13' SBA 800.....Runs bad

[Tunneltwister]

I wanna try and keep the explanation simple to not create confusion, but here is the background story. I purchased a 13 800 SBA with 4400 miles in Aug of 18. I was told by the seller he was the second owner and he did a MTNTK kit on it and he had roughly 800miles on the rebuild. By the feel of the recoil starter it has a ton of compression and feels healthy. I had done some research before buying it and was aware that these can be a bit quirky. I was told they do run lean in the 5500 to 7700 so I purchased and installed a Dobeck unit to adjust fuel and it also has wide band AFR sensor and gauge. Here are my issues/ concerns from our first trip out this past weekend.
1. Sled ran/runs great until WOT at which after about 3-4 sec it throws a DET code and goes into limp mode, I also noticed the AFR in the 5800 range of about 16:1. I shut the sled off, restarted and it ran good untill WOT again..We did this for a bit until dinner time then ate and had some beers then went to bed.
2. Sat morning. Sled ran good under normal conditions hammering on it a bit but not hard, rode for about 6hrs. Towrds the end of the day the idle became sorta eratic but not consistently, at one point it died but did restart.
3. Sun, rode about 100 miles. After about 60 miles it developed a slight bog, when we got back to the room we loaded up and headed home.
So, this is what I am doing as I write this and if you think anything else should be done please speak up. Also do you think these series of maintence procedures and new parts should fix it...? I have inspected everything at every point, this is my repair list...
1. New fuel filter
2. Injectors are off being sonic cleaned and flow tested
3. Vforce reed valves...What can or should I expect to see from these..?
4. Cleaned throttle bodies and exhaust valves.
5. New spark plugs.
6. I will be adjusting the TPS sensor.
So thats my list, can you think of anything I may have missed or over looked...?

 

[live2beel]

Check fuel pump psi. Check ground wires. Check the TSS. Plug wires and caps.

 

[Tunneltwister]

Check fuel pump psi. Check ground wires. Check the TSS. Plug wires and caps.

Whats the TSS and how would one go about checking the fuel preassure..?

 

[SRXSRULE]

You really should check the compression to see what you have to start with.

Next, if the sled is stock I would ditch the dobec controller. It just isnt needed and is another variable to cause problems.
Fuel filter and injector cleaning is great.
The V-force reeds are not great and cause problems on these sleds. Low idle
Wide band sensors on a 2-stroke dont last long, and you also must do some comparison testing of air-fuel numbers to actual piston wash / plug color. Again, this is not needed on a stock sled.
Cleaning the exhaust valves is great, make sure the bellows are not torn, and the air ports are clear.
TPS adjustment is HUGE. make sure its done exactly right. You need to set the base setting before the idle setting.
When you do new spark plugs, I would install new plug wire caps.

 

[SRXSRULE]

Whats the TSS and how would one go about checking the fuel preassure..?

TSS = Throttle safety switch

You need to install a fuel pressure test port, and hook up a gauge. They use automotive style fittings. Many parts stores loan tools out for free. They would have a fuel pressure testing kit.

 

[phatboy07]

I have the same sled with the same fix kit. I had to get my TPS adjusted as I had bad idling and low RPM fluctuations but the sled ran great everywhere else. Once adjusted I had no issues. Fuel filter is a good thing to change as its not to difficult. I installed the "newer" vfroce 3R reeds during the fix kit install and I never had any problems after I had my TPS adjusted so I think if you change those out its not a bad thing...there good reeds.
As far as a fuel controller I was going to get and run the same one you have but not sure on what numbers to start with so I haven't purchased it yet.
Your list is a good all around maintenance list of things to do regardless so I would definitely do those things and see how to goes. The problem is if you do all those things at once you may not know exactly what the problem was to begin with. But if you do all those checks and it runs great then maybe it doesn't matter in the end.

 

[Tunneltwister]

I have the same sled with the same fix kit. I had to get my TPS adjusted as I had bad idling and low RPM fluctuations but the sled ran great everywhere else. Once adjusted I had no issues. Fuel filter is a good thing to change as its not to difficult. I installed the "newer" vfroce 3R reeds during the fix kit install and I never had any problems after I had my TPS adjusted so I think if you change those out its not a bad thing...there good reeds.
As far as a fuel controller I was going to get and run the same one you have but not sure on what numbers to start with so I haven't purchased it yet.
Your list is a good all around maintenance list of things to do regardless so I would definitely do those things and see how to goes. The problem is if you do all those things at once you may not know exactly what the problem was to begin with. But if you do all those checks and it runs great then maybe it doesn't matter in the end.

I agree with the to much at one time, but iam in there so I do not wanna go back....The Dobeck so far is very easy to use and I am so far happy with it...

 

[Webfoot_M3]

Had a 14 that had intermittent wide open bog and DET. Then idle became erratic (idled high mostly but lots of fluctuation). Turned out to be a bad crank bearing seal in the PTO side. Might be something to check. I believe we sprayed starting fluid around the seal with it idling to find the leak.

 

[Tunneltwister]

Had a 14 that had intermittent wide open bog and DET. Then idle became erratic (idled high mostly but lots of fluctuation). Turned out to be a bad crank bearing seal in the PTO side. Might be something to check. I believe we sprayed starting fluid around the seal with it idling to find the leak.

This is something Ive considered, the idle is not eratic enough for me and the symptoms arent to extreme for to go there yet..

 

[Tunneltwister]

So right now the TPS sits at 5volts at my base. It also does not fluctuate when when the throttle blades are moved so I have assume that the tps took a dump....any thoughts from anyone...?

 

[SRXSRULE]

So right now the TPS sits at 5volts at my base. It also does not fluctuate when when the throttle blades are moved so I have assume that the tps took a dump....any thoughts from anyone...?

PM'ed you. Your test probe is on your 5 volt reference wire, you need to switch to the signal wire to get you readings.

Also, you need to do the other steps in the testing which involve unhooking the throttle cable and backing off the adjusting screw.

 

[Tunneltwister]

Yes I did the other steps, my lack of reading comprehension got the best of me while reading the wiring....700 and .940ish...now

 

[Tunneltwister]

Sled runs like a raped ape, I am thinkin will all the work I did the fuel filter was the culprit...

 

[phatboy07]

What settings on your dobeck controller are you running if you don't mind me asking?