Point-Seven-five wrote:Mass Air Flow sensor. 

It's in the air box above the filter and tells the engine controller how much air and, by inference, oxygen is coming into the engine for combustion.

RicK G wrote:If the throttle bypass screws are set correctly and the bypass in the MAF then you will get minimal change screwing the throttle bypass out but it will change things if they are screwed in.

I'm in exactly the same boat you are with my bike and it's very frustrating.when chasing down the problem I found I had low compression of 100 psi per cyl and was able to find a good used engine for a good price.  It was cheaper for an engine than to get the head done etc.  when i first started it, it ran great.  Then it reverted to its old self which made me chase manifold leaks etc.  had fun with those Oekiter clips, bought the wrong throttle cable, but was smart enough to buy the proper hose clamps on McMaster Carr as a backup.  Basically lit $100 on fire.  But who are we kidding.  We love spending money on motorcycles.  I adjusted with vacuum gauges the throttle linkage screws.  I was able to get 1,2 & 3 cylinder to be synced but just could not get cyl 4 to be close to the others.  I will have to take off the tps switch and the choke switch as well and see if that changes.  Im also having a hell of a time with the throttle cable connection to the chain and geared wheel that connects to the throttle Puccini wrote:

Point-Seven-five wrote:Mass Air Flow sensor. 

It's in the air box above the filter and tells the engine controller how much air and, by inference, oxygen is coming into the engine for combustion.

How reliable are they?  I've got an 85 K100RT that idles and runs good for the most part but it has a unsettling habit of (every now and again) sputtering and stalling when your accelerating off of idle.
And very rarely at speed I'll get a short buck out of the engine 

Usually in 1st  gear.  I did plugs, injector cleaning, wires, fuel filter. I understand the fuel pump was replaced just before I got it. Speedo shows 28K miles and I suspect it doesn't have more than 35K on it.
Cleaned the ignition switch, kill switch is ok.
Tried unhooking the TPS and no change.
replaced the fuel lines.
I thought it was vapor lock but it idles great even when it's really hot.
No indication of an electrical failure when it happens. All gauges stay on , no indicator lights,

I cleaned the tank bottom plug for the fuel pump so I think thats ok also.

I am installing the fuel line heat insulation wrap just to cover that base. But I am annoyed with this problem and want to fix it. Any Ideas?

Puccini wrote:

RicK G wrote:If the throttle bypass screws are set correctly and the bypass in the MAF then you will get minimal change screwing the throttle bypass out but it will change things if they are screwed in.

You totally lost me.

I don't understand what your trying to say.
Can you expand on it?

Bekman wrote:

I'm in exactly the same boat you are with my bike and it's very frustrating.when chasing down the problem I found I had low compression of 100 psi per cyl and was able to find a good used engine for a good price.  It was cheaper for an engine than to get the head done etc.  when i first started it, it ran great.  Then it reverted to its old self which made me chase manifold leaks etc.  had fun with those Oekiter clips, bought the wrong throttle cable, but was smart enough to buy the proper hose clamps on McMaster Carr as a backup.  Basically lit $100 on fire.  But who are we kidding.  We love spending money on motorcycles.  I adjusted with vacuum gauges the throttle linkage screws.  I was able to get 1,2 & 3 cylinder to be synced but just could not get cyl 4 to be close to the others.  I will have to take off the tps switch and the choke switch as well and see if that changes.  Im also having a hell of a time with the throttle cable connection to the chain and geared wheel that connects to the throttle Puccini wrote:

Point-Seven-five wrote:Mass Air Flow sensor. 

It's in the air box above the filter and tells the engine controller how much air and, by inference, oxygen is coming into the engine for combustion.

How reliable are they?  I've got an 85 K100RT that idles and runs good for the most part but it has a unsettling habit of (every now and again) sputtering and stalling when your accelerating off of idle.
And very rarely at speed I'll get a short buck out of the engine 

Usually in 1st  gear.  I did plugs, injector cleaning, wires, fuel filter. I understand the fuel pump was replaced just before I got it. Speedo shows 28K miles and I suspect it doesn't have more than 35K on it.
Cleaned the ignition switch, kill switch is ok.
Tried unhooking the TPS and no change.
replaced the fuel lines.
I thought it was vapor lock but it idles great even when it's really hot.
No indication of an electrical failure when it happens. All gauges stay on , no indicator lights,

I cleaned the tank bottom plug for the fuel pump so I think thats ok also.

I am installing the fuel line heat insulation wrap just to cover that base. But I am annoyed with this problem and want to fix it. Any Ideas?