engine is now out and semi stripped.

Bike actually unsiezed and started back up when home as it was cool.

Piston skirts + bore walls have scuffing/scoring, this explains the noises i could hear, not sure yet how to measure the bottom end for play, i can wiggle the piston around and it has a bit of free play on the rod, the rod has a small amount of up and down play, i have a service guide in the garage so i can measure it all at some point.

Piston also had a LOT of large flakey carbon deposits on the top, i think this stuff has been dragged down the cylinder helping it to mark the bore.

Just waiting for that RMR 125 engine to turn up now so i can fit it into the bike and see how it runs, then i will rebuild the hyosung lump, mosy probably going to rebuild it as a 150, might as well, it works out cheaper that buying genuine hyo piston + barrel!??!

Head/cam/followers are all perfect, no wear at all that i have noticed so far :D

Logged
2005 - RT125D (Karion)

birdmove

  • Learner rider
  • **
  • Offline Offline
  • Posts: 34
    • http://
Re: 125 Single Cylinder upgrades
« Reply #6 on: May 10, 2013, 07:15:54 PM »

  Just wondering how many miles you have on that 125cc engine?
Logged
<br /><br />&nbsp;&nbsp;&nbsp; jon in puyallup

s-m

  • Learner rider
  • **
  • Offline Offline
  • Posts: 35
Re: 125 Single Cylinder upgrades
« Reply #7 on: May 11, 2013, 08:05:31 PM »

Hello, i bought the bike with 9000km on it last summer, it now has around 16500km on it

The past year it has spent most of its life being thrashed up and down a dual carrigeway :)

I currently have the engine in parts, the conrod bearing has failed, the rest of it looks pretty good to be fair, had the piston/bore marks checked out and they are apparently OK to reuse, the noise i was hearing was the conrod bearing as it broke down, i was not sure if i could use a Suzuki Conrod, so i ordered a full new crankshaft from HyosungSource, it is supposed to be delivered by monday 13th, but it has been sitting in UK customs because of a "Missing Invoice" for the past 2 days  :(

I found some metals parts around the sump plug metal filter, probably parts of the bearing!

Never managed to get the Superbyke RMR engine to run correct in my bike, not sure why, i figured i had spent 2 weeks trying to get the thing to run properly, and in that time i could have fixed the original engine, so i removed it, will sell it on once the bike is up and running again.



Logged
2005 - RT125D (Karion)

s-m

  • Learner rider
  • **
  • Offline Offline
  • Posts: 35
Re: 125 Single Cylinder upgrades
« Reply #8 on: May 11, 2013, 08:12:21 PM »

Some information for future users, the hyo has a lot of different parts from the suzuki engine, this what i have found so far.

Crankshaft is different, timing chain teeth are larger and uprated.
Timing chain is twice and thick and uprated
Front sprocket is spaced differently, it also has different splines.
Gear shifter is spaced differently, this and the front sprocket is most probably due to the fat RT rear tyre needing extra chain clearence.
My bike has kickstart and electric start.
Stator/ign wire connectors are reversed but the wire colours are the same, the superbyke engine also has more spare wires, i think they might be specific gear indicators?
Head/cam are totally different, not interchangable due to the different timing chain, you cant mix and match (i tried)
Inlet port on head is around 26mm on the Hyo, the superbyke engine is 22mm, i suspect the hyo engine pushes a LOT more air/fuel due to its improved head/cam setup.
Logged
2005 - RT125D (Karion)

Pages: [1]