newb cant figure it out

S

skiball83

New Member
Posted earlier didnt get the responses I needed. Built my first mb. Grubee 66cc gt5. I get half power 10-15 minutes into a ride, with a lot of 4 stroking after op temp. Changed the carb, mag seal was leaking so new seal and mag. Sealed head and bottom with rtv. Sealed intake and carb with rtv. Carb clip at 2nd notch (nt) original was cns, same problem. Gas cap is venting. Spark plug was changed to the other factory one in the kit gapped at .28. New plug boot and wire from autozone. Not running the factory screen fuel filter, have an inline aftermarket from autozone. Cant figure it out. Can someone please give input.:-||
 
Try increasing the spark plug gap to .032 or .034. If that doesn't help try running it without the air filter on just to see what happens.
 
Running without the filter just dosnt sound like a good idea. Especially cause its a new carb, dont think the filter will make a differance at this point. Will try regapping. Anyone else whanna chime in?
 
It's not likely the problem, but you said you sealed the head and bottom gaskets with RTV, that's not going to last very long.

If it is four stroking once it is warmed up, it is more than likely running too rich. What does the plug look like? Is it black and oily? If that is the case and you are at the 2nd notch on the C clip, try going leaner- up to the first notch. If that gets you closer, you are most likely going to have to get a smaller jet, and start the tuning process over.

You could also try bending the tab on your float so it sits lower in the float bowl, which can lean out the carb a bit.

Finally, what gas to oil ratio are you running? A higher ratio will give you a richer final mixture. 32:1 is twice as much gas to oil as 16:1.
 
Running 35:1 oil mix. Gonna play with the gap as soon as I can and get back to you guys about the spark plug condition. The plug only has about 6 miles on it. When it starts losing power and 4 stroking I will pull it. Also will move the clip up a notch if conditions allow. Anything else I should try.
 
The newb just figured it out. Sorry it took so long to get back but I do have to work you know. Tried gapping at 3 different settings ended up that it likes what I had it set at origianally @ .028. Went through everything exept the exhaust. Double checked everything but the exhaust. Desided to check the exhaust. Took it off. Its the cat type on the new GT5. Blew through it and it was really hard, especially because I tested it before installation by blowing through it. I tried spraying brake cleaner through it 4 times. Got a bunch of gunk out. Blew through it and still clogged. Desided what the heck. Got my drill with a 1/4" bit on it and an extention. There are 5 holes on a disk that I guess keep the guts in on mine. Drilled though all five holes. Washed it out by putting a rubber hose in and hooking it up to my slop sink faucet. Forced hot water through it for about a minute to make sure there was no particles left in it (from the inlet side). Put it on the bike and it started up real fast. Idle was a bit higher so it turned it down. Let it warm up for about a minute and gave it a little gas. The rpms screamed. I was shocked. It never reved up that fast. Let it warm up for another minute. I couldnt wait to get on this thing. Started peddeling and released the clutch. I dont think I have ever smiled so hard in my life. The low end power is amazing. Reached top speed in about half a block. Going as fast as traffic. Finally this thing is a rocket. Now to get a new 36t gear it was reving so hard I thought it was going to grenade on me. YEAH!!! For all you running the stock pipe on the 2010 Grubee GT5 DRILL OUT YOUR EXHAUST.
 
Thanks for the update. Your four cycling was caused by too much back pressure not allowing proper scavenging and that is a common thing with two strokes with too long/too restrictive exhausts.

There was an "exhaust throttle" that was used for some time on old Cox model engines, it worked sort of the same way- it restricted the exhaust enough that they four stroked, and " throttled down".
 
Well I felt I owed it for the advice. Maybe this will help someone else, who knows. Ive noticed that not following up is a problem with newbs on this site. They just come on for the advice and not give us the reply on what worked. Its like they drop off the face of the earth and thats not right. Thanks everyone for trying to help, it is appreciated.
 
Congratulations and glad you're enjoying your bike.
Just curious...How much louder was your bike after the drilling?
Tom
 
I routinely remove my cat converters.

After removing the muffler end, remove the screw at the front of the muffler, and they useualy fall out. sometimes tou have to tap the muffler end on a wood bench to get them out.
 
its amazing what a proper exaust can do for theese things!! am I the only one that gets the worst running gt5's?
 
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