wanting to put 4 mm crank in

[kodie]

ive never put a crank in that was + XX mm's. what kinda difference is a 4mm gonna make in my bike? also when i do this im gonna bump up to 60 over instead of staying at 40. below is a list of what its got going on. also will i be able to stay with pump gas or will i have to change to race gas?

 

 

.040 wiseco pistons 360cc, Wiseco hotrod crank Racelogic porting/polish woods port, 30mm keihn pwks, Procircuit platinum pipes, w/spark arrestor silencers, Boyesen rad valves, Adj. timing plate set at +3, Noss head 21 cc domes.

 

 

P.S. what brand should i go with?

Edited February 20, 2008 by kodie

[dajogejr]

You'll get about a 7% increase in torque and hp IF you match the cylinders to accomodate a longer stroke.

 

Do not go 60 over unless the motor is worn and needs to be bored to be back in spec, otherwise, you're wasting two bores...they make .050 pistons.

[trex banshee]

if your cylinders do not need bored to .060 i wouldn't do it. Your just wasting the life of them.

[trex banshee]

You'll get about a 7% increase in torque and hp IF you match the cylinders to accomodate a longer stroke.

 

Do not go 60 over unless the motor is worn and needs to be bored to be back in spec, otherwise, you're wasting two bores...they make .050 pistons.

 

beat me to it man..

[Ducman]

When you get the cylinders ported (for +4mm stroke spec) they will need to be bored and port windows deburred/chamfered to clean up after porting. No need to go any bigger than necessary, it wont add any power to go to a larger dia piston, power difference between .040 and .060 is nothing. When you get the cylinders bored it is a good idea to have the new pistons on hand when the bore is being done for the machinist to check tollerences, probably not necessary if it is a reputable builder, but needed if its the local machine shop.

 

Pump gas will be fine with 21cc domes. Another thing to research and think about, are you going to use custom cut domes or a spacer "stoker" plate under the cylinders to make up for the +2mm higher max piston stroke height.

[kodie]

When you get the cylinders ported (for +4mm stroke spec) they will need to be bored and port windows deburred/chamfered to clean up after porting.

 

is there anything else im gonna have to do when i put this stroke in? like i said ive never done this so all this information is new and good learning material for me so thanks for all that have replied. and im not asking for an exact amount but could somone throw a ballpark $ amount out there for average cost for it all?

[jbooker82]

Your putting in a Hot Rods Long rod 4 mill stroker crank right

 

You will need.

 

795 series pistons. (these are needed because the long rod crank has conecting rods 5mm longer than stock so you need pistons with the wrist pin moved up 5mm)

 

Since you already have a cool head ditch the spacer plate and get a set of custom cut 4 mill stroker domes from Noss Machine. Since your adding 4 mm of stroke the piston falls down in to the cylinder 2mm farther and the top of the piston comes up 2mm farther. You can run a 2mm spacer plate so the head doesnt hit or you can get domes that are cut for the clearance. The stroker domes are 100% better way to go. Less chance of an air leak since you dont run the spacer plate.

 

Porting to match your riding style. Make sure you tell them that your building a 4 mill so they port the cylinders for it and you will take full advantage of the 4 mill crank.

 

josh

[Ducman]

Porting to match your riding style. Make sure you tell them that your building a 4 mill so they port the cylinders for it and you will take full advantage of the 4 mill crank.

 

josh

pluss tell the porter if you are going to go with stroker domes or the spacer plate.

 

Here's a good website link below for part/price comparisons.

 

Vitos

 

Vitos also, or at least used to sell a +4mm standard rod crank that still requires the spacer plate or domes but allows the use of standard pistons, not 795 series.

[sheefreak]

If they are already ported for stock stroke, you are gonna have a hard time finding someone who will report them for the 4 mill setup. I can't tell if you mean they are already ported, or you are having them ported w/the new crank.

[kodie]

sorry should have made it a little more cleare here is what is done to it right now

 

.040 wiseco pistons Wiseco hotrod crank, Racelogic porting/polish woods port, 30mm keihn pwks, Procircuit platinum pipes, w/spark arrestor silencers, Boyesen rad valves, Adj. timing plate set at +3, Noss head 21 cc domes

 

yes there is a woods port on it right now but if i have to ill report them

Edited February 20, 2008 by kodie

[sheefreak]

What are you wanting to do w/this setup?

[kodie]

right now i do mostly woods riding and take on a few hill climbs

[kodie]

i looked at noss's website and there wasn't price for custom domes for a 4 mil stroker. what do they cost?

[spurdy]

i looked at noss's website and there wasn't price for custom domes for a 4 mil stroker. what do they cost?

Mine were $80 a set.

[kodie]

so after i get it in and its all done properly will i be able to notice the change from stock stroke to 4 mil? and what kinda differences will i see? just more power and torque?