Secondary Butterfly valve not opening according to throttle

[Dafeimao85]

Hi All,

I manage to retest whole bike again

I guess I found the reason why my engine bog

What happen as per topic it's not opening

When I on the engine, the butterfly valve went to 100% open. When I start it close and maintain at close position. No matter how I Rev the engine it remain close. After I off the engine, the valve then open back to 100%

Primary TPS voltage is working correctly. Ecu is getting TPS data but somehow the stva is not responding to the TPS.

Anyone has any idea about this? I try to Google but found nothing.

[Dennis]

Make sure you are at an RPM and throttle opening that will open the STP enough for you to see. Reference STP map below.

[Dafeimao85]

Make sure you are at an RPM and throttle opening that will open the STP enough for you to see. Reference STP map below.

View attachment 1693941

Hi thanks for the help,

So rpm below 3k should still be at 10%.

So that means my stva is working?

May I ask what is the top row 8.1, 16, 30, 60......

[Dennis]

Hi thanks for the help,

So rpm below 3k should still be at 10%.

So that means my stva is working?

May I ask what is the top row 8.1, 16, 30, 60......

That should be Throttle Position Sensor reported position, which is the primary throttle.

This doesn't mean the secondaries are working for sure, but considering they open before starting (if I read your post correctly) and then move to nearly closed it seems they are working as intended at least initially.

[Dafeimao85]

That should be Throttle Position Sensor reported position, which is the primary throttle.

This doesn't mean the secondaries are working for sure, but considering they open before starting (if I read your post correctly) and then move to nearly closed it seems they are working as intended at least initially.

Hi Dennis.

Thanks for the data. With the help of the data. I went back to the fuel pump which I had suspected and solve the issue.

[Dennis]

Hi Dennis.

Thanks for the data. With the help of the data. I went back to the fuel pump which I had suspected and solve the issue.

No problem. My thought was the big fuel filter (not the sock). Not sure which part you ended up changing.

[Dafeimao85]

No problem. My thought was the big fuel filter (not the sock). Not sure which part you ended up changing.

Its like you mention in early Jan. The metal mesh strainer.

Gen 1 pump suction is metal mesh strainer > pump > socks filter.

Gen 2.5 pump suction is metal socks strainer > pump > metal mesh filter.

That's why i am having a hard time because in my understanding. The socks capture the finest carbon. While the mesh is just like a back up.

And my fuel flow test came back passing. I get about 230ml of flow in 10 sec. I do not have a pressure gauge which I can't determine the pressure. But in theory, if a clog occur at the filter. Both pressure and flow should have drop. I don't understand why it can pass the flow test.

I have not yet replace it. I only use a carb cleaner to back purge the filter and the busa roar with about 100miles before it starts to bog again. But at least with the test, it shows me the problem is not mechanical. It's definitely the filter.

[Dennis]

Be aware replacing the component you are pointing to. I don't believe Suzuki sells that separately. I doubt an aftermarket part would exactly fit. That part has the fuel pressure regulator. You can buy the whole plastic assembly (normally white on Gen2) as aftermarket, but I have seen they can have the incorrect fuel pressure. It would seem to run ok but may not make peak performance like it would with the correct pressure. If you have a way to tune the bike it's not such a big deal.

I expect my fuel pump/filter to die soon on my 2008 because it is 17 years old now. I plan to buy the entire assembly from Suzuki for the ridiculous price just to make my life easier.

[LC4CARL]

Be aware replacing the component you are pointing to. I don't believe Suzuki sells that separately. I doubt an aftermarket part would exactly fit. That part has the fuel pressure regulator. You can buy the whole plastic assembly (normally white on Gen2) as aftermarket, but I have seen they can have the incorrect fuel pressure. It would seem to run ok but may not make peak performance like it would with the correct pressure. If you have a way to tune the bike it's not such a big deal.

I expect my fuel pump/filter to die soon on my 2008 because it is 17 years old now. I plan to buy the entire assembly from Suzuki for the ridiculous price just to make my life easier.

Maybe I should do that on my '05 too.

[Dafeimao85]

Be aware replacing the component you are pointing to. I don't believe Suzuki sells that separately. I doubt an aftermarket part would exactly fit. That part has the fuel pressure regulator. You can buy the whole plastic assembly (normally white on Gen2) as aftermarket, but I have seen they can have the incorrect fuel pressure. It would seem to run ok but may not make peak performance like it would with the correct pressure. If you have a way to tune the bike it's not such a big deal.

I expect my fuel pump/filter to die soon on my 2008 because it is 17 years old now. I plan to buy the entire assembly from Suzuki for the ridiculous price just to make my life easier.

Hi Dennis

Try Google webike.

AD do not sell the parts seperately. From Revzilla I manage to get the part number and directly order from webike.

2008 Hayabusa Parts Number

For my pump I brought after market from high fuel flow. My buddy 08 Busa brought from AEM. Bottom line about the fuel pump in my experience is just change the pump. The rest use back original which again can be order via webike.

For the regulator I plan to keep the original as back up if the new 1 is giving me any problem.

Fyi: 2008 busa fuel pump assemble part number is 15100-15H00. Webike is selling around usd 550 include shipping.

If you buy from quantum fuel system do buy only Fuel pump and cable only, then seperately purchase these following part number

QFS pump $90
China made pump $60 from ebay

Then rebuild ur fuel pump kit by replacing the China filter and strainer, and quantum pump. The rest use back the exisiting item on your current pump.

The Filter for Gen 2 is ridiculously expensive! Even from webike cost almost $300.

If you follow my recommendations I believe it cost you about $170.

[Dafeimao85]

Maybe I should do that on my '05 too.

As a mechanical back ground born

I truly believe if it ain't broken, don't fix it.

If my bike did not give me a cold start stalling. I believe I would just do the regular EO changing and ride until it broke.

[Kiwi Rider]

I truly believe if it ain't broken, don't fix it.

OK, but isn't 'preventive maintenance' a thing?
. . . replace when it's aged and BEFORE it breaks or fails?

[Kiwi Rider]

Hi Dennis

Try Google webike.

AD do not sell the parts seperately. From Revzilla I manage to get the part number and directly order from webike.

2008 Hayabusa Parts Number

For my pump I brought after market from high fuel flow. My buddy 08 Busa brought from AEM. Bottom line about the fuel pump in my experience is just change the pump. The rest use back original which again can be order via webike.

For the regulator I plan to keep the original as back up if the new 1 is giving me any problem.

Fyi: 2008 busa fuel pump assemble part number is 15100-15H00. Webike is selling around usd 550 include shipping.

If you buy from quantum fuel system do buy only Fuel pump and cable only, then seperately purchase these following part number

QFS pump $90
China made pump $60 from ebay

Then rebuild ur fuel pump kit by replacing the China filter and strainer, and quantum pump. The rest use back the exisiting item on your current pump.

The Filter for Gen 2 is ridiculously expensive! Even from webike cost almost $300.

If you follow my recommendations I believe it cost you about $170.

Great info you shared right there . . thanks!

[Dafeimao85]

OK, but isn't 'preventive maintenance' a thing?
. . . replace when it's aged and BEFORE it breaks or fails?

Preventive maintenance is the normal maintenance.

If normal maintenance is taken care of, it won't fail you anywhere far. The important is once a sympton is shown then a corrective maintenance is needed.

Again like my case the cold start stalling shown that's why I started all the trouble shooting.

If I leave it as it is then a more serious problem will prevail.

[Dennis]

Hi Dennis

Try Google webike.

AD do not sell the parts seperately. From Revzilla I manage to get the part number and directly order from webike.

2008 Hayabusa Parts Number

For my pump I brought after market from high fuel flow. My buddy 08 Busa brought from AEM. Bottom line about the fuel pump in my experience is just change the pump. The rest use back original which again can be order via webike.

For the regulator I plan to keep the original as back up if the new 1 is giving me any problem.

Fyi: 2008 busa fuel pump assemble part number is 15100-15H00. Webike is selling around usd 550 include shipping.

If you buy from quantum fuel system do buy only Fuel pump and cable only, then seperately purchase these following part number

QFS pump $90
China made pump $60 from ebay

Then rebuild ur fuel pump kit by replacing the China filter and strainer, and quantum pump. The rest use back the exisiting item on your current pump.

The Filter for Gen 2 is ridiculously expensive! Even from webike cost almost $300.

If you follow my recommendations I believe it cost you about $170.

I normally use RonAyres microfiche, which is the same as Revzilla. I've replaced the pump on several bikes, normally with the Walbro pump which requires a little bit of modifications. With Ebay and even sometimes Amazon you have to be careful that you aren't getting a fake Walbro pump. I'll try Webike if I need to replace the entire assembly. Hopefully it is an original Suzuki part.

[Dafeimao85]

I normally use RonAyres microfiche, which is the same as Revzilla. I've replaced the pump on several bikes, normally with the Walbro pump which requires a little bit of modifications. With Ebay and even sometimes Amazon you have to be careful that you aren't getting a fake Walbro pump. I'll try Webike if I need to replace the entire assembly. Hopefully it is an original Suzuki part.

Webike I see looks genuine japan made.

I also help my circle of friends to get some other brand parts for other bikes. All seems genuine to me.

Only thing I believe has to becareful is like ecm should not buy from webike. Japan ecm have alot of restriction even the Japanese brought ecm from outside of Japan.

I had a friend happily brought a 03 Gsxr 1000 years back because it was damm cheap. But the bike will never pass 120mph (regardless of gear but rpm can Rev to 11k on gear 3 to 120mph but on gear 4 9k rpm 120mph). It was very weird and internet info sharing 18 years back was not as strong as currenty (search engine was not strong, didn't even think about online forum as far as the states). He had no choice but send the bike to AD only to be told it's a Japanese ecm.

He then proceed to ebay in a USA ecm and the bike works like a charm.

[Dennis]

Webike I see looks genuine japan made.

I also help my circle of friends to get some other brand parts for other bikes. All seems genuine to me.

Only thing I believe has to becareful is like ecm should not buy from webike. Japan ecm have alot of restriction even the Japanese brought ecm from outside of Japan.

I had a friend happily brought a 03 Gsxr 1000 years back because it was damm cheap. But the bike will never pass 120mph (regardless of gear but rpm can Rev to 11k on gear 3 to 120mph but on gear 4 9k rpm 120mph). It was very weird and internet info sharing 18 years back was not as strong as currenty (search engine was not strong, didn't even think about online forum as far as the states). He had no choice but send the bike to AD only to be told it's a Japanese ecm.

He then proceed to ebay in a USA ecm and the bike works like a charm.

Yeah, an ECU for a Busa is easy enough to buy used I wouldn't even think of buying a new one. Even so, I expect the new one could be flashed with a US map. I'll try them when I need a fuel pump/filter assembly.