Full Teardown： QJMotor Sai 450 Engine – The Ninja 400 Clone？

Chenjongsi 450 engine. Everyone has been urging me to release this video quickly. Well, here it is. This engine was developed through reverse engineering. Of the legendary Ninja 400 engine. Then, QJ motor increased the crankshaft stroke. And that's how we got the 450 cubic centimeters displacement. Now let's look inside. First, let's check the clutch. This clutch small drum, inner hub. Is likely manufactured by Chenjong themselves. Let's take a look at the clutch plates. For these plates. They are using FCC paper-based clutch plates. FCC paper-based materials are imported from overseas. No need to look at the large drum, outer basket. It's definitely made by Chenjong themselves. Let's check the bearings. From this side, the bearing brand isn't visible. Everyone knows the Ninja 500, right? Its actual displacement is also around 450 cubic centimeters. It also uses an increased, crankshaft stroke to achieve the higher displacement. Since Chenjong did the exact same thing. Could we say? Chenjong anticipated Kawasaki's next move? Because the previous Ninja 250 and 300 twins. Were also upgraded by changing the stroke. The simplest ways to increase engine displacement. Are either increasing the bore. Or increasing the crankshaft stroke. Most manufacturers do this. As for Chenjong's assembly quality. It really needs some improvement. This spot is supposed to have one ceiling ring. But this engine came from the factory with two installed. You can't just give away extra parts like this. Chenjong needs to step it up. Building up from scratch, Chenjong is still quite impressive. Alright, let's look at the camshaft. I previously posted. A video about the downgraded Ninja 400 camshaft. You guys know that one, right? In the past. The Ninja 400's camshaft and materials. Were definitely better than this Sai 450. But now, for camshafts produced after September 2023. They are the same as Chenjong's. They are using spheroidal graphite cast iron. Which means. To all the Ninja 400 owners. If your camshaft wears out. Don't stress over it. Save your money and just buy a Chenjong replacement. It saves a lot of money. Look at this valve lifter, bucket. This is well made. The top has a DLC, diamond-like carbon, coating. Even the Ninja doesn't have DLC here. Finally found something better than the Ninja. Regarding the gaskets, I've posted a video before too. Even if you buy a full gasket set. You can use them directly on a Ninja. An OEM Ninja gasket set costs around 1000 Renminbi. This set costs less than 200 Renminbi. Isn't that a great deal for your garage? Tell me, isn't that a massive saving? Chenjong's gaskets are perfectly fine. They won't cause any oil or water leaks. Now let's look at the cylinder. The Ninja uses a ceramic-coated cylinder. This Sai 450 does not. It uses a cast iron liner instead. You can tell from this part. But look at the price difference. It's only 20 000 plus RMB. The Ninja 400 is nearly 50 000 Renminbi. With such a huge price gap. Not having a ceramic cylinder is to be expected. We can't be too demanding. Now check out the piston. The piston is cast. The entire piston skirt has a graphite coating. And the piston top has micro arc oxidation treatment. This process is slightly better than the Ninja 400's. However, the Ninja 400's material is a bit better. The Ninja uses high silicon aluminum alloy. Both have their pros and cons. Another reminder for Ninja owners, if you have a scored cylinder and find the OEM Kawasaki parts too expensive to replace, just get the Sai 450 set. Pistons and rings included. Just think about how much you'll save. To put it in perspective, those used Ninja 400 pistons sold online cost 400 to 500 Renminbi just for the piston. But a brand new Sai 450 piston and ring set doesn't even cost 1000 Renminbi. Don't you feel like thanking Qianjiang? Many guys who bring bikes to me for repair are quite grateful for this. Since I've shared this, give this video a like, will you? Consider it a reward for this money-saving tip. I've actually ridden this bike too. I've taken it on the track, and it felt pretty good. That's me in the photo. Whoever took that photo, contact me to leave your address. How does this bike perform on paper? You can check the Jidong app. They have real-world tests for the Sai 450. Acceleration, braking, fuel consumption, and horsepower. Let's remove the bearings. Let's see the brand. And see if my guess was right. The bearings are indeed CNU brand. P6 grade bearings. And here are the NSK bearings. This is the balancer shaft. Water pump drive gear. Now let's look at the connecting rod bearings, bushings. As for the rod bearings, they look like copper-based bearings. The brand is Johnson Controls, Bakert. Now let's check the timing chain. The timing chain is from Did Japan. Right, check the crankshaft bearings. They are also copper-based bearings from Johnson Controls. Alright, the teardown is complete. The crankshaft is forged. All current mainstream crankshafts are forged. As for the main and counter shafts, and the gears, they are compatible with the Ninja. The cylinder head and camshafts are also good. Thumbs up for the DLC valve lifters and oxidation process. Alright, that's it for this teardown. Thanks for watching.