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CPI or shearer for my mods?


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on that big of an engine windy i dont get why he would say they would work well.. i could see CPI big bores maybe yes... but SB's on that big of an engine if far fetched to say it would do good... i think he pulled you in for a quick sale...

 

 

 

But like I stated in earlier posts.. and like Tyler just stated up top.....

 

he shouldnt even be considering between shears or CPI's with this build

 

 

Well a lot of people are brainwashed into thinking bigger is better. I had BB CPI's on my 472 motor and it was only hitting 81 HP. We installed the BB Shearers and the motor jumped to 95 HP.

We called Matt and he said to run the SB pipes to see an even better front side curve. So I bought (used from a site member here) a set of SB pipes and Matts predictions about the curve were spot on. It was hard to walk away from the strong performance of the BB pipe. But after dyno testing them all......I was happy to see that Matt was correct about the peak numbers being the same as his BB pipe, yet my torque numbers were even better down low with the SB's.

With the Shearers....535 is the cutoff point between SB and BB. The guys who are running the BB's on smaller motors and prefer them over the SB pipes are usually running a lot of timing. This tricks the pipe into acting like a smaller pipe. But the reality is that in many situations.....if they were willing to go with the smaller pipe and take timing out, they would see an overall gain in power.

 

But that's just some feedback about the great drag pipe debate......We're WAY off topic here. LOL.

 

I've found the FMF's to be very strong running overall pipes in all my dyno testing. Sometimes pipes that have a "Strong Hit" are flat on the front side power and just finally kicking in in the higher RPM's. The FMF's might not HIT like the T-5's........but they might have better overall power. For MX it's a little hard to beat the predictability of the FMF power band. Others also like PC's.

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There are a few posts with people here just regurgitating info. From reading each post it seems weird what people are reccomending as if they didnt fully read what the original poster had said. First he has a what is a mx port, but it could be fairly aggressive depending who ported it.(who did port it march) He mentions that he does long straight pulls, which makes think of the guys who ride open fields, power line trails, fire roads which would definitely make something like the CPI or Rocket, maybe even the PT hi rev would be pretty good choices. After all the hi rev was the pipe of choice for a few pikes peak winners who needed to come out of the turn yet wick it out for long runs. March says it is on trinity pipes already and he is looking for a bit more pull so I don't quite think FMF, Pro Circuits, or similar pipes would be the solution.

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Thank you a lot trickedcarbine!! Now theres someone who understand what i said .. i dont want these fucking fmf or procircuit pipes.. i sold my trinitys and i dont want to have worst than i used to have.. by the way it doesnt mean that i will not change my port job and have bigger carbs.. in my place everyone have trinitys fmf t5 paul turner soshearer and cpi are what i want.

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Thank you a lot trickedcarbine!! Now theres someone who understand what i said .. i dont want these fucking fmf or procircuit pipes.. i sold my trinitys and i dont want to have worst than i used to have.. by the way it doesnt mean that i will not change my port job and have bigger carbs.. in my place everyone have trinitys fmf t5 paul turner soshearer and cpi are what i want.

Give the CPI's a go, they will probably do ok with where your at mod wise. The 33's you have will probably be ok to. Of course you could see even better gains with proper porting and what not. But that is down the road. There are a ton of north west dune bikes that run the CPI pipes and 33's for shooting idiot holes. So they will probably be more then fine to get in tight stuff for a bit and come out blasting the open land full wick.

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People here have got to realize that some times you just have to make what you have work the best you can. Not every one can just call a builder and say hey I wanna run this pipe, build the motor around it, and then go write a check. That motor could easily pull CPI pipes with race gas domes and timing. Guys out west are doing it in Oregon on stock stroke motors on very conservative porting. I'm not saying it is the best, but I am saying it can be done.

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that's right tricked, i don't have money to put new mods on my bike, i got my shee and i did about 15 tanks of gaz and i blow my engine three times.. by the way, what if i run my cpi's with stock carbs? and there is a picture of the same port job as me.. its not a big port.

. images.jpg

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Tricked... he can run CPI's but hes going to need higher timing and compression to get the full juice out of them... odds are he isnt going to be running higher octane... You will still be shocked how well PC's or other pipes in that catagory it will run depending on the engine set up... each pipe has their place with the engine....

 

Like mentioned before.... zilla had a aggressive trail port... Shears and FMF's had the SAME peak hp except the fact that FMF's peaked out earlier and hit much sooner... was the bike any faster between the 2 pipes... nope...

 

 

picking a pipe will not completely determin if your engine is a trail or drag bike... it all has to work together. I still say he will not see optimal results running CPI's unless he steps up his game on his cylinders.... OR increases his PSI and timing but in doing so needing to run race fuel....

 

 

thats like asking for drag cylinders but wanting to be a low mid trail bike and asking if FMF's or PT mid revs will do the trick... will it work.. yes... will your bike run properly the way it should... probably not...

 

 

Get CPI's if you want to try them.... they might feel faster mid - top but they may not be in all reality cause your engine is just more peaky compared to a pipe that came on smoother n hit sooner

Ahh, so you are learning grass hopper.... That FMF to shearer comparison is the type of scenario I was trying to explain to you when you were looking in to a pipe with a little more grunt out of the hole. Cant help but feel like this is the same kinda stuff i was talking about with ya a while back. On the smaller stock cyl builds it is very possible for what most people say are junk trail pipes to peak the same numbers as big inframes just earlier. The CPI will probably be a bit more of a peak though. He had the stage 4's and obviously he is committed to a higher strung pipe to see what it does. Can't go wrong with the CPI in my Experience. March, let us know if it needs more fuel then the trinitys. That will be a fair indication that it makes a little more power.

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