also can anyone give me base needle setting for it...thanks
(my other nova was 4 and half turn for top / 3 half for bottom ...)

Can anyone who owns a modified JP FX 12 T-03 measure the height of the exhaust port from the top of the sleeve?I want to see how my stock port measures up..

Thanks,
Mark

already got the motor running....previously the top endd was rich and the bottom end was lean....now its running well....just need fine tuning for race pace...

I have a JP X12, when I took the engine apart I noticed that the bore thru the crank is the same size all the way thru it except for the end right where the counter weight is. It looks to be something in the casting of the crankshaft. The hole that the fuel comes thru gets smaller by about 1mm. Does this sound normal? If not can I smooth it out with a dremel? Anyone have any thoughts on this one?

It is probably to improve flow while still keeping the hole at a legal size. If it is something JP did, dont mess with it.

it's called venturi system........
it's supposed to work as the venturi on carb intake, but I don't think it makes any difference, I also have tried a M. Rossi shaft in a JP and the engine worked even better and less crictical........

I thought that a venturi was used to suck liquids from a tube in the center of the venturi. Does not sound right to me. Do you mean a volacity (spell?) stack.

the venturi accelerates the fluid..........

flow keeps the same, then the reduction of the area demands higher fluid speed..........

this is why it doesn't make any difference (in my opinion of course), the mixture quantity that gets in the crankcase is pretty much the same, it just gets in faster, which in my opinion means nothing since the matter is how MUCH mixture is entering and not how FAST it's done......

....... well that was not what happened during race...the engine would cut off in the mid of the 5 min. heats ( in all 3 heats)...
idling was fine , . ( and it was always easy to restart after stalling) my temp. is only 98' celcius....

Flaming out is often caused by too rich setting. You can close the top needle a little bit more if you're still running on 98C in your country.

Sounds like it needs to be leaned out. That temp is a little low but not by much. I usually will run around 240 deg F. which is I think around 115 deg C.

If the engine starts up quickly that is most likely what is happening because if you overheat the engine it will take a while to cool down enough to start up again.

thanks guys....

Is the JP2 a good pipe for a FX21B5N?

JP-O.S engines coming soon! www.mugenracing.com

NismoSkyline17,

i've used the JP2 with both my max M5T (nova P5 based like ur B5) and V-Spec, works well with both engine. good mileage(8+mins on my M5) and excellent durability.

the JP2 is a top-end pipe, suitable for engines with lotsa bottom power. not the most power overall tho. the nova/RB 86 will give your B5 the most top-end power (at the expense of mileage and durability).

and btw, if you're getting the JP2, get the polished version. i've tried both polished and hardcoated, the latter seems lesser powerwise.