Thanks to you all for the info so far and i think perhaps i will try using a 1.0 spring as i have been using only 1.1 springs and the power is phenominal.
perhaps its revving to hard and chewing the gas and also i will buy a new fuel tank and check the bottom end again with the pinch test
Cheers all:flaming :

my buddy has a n21 bf!.. and he is running 20% fuel!...i was just wondering what shims should he run for best performance with 20%?...and when he wants to bump it up to 30% What shim should he add?

I know there will be others to give different advice but I would have your friend change now to 25% as it is the persentage listed by Novarossi for it's .21 engine's, I think 20% is to low nitro content for .21 engine's as it is mainly used for .12 engine's. I am sure it is not hirting anything but I don't think it can perform as it could be with the % it was listed at. That being said I am sure the stock shimmimg for your friends engine .8 with 2 x aluminum shims and 1 x copper shim, he can bring the shims down to .7 by removing 1 of the aluminum and replacing it with a second copper but to be sure measure the shims as you can get the copper shims in .1 and .2 sizes. The aluminum shims are .3 in size.

Hope this helps

Sean

I always thought 20% worked great, but 25% is my choice for .21 engines...

Depending on when you bought that Nova bf 3 port...

If it's an 09' or earlier it should be shimmed .70 that is two alluminum thicker shims that are .30 each, and the copper .10 shim that hides in between the all shims or under the head button, and that's perfect for 20 or 25% fuel no worries....

If it's a brand new BF made in 2010 then it has two Allu. too, but with a brass .20 shim that makes it .80 that's for 30%...Look on the box or on the paperwork for the year it's made.....

It's confusing because the copper and brass shims look similar, but you can tell if you measure, which I never do, or have ever seen copper or brass JK and they should really come with an extra .10 shim in the box for those who run less than 30%, if not ask around and I'm sure someone would have one...

Should I buy a set of calipers????

I got a camber gauge and don't use that either...

I got a temp gauge and only use that on break in...

I don't even have a ruler....

I have an ice chest though.....

right now it has the 2 allum. .3mm and 1 brass or copper.2mm shim and runs great@!...but i was just wondering if we took out .1-.2mm of shim if it would have more performance!...so whats the standard shimming for 20%?...,7mm?....and then .8mm of shims for 30%?

this is for my buddy!...HE RUNS NOVAROSSI MOTORS!...anyways...im trying to help him get more power out of his 3port! lol!...but im not a NOVA guy so i dont want to just start removing shims with out asking you guys first!

Hey guys.
Do you think a Plus 4 Team, NovaRossi 41030 manifold and Go EFRA 2072 would make a good combo?

Much appreciated.

I have just run in my 1st Nova offroad engine, +21-7FMS. I ran it in on the breakin bench doing the heating up before start over the 1st Litre ETC.
The past weekand I ran its 1st race. I went thru around another Litre of fuel.
I just striped the engine as I do after every race meet to inspect bearings and rod. After I removed the back plate I noticed the rod had alot of slop on the crank pin. I removed the crank and measured the pin.
Pin @ TDC 4.81mm
Pin @ 3oclock 4.92mm
.10mm out of round

Whats your thoughts on this? To me its not good.

I really never measured the crank pin. I can say that running a race after one litre of fuel isn't good. I would say about 1/2 gallon (almost 2 Litres.) is raceable, a nice easy day......

I'm sure someone will know what is ok for the pin.

advfuel,
No, not good. Excessive crank pin wear. Along withThe conrod bushing likely worn an aprox same amount the fit is fair at best,in its outer limits now.
I think you would have had better breakin results on the ground, with very easy throttle atleast another 1/2 gallon.
Hope this helped

RayAracing

what do you gyus think about th p5??

Great truggy motor in my opinion. Very smooth, lots of low end. I actually seen one screaming in a buggy but it was a "P5 Tuned". Never seen one until the other day, no idea where he found that one at.

but do you think it`s better than a +4 for a buggy?

No

No, I run the plus 4 in buggy and its a dream. Seriously love that motor, I even tried in the truggy and it runs just as great. I like the 9901 and the 21021 header in buggy and the 2884 with the 21021 in truggy.

I am going to try the new OS Speed only because im curious . Prior to this I would probably only run plus 4's in buggy and truggy. Great motor