loss of power after riding fast for a while

[andyj812]

Hello, I went for a ride on my Will today (Bashan Bs250gy-9) and was after about 20 miles on the highway (actually got up to 60 by gps) I suddenly lost power and couldn't do any more than 51. I reached my destination after another 5 miles. I let the bike sit for a few minutes I got back on the bike to return home. It ran fine for about 5 miles (55+) and then suddenly lost power (max speed 41 gps). I pulled over the side of the road and turned the bike off and opened the gas tank. After closing the gas tank I started the bike and it ran fine the rest of the way home. The last time I went for a long ride I stopped and got gas and was surprised how much better the bike ran afterwords and thought must be better gas. I always run 93 octane and usually has fuel stablilezer if it comes from gas can. I suspect that when I go for long rides the gas tank is not able to vent fast enough and opening the gas tank lets air in. When I open the tank on the side of the road I did not here the shhhhh sound of air rushing in.

Another problem I have is the engines often dies when coming to a stop when clutch pulled in. Sometimes hard to restart. May be that I have the idle set too low if I hold the throttle open a little it usually doesn't die at stop signs. It starts very easily if I turn it of and when cold with out choke if it doesn't die on it own. Where I have the idle set sounds right to me but I don't have a tach to know exactly where its set at

[JTHSPACE]

Certainly sounds like a vacuum lock, have you changed the gas tank cap from the original? Some have an air hole so you could check to see if it is blocked - usually found on the cap on the side below the tank seal. Also check your air filter - is it a wet type (oil?). Maybe too much oil in the filter? Check vent tubes from carb and engine to see if they are blocked.

Sounds like idle is set too low, I prefer to have a slightly fast idle around 1000 to 1200 especially as my bike is new and still a bit "tight" even though the manual says the run-in period is a day!!!

Jeff

[SpudRider]

You might have a bad CDI unit. Do you have a spare CDI unit?

[andyj812]

Originally Posted by JTHSPACE

Certainly sounds like a vacuum lock, have you changed the gas tank cap from the original? Some have an air hole so you could check to see if it is blocked - usually found on the cap on the side below the tank seal. Also check your air filter - is it a wet type (oil?). Maybe too much oil in the filter? Check vent tubes from carb and engine to see if they are blocked.

Sounds like idle is set too low, I prefer to have a slightly fast idle around 1000 to 1200 especially as my bike is new and still a bit "tight" even though the manual says the run-in period is a day!!!

Jeff

I don't see any vent holes in tank or in cap. The bike only has 450 km by the odometer. I have checked the air filter but the vent lines appear to be free of kinks.

[andyj812]

Originally Posted by SpudRider

You might have a bad CDI unit. Do you have a spare CDI unit?

no I don't have a spare CDI unit, is Ebay the best place to get one? Are the all standard for cinese bikes? thanks for the help, Are there any other spare parts I should order as well?

[andyj812]

Originally Posted by JTHSPACE

Certainly sounds like a vacuum lock, have you changed the gas tank cap from the original? Some have an air hole so you could check to see if it is blocked - usually found on the cap on the side below the tank seal. Also check your air filter - is it a wet type (oil?). Maybe too much oil in the filter? Check vent tubes from carb and engine to see if they are blocked.

Sounds like idle is set too low, I prefer to have a slightly fast idle around 1000 to 1200 especially as my bike is new and still a bit "tight" even though the manual says the run-in period is a day!!!

Jeff

The idle may be set to low i'm gonna adjust it the next chance I get to ride. The next time I plan on a long ride I'll put the spare key in the gas cap and if does it again Ill open the gas cap to vent instead of stopping and see if that fixes. thanks for the help. I wish I could find a capatable new "dash" with magnetic pick up speedometer and a tachometer for a reasonable price.

[SpudRider]

Originally Posted by andyj812

no I don't have a spare CDI unit, is Ebay the best place to get one? Are the all standard for cinese bikes? thanks for the help, Are there any other spare parts I should order as well?

The CDI units occasionally fail for all motorcycles. However, the Chinese CDI units have a reputation for failing more frequently than others. Therefore, it's a very good policy to have a spare CDI unit on hand. The spare CDI unit also greatly facilitates troubleshooting the electrical system.

The CDI units are not universal, and can be different for each motorcycle. Check your wiring diagram. You need to determine whether you have and AC-CDI, or a DC-CDI unit. Among other places, eBay is a good place to find a spare CDI unit for your Honda cloned engine.

Besides getting a spare CDI unit, it's always a good idea to have extra levers, cables, et cetera.

[andyj812]

Here is the wiring diagram that is in the generic owners manual (seems to cover many bikes and not this bike specific). Since the CDI comes straight off the generator I'm gonna say its an AC fired CDI.

[andyj812]

Here is a pic of my CDI unit it its any help but from what I have looked up the ac and dc have same pin config

[Weldangrind]

Make sure that a replacement CDI has the same dimensions. As you've seen, the pinout is the same, so that's not an indicator.

I recommend that you adjust the valves.

[andyj812]

Originally Posted by Weldangrind

Make sure that a replacement CDI has the same dimensions. As you've seen, the pinout is the same, so that's not an indicator.

I recommend that you adjust the valves.

I adjust the valves at 300 km about 180 kms ago, It took my several times adjusting to get the feeler gauge to read right after I rotated the engine after adjustment, I used the specs provided on the manufactures plate: .04mm intake and .06mm exhaust. The adjusting wasn't as bad as getting the plastics to line back up because the gas tank had to be unbolted and moved back in order to get valve cover off. I will check the valves to make sure they are still in spec sometime this week.

[andyj812]

Originally Posted by Weldangrind

Make sure that a replacement CDI has the same dimensions. As you've seen, the pinout is the same, so that's not an indicator.

I recommend that you adjust the valves.

I ordered 2 of these for 5.99 plus free shipping

http://www.ebay.com/itm/191301760846...846%26_rdc%3D1

[SpudRider]

Perhaps I am mistaken, but I believe the wiring diagram indicates you have a DC-CDI unit. I see an input from the pickup coil on the stator, but I don't see any input from a source coil on the stator. Instead, I see 12V DC coming as an input from the battery via the kill/run switch.

However, the wiring diagram could be wrong, since the size of you CDI unit indicates it is a smaller, AC-CDI unit, rather than the larger, DC-CDI unit.

http://www.ebay.com/itm/GY6-DC-CDI-B...75c7eb&vxp=mtr

[andyj812]

Originally Posted by SpudRider

Perhaps I am mistaken, but I believe the wiring diagram indicates you have a DC-CDI unit. I see an input from the pickup coil on the stator, but I don't see any input from a source coil on the stator. Instead, I see 12V DC coming as an input from the battery via the kill/run switch.

However, the wiring diagram could be wrong, since the size of you CDI unit indicates it is a smaller, AC-CDI unit, rather than the larger, DC-CDI unit.

http://www.ebay.com/itm/GY6-DC-CDI-B...75c7eb&vxp=mtr

The CDI I ordered has the exact same deminsion so hopefully it is correct. I cant believe I stopped looking at the diagram after the stator. this is all a learning experience and I'm learning a lot from you guys. If its the wrong one I'll stick them back on ebay or post them on here and see if anybody wants to trade for a rear rack that I can modify along with the 44t rear sprocket I ordered

[Weldangrind]

You may find that the new CDI does not allow the engine to shut off. If that's the case, your wiring harness can be slightly modified to work with it. Be prepared to stall the engine the first time you try the CDI.