300cc Kit

[sqwert]

Originally Posted by NzBrakelathes

Cheers mate
The O ring at the manifold is hard to get, nothing online and the dealer can be 10 days to never to get stuff.
Funny thing is CSC on stuff can be easier then local here in fact and on small parts its not much more then here etc.
Left side cover is cause it is easier to manage the chain etc, but to be fair I reuse the gasket as they didn't break in the past but hey it might be useful another time worst comes to worst.
RX3 you need to remobe the frame around the engine and drop the bolt under the engine near the swing arm put you tongue out left then right whistle and fart a moment for the bits to come up and out as that metal bar gets in the way etc
Mine is together - needs oil and test start after I fit the FOG HORNS for safety.

I had to pop the side cover to get the cam chain unknotted. Like you, reused the original gasket. Probably can get you a few thousand intake O-rings from a local seal supply for next to nothing. May I ship some to your shop without getting you in trouble with import duties? Most dependable and cheapest shipping? Would like to express thanks for your efforts putting the kit together and doing business in Engrish. Will check for O-rings at shop tomorrow.


CSC charges a small fortune for shipping a single small part. Everybody does. All the small package carriers are union and have to charge a fortune to cover labor costs. I understand Chinese officials execute union organizers, probably a good idea because if it wasn't for unions Zong Shen would be building its bikes in the U. S. of A. since we have about half our citizens and several million illegal aliens mooching off the taxpayers instead of working and supporting themselves.

Still reassembling, fitting skid plate and other stuff, including illegally loud horns and illegally bright extra lights front and back. Found some small emergency vehicle lights about 10 times brighter than stock turns and brakes, converting to a 3-wire tail/turn/brake system using a trailer light convertor. Thinking about using the stock brake and 3 LED oblong trailer lights with red reflector edges for tail so should be extra bright, then using 4 super bright emergency lights for turn and brake, extra extra bright. I figure if I blind people they will know I am there since the #1 excuse morons who run into motorcyclists give is, "I didn't see... ." Well, if you can't see these lights you are way to blind to be driving.

[NzBrakelathes]

Bike ran yesterday on 300cc kit, big brakes done but few things to finish before full test ride

[NzBrakelathes]

1 small tweak was needed - the caliper was a little off center to the rotor and I added in a 1mm washer between fork bolt mount and the plate, it was rubbing a little on the inner pad.

Nice upgrade but I do want to inform people well of what is what so they can make a well educated decision if to or not to buy etc

[2LZ]

More miles on the 300 kit:

Absolutely loving the mid range. It's so nice to be able to go through a low speed tight turn and just roll the throttle on from 3500 R's and pull out. I'm doing all my riding between 3500 and 6500 now. I'm actually thinking of going back to stock gearing again because it may pull it real nice now.

Again, I'm taking it super easy due to the new bore and piston but I'm getting the suspicion that it's leaning out up around 7000 and the mapping is shackling it, but just a guess. It seems to really flatten out above 7 so I don't go there much.

sqwert, you'll get used to gutting the RX3 to work on it. It is a pain at first but I can take it down in about a half hour with a beer. That is one thing I do prefer with our little dual sports, it's just like the old days. It's just a bike with no extra styling crap.

[sqwert]

Together.

Used Mobil 1 20W50 full synthetic for assembly, Valvoline 10W40 dino for crankcase. Jug and slug need to break in so dino for break in is appropriate. Relatively thin viscosity allows quicker pressure build and oil pump effectiveness to all internals.

Cycled key 3 times to prime EFI. 3 seconds on starter button and fired right up. Was going to hold at idle until oil light went off, but light off about 2 seconds after engine fired. Right oils for assembly and break in make a difference.

Held throttle 3000-3500 rpm for about 10 minutes because that's the way I always start rebuilds. Read an article on why years ago but can't remember the reason since I'm old, dropped on my head, and dain bramaged. If memory serves variable high idle shifts hot spots in combustion chamber and provides a lot more clean, cool oil at higher volume and pressure than idle speed. This reduces temperatures and wear the first few minutes of break in. There are always madnesses for my reasons, but sometimes I just have to wait until the whys pop up out of my sleepy, old brain cells.

Anywho, fuel/air playing around at first, would not idle without threatening to die, but once heated up until fans kicked on things began to smooth out.

Let engine cool while reinstalling decorations and seat, then fired it up another 10 minutes. Held 3000-3500 a couple minutes, than blipped idle to 3500. Smooth idle this time around, still a little rough near 3500rpm.

Letting it cool while typing this. Then, off to check on O-rings for NZ. Seal supply is 17 miles of 45-50mph hilly, curvy gravel road, perfect for initial break in.

2LZ, I don't do beer. I expect you are right, though, I'll get faster as I gain experience and remember (if that still works) where everything plugs in. Assembling things in the wrong order means 1/12 turn and flip the wrench, 1/12 turn and flip the wrench, 1/12 turn and flip the wrench, ... . Not going through that again. I expect the easiest thing would be to just unbolt whatever's on top, then reassemble the opposite order. Do you have a carb or EFI?

[2LZ]

Originally Posted by sqwert

Do you have a carb or EFI?

EFI. I wish I had a carb.

[sqwert]

Originally Posted by 2LZ

EFI. I wish I had a carb.

Only time I wish for a carb is working on or with EFI. Carbs are so simple! On the other hand, EFI provides a much wider powerband with better throttle response and off idle than any carb with the same peak power.

Rode over to fetch some O-rings. Don't look right. Yuck.

Great ride on curvy, hilly country road. 300cc kit with EFI will pull 6th smoothly from 18 mph (idle speed) right up to 6000rpm with no unexpected dead spots or power loss. Very nice. Much improved off-idle power output, keeps building to 6000rpm. Might go further, that's all
I've turned it so far.

Off to ride some more hills and curves up to 6000rpm.

[ChondaChondaChonda]

Hammered my big bore for 9 hours yesterday and 4 hours this morning. Absolutely flawless and it pulled everything I aimed it at. Lots of 2nd gear singletrack.


Lots of places it was bouncing off the rev limiter.



EFI is awesome when you ride lots of big elevation changes. This section of transfer road took us to 9818 today.

[NzBrakelathes]

I am off to the farmer bike flee market today - add some KM on the bike (FARK nose what you boys call MILES) the places is miles away so will ad around 65km today

[ChondaChondaChonda]

Originally Posted by 2LZ

EFI. I wish I had a carb.

2LZ- I just recently purchased a GPX that has the NC250 with a carburetor. I have not even put gas in it yet - It's identical to the one in the picture above. I will be converting it to EFI and I will give you the carb if you'd like.

[sqwert]

210 miles on the 300cc today.

Starts as easy as the 250.
EFI self adjusts with a few minutes of riding up to 6000rpm, as fast as I went during break-in.
Better throttle response idle through 6000rpm.
More power idle through 6000rpm.
Throttle less open speeds up to 65mph.
More compression breaking when throttle is closed.
68.57mpg, previous best 66mpg, past average about 62mpg.
Less shifting on curvy and hilly roads or in traffic.

So far very happy with improved performance on the paved back roads. Can't wait to complete break-in as performance is still improving with miles as parts break in.
Jump in fuel efficiency may be a fluke, but maybe not. Nice surprise.

Ride to breakfast in the morning, then fresh dino oil to complete break in. Then another couple hundred miles on the back roads. Looking forward to full synthetic Mobil 1 going back in. Mobil 1 was worth 3mpg over dino Valvoline way back when. A similar improvement over dino Valvoline this time will make 71-72mpg a reality. Sweet, what with the price of gasoline going up again.

[2LZ]

Originally Posted by ChondaChondaChonda

2LZ- I just recently purchased a GPX that has the NC250 with a carburetor. I have not even put gas in it yet - It's identical to the one in the picture above. I will be converting it to EFI and I will give you the carb if you'd like.

I'd love to try it but I'm afraid what wouldn't work if I tried the swap. Thanks tho!
My main concern with the EFI is that it seems to lean out in the high R's that jetting would handle easily.....
I can't remember the last time I saw a real trials tire on a bike other than the ones rotting on my old Yamaha.

[NzBrakelathes]

Originally Posted by ChondaChondaChonda

2LZ- I just recently purchased a GPX that has the NC250 with a carburetor. I have not even put gas in it yet - It's identical to the one in the picture above. I will be converting it to EFI and I will give you the carb if you'd like.

What EFI are you fitting? What is the cost etc?

[sqwert]

Rode with Sam She Am to breakfast. Sam rides a 250 Ninja. Where we pulled onto the highway a hill blocks the view of oncoming traffic, in this case three jacked up 4x4 pickups with really big tires racing down the highway WFO. Those half-ton pseudo-monster trucks don't have the brakes to stop, or even adequately slow, those tall, heavy, slow turning mud grips. Had to take the RX3 to the limit to avoid being run over by those trucks that were not being operated with the ability to stop in the assured clear distance ahead maintained.

Full throttle, 9000rpm shifts through 3 gears, kept about 3 feet (1 meter) between my taillight and the first truck's bumper. I did not notice any dead spots, just steady power all the way to 9000rpm. I think folks with EFI breaking their 300 kit in gently will be nicely surprised after some highway miles. I did about 220 miles (350km) yesterday running 50-65mph on hilly, curvy roads. I think the EFI reset itself to higher speeds with the extra displacement under those conditions. I'm not so sure any reset could occur for high engine speeds if the engine doesn't turn them. Maybe the higher speeds need to have some semblance of load to reset properly rather than just down shifting to spin the engine? Maybe higher speeds need to be run for several minutes for the EFI to reset properly, like down the highway at 65mph for 10 minutes? Don't know for sure, but if I was breaking in my 300 kit properly as possible (okay, I'm trying) I'd be patient, put in the miles, switch to synthetic oil, then give it a good run. I expect that all the worry about EFI tuning will then go away. Just takes time and miles, maybe?

I'll read a new plug after the first 1000 miles and fresh synthetic oil. Then I'll consider if necessary to remap.

Anywho, time to change the oil and head to Memphis for BBQ.

[2LZ]

Originally Posted by sqwert

I expect that all the worry about EFI tuning will then go away. Just takes time and miles, maybe?

I'm hoping. I think a big part of the problem regarding my top end is one, I am breaking it in mildly but two, there's no where to open it up around here! It's all twisty country back roads and canyons....which the RX3 shines at, actually.

After the break in, I may run in over to HWY 88 for some highway speeds.