300cc Kit - Page 34

Huck369 · 01-22-2021, 02:35 PM

Quote:

Originally Posted by ChopperCharles

I contacted dynojet and they said they don't have one and have no ETA on when one will be made. But if a bunch of people start asking for one, they may change their mind.

How does the 283cc kit work for 75mph? I have no problems with the 250cc at this speed, but I'm not sure if the 283cc will have the top end to be able to maintain 75 on the highway.

I'd even be willing to downgrade to a carb maybe, if it would work without stripping everything out.

Charles.

Honestly, I didn't notice a change in top end with the 283 kit, BUT, the bottom and Mid-Range is significantly better, I think the top end would need some tuning, and maybe a free'r flowing exhaust (still running the stock exhaust on mine) to get the most out of the big bore kits......but it needed some more on the lower end, so I'm happy with the 283 kit

ChopperCharles · 01-22-2021, 03:30 PM

I probably need to replace my cylinder head, and if I'm going to do that amount of work I might as well install a big bore kit. And my thinking is that I don't want to lose any top end at all. I can hit 81mph at 10,000 rpm in 6th with my current gearing and tire choice, and that makes cruising at 75mph possible. 70 is the sweet spot with power left for passing. I don't want that to change, unless it's for the better.

I'd go straight to the 84mm 300cc kit if I knew there was a fuel controller capable of compensating for the leaned-out top end. I already toasted my valves once, I don't want a lean-ass mixture causing problems on down the line.

I'm even considering a carb conversion.

Charles.

Lukas · 02-07-2021, 02:51 PM

Gentlemen, I found on youtube a video in which a Russian guy installed 298cc cylinder with 84mm piston and 17mm pin, because he did not check with the seller whether the pin is 16mm and did it with bushings in the piston The Russian guy claims that the power at the bottom increased, but at the top decreased and the max speeddecressed too, what do you think about it I attach the video.

banfield · 03-09-2021, 06:48 PM

looking for gas fuel tank for my bike anyone help me

calvarez · 03-10-2021, 10:38 AM

Quote:

Originally Posted by banfield

looking for gas fuel tank for my bike anyone help me

You'd probably get better results starting a thread for that instead of posting into an unrelated thread.

Chris_Top_Her · 03-14-2021, 12:59 AM

There are other tuning options, I just hooked ECU hacker to my bike to read a code, looks like you can tune with that, although I haven't tried anything yet

ChopperCharles · 03-17-2021, 07:32 PM

Quote:

Originally Posted by ChondaChondaChonda

Worth it power wise - yes. It's not just the added cc's, but more compression. The motor pulls harder at all rpms across the spectrum. It's not going to turn it into a 50hp MX king, but it's a nice solid bump.

I have not noticed that the gas mileage is much different. I did notice that the first few times out on the big bore my wrist was getting sore- I realized it was because I was having to modulate the throttle at a lower opening which made it sore.

Very easy install. I'm a rookie on motors and it was pretty easy on the LXR. In chassis.

The EFI adjusted with zero issues. I would say it starts far better than before- possibly due to the unshrouding of the valves in the bigger cylinder.

Pretty simple swap on the LXR; probably a little more teardown on the RX3.

Is there a walkthrough somewhere for doing the big bore install? Specifically, I'm concerned with how to set the valve timing when putting the head back on. With no service manual there's just no information available anywhere.

Charles.

ChondaChondaChonda · 03-18-2021, 12:44 AM

Quote:

Originally Posted by ChopperCharles

Is there a walkthrough somewhere for doing the big bore install? Specifically, I'm concerned with how to set the valve timing when putting the head back on. With no service manual there's just no information available anywhere.

Charles.

There is an NC250 manual in Spudriders post here:
http://www.chinariders.net/showthrea...t=nc250+manual

The hardest part is getting the rings and wrist-pin in; I did it the hard way the first time and tried to push the cylinder down onto the piston assembled. It is much easier to put the rings on and push piston into the cylinder first. Then drop it over over the connecting rod end and put in the wrist-pin.

The timing marks are easy to line up and the cam sprocket is marked well so it's just a matter of lining everything up.

ChopperCharles · 03-18-2021, 01:10 PM

Perfect. That's great to know.

What are your thoughts on buying a new head from CSC and installing valves in it myself, vs buying one from AliExpress with the valves already installed?

Charles.

franque · 03-18-2021, 02:16 PM

Since the motor is a Zongshen exclusive, I would imagine China is protecting the intellectual property of a Chinese company within their borders... I've not heard of these being ripped off, but if you want to have recourse if there's a problem, it would be better to go through CSC. I've had problems with aliexpress customer service after the fact, and depending on the price difference, it might not be worth the gamble of something damaged in transit, for example.

calvarez · 03-18-2021, 02:26 PM

China...intellectual property...LOL!!!

franque · 03-18-2021, 04:40 PM

They protect what they perceive as their own, even if they don't care about anyone else's.

calvarez · 03-18-2021, 05:23 PM

I know, I've seen a case of them going after the ORIGINATOR because they thought the Chinese ripoff should be protected. He brought manufacturing back to the US pretty quickly.

ChondaChondaChonda · 03-18-2021, 06:03 PM

Quote:

Originally Posted by ChopperCharles

Perfect. That's great to know.

What are your thoughts on buying a new head from CSC and installing valves in it myself, vs buying one from AliExpress with the valves already installed?

Charles.

What's wrong with the current head?

I've bought the AliExpress head and it seems like the same quality. (YMMV!)

ChopperCharles · 03-18-2021, 08:01 PM

The exhaust valves won't stay adjusted for even 500 miles now. Either bad metallurgy in the existing head or valves, or I burned the valves and potentially damaged the valve seats when my bike went lean when my injector clogged up while the valves were too tight.

I could just replace the valves and hope for the best, but if I'd rather only take it apart once.

Charles.

03-14-2021, 12:59 AM	#501
Chris_Top_Her Join Date: May 2020 Location: San Antonio, Texas Posts: 62	There are other tuning options, I just hooked ECU hacker to my bike to read a code, looks like you can tune with that, although I haven't tried anything yet __________________ CSC RX4 2020
	1

03-18-2021, 02:26 PM	#506
calvarez Join Date: Sep 2018 Location: Peoria, AZ Posts: 334	China...intellectual property...LOL!!! __________________ 2016 RX3 2002 Honda CBR1100XX
	0

03-18-2021, 05:23 PM	#508
calvarez Join Date: Sep 2018 Location: Peoria, AZ Posts: 334	I know, I've seen a case of them going after the ORIGINATOR because they thought the Chinese ripoff should be protected. He brought manufacturing back to the US pretty quickly. __________________ 2016 RX3 2002 Honda CBR1100XX
	0

01-22-2021, 03:30 PM	#497
ChopperCharles Join Date: Feb 2018 Location: RDU, NC Posts: 677	I probably need to replace my cylinder head, and if I'm going to do that amount of work I might as well install a big bore kit. And my thinking is that I don't want to lose any top end at all. I can hit 81mph at 10,000 rpm in 6th with my current gearing and tire choice, and that makes cruising at 75mph possible. 70 is the sweet spot with power left for passing. I don't want that to change, unless it's for the better. I'd go straight to the 84mm 300cc kit if I knew there was a fuel controller capable of compensating for the leaned-out top end. I already toasted my valves once, I don't want a lean-ass mixture causing problems on down the line. I'm even considering a carb conversion. Charles.
	1

02-07-2021, 02:51 PM	#498
Lukas Join Date: Jan 2021 Location: A small Polish empire Posts: 244	Gentlemen, I found on youtube a video in which a Russian guy installed 298cc cylinder with 84mm piston and 17mm pin, because he did not check with the seller whether the pin is 16mm and did it with bushings in the piston The Russian guy claims that the power at the bottom increased, but at the top decreased and the max speeddecressed too, what do you think about it I attach the video.
	0

03-18-2021, 01:10 PM	#504
ChopperCharles Join Date: Feb 2018 Location: RDU, NC Posts: 677	Perfect. That's great to know. What are your thoughts on buying a new head from CSC and installing valves in it myself, vs buying one from AliExpress with the valves already installed? Charles.
	0

03-18-2021, 02:16 PM	#505
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	Since the motor is a Zongshen exclusive, I would imagine China is protecting the intellectual property of a Chinese company within their borders... I've not heard of these being ripped off, but if you want to have recourse if there's a problem, it would be better to go through CSC. I've had problems with aliexpress customer service after the fact, and depending on the price difference, it might not be worth the gamble of something damaged in transit, for example.
	0

03-18-2021, 04:40 PM	#507
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	They protect what they perceive as their own, even if they don't care about anyone else's.
	0

03-18-2021, 08:01 PM	#510
ChopperCharles Join Date: Feb 2018 Location: RDU, NC Posts: 677	The exhaust valves won't stay adjusted for even 500 miles now. Either bad metallurgy in the existing head or valves, or I burned the valves and potentially damaged the valve seats when my bike went lean when my injector clogged up while the valves were too tight. I could just replace the valves and hope for the best, but if I'd rather only take it apart once. Charles.
	1