Intruders-Alert

Runs GREAT untill absolute full throttle in 1st and 2nd.
3,4,5 problem seems to go away, but its flying so fast I run outta road before I can be 100% sure.
Can the "boost sensor"
be bad? Cause at 157.5 it theoretically should be showing more of a rich color on the porcelain shouldn't it?

he is running 165 rear
157.5 front
3rd clip on needle

was running high octane he is now on 87
origional problem was backfiriring and popping and power missing after adding pods and changing pipes.
he has baffles

maybe a float level issue?

plugs both seem dry despite the big jets 1 mile above sea level
https://ibb.co/k0k6jjC

The1Chef wrote: ↑

Sat Jul 17, 2021 2:00 pm

Runs GREAT untill absolute full throttle in 1st and 2nd.
3,4,5 problem seems to go away, but its flying so fast I run outta road before I can be 100% sure.
Can the "boost sensor"
be bad? Cause at 157.5 it theoretically should be showing more of a rich color on the porcelain shouldn't it?

he is running 165 rear
157.5 front
3rd clip on needle

was running high octane he is now on 87
origional problem was backfiriring and popping and power missing after adding pods and changing pipes.
he has baffles

maybe a float level issue?

plugs both seem dry despite the big jets 1 mile above sea level
https://ibb.co/k0k6jjC

Possible vacuum leak or carb sync
Change in fuel octane may have the same results if synced with the higher octane
I would start with carb sync tools (not sure which one you have) and checking for vacuum leaks at the same time.

My guess because it shows up after 3/4 throttle

he has checked for vaccum leak by spraying carb boots. has synced and resynced but not sure if he has since running the 87 octane.
I mentioned possibly pinhole in carb diaphram but I guess could also be a crack in the vaccum line.
I will have him check those things and ask about sync after fuel change

he is awaiting approval to join in here

The1Chef wrote: ↑

Sat Jul 17, 2021 3:19 pm

he is awaiting approval to join in here

Holy crap - there's an application process for this place?

When you say WOT in 1st and 2nd - could he be hitting the rev limiter?

hillsy wrote: ↑

Sat Jul 17, 2021 3:38 pm

The1Chef wrote: ↑

Sat Jul 17, 2021 3:19 pm

he is awaiting approval to join in here

Holy crap - there's an application process for this place?

When you say WOT in 1st and 2nd - could he be hitting the rev limiter?

Yes It could be I hadent thought of that
Do Intruders have factory rev limiters??
Some after market Ignition modules do

Im still leaning towards a vacuum leak because of the condition of the plugs

They've been putting rev limiters on Jap bikes since the mid 80s.

FallenAngel wrote: ↑

Sat Jul 17, 2021 4:39 pm

hillsy wrote: ↑

Sat Jul 17, 2021 3:38 pm

The1Chef wrote: ↑

Sat Jul 17, 2021 3:19 pm

he is awaiting approval to join in here

Holy crap - there's an application process for this place?

When you say WOT in 1st and 2nd - could he be hitting the rev limiter?

Yes It could be I hadent thought of that
Do Intruders have factory rev limiters??
Some after market Ignition modules do

Im still leaning towards a vacuum leak because of the condition of the plugs

I never thought about the rev limiter. I guess it could be but the plug condition shows lean to me so with jets thatvsize and white on both plugs I still think an air leak somewhere.
He hasnt found a road with space to test WOT in 3 4 5
He did doba resync after the 87 ran through the system which helped a little more but still not there.

And yes, I guess because of bots and countries etc there is an approval process. Only requirement is that you are actually human lol

Your plugs look normal A little sooty but normal
Is the bike completely warmed up?
Honestly I wouldn't worry about it missing during wide open throttle its a cruiser

Yes, these have a rev-limiter on them that kicks in at about 7,000 rpm, if I remember the rpm correctly. The rev-limiter starts cutting the rear cylinder out.

On both my 87 and 99 it kicked in at about 65mph in 2nd, didn't have enough power to get into it in 3rd and 4th.

The plugs look like it is running rich with the soot on them. With the alcohol in the gas, the plug's porcelain should be white.


White porcelain showing no signs of carbon build-up, cracking, peppering, or oil deposits is considered an ideal spark plug after a run. Half of the ring around the spark plug shows discoloration from heat. The other half is not discolored. This is a common baseline goal with many tuners. The outer strap shows reasonable (ideal) heat indication at the bend, although not visible from the photo.


https://www.enginelabs.com/engine-tech/ ... ent-fuels/

So I have forwarded all of the resposes from here.
He has done a light test to the diaphrams to check for holes.
Is that a conclusive way to test?

He asks

What does the boost sensor do exactly?
does it sense hard acceleration? but only in upper gears?

Thanks again guys

It acts as a vac advance like on the older cars.