Engine build up.

J

Jer

New Member
#1
#1
Ok, I am starting to build me an engine for my mini bike. Im gong with a 5 hp and was just going to get a little advice while building this. I intend to keep you updated with pics throughout my build. So to get it started...






















Apparently whoever had this engine first removed the govenor without upgrading any internal componets and it blew up. It caused a huge crack in the side of the block which can be seen in the third to last pic. Its a shame too cause I really like this block. It has the roller bearing crank shaft in it. Speaking of crank shaft you can see in the pic it seems to be marked up pretty bad from the old rod. Can this be polished or should I just buy a new one? And can I have someone who does aluminum welding fix this block? Somone suggested JB Weld but I would much rather do this right. Thanks
 
125ccCrazy

125ccCrazy

Well-Known Member
#2
#2
unless you have a buddy that can heliarc the block most welding shops will charge more than you could find a good block for.....I'd search over on Bob's karting, someone there will have one, possibly already modified...

You can try polishing thecrank but I'd mic it before and after polishing....it may have to be turned .010 under if it's off spec too much..
 
J

Jer

New Member
#3
#3
Ok. Thanks. Im talking to a buddy right now who does aluminum welding to see what he thinks. It should hold up right? He is supposed to let me know if and when he can do it.
 
J

Jer

New Member
#4
#4
Ok, you called it. He never said what it would cost but he did say it would be cheaper to buy a new block. So can someone point me in the right direction to one? I tried looking on Bobs Karting but didnt see anything. Any help would be greatly appreciated. Thanks
 
C

C9H13NO3

Active Member
#5
#5
Jer said:
Ok, you called it. He never said what it would cost but he did say it would be cheaper to buy a new block. So can someone point me in the right direction to one? I tried looking on Bobs Karting but didnt see anything. Any help would be greatly appreciated. Thanks
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I have one for sale.

Iron bore, dual bushing. Could use a honing, but I can do that before I send it.
 
The Restore Kid

The Restore Kid

New Member
#8
#8
C9H13NO3 said:
I have one for sale.

Iron bore, dual bushing. Could use a honing, but I can do that before I send it.
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Jer said:
Iron bore? Will I need a different piston for that? Do you have pics you can post? Whats your price? Thanks
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I think it's a complete engine??

125ccCrazy said:
there may not be any dual bearing blocks posted on Bob's at the moment but if you put up a wanted ad someone should chime in....
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I have two dual bearing sleeved engines and one DU bushing sleeved block.. :deal: http://www.oldminibikes.com/forum/m...ggs-dual-bearing-i-c-horstman-h-beam-rod.html
 
J

Jer

New Member
#11
#11
Ya, I noticed the prices for each after I had posted that. I may be intersted in the block. Im assuming that is not the stock crank for that engine because it dont have any bearings on it?
 
The Restore Kid

The Restore Kid

New Member
#12
#12
Correct.. The crank is from an older dual bushing engine.. You'd have to buy new bearings along with anything you were going to add, but they bolt in all the same.. Only major difference is the rear journal on the bushing engine is longer, so the clutch slides on and stops located where it would as if it were a bushed side cover.. Sticking out like 3/8 of an inch.. Or you can turn down the little bit of extra so the clutch can slide on farther, then you have a crank shaft 3/8 of an inch longer than everyone elses.. :laugh:
 
J

Jer

New Member
#16
#16
I have another question.... What is the biggest advantage of having the bearing rather than just the bushings? I intend to go with billet rod, remove the govenor, and have different cam, valves, springs, etc. Can I get away with just having the bushing block rather than the bearings?
 
The Restore Kid

The Restore Kid

New Member
#17
#17
Hell yes.. The bearings just reduce drag by like ten fold.. They spin a lot faster and easier.. Accelerate faster, last forever aposed to until the bushings wear out.. They are just a lot more durable and can handle abuse better.. Go just a tiny bit faster.. :shrug:
 
J

Jer

New Member
#18
#18
Awesome. Well I want your block as long as there are not any huge holes through it. Which you said there wasnt so I am interested in that. I will have to part with a different engine tho before I go and buy another. Have too many and they are starting to get in the way! LOL
 
J

Jer

New Member
#19
#19
Ok, I scrapped the first engine. It turns out I have another 5hp engine that has the bearing in it but its only on one side of the block. Maybe I will find another one later on and finish the first project. So here are pictures to my 2nd engine that I am going to tear down and rebuild. First thing I have to do is get it all cleaned up....













 
J

Jer

New Member
#20
#20
OK guys. I know you have been checking out my post to see for updates but I been kinda busy here. It turns out that the original block I had that was cracked is now currently undergoing some surgery and will hopefully get back to me sometime this week. My kickass neighbor actually does some aluminum welding and he said if it works, I owe him $20 bucks for his time. The best part is he can leak test it when he is done and if it dont work, I dont pay. So thats pretty cool. He told me tonight the he does a ton of welding on the side so a custom frame may be in the works at some point. Keeping my fingers crossed that this one pulls through!
 
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