picco g1 xp modded big problems

[mark-1988]

hi there,
as the title say's i am having problems with my picco g1 xp pro modded, it will not run properly at all. the top end seem's to be fine really powerfull but the bottom end just won't have it. i am getting really fed up with it now as i have tried and tried and no cigar , just a shame with it being a good engine so please if any one could help i would be more than gratefull.

thank you mark . . .

 

[Scrogg]

Medium to cold plugs, 30% Nitro with low oil. 10-12% oil is good. Not being able to set the bottom end is a tell tale sign of a small air leak in the carb, engine, exhaust pipe or fuel tank or lines. My Picco's like to suck air at the carb boot at full throttle. Check that t he boot is air tight.
Also another problem with older Piccos is the carb body sucking air only when it's warm.
I run a bead of sealant or JB weld around the aluminum/composite carb joint to solve the issue.
One other thing, the smooth exhaust ports require special exhaust seals. If this is a big block engine, use the HPI purple Savage header gaskets. They are a cheap durable option. It's one of those issues MTL.

 

[mark-1988]

hey mate.

cheers for the reply and info, i have sealed all the carb and head well everythin really.i took it out today tuned it and it sat there spinning all 4's. the power is back it just seem's to loose it when it starts getting warm.

 

[Metalhead Matt]

You can't tune an engine until it's warm.

 

[Scrogg]

As in the piston and sleeve feel too loose? As long as it idles and you can get the engine to hold a tune, it's fine. If not, you need to have it repinched and install new bearings, possibly a rod.

 

[mark-1988]

hey mate,
i have asked a friend to try and get me either it pinched or a new piston and sleve. it is a little slack but does idle and hold a tune but is down on compression a little. so thank you for the help and advise and will post up how it goes with either th epinch or new internals cheers again.

 

[Scrogg]

hey mate,
i have asked a friend to try and get me either it pinched or a new piston and sleve. it is a little slack but does idle and hold a tune but is down on compression a little. so thank you for the help and advise and will post up how it goes with either th epinch or new internals cheers again.

If it idles and holds a tune, put a set of fresh bearings in it. Check the rod. You can get away with a little slop in a rod as long as you keep good bearings in it. Bearings actually help restore compression. Front bearings can leak that bad. The excess movement in the worn bearings causes the piston to go too far up and down in the cylinder. This causes erratic sometimes impossible uning. If you replace the bearings in time, you can keep going no problems. My Picco is raced hard, I put main bearings in it every 3 gallons. Front bearings every 2 gallons. I have over 6 gallons on it. It runs just as good today as it did with1 gallon on it. Actually it runs better. Don't confuse pinch with compression. Two different things. Proper compression comes from the fuel/oil in the grooves in the piston + the piston sleeve fitment. Rotate the engine over with either fuel or oil in it, if it is slightly difficult your good.
My Buddy has an Ex-Tech .24 with 5 gallons, feels like it has zero compression. At 4 gallons it started running bad. He changed both bearings, it's stronger than new and holds a tune like it is new. He used to believe in the theory of " IF it is not broke don't fix it." He now knows to stay on top of the bearings.
Picco's are race mills, they need bearing changes as do all race engines.
RTR engines don't see as many RPM's nor do they take abuse from starter boxes. They can go longer, but I still rec. changing bearings no less than every 3 gallons.
Changing the front bearing every 1-2 gallons keeps the main bearing from wearing, extending their life cycle.