Just wanted to give an update, the hotter plug did the trick, I was even able to richen up the low end a bit. Another question though... How long should a tank of fuel last with these rich break in setting doing about 50% throttle runs of about 40-50 feet with idling in between to keep temps in the 200-220 range?

From what I experienced in my first break-in, during the latter stages, each tank seemed to last anywhere between 5-10 minutes, depending on how long each "run" is.

Can anyone confirm how many head shims or what the factory clearance should be on a stock Btta should be?

should be 2 - at .3 and 1 at .2 to give a total of .8

Thank you my friend.

What kind of glow plug would you guys recommend for me to run on a P5 XLT? I'm running 30% VP Pro fuel, and also live in CA where the weather is blazing hot. Thanks

Edit : anyone know the factory settings for this engine? Sorry if its been asked before

Just got off the NR site and they have all the stock settings for just about every motor they made. Check there.

On to my question....

I have a chance to buy a BNIB PLUS.21-4BTTS for a great price, but I have absolutly no experiance with NR and cant find any write up about the this engine. Need to know about power curve, use in a buggy or truggy, what pipes and is it even for off road?

Thinking of getting onboard with these motors, as I see great results from the top pro to our local guys.

It is a great engine. Adam Drake runs 9901SS/41021.

I like the 41021 and 2096 pipe combo on the plus 4 engines or a werks 2058 pipe/header if you have that. The plus 4 is a great buggy engine, very smooth and good top end and great runt time.

I like the 41021 and 2096 pipe combo on the plus 4 engines or a werks 2058 pipe/header if you have that. The plus 4 is a great buggy engine, very smooth and good top end and great run time.

What pipe is this on Teemu Leinos HB / Keep Off 21 4?

What pipe is this on Teemu Leinos HB / Keep Off 21 4?

I think its a O.S. pipe maybe a 2090

Try O'Donnell 97t or 99t factory setting hs 3.5 out ls 5 out or best to just go both out slightly 1/2 turn from flush

Remember 0,8 mm is for break-in and 30% nitro. Go down to 0,7 mm if you run 25% nitro.