Pressing Con-Rod Into Crank

Rob Abbott /

Noob here - rebuilding my ZA50 and want to replace my con-rod/bearings. I am having trouble finding a local machine shop in Northern Virginia that will press the new con rod into the crank. Know any shops that I can ship to?

Thanks in advance.

Re: Pressing Con-Rod Into Crank

Had an oddball moped crank redone by this company. Great work good communication and fair price. I sent him a new crank with conn rod and a crank with a bad rod. He put the new rod on the old crank as that was the only way to fit it to the engine. Balanced and ready to install, all old stuff returned to me. http://www.mrcrankshaft.com/

Re: Pressing Con-Rod Into Crank

Rob Abbott /
roba OP

Thanks Bob! I'll give them a try.

Re: Pressing Con-Rod Into Crank

Found this guy but have not used him or made contact. Worth a look. Has a web site.

Cheapsk8s moped crankworks

Says he's near cincinatti.

Re: Pressing Con-Rod Into Crank

> Keith K Wrote:

> -------------------------------------------------------

> Found this guy but have not used him or made contact. Worth a look. Has

> a web site.

>

> Cheapsk8s moped crankworks

>

> Says he's near cincinatti.

http://www.mopedcrankworks.com/home

Re: Pressing Con-Rod Into Crank

Rob Abbott /
roba OP

Thanks Keith. I have emailed him twice with no response. Bummer!

Re: Pressing Con-Rod Into Crank

Dirty30 Dillon /

Fairly certain moped crank works is out of business and he has been dodging people in the community for work undone

Re: Pressing Con-Rod Into Crank

damn, that sucks. I had a few cranks saved by moped crankworks. rollerbearing'd a ZA crank, salvaged a busted garelli crank cheaper & better than I could've replaced it, and a few other times he'd saved the day too

but hell, even '77 once ran a quality respectable business, and we can all miss those days while admitting: there aint no money in mopeds.

Re: Pressing Con-Rod Into Crank

is it really that hard if u had a press and a dial indicator? i have a hf press and an indiactor just never attempted, maybe this year.

Re: Pressing Con-Rod Into Crank

Probably Fred /

> pat splat Wrote:

> -------------------------------------------------------

> is it really that hard if u had a press and a dial indicator? i have a

> hf press and an indiactor just never attempted, maybe this year.

You need a bit more than that, you need to have the correct jigs for the hole and sides as well as something perfect to the put the pin in and out, also when you change the pin it does make it a bit looser so Learning how pin or tack the crank is useful for a performance build, you really wanna recondition the crank to be almost like new,

I saw it done by skilled Mechanic With the proper stuff and big hydraulic press and it looked relatively easy but he had but it was in machine shop and he was doing it for years, he had all other tools at his disposal for cleaning polishing etc. also

He needed very little tweaking with wedges and hammer to get the motorcycle crank true when done and all surfaces were smooth and free of pits for good sealing,

Get a 30 ton press, wedges brass hammers all the tools that are needed make jigs Metal doll rod stock and practice on about a dozen cranks then start working on cranks for money,

Re: Pressing Con-Rod Into Crank

♣Slew Foot♣ /

I had 3 machinists and a farm kid do a3 to a35 pin and one bat m48.

I would recommend buying a new one if available. All but one the machinists did failed. The farm kids m48 and a3 held but I have some bluing..

Re: Pressing Con-Rod Into Crank

Try MrCrankshaft.com

Re: Pressing Con-Rod Into Crank

Rob Abbott /
roba OP

Hey All - I actually spoke with Mr Crankshaft (a.k.a. Vince). Friendly fellow who seems to know his stuff. I'll let you know how it turns out.

Re: Pressing Con-Rod Into Crank

Keep us posted. Thank you.

Re: Pressing Con-Rod Into Crank

Dirty30 Dillon /

Mr Crankshaft is an industry standard, he is legit.

mopedcrankworks is the grey area.

Re: Pressing Con-Rod Into Crank

You don't need Jigs, you need basic hand tools you can buy at HF and patience

You need a 12T harbor freight press. ~$100

buy some cheap 1-2-3 Blocks. ~$20

Get a lead hammer ~$20

Get some V blocks ~$20

Get a fox wedge ~$5

Get a dial indicator and mag base. ~$40

All of this stuff can be had for a few bucks.. maybe you already have some of it.

Use the 1-2-3 blocks to align the pin. Really any precision block will work. This will allow you to start the pin straight.

Heating the crank lobes helps the same way it does installing bearings. don't rush though.. it will go in cold as well.

Start the pin. check push it more, check.. see the pattern?

Once you have the pin seated in one half, align the other side with the blocks and push it on.. get some feeler stock and check your rod thrust clearance. Don't overdo it . it helps to measure the pin, measure the cheeks and put a piece of shim stock under the pin when doing this to make sure you don't just drive the pin too deep in the side you have already done.

Then it is dial indicator and check time. Hit liberally with lead hammer and get runout to within .002 Less is always better. I shoot for less than .001 if its going to see 10k plus. Use the wedge to spread the cheeks if they are running out in a "v". It's a lot of brute force and ignorance.

I've done this many times making custom crankshafts for stuff.. either changing rod length or small end pin diameter.

It's really not rocket science... and you learned something.

There are a few youtube video's on how to do this.

Re: Pressing Con-Rod Into Crank

Rob Abbott /
roba OP

I really appreciate the detail and would like to learn something new. However, the machine shop will do is for less than $100 - and if I were to buy the tools to do it myself I'd probably never have the opportunity to use them again.

I watched the videos, though. Very tempting.

Re: Pressing Con-Rod Into Crank

Probably Fred /

> Joel P Wrote:

> -------------------------------------------------------

> You don't need Jigs, you need basic hand tools you can buy at HF and

> patience

>

> You need a 12T harbor freight press. ~$100

>

> buy some cheap 1-2-3 Blocks. ~$20

>

> Get a lead hammer ~$20

>

> Get some V blocks ~$20

>

> Get a fox wedge ~$5

>

> Get a dial indicator and mag base. ~$40

>

> All of this stuff can be had for a few bucks.. maybe you already have

> some of it.

>

> Use the 1-2-3 blocks to align the pin. Really any precision block will

> work. This will allow you to start the pin straight.

>

> Heating the crank lobes helps the same way it does installing bearings.

> don't rush though.. it will go in cold as well.

>

> Start the pin. check push it more, check.. see the pattern?

>

> Once you have the pin seated in one half, align the other side with the

> blocks and push it on.. get some feeler stock and check your rod thrust

> clearance. Don't overdo it . it helps to measure the pin, measure the

> cheeks and put a piece of shim stock under the pin when doing this to

> make sure you don't just drive the pin too deep in the side you have

> already done.

>

> Then it is dial indicator and check time. Hit liberally with lead

> hammer and get runout to within .002 Less is always better. I shoot for

> less than .001 if its going to see 10k plus. Use the wedge to spread

> the cheeks if they are running out in a "v". It's a lot of brute force

> and ignorance.

>

> I've done this many times making custom crankshafts for stuff.. either

> changing rod length or small end pin diameter.

>

> It's really not rocket science... and you learned something.

>

> There are a few youtube video's on how to do this.

My 12 ton harbor freight press didn't work to break free a Za50 crank but a 20 ton did like it was nothin

The 12 ton

Re: Pressing Con-Rod Into Crank

I have a 12t that I found on the side of the road on garbage day that works great. Its been used so much the main frame is twisted.

I do have a piece of 1" plate on the table though.. table deflection will eat up your force.

Re: Pressing Con-Rod Into Crank

im lazy, where do i buy blocks, wedges, v pins and lead hammer, i have a 20 t on press and the indicator.

Re: Pressing Con-Rod Into Crank

We have KMS, Princess Auto, Busy Bee tools here in canukia

US peeps would try Harbor Freight, Grizzly tools, China?

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