Shims and 30% nitro?

[sharkattack99]

i was doing some reading and i was reading about having to add or remove shims depending on what nitro content you are running i have a picco with stock head shims and I'm running 30% nitro do i need to add or remove head shims? cause I'm trying to get a tune on it so i can get a gallon of fuel through I'm not trying to do a performance tune cause I'm still in the break in process, i just want a good enough tune so can get a gallon through it, or more. but i was wondering about the head shims.

shark

 

[JoeGuam]

i was doing some reading and i was reading about having to add or remove shims depending on what nitro content you are running i have a picco with stock head shims and I'm running 30% nitro do i need to add or remove head shims? cause I'm trying to get a tune on it so i can get a gallon of fuel through I'm not trying to do a performance tune cause I'm still in the break in process, i just want a good enough tune so can get a gallon through it, or more. but i was wondering about the head shims.

shark

The picco manual states the amount and type of shim. If I am not mistaken it is (2) .2mm and (1) .1mm for 30%.

 

[sharkattack99]

U wouldn't know what the stock shims are by any chance would u.

 

[sharkattack99]

Well according to the manual that's what is in there already.

 

[f1n3sse]

i don't think your supposed to break them in with 30% I'm sure you could but i think the less nitro with a higher oil content for break in is recommended

 

[Bankrupter]

I didnt change shims for run in and I even took one out after she was well worn in for more jam on 30%. The recommendation from OFNA is to protect the motor. Its sound advice if you don't know what detonation sounds like. I can tune and know what is good and bad for the motor so never had a motor detonate.

 

[sharkattack99]

so then i should just leave it alone then?

 

[Bankrupter]

so then i should just leave it alone then?

Just leave it a lil fat and don't worry about it. Get her run in and happy. Its going to take a good gal b4 shes not going to spike temps and be unhappy so take your time. Just be careful with -=HOT=- plugs. Not so much concern with med and colds

 

[sharkattack99]

alright i will just leave it alone then, yeah I'm using med plugs iv almost got a gallon through it, having trouble keeping it running to get that gallon through it, i set the idle gap at .5mm (fatory setting) but it won't idle worth a damn. once i get it going but i let the throttle off, and it goes to an idle then does. which tells me I'm rich but when i do about a half throttle pass and let off the throttle it doesn't drop to idle right away like it should.

 

[Bankrupter]

alright i will just leave it alone then, yeah I'm using med plugs iv almost got a gallon through it, having trouble keeping it running to get that gallon through it, i set the idle gap at .5mm (fatory setting) but it won't idle worth a damn. once i get it going but i let the throttle off, and it goes to an idle then does. which tells me I'm rich but when i do about a half throttle pass and let off the throttle it doesn't drop to idle right away like it should.

Sounds like my old picco ... I had to close and lean the LSN till it would do both. it was near .5 when I was done.

 

[Purenitro]

Use a MC #59 for break-in settings, the hotter plug will help it start and idle better with the richer needle settings. Move to the MC #8 for performance tuning, depending on your elevation you can even remove the thin head shim and run 30% with no worries.

 

[sharkattack99]

i ordered 2 mc #59 hot plugs and should be here saturday from a main, but why does it act like its lean with the passes but also act rich with the will not idle? thanks

 

[Purenitro]

Lean on the HSN and rich on the LSN. Remember that the LSN is what controls the idle, do not adjust the HSN when it comes to low end tuning, the HSN takes control with about 1/3 throttle and is intended to control the fuel metering at WOT.

 

[sharkattack99]

oh ok so i need to richen up HSN and lean my LSN more. hopefully saturday they will get here and i can get somemore fuel almost gone and i can run it with the hot plugs on sunday. thanks.