Pipe questions.

[Burns310r]

Heres my engine stats.

ESR 330PV
Vforce 3 reeds
38mm A/S 185main 45pilot
FMF Fatty Pipe/Power Core 2
UNI filter
Pump Gas dome


I just bought a CR ignition but havent put it on yet.


I dont feel like the engine pulls through the entire rev range as powerfull as it should. Im hoping to have Neil Port it this winter.

But would i gain a more broad power band with another pipe?? Is the FMF undersized for the 330?


I have never ran another pipe really. And always loved it on my 310 and 250 engines.

Also the engine runs a little hot with my jetting, which i think it should be a bit rich as it is. Im getting 200-210 degrees

[Lasher]

I am not sure but it sounds like the FMF may be the "smaller" stinger. I remember reading that the big bore motors liked to have the larger diameter stinger and your symptoms sound like that could be the issue.

As for make/model (other than stinger size) you need to make the port timings with the pipe (pressure waves and that stuff).

[Burns310r]

So what pipe and stinger would you recommend.

[Lasher]

I am still on a "small bore" R, so I have no experience.

If you are going to get it ported by Neil, ask him what he would recommend. I think the ESR pipes are the larger stinger and if he is going to port the motor over the winter (I am doing the same this winter) then he could tell you which pipe would fit best for his porting.

[8686]

Burns310r, you race mx, right? I can tell you right now that Neil will probably recommend a nice low-mid port. That being said, an ESR TRX7 would work awesome with that setup. Should smoke the FMF pretty good.

Also, from my experience, I haven't found the V-Force reed setups to be the best for low end throttle response, which is very important when mx racing a 250R.

[Burns310r]

ya i race mxn the cylinder is a esr trx9 port i believe. im wanting strong power everywhere. seems to me now that it has great bottom but quits pulling as hard on top. it does pull everywhere dont get me wrong. im just wanting more throughout the rev range.

is it easy to find a trx 7 pipe anymore? does the silencer matter at all

[8686]

Originally posted by Burns310r
ya i race mxn the cylinder is a esr trx9 port i believe. im wanting strong power everywhere. seems to me now that it has great bottom but quits pulling as hard on top. it does pull everywhere dont get me wrong. im just wanting more throughout the rev range.

is it easy to find a trx 7 pipe anymore? does the silencer matter at all

Well the TRX7 is the new low-mid pipe. The TRX6 was the old one. Both are great pipes.

Actually, the new TRX5R might be right up your alley.

[Pumashine]

Originally posted by 8686
Well the TRX7 is the new low-mid pipe. The TRX6 was the old one. Both are great pipes.

Actually, the new TRX5R might be right up your alley.

If he has an ESR trx9 port job wouldn't he want a ESR trx9r pipe?

[8686]

Originally posted by Pumashine
If he has an ESR trx9 port job wouldn't he want a ESR trx9r pipe?

No. The TRX9 port is an all around (mostly midrange) port job. The TRX9 pipe is a mid-top end pipe, definitely not ideal for most motocross racing.

[C-LEIGH RACING]

That FMF could be holding it back some & as already noted, the stinger is quite a bit smaller than say an ESR or CT pipe.
Smaller the stinger I.D. more heat it will hold inside the pipe & directly back into the engine.

The ESR or CT pipes, the ID of the stinger on those, is larger than the expanded coupling part on the FMF silencer tube.

With a TRX9 port, that ESR TRX5 should give you a bit of rev, not a lot but a bit more than the FMF will provide.
The ESR TRX5 R, I've never had my hands on one of those, so dont have any details how it works. The TRX5 center mount, it will give the engine just a little bit more rev over what the TRX 5 will because it is just a bit shorter build.

It might be interesting to you, just testing to try different sprockets. Those ol big bores love to grunt & pull & you might find that different gearing could make you faster & make up for the rev you think you need at the top or that the engines not providing.
Neil

[Burns310r]

Thanks for the advice neil.

I actually already ordered a 14t front and 37 rear. I will start with the 37 rear and see if that gets me where i want to be.


I was thinking the same thing about gearing after my last race. I think Im shifting to much.


On the pipe, i like the fact you think it could be holding heat in my engine. Because i have been having trouble getting good temps. So i guess a new pipe is in order for this engine.

That works though, im needing to find another frame to put all my spare parts on. So now i guess i have a FMF fatty to put on my spare bike.