Author Topic: 750 stroker motor (Read 2940 times)

cbr954 · « **on:** December 05, 2015, 11:15:59 am »

Just bought this stroker motor in parts. I measured out the stroke at 74mm. They used stock length Carillo rods with 73mm Arias stroker pistons, the pin intersects the oil ring groove, as well they also had to use a .09" spacer under the RC block. I was hoping it had shorter rods and standard type pistons. I find it odd that Arias used 3 piece oil ring without any support at the wrist pin. But it was a dedicated drag motor so I guess they didnt care too much about some oil usage? Now contemplating if I want to run it or not. Might just swap the RC block onto my other drag motor to get rid of my oil leak. Anyone ever used pistons like this?

754 · « **Reply #1 on:** December 05, 2015, 11:48:11 am »

Nice score the pin arrangement is like that on stroker..
That spacer sounds awful thick..
Did you ever use that other RC block ? Which ne is the leaker ?

cbr954 · « **Reply #2 on:** December 05, 2015, 12:51:37 pm »

Yeah fixed the post supposed to be .09". No the other block is the one that got broke, is on the shelf along with some other RC parts.

754 · « **Reply #3 on:** December 05, 2015, 02:03:11 pm »

Are the journals hardchrome... Any frosty looking edges? Was it street or stip ? What is on the tapered end of crank?
Did you get the chassis?

cbr954 · « **Reply #4 on:** December 05, 2015, 03:11:41 pm »

just the motor no chassis. It was a strip only motor, was used up in PA. just a bolt in the end of the crank. Not sure on the journals but they are in very good shape.

scottly · « **Reply #5 on:** December 05, 2015, 05:20:08 pm »

The stroker pistons I've seen had buttons in the pin holes with a groove to support the ring.

cbr954 · « **Reply #6 on:** December 05, 2015, 05:55:10 pm »

Quote from: scottly on December 05, 2015, 05:20:08 pm

The stroker pistons I've seen had buttons in the pin holes with a groove to support the ring.

Thats what I have seen also, either that or the groove is wide enough to put a support ring in with the oil ring, which is what I run in 347 ford stroker motors. Never seen one run with neither. I would be afraid of the oil ring end catching on the wrist pin hole but it was run this way and no damage done so I dont know what to think.

gschuld · « **Reply #7 on:** December 06, 2015, 06:30:10 am »

74mm stroke. That's bigger than usual. RC, for example, welded up cranks at 1/4" (6.35mm) increase. So basically 69mm stroke for their stroker cranks.

Going from 63(stock) to 74mm stroke is 11mm. 11mm is a .43 inch increase! Would you mind verifying the stroke to double check?

George

cbr954 · « **Reply #8 on:** December 06, 2015, 08:05:18 am »

Its been double and triple checked.

Bill/BentON Racing · « **Reply #9 on:** December 06, 2015, 08:15:14 am »

Hmmmmm. I have a 70mm Stroker Crank with stock length RC Golden rods.

, Bill

cbr954 · « **Reply #10 on:** December 06, 2015, 08:34:47 am »

Bill, do you have stroker pistons to go with it? Started to tear things apart for inspection and one of the pistons has some damage in the wrist pin bore, will have to either have custom pistons made or get some shorter rods and use std pistons I already have.

joe p · « **Reply #11 on:** December 06, 2015, 10:43:16 am »

I ran them pistons with with stock stroke with 1/8 under Gold rod. It's like 900cc, 754 you have them rod don't you. I got all that stuff form Dynoman. It ran 10.50 with my big ass on it.

754 · « **Reply #12 on:** December 06, 2015, 10:57:22 am »

I still have the rods, and I think the pistons.. And now a stroker crank.... Need to throw a motor together using that..

Bill/BentON Racing · « **Reply #13 on:** December 06, 2015, 01:19:08 pm »

754, pics please,

, Bill

754 · « **Reply #14 on:** December 06, 2015, 01:51:56 pm »

Not right now

NitroHunter · « **Reply #15 on:** December 09, 2015, 05:51:12 pm »

Does a standard 750 cam chain will work with that much block height?

cbr954 · « **Reply #16 on:** December 16, 2015, 03:15:09 pm »

there is only .09" extra block height. Stock timing chain still fit, its just more of a pain to get it all together. Was going to rebuild this stroker motor but everyone says it wont last because of the big stroke so I will put this motor on the shelf until I can afford a smaller stroker crank then have stroker pistons built for the new stroke.

Bill/BentON Racing · « **Reply #17 on:** December 16, 2015, 04:06:55 pm »

Oh man c'mon. ..someone built it....you can do it, biggest stroker I ever heard of. I wanted to hear it! I'm about to dig out my 70mm stroker with stock length RC Golden Rods, Bill......maybe just to look at! Lol.

cbr954 · « **Reply #18 on:** December 16, 2015, 04:39:47 pm »

I was hoping it wasnt such an odd ball stroke size, never would have guessed that it is what it is. If one of the pistons wasnt damaged it would be going together but the cost of custom pistons has shelved this build for now.

dragracer · « **Reply #19 on:** December 16, 2015, 09:30:31 pm »

What about using stock 900dohc rods and a standard piston to get the proper deck height?? The sohc 900 rods are stronger than stock and 1.5mm shorter. Standards pin location might put the piston close to where you want things.

Just throwing it out there since you seemed excited about that big stroker crank. Its got your money now, why not make something happen.

gschuld · « **Reply #20 on:** December 16, 2015, 10:04:09 pm »

Actually, I think it's the dohc cb750 that has the 1.5mm shorter(than sohc)rods rather than the 900.

Those Arias stroker pistons, what kind of markings are on the inside? FWIW, MTC sold a welded up stroker kit back then that used factory length rods and special reduced compression height "stroker pistons" instead. Any chance your pistons are MTC stroker pistons?

George

cbr954 · « **Reply #21 on:** December 17, 2015, 06:31:38 am »

The pistons are 73mm Arias 287-ss. I sent pictures to Buzz at dynoman, he seems to be confident they had come from RC, some of the later ones that they sold.

I got a quote from buzz for $785 for stroker pistons...not really bad considering the work to build the pistons the way they need to be and the compression I want. If it wasn't for the fact that I just put a bunch of money into two motors to start drag racing next year I would do it but getting the two bikes going is more of a priority. I actually bought the motor more for the head and rc block and the Carillos as the owner wasn't 100% sure that it even had a stroked crank so I bought it under the assumption it was stock stroke, plus I got it for a really good deal. I still hope to build it sometime.

MRieck · « **Reply #22 on:** December 17, 2015, 09:16:59 am »

i wouldn't think about using that crank without magnafluxing it. The last RC stroker crank I saw magnafluxed had spider web cracks all over the place. Shelf duty only.

cbr954 · « **Reply #23 on:** December 17, 2015, 10:38:00 am »

I was going to send it to Jay to check it over but dont think I will be using it anytime soon.

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Author Topic: 750 stroker motor (Read 2940 times)