Finally fixed the GTX bog...but I have another problem!!

[Rampage]

Well after servicing the valves, and cleaning the front fuel filter, and flame arrestor grate, new fuel lines.... I still had the same high rpm bog. So took the carbs off and gave them to Capt Scale. He found that both filters in the carbs where very dirty. He put some new ones in and we put it all back together, and now it runs better then ever. Its hanging right at 6,900 rpm with no problem....and hitting 59 mph on the gauge!! Now the new problem is after its nice and hot, and I shut it off...then re-start it...I can hear a pinging noise (like a spark knock), and small backfiring in one of the cylanders, and its runs pretty rough for a few till I open it up. Plugs are nice and brown, almost on the rich side. Compression is 160 and 170. Any ideas? Weak coil maybe?

 

[dsw222]

160 and 170 compression... do you have a high compression aftermarket head?

 

[Rampage]

nope...its a stock motor with 140 hours on it.

 

[dsw222]

nope...its a stock motor with 140 hours on it.

is that a 951 engine? interesting that the compression is so much higher for being stock... i thought they were supposed to be 135-150... but maybe the 951 is supposed to be higher?

 

[Rampage]

Its the 787 motor. I tested it with 2 diff gauges..same results.

 

[Rabid]

choke come loose?

 

[Dr Honda]

170 is high for a stock 800 engine. It could be ignition/fuel "Knock". Heat can aggravate the problem. Make sure you are running premium fuel.

If that was my engine, I would do a check on the squash band. I saw 2 engines roasted this summer because someone decided to run a thin base gasket.

Is this knock at idle? Do you have to go to full throttle to clear it out... or just a little extra throttle?

 

[Rampage]

Its pretty much when just starting to accelerate from idle.. I have to give a little more then half throttle to get it to clear.

 

[SabrToothSqrl]

Gtx

I have a GTX LTD as well, and it's running about 5 MPH and 2000 RPM shy of where it should be.

New impeller and wear ring

all new fuel lines

new fuel filter.

I swapped the water reg with my known working XP one.(no change)

Also replaced a broken air line from the block to RAVEs, also cleaned the raves.

also new spark plugs...

the ONLY thing left I can think of is the filters in the carbs.

how hard are the carbs toget off / change?

thanks!

 

[Rampage]

yours is the 951.. I think they are a little tough to get to, because of that one exhaust bolt

 

[Rabid]

any new updates on the troubleshooting?

 

[Rampage]

not yet..I found where my bad cavitation problem was coming from. Some how the hose clamp around the carbon seal came apart. Im going to put some fresh plugs in it, and try it again...

 

[seadooya]

check the n/s assy. Sounds like, ones' sticking. Make sure "BOTH" tangs, are flush with inner carb body for accuracy if you dont have a pop-off gauge.