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cpi's vs shearer's


man27

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Hi guys I would like to know what pipes would work best for my mods.I'm running stock cylinders that have been bored 66mm and have been ported for a 4mm stroker crank .The crank is a hot rods 4mm 5mm long rod ,the pistons are wiseco pro lites ,reeds v force 3s ,vito's hemi head 24cc domes ,ricky stator 4+ timing advance,vito's water impeller,34mm mikuni carbs 390 mains 30 pilots clip in the 3rd position, tors removed,I 'm running 110 race gas 32:1,I 've been running pro curcuits.I want to run in frames if that makes a differance.I would like to know my hp but there 's not a dyno around so if someone could get me close I would appriciate it,I 'm thinking around 65 or so.Thanks for the help man27

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Hi guys I would like to know what pipes would work best for my mods.I'm running stock cylinders that have been bored 66mm and have been ported for a 4mm stroker crank .The crank is a hot rods 4mm 5mm long rod ,the pistons are wiseco pro lites ,reeds v force 3s ,vito's hemi head 24cc domes ,ricky stator 4+ timing advance,vito's water impeller,34mm mikuni carbs 390 mains 30 pilots clip in the 3rd position, tors removed,I 'm running 110 race gas 32:1,I 've been running pro curcuits.I want to run in frames if that makes a differance.I would like to know my hp but there 's not a dyno around so if someone could get me close I would appriciate it,I 'm thinking around 65 or so.Thanks for the help man27

more info what are you going to be doing?dunning,drag race,trail riding.anyway theres another topic some where on here,that talks about diffrent pipes,and what each difrent brand,and model is best at.[ill try,and find] :banghead:

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more info what are you going to be doing?dunning,drag race,trail riding.anyway theres another topic some where on here,that talks about diffrent pipes,and what each difrent brand,and model is best at.[ill try,and find] :banghead:

I ride some trails but mainly drag race :smile:

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CPI fit is garbage... they also leave VERY little room to make carbs adjustments... they come on the pipe sooner then shearers but fade off...

 

Shearers fit very well with the execption of the left side it has to be shimmd to not tap the head... but you can move it out using a few washers or do it right and get some nylon shims ...

the stinger desgin is much better on the shearers too.. they come much higher from the filters then the cpi...

they come on the pipe a little later then cpi but they pull much muhc harder and never letup!

 

im a BIG fan a shearers...

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CPI fit is garbage... they also leave VERY little room to make carbs adjustments... they come on the pipe sooner then shearers but fade off...

 

Shearers fit very well with the execption of the left side it has to be shimmd to not tap the head... but you can move it out using a few washers or do it right and get some nylon shims ...

the stinger desgin is much better on the shearers too.. they come much higher from the filters then the cpi...

they come on the pipe a little later then cpi but they pull much muhc harder and never letup!

 

im a BIG fan a shearers...

i agree w banshee man.shearers have more top end. :banghead:

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My question is this....you're running 24cc domes? I didn't know they made them that big?? Do you mean 22 or 21cc domes?

And if so, you're wasting your money on race gas....you don't need it with that low of compression. 20cc or smaller, then you'll probably need some.

 

I'll agree with above, more top end with Shearers, FAR better fit and design, but...you'll pretty much have to remove the airbox. CPIs are good pipes, but...I'm not a big fan of their design or fit.

 

Who did your porting, and how aggressive? 65 would be a stretch unless you have some pretty aggresive porting in my opinion...

 

You will probably only get 2 to 5 HP by going from PC to CPI or Shearer pipes....and at a higher RPM, so...keep that in mind with how/where you ride.

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My question is this....you're running 24cc domes? I didn't know they made them that big?? Do you mean 22 or 21cc domes?

And if so, you're wasting your money on race gas....you don't need it with that low of compression. 20cc or smaller, then you'll probably need some.

 

I'll agree with above, more top end with Shearers, FAR better fit and design, but...you'll pretty much have to remove the airbox. CPIs are good pipes, but...I'm not a big fan of their design or fit.

 

Who did your porting, and how aggressive? 65 would be a stretch unless you have some pretty aggresive porting in my opinion...

 

You will probably only get 2 to 5 HP by going from PC to CPI or Shearer pipes....and at a higher RPM, so...keep that in mind with how/where you ride.

Both domes have 24 stamped on them so I'm sure thats what it means,the guy I bought the head from said they were 24cc big bore domes but he maybe wrong.This is the first banshee I've ever built as for the fuel my compresion is 170 psi on both cylinders and vito's states plainly that they don't recommend going past 170. :thanks:

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Both domes have 24 stamped on them so I'm sure thats what it means,the guy I bought the head from said they were 24cc big bore domes but he maybe wrong.This is the first banshee I've ever built as for the fuel my compresion is 170 psi on both cylinders and vito's states plainly that they don't recommend going past 170. :thanks:

 

Don't take this the wrong way, but something doesn't add up. The domes are marked wrong (and you don't use big bore domes until you get into big bore pistons...which, I didn't read in your list of mods...just a 66 mm piston which is .080, not considered a big bore)...

IF those domes are 24cc and your gauge is accurate, there is no way it has 170PSI...no way.

 

Talk to Lane @ Vitos...he knows his shit and is a great guy to talk to.

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Well, lots of shearer guys here, so I will throw in my CPI vote. I like the CPI pies for a couple reasons... I LOVE the way they look (I had unstamped ones BTW). Yes, they fit kinda crappy on some bikes, but if you don't mind taking some time with shims or other nick-nack things to adjust the fit, they work fine. They do hit the filters sometimes which I hate. But more than anything, I like the power they produce. Not all up on top, but enough to drag race with. They start to hit late in the mid-range, which makes them good for dune riding (which is what I do) but still give some up top, which is nice for drag racing. They do die off a little too soon for me sometimes, but I still like them.

 

I have CPI and shearer pipes and use them for different types of riding. If I were building a dune bike I would go with CPI. If I were building a drag bike I would go with shearer.

 

- Jared

Edited by BigRed350x
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Don't take this the wrong way, but something doesn't add up. The domes are marked wrong (and you don't use big bore domes until you get into big bore pistons...which, I didn't read in your list of mods...just a 66 mm piston which is .080, not considered a big bore)...

IF those domes are 24cc and your gauge is accurate, there is no way it has 170PSI...no way.

 

Talk to Lane @ Vitos...he knows his shit and is a great guy to talk to.

I 'm thankful for the reply and I won't take nothing the wrong way, how do you measure the domes,and 1 more ? The domes have some dings on them will it hurt performance? thanks

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when you say dings... how bad are the dings? if they aresmall then no nothing your going to feel... but it would be smart to spend 50 bucksand get new ones ... also youll get ones that are smallbore and a size you know...

 

Dave correct me if im wrong

but if im not mistaken,stock dome messure right at 23cc's? and your saying you have 24? thats less room for compression then stock and your running a stock crank? like said above something not adding up casue your psi shouldnt be anywhere near 170... you should be at like 120...what kind of gauge did you use?

Edited by Bansh-eman
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when you say dings... how bad are the dings? if they aresmall then no nothing your going to feel... but it would be smart to spend 50 bucksand get new ones ... also youll get ones that are smallbore and a size you know...

 

Dave correct me if im wrong

but if im not mistaken,stock dome messure right at 23cc's? and your saying you have 24? thats less room for compression then stock and your running a stock crank? like said above something not adding up casue your psi shouldnt be anywhere near 170... you should be at like 120...what kind of gauge did you use?

Hi guys I would like to know what pipes would work best for my mods.I'm running stock cylinders that have been bored 66mm and have been ported for a 4mm stroker crank .The crank is a hot rods 4mm 5mm long rod ,the pistons are wiseco pro lites ,reeds v force 3s ,vito's hemi head 24cc domes ,ricky stator 4+ timing advance,vito's water impeller,34mm mikuni carbs 390 mains 30 pilots clip in the 3rd position, tors removed,I 'm running 110 race gas 32:1,I 've been running pro curcuits.I want to run in frames if that makes a differance.I would like to know my hp but there 's not a dyno around so if someone could get me close I would appriciate it,I 'm thinking around 65 or so.Thanks for the help man27

 

 

The guy is saying he has a 4mm stroker crank and cylinders are 66mm with some porting. As for the 24cc domes, I've never heard of anyone using that size and getting 170 psi for there compression, but if thats what you're getting for your compression check its good your using race fuel.

 

I don't know how to quote what he wrote sorry

Edited by 400ccStroker_shee
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when you say dings... how bad are the dings? if they aresmall then no nothing your going to feel... but it would be smart to spend 50 bucksand get new ones ... also youll get ones that are smallbore and a size you know...

 

Dave correct me if im wrong

but if im not mistaken,stock dome messure right at 23cc's? and your saying you have 24? thats less room for compression then stock and your running a stock crank? like said above something not adding up casue your psi shouldnt be anywhere near 170... you should be at like 120...what kind of gauge did you use?

 

If you look on Dave Noss's site, it will tell you that stock is 22cc. However, I've read here and elsewhere that a stock head (OEM) is 23cc...so, I'm not 100%....and to be honest, I've never measured a stock OEM head for cc volume.

Either way...as said, 24cc should produce no where near that PSI...

I didn't even know they made 24cc domes...never seen 'em before!!

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