GN125 vs 150 kit 0-100 ADVGN 

That's a good ride on a GN. I took my stock one away for a 3 day ride late last year, went great. Just put my advgn back together with dr125 head, big cam, and 150 kit. So hoping for a bit of improvement testing before the next big changes

Thanks, I need to sort out my computer and put some more videos up.

Beats walking

cool, i have thought about adding an oil cooler, but i will do some temperature monitoring first. I have an extra big big block kit in the works, so might have a bit of extra heat

@@tortron its hot here all the time . and i like to keep pushing it ,as i cant get a new bike in raro , protective duty on bikes over 125cc Like %150 On The CIF , this was going to be the year for playing , so if i get a new bike in NZ i only pop down for 3 weeks a year normally , so it looks like i will have to use my brothers Velocettes , and just thump around Auckland

@@chrisgreig5628 yeah this one gets hell on dirt tracks fully loaded up, on the open road i dont think it would get too hot (although peak summer coming from the motorway to town driving was warm)

Yeah I have some other sprockets ready for testing (and a 6 speed gearbox). For me I'm mainly looking for an OK top speed, but good acceleration through corners and holding speed uphill, which suits the riding I do on this bike

Yes I usually go for about 0.010 on the ring gap on my pistons. Do you have a GN125 workshop manual? There's one floating around online free

@@tortron hi mate, I found a PDF version online it's for the newer GN125 F model it's good, I've been looking through it very handy to have

Just put a whole dr200 engine in its almost double the HP of the GN125. To take a GN125 to 200cc you need to get a cylinder sleeve and take it out to 65mm and stroke it by up to about 8mm using an lt160 conrod. It has been done, getting 212cc. Can't go much bigger than 70mm on the piston before it's too big for the headbolts. You could use a Dr200 cylinder on the GN125 bottom end, but finding a good piston to use is the hard part, as the GN125 has a 14mm pin, there's some Honda cbf150 pistons that would work with the GN125 head as they are flat topped (come in 63.5 and 65mm). Dr200 head has a large chamber so compression would not be great. Basically the best and fastest and most reliable way to double your hp is just put the whole dr200 engine in

Thank you for your quick response mate, appreciate it

@@ZippoMan747 you will get about 180cc with just the Honda piston and bored cylinder. I think this is a good option with the Gn125 head. But you might want to put bigger valves in, they are kinda small, and maybe a Dr200 camshaft

On this bike I use the standard carb, even with 150cc and race cam, it still takes factory jets, tested with an oxygen sensor its good thought all throttle openings. For a little better performance try a pumper carb with direct pull slide, it gives you more "snap" off the throttle.

For 80/100km max, do you have a tachometer? If the bike is travelling this fast in top gear at about 8000rpm, you should change the sprockets (bigger front, smaller rear) and it should travel 100kph fine. If the bike is lacking power, then there is some other issue

@@tortron good to know man thanks for the tips, I'll try eBay for a direct pull slide 👍👌

@@upsidedown1986 yeah it won't give you any more top speed, but it will change the feel of the bike. I have 2 Dr200's (very similar engine to GN125) one with pumper carb and one with the cv carb and the pumper is so much more agressive

@@tortron I'll try a larger front sprocket with smaller rear, the bikes pulls away great 4th feels great then 5 just keeps the speed steady, I'll keep an eye on the tachometer when I'm out riding tomorrow, your channel is good, thanks again man 👍😎

If your bike has a flat top 125cc piston in it you should use 2 base gaskets. (The supplied piston has a slight dome on it and this causes a pre-ignition problem under some conditions, with 2 base gaskets I did not have that problem). Most importantly, before installation you need to have the bore matched to the supplied piston. I have found that the clearance is too tight (if you don't do this you will probably seize the bike within 100km, I have done it before thinking it would already be matched). You can do this in about 60 seconds with a dingleball hone, but you would need to be able to measure the piston to bore clearance. (I have bore gauges and calipers, but you could do it with just a feeler gauge and some careful measuring) or just take it to a machine shop, it should be a quick and cheap job. Then you need to gap and install the rings. Then you can install it. I suggest the weisco break-in method

Clearance between piston and cylinder should be minimum 0.04mm (maximum allowance of up to 0.12mm). Measured at about 1.5cm below the oil ring and 90 degrees to the pin

@@tortron i have a flat piston on it so automaticaly i should use 2 base gasket im on high comp right know 00 gasket so when i change the bore ill install 2 base gasket and the head gasket? Or i can still do i highcomp 0 gasket on the head the piston i bought i slight dome type

@@tortron the piston and the cylinder did not match so im still going to bring it on the matchin shop what should i say to the machine shop?

@@classix2132 Ask them to hone the cylinder to size. Take the piston and rings with you. clearance should be as in the comment above (you can find this in the manual, available to download free online, its in the information in the back pages) If they work on engines they will know what to do

First make sure the piston to bore clearance is in spec, I had a couple show up too tight out of the box. Then I usually follow wiesco break-in procedure getting it up to temp a couple times powersports.wiseco.com/blog/proper-engine-break-in-after-a-rebuild

@@tortron thank you 👍

Makes a big difference if you ride on the open road. Leaves standard gn125s behind.

Really made the bike nicer on the highway. It will hold speed uphill! Haha. You can also put in a stock dr200 cam or stock lt230 cam for a good increase. They are usually pretty cheap on ebay used. I just put in a hotcams stage 1 for a lt250 and it has about the same performance as the 150 kit over just the 125. If you can, get the cylinder matched to the piston they supply. I have had them seize up twice because they are slightly too big

@@tortron yes! I was tossing around the idea of throwing a dr200 motor on, since it bolts right up, so no frame modifications necessary. We’ll see what happens😈

@@ConnorGMedia Yeah the dr200's are very common here as they make a df200 for the farmers. They have twice the hp and go right in. All the ones here have a kickstart. I would stay with the 125 base as a challange, but swap the dr125 so i get the kickstart too. You can use quad bike parts to make the dr200 bottom end into a 400cc

@@tortron care to elaborate this sentence? I'm really interested on this 400cc upgrade.

@@TheSilviu8x sorry I should say use the GN250 bottom end, and suzuki quad parts (cam chain is on the other side of the head) you can build what's basically a gn400 engine with the right conrod. can buy a big bore kit to take it to about 300cc. DR200 can go to about 230 with an off the shelf kit. Are you messing with a GN125 engine? Take the crank out and have the big end machined about 10mm lower, use a lt160 con rod, or have your original one heated and squashed shorter (or convert to a different conrod as the little end does not give you a lot of choice for pistons. From memory it was pretty off the shelf to get a 190cc stroker. Useful if you need the cylinder to say 125 for legal reasons. Otherwise ust out in the stock DR200 engine with a Pumper carb and fmf exhaust and you have doubled the power