Go Back   DIY Go Kart Forum > Announcements & Suggestions > FAQ & Articles

Notices

Closed Thread
 
Thread Tools Display Modes
  #1  
Old 06-30-2008, 08:46 AM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default My lil' 5HP guide...

I wrote this for a member, so I decided why not to share it with everybody You can never learn too much

Cheap power:


First of all, get out your dremel, and your little barrel like sand paper.

1) Port. Clean up any rough casting when it came out of the factory. Mine had huge amounts of this, just sticking out. Sand all that down, then round any sharp corners you see. Don't sand the seats though!

Do the same with the exhaust port. The intake can be a little rough, but the exhaust port should be much smoother.

Then, cut the eyebrows. (Pics can be sent for an example upon request). These are the bits of metal sticking inbetween the valve/seats, and the cylinder hole. By sanding these down, you increase flow by a huge amount. This isn't offset by the amount of compression you lost either. The amount of flow gained is great!

Just a tip on the porting - Don't go wild. You want to slightly port it out. Anymore, and you'll lose velocity. It'll have horrible acceleration, ect...

Rods:
Stock steel dippers hold at around 4200-5000RPM. The rod goes at 5000RPM.

A Raptor THREE (3) rod can hold up to 7000RPM. The dipper is integrated into the rod, so no worries there. A ARC Billet connecting rod or any other can pass 8,000 with no problems. They can also withstand bursts of 10,000RPM.

There are many combinations of rods. The stock length Briggs 5HP rod is 3.875". There are much longer ones too, such as 4.475", ect. These are rods made for special pistons, Wiseco for an example. Longer stroke, "shorter" piston.

EDIT - If you want to stick with the stock rod, go the safe route and get a nylon dipper. This will only prevent dipper breakage, it will NOT prevent the rod from breaking at 5000+.

Heads:
You want a good flowing head. Not a high compression head, as those lack flow. Have you heard "Put on a 4HP head! It gains huge amounts of compression!" WRONG. The amount of flow lost offsets the amount of power gained. Stick with the 5HP head. Get a Raptor BluePrinted head for $30 on eBay, and if you get a milled head, or one milled yourself, don't ever buy one or get one milled over .030. Any more than that, and again, flow starts to decrease. You won't notice any more speed from this, but more torque and power in the middle end.

An easy way to spot these heads are by the numbers on the heads. If the head has a "10" on the top, it is a 4HP head. A 5HP head will have a number "13".


Cams & Springs:

Ahh cams... the best way to gain power. As you probably already figured out, more lift = more power. However, not always. You have to focus on other things, such as duration. To make it short, the most popular cam sold today is the 94ss "Cheater" cam. They retail around $60. There are many more, but the 94ss is the most popular cam around.

By getting one of these cams, and revving high, you'll need better springs and retainers. You could get a whole new dual spring set, with retainers and keepers, or just new springs, with hardened retainers.

Any performance cam will do fine. The only thing difference, is the higher the lift, the heavier the springs will need to be. Also take in mind the heavier the springs, the more power it will suck. Getting a [for example] .265" lift cam, and using springs for .600" lift or so, will be a huge waste.

The 94ss cam is recommended by me, but any other cam do. Just take in mind you may have to cut (relieve) the valve area of the head if you go too high lift of a valve. Now to 2 terms you'll probably encounter:

Coil bind - When the coil cannot be compressed anymore, but the engine wants it to... (basic definition), = parts break.

Valve floating - Valve float is an adverse condition which occurs when the poppet valves on an internal combustion engine valvetrain do not remain in contact with the camshaft lobe during the valve closure phase of the cam lobe profile. This reduces engine efficiency and performance and potentially increases engine emissions. (Wikipedia)

In other words, the valve does not fully close in time when the piston comes up, or the valve starts "bouncing". This can cause (on OHV engines) bent valves. On flatheads, it will just not rev anymore. Either way, you'll notice it when you start revving higher.

Valves:
You want light, and good flowing valves. I'm guessing you have seen those "blueprinted" valves on eBay. Some people says it makes no difference just that it lightens your wallet, while others say that it makes a good gain. The truth is, well it can be both. Poorly "blueprinted" valves can yield no gain, while quality BPed valves can see a gain. So don't go buying $10 BP valves from a random auction.

Valve lapping - The most common action done when wanting the valve and seat to have a good seal. You start off with a rough compound, and then either (for water based ones) add water to get a smoother compound, or use the "smooth" compound already supplied. You will usually not need to use a drill to do this. Doing this too many times is also hard on the seats.

3/5 angle valve seat cutting - The "race" cut. Many motorcycle shops or other shops do this. Many people say they saw a bigger gain with a 3 angle cut than bigger valves. If you can get someone to do this cheap, go for it! Usually they're "Competition cuts" or something on that line.


The Block...:

The very last thing you want is a worn or cracked block, no? The most common place for breakage is the lifter area. The exhaust lifter area to be more specific. To prevent this, due to high lift cams and such, many people weld more material on to the lifter area to increase strength. Which leads me to another area, lifters. Try and get your hands on BILLET lifters. They're cheap. I'm going to grab 3 sets today for $5. Stock length. Longer ones can be found (which aren't needed unless you have a special cam) for other prices.

Remember, you want valve lash! You don't want to end up with a burnt valve. You can grind the lifter a bit to increase lash.

Aluminum Bore - Also known as the "Kool Bore". These blocks are very forgiving during the normal use.

EDIT: I was incorrect, Kool Bores do NOT have a sleeve - these are only to I/C motors (steel/cast iron sleeve motors). Kool Bores are popular, cheap, but wear down and must be re-sleeved if you wish to re-use it after you've gone through all the "oversize" sizes.

Steel Bores are loved for their durability, lack of using a chromed piston, ect. They generally come with bearings, unlike Kool Bores with bushings.

Another thing to take into mind, aluminum bores (Kool Bores) require a chrome plated piston. It isn't the chrome like you see on mufflers or grills. You can identify this by (Briggs and Stratton pistons only, 5HP only) a 4 on the bottom of the piston. A 4 indicates chrome plated, while a 6 indicates it was made for a cast iron sleeve. Kool Bores also wear faster, and do not last long in racing. But honestly, as long as you keep up with oil changes, don't go throttle crazy half the time, you'll be fine.

Cast iron sleeves - Also known as "I/C" engines, or Industrial/Commerical engines, have a cast iron ("steel") bore. These can use both the non chromed or chromed piston (4 AND 6). These CAN be honed and bored, but recommended not past the sleeve, for the reasons mentioned above. These are "heavier duty", and last longer than the Kool Bores. These are the most common block found in 5HP flathead karting.


Crankshafts:
As you know, bushing cranks are usually what most people have. These will handle fine up to around 7,000, where problems start occuring (oil starvation most likely).

And as you have seen, there are cranks with bearings. These cannot be easily removed, and are not slide on-side off bearings. These are pressed into the crankshaft, and require special tools to remove. They come in 2 standard sizes, the bigger ones, and the smaller ones (how easy it that? ). If you wish for a bearing crankshaft, you will need either one with a big/small bearing, and a side cover that corresponds to your bearing size.

Flywheels and Coils:

Cast iron flywheels are the most commonly used ones to date. And also the most dangerous. Never spin one over 7,000. Over 6,000, they are the danger zone. People have spun the Clone's flywheels at 6,500. One's shattered at 5,800.

Billet flywheels save lives. ARC has (JMO) the best. The Clone one has been lab tested to take 12,000+ RPMs. This can probably be said for the 5HP Billet ones also. These are around $200 shipped. Also I'm experimenting with a much cheaper alternative. ($50 haha!)

Coils. I'm hazarding you've seen HOT Coils around? Again, people have had positive experiences with them, and people with no differences. IMO, the stock coil is fine. All you need is a spark to get the mixture to ignite.

I've given most of my learned information to you. Use it well. Hope this helped you in something!


This was COMPLETELY written by me

Meh... it probably stinks, but yall probably got something outta it.

Last edited by oscaryu1; 07-13-2008 at 10:03 PM.
The Following 89 Users Say Thank You to oscaryu1 For This Useful Post:
2or3wheels (07-01-2008), 2strokedude (01-23-2010), adsum (10-15-2014), Ahmed (03-26-2014), Banny (06-14-2014), BirdFanatic (10-10-2014), birdman58 (04-14-2010), Bluethunder3320 (07-17-2011), BradenM (12-04-2008), bucci (04-01-2013), chachaman811 (07-18-2011), chain (01-24-2013), chavesr11 (08-31-2009), Chrisrook (06-05-2013), CooperJS (12-26-2012), CRN13 (06-04-2011), Daniel Donaldson (11-15-2013), DCC! (07-05-2009), droptopmaro (02-13-2011), DudeRadster (12-04-2011), DustinWolfe (01-04-2012), EagleTalons (06-09-2009), ed1380 (06-30-2008), el~bryce`o (08-17-2008), emanuJ (08-27-2009), Ferrari motors15 (05-04-2009), flowerman (10-20-2009), freakboy (08-20-2009), genesisdriver (03-11-2011), GoAlterBridge (09-23-2008), Gokartbill (04-18-2014), Hellion (05-29-2016), Hendu3270 (01-11-2011), Hex429 (06-10-2009), Ibnzmonkey (01-21-2009), jacko206 (08-05-2009), Jake.B (02-02-2012), James.Ait.2013 (07-23-2013), jandj (11-05-2009), Jasn (04-23-2011), jeepman09 (03-05-2009), jk95ht (04-29-2011), JoeM0e (12-16-2011), JTSpeedDemon (05-19-2019), karl (02-26-2011), kendelrk (05-08-2011), kibble (06-30-2008), kieranruffell (01-23-2014), Leem1994 (02-01-2009), mafyougrover (06-22-2010), Magice (06-30-2008), marriott1066 (04-14-2009), masteryota (10-27-2012), Mcdriver (08-31-2016), mike75925 (06-14-2009), mister twister (12-29-2011), Mrbirmi (12-10-2013), mrfreyguy (10-24-2009), newrider3 (06-30-2008), NickKlügs (04-12-2015), nickzom (02-13-2009), nixta (10-19-2014), redcali (06-30-2008), Rotore (09-04-2009), r_chez_08 (05-15-2010), sayre315 (07-28-2008), shovelhead (05-20-2010), sideways (09-06-2009), sirrra1797 (10-28-2011), slammedkart (03-30-2009), SmallEngineDave (04-29-2011), Smurph (10-20-2009), solomon (04-26-2010), South Kart3377 (05-06-2011), squat251 (06-23-2009), tenlizard (11-03-2008), TravisD (04-23-2009), tundrabeagle3 (06-03-2012), txluke (05-22-2011), tykenfitz (01-26-2010), vgk (02-27-2010), Volksdad (04-25-2016), whapit (11-06-2014), Will (11-24-2013), yellowkart (10-07-2010), youngn (12-28-2008), Zombient (01-20-2016), zrawk95 (08-31-2010)
  #2  
Old 06-30-2008, 09:54 AM
redcali redcali is offline
Senior Member
 
Join Date: Apr 2008
Posts: 171
Thanks: 3
Thanked 10 Times in 9 Posts
Default

very nice and well written.
The Following 2 Users Say Thank You to redcali For This Useful Post:
rokor (01-18-2009), whait86 (03-24-2012)
  #3  
Old 06-30-2008, 11:59 AM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

Thanks!
  #4  
Old 06-30-2008, 12:18 PM
ed1380's Avatar
ed1380 ed1380 is offline
Banned
 
Join Date: Mar 2007
Location: ATL, GA
Posts: 1,182
Thanks: 9
Thanked 26 Times in 26 Posts
Default

very nice. where was this earlier? i honed a cool bore


Quote:
(Ahem ed... )
whats this about?
  #5  
Old 06-30-2008, 02:24 PM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

I/C Internal/Combustion

Hehe

Oh darn. It's not recommended, the only thing recommended is wearing it down to the next piston/ring size needed, which is usually .010 oversize.
  #6  
Old 06-30-2008, 02:53 PM
newrider3's Avatar
newrider3 newrider3 is offline
Senior Member
 
Join Date: Aug 2007
Location: Colorado
Posts: 1,674
Thanks: 58
Thanked 124 Times in 95 Posts
Default

Very nice. Don't forget DU bushing crank bearings. Much much better than plain bearing alumnium surfaces. They are used on the flywheel side. Also, you or a shop can drill an extra hole into the flywheel side bushing to provide extra lubrication. Also, I don't know where you heard Kool Bores can't be bored or honed? It is done all the time, as long as you don't hit an air pocket or go too thin.
  #7  
Old 06-30-2008, 03:16 PM
kibble's Avatar
kibble kibble is offline
I banned myself
 
Join Date: Mar 2007
Posts: 2,766
Thanks: 35
Thanked 129 Times in 114 Posts
Default

Good work oscaryu, I guess this thread should be stickied.

Actually, I'll sticky it and move it to the engines forum. That's where it should be.
__________________
"At the enrichment center we believe that if at first you don't succeed, you fail." GLaDOS - Portal
  #8  
Old 06-30-2008, 03:58 PM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

Quote:
Originally Posted by newrider3 View Post
Very nice. Don't forget DU bushing crank bearings. Much much better than plain bearing alumnium surfaces. They are used on the flywheel side. Also, you or a shop can drill an extra hole into the flywheel side bushing to provide extra lubrication. Also, I don't know where you heard Kool Bores can't be bored or honed? It is done all the time, as long as you don't hit an air pocket or go too thin.
I know that, but it's not recommended that you hone to the point that the sleeve is almost gone. Many people bore these, yes, but then also place a (most likely) cast iron sleeve in it. Boring, and resleeving.

Thanks Kibble! To think a PM got to this
  #9  
Old 06-30-2008, 04:05 PM
newrider3's Avatar
newrider3 newrider3 is offline
Senior Member
 
Join Date: Aug 2007
Location: Colorado
Posts: 1,674
Thanks: 58
Thanked 124 Times in 95 Posts
Default

There is no sleeve in a Kool bore. Thus the name, as it is plain aluminum.
  #10  
Old 06-30-2008, 04:55 PM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

Interesting. I've been reading the opposite from another forum. Oh well, learn as you go. Thanks for clearing that up!
  #11  
Old 06-30-2008, 08:39 PM
sayre315 sayre315 is offline
Rupp enduro
 
Join Date: May 2008
Location: Oklahoma
Posts: 848
Thanks: 14
Thanked 13 Times in 13 Posts
Default

usally, wat does brake on the cenecting rod wwhen it spins at to many RPM's?
  #12  
Old 06-30-2008, 08:41 PM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

How many RPMs to be exact?
  #13  
Old 06-30-2008, 09:02 PM
newrider3's Avatar
newrider3 newrider3 is offline
Senior Member
 
Join Date: Aug 2007
Location: Colorado
Posts: 1,674
Thanks: 58
Thanked 124 Times in 95 Posts
Default

Quote:
Originally Posted by sayre315 View Post
usally, wat does brake on the cenecting rod wwhen it spins at to many RPM's?
First, you'll lose the tin dipper. A bit higher than that and the rod just snaps.
  #14  
Old 06-30-2008, 09:25 PM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

And you get a free hole on the side of your block
  #15  
Old 07-01-2008, 10:25 PM
jr dragster T's Avatar
jr dragster T jr dragster T is offline
Senior Member
 
Join Date: Jul 2007
Location: Cold place
Posts: 3,966
Thanks: 18
Thanked 170 Times in 153 Posts
Default

And maybe you will get a few surprises at the bottom of the block when pulling the side cover off. Try it and then you will get the surprise.
  #16  
Old 07-02-2008, 07:22 AM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

A lottery ticket?
  #17  
Old 07-04-2008, 09:34 AM
jr dragster T's Avatar
jr dragster T jr dragster T is offline
Senior Member
 
Join Date: Jul 2007
Location: Cold place
Posts: 3,966
Thanks: 18
Thanked 170 Times in 153 Posts
Default

Nahh try it and find out.
  #18  
Old 07-04-2008, 12:41 PM
Kenny_McCormic Kenny_McCormic is offline
Kartless....
 
Join Date: May 2008
Location: Michigan Troll
Posts: 4,537
Thanks: 10
Thanked 201 Times in 182 Posts
Default

Quote:
Originally Posted by oscaryu1 View Post
A lottery ticket?
I played this game a couple times, I will tell you the secret, pm me. This guide is forgetitng the cheapest power, yank the gov and use a 12 inch pipe nipple for an exhaust.
  #19  
Old 07-28-2008, 09:14 PM
sayre315 sayre315 is offline
Rupp enduro
 
Join Date: May 2008
Location: Oklahoma
Posts: 848
Thanks: 14
Thanked 13 Times in 13 Posts
Default

any body got picture of the eyebrows?
  #20  
Old 07-28-2008, 09:30 PM
oscaryu1 oscaryu1 is offline
Senior Member
 
Join Date: Mar 2008
Posts: 2,767
Thanks: 6
Thanked 148 Times in 60 Posts
Default

Yup, lemme find it in my many pages of Photobucket...
Closed Thread

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:21 AM.