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Discussion Starter · #1 ·
Hello this winter I am ether boreing to 102mm or 105mm. My qestion is what are the pros and cons of having a 4+ crank or a 8+ crank? Also I understand that to bore to 105mm you need to have the case bored up when changing the crank is it almost ready to take to the machine shop to have bored? And one last ? how much of the case do you have to disassemble for the shop to do the boring on its. Thank you guys so much for your time, I have never been in a forum this helpfull!!
 

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And one last ? how much of the case do you have to disassemble for the shop to do the boring on its.
If the shop / you didnt strip them clear down I would be worred about not getting all the metal shavings out. Wouldn't take very many pieces of small metal in a bearing to ruin the bearing and anthing else the part is conected to.
 

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Don't forget if you go bigger then a 102mm then you will probably need FCR's. A 720 will be okay with stock carbs but if you go a 762+up then you will need them. I would give Barker, Gesick or Kenz a call if you wanna build a big motor because I don't think a +8mm is just a drop in crank and they are the guys that build them.
 

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Discussion Starter · #4 ·
OK right now i have an edelbrock carb um air box and monster duels. Do you think the carb could take it?
 

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Most people do not even run that carb setup. There were a lot of them sold when they first came out. It wasn't to long later you could pick them up cheap second hand. Lots of complaints of tuning issues.

A single carb on a raptor doesnt make more power. I would stick with the dual stock carbs before I would go to a single. Dual FCR's are the way to go for performance.
 

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Hello this winter I am ether boreing to 102mm or 105mm. My qestion is what are the pros and cons of having a 4+ crank or a 8+ crank? Also I understand that to bore to 105mm you need to have the case bored up when changing the crank is it almost ready to take to the machine shop to have bored? And one last ? how much of the case do you have to disassemble for the shop to do the boring on its. Thank you guys so much for your time, I have never been in a forum this helpfull!!
The +8 is not a drop-in and go item. This requires spacer plates and quite a bit of technical expertise. The +4 is a drop-in crank with two choices. 1. The Hot Rods which has the stock length rod and requires a special piston with the pin bore relocated 2mm (that's the crank I run). and 2. The Tim Barker Crank which has the 2mm shorter rod and allows the builder to use the shelf pistons available for Raptor rebuilds. --The rod length can also be a technical issue depending on what you plan on doing with the bike. Currently The Hot Rods set up has only the JE 11:1 piston with 2mm off set pin on the shelf and two custom CP 13.5:1 pistons offered by Kenz and Looneytooners only, I believe.
To do the 105mm you will need to strip the the case bolt it up and bore it to match the new Cylinder bore which will require a new sleeve to go the 105mm. Great set up with a stock stroke Hot Rods Crank and Rod or even a +4mm but I'm not sure how easy it is to find pistons since I have not ran a 105mm motor.
FCR carbs are the way to go for all around performance.
Be sure you define what type of riding you plan on doing before you spend tons of money and select a cam that matches your riding requirements. Good luck.
 

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Discussion Starter · #8 ·
So it sounds like the +4 is the way to go. I am going to use a stoker piston, I figured a high compression since ever thing i have at my house uses race fuel already, just have to figure out how to get the lawn mower to use it. Thanks again for your help if it wasnt for people like you my quad would just be a lawn ornament
 
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