Author Topic: Cobra motor disassembly and rebuild (Read 107795 times)

Bill/BentON Racing · « **Reply #675 on:** November 21, 2016, 12:10:25 PM »

Yep, expensive lesson learned! Broke the block in at least 4 places! Ugly, what an explosion it was....

PeWe · « **Reply #676 on:** November 21, 2016, 12:52:58 PM »

There is another thread where they stated that Carillo H beam is overkill for a CB750. I saw a photo here with a killed one, over and over again....over kill?
Good to have a project to keep going with and keep the good spirit going and inspire others on this forum.

Bill/BentON Racing · « **Reply #677 on:** November 21, 2016, 01:52:31 PM »

Well thank you, I do try, Bill...with a little help from my friends!

TurboD · « **Reply #678 on:** November 21, 2016, 02:24:19 PM »

Quote from: PeWe on November 21, 2016, 12:52:58 PM

There is another thread where they stated that Carillo H beam is overkill for a CB750. I saw a photo here with a killed one, over and over again....over kill?
Good to have a project to keep going with and keep the good spirit going and inspire others on this forum.

I am completely confident saying the Carillo rod did not break on its own in a 100HP engine, something else prompted it. And especially in just a handful of passes. I have been running completely stock rods to 11,000 RPM for a season now.

Bill/BentON Racing · « **Reply #679 on:** November 21, 2016, 03:25:02 PM »

dragracer · « **Reply #680 on:** November 21, 2016, 04:07:22 PM »

Bill's holding onto a nice set of brand new rods for his friend in SC. Isn't that right Bill? Something about holding that check to apply towards funding those rods?? Is that what I heard Bill?? Lol. Help a poor, struggling young man out over here.

754 · « **Reply #681 on:** November 21, 2016, 04:58:25 PM »

Quote didnt work,
KMB 69.....I will get pics soon .. One crack goes from sprocket shaft to the big oil galley behind #1 cylinder..

Medyo Bastos · « **Reply #682 on:** November 21, 2016, 05:21:18 PM »

Billy I've got a bag full of pins wrapped up and tucked away under the bed

Sent from my iPhone using Tapatalk

Jerry Rxman Griffin aka MuthaF'er · « **Reply #683 on:** November 21, 2016, 06:40:22 PM »

Quote from: Bill/BentON Racing on November 20, 2016, 05:56:57 PM

Yep, I realized how lucky I was......It was running so good, love the color of the top of pistons

Mike oughta be able to clean up that chamber

Bill/BentON Racing · « **Reply #684 on:** November 21, 2016, 06:51:26 PM »

Frank, I'll work on that....be a good start on your build.

, Bill

dragracer · « **Reply #685 on:** November 21, 2016, 06:59:07 PM »

Quote from: Bill/BentON Racing on November 21, 2016, 06:51:26 PM

Frank, I'll work on that....be a good start on your build. , Bill

Now we'll get to see how much power those rods can take. This ain't gonna be strictly a N/A build. I see lots of potential down track clutch slippage coming unless I use heavy duty springs or a lockup. Wondering how deep in the nines we can get this one.

Bill/BentON Racing · « **Reply #686 on:** November 22, 2016, 04:06:37 AM »

You hoofing gas! Lol Frank's 750 Nitrous Express! Someone for sure going 9's! LMAO, Bill

PeWe · « **Reply #687 on:** November 22, 2016, 09:56:56 AM »

About RC lighter (thinner) wrist pins.
This setup worked better without failure back in the days whith Golden rods, right? The softer metal with more flex and less force banging the wrist pins than a newer steel rod. A kind of shock absorber in the rod.

I searched for alu rods when I have read at the hiPo froum and Internet that Nitro engines use aluminum rods.
http://www.dragzine.com/tech-stories/engine/debunking-aluminum-rod-myths-with-grp/

Bill/BentON Racing · « **Reply #688 on:** November 23, 2016, 05:13:11 PM »

Here you go, just played Ronnie Wood's I'm a lucky man! Just damn....never see one like this, N/A engine Wow!

Bill/BentON Racing · « **Reply #689 on:** November 23, 2016, 05:24:34 PM »

I know that's not where I left that ring!
I believe this piece broke the primary chains, it's wedged in tight!

BPellerine · « **Reply #690 on:** November 23, 2016, 06:11:41 PM »

after all the engines you have taken apart,if you haven't seen it nobody has!wow.billp

MRieck · « **Reply #691 on:** November 23, 2016, 07:10:20 PM »

Quote from: PeWe on November 22, 2016, 09:56:56 AM

About RC lighter (thinner) wrist pins.
This setup worked better without failure back in the days whith Golden rods, right? The softer metal with more flex and less force banging the wrist pins than a newer steel rod. A kind of shock absorber in the rod.

I searched for alu rods when I have read at the hiPo froum and Internet that Nitro engines use aluminum rods.
http://www.dragzine.com/tech-stories/engine/debunking-aluminum-rod-myths-with-grp/

My understanding was there was no manufacture known for the pins. They were old..... and .....well....you get it. No guarantee on them.

MRieck · « **Reply #692 on:** November 23, 2016, 07:12:10 PM »

Short pins ...etc.....etc..... etc......etc We get it.

Bill/BentON Racing · « **Reply #693 on:** November 23, 2016, 07:18:39 PM »

Here's some more "short" pins!,
A piece of the pin found in the cases.

dragracer · « **Reply #694 on:** November 23, 2016, 08:20:21 PM »

Since you brought up the subject of forgetting to add oil, here's the results of my screw up from several years ago. MTC was proud of that one piston they had to cut for me to match the originals. Almost as much as a set of 4.

Medyo Bastos · « **Reply #695 on:** November 23, 2016, 08:49:54 PM »

Quote from: Bill/BentON Racing on November 23, 2016, 05:13:11 PM

Here you go, just played Ronnie Wood's I'm a lucky man! Just damn....never see one like this, N/A engine Wow!

Billy there is a problem with this oil pump ~> http://forums.sohc4.net/index.php?action=dlattach;topic=153782.0;attach=339817;image those socket head bolts are not anodized red

754 · « **Reply #696 on:** November 23, 2016, 09:09:43 PM »

So bill, it appears these were rescue cases ? Previous chain damage, and on their second life...

dragracer · « **Reply #697 on:** November 23, 2016, 09:29:27 PM »

I'm going to be sure to have my wife fabricate some engine diapers for us by next season. Got one on my top gas Kawasaki we can use as a basic example. They may not be NHRA/SFI approvable but if they contain several ounces of oil, it'll at less give you an opportunity to roll to the side of the track without completely oiling it down and will keep the slick stuff off the tire so the rider stays upright til the bike stops. I'll get this going while she's on Christmas break from her tutoring business.

Retro Rocket · « **Reply #698 on:** November 23, 2016, 11:21:58 PM »

Geeze Bill, this reminds me of an old British Paints advertisement from the 1970's here in Australia, it went like this "If a jobs worth doing, its worth doing well "

PeWe · « **Reply #699 on:** November 24, 2016, 03:14:59 AM »

Newer pistons coating should evolve so no damage will happen for a small detail as no oil

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Author Topic: Cobra motor disassembly and rebuild (Read 107795 times)