Crank rebuilding S/E Qld

[graham]

Hi folks, have just started a crank rebuilding business read all about it at:


crankshaftrebuidingservices.com.au

Graham

[johnnie5]

you could get the address correct

http://www.crankshaftrebuildingservices.com.au/

[2TInstitute]

Graham, what does a twin crank rebuild cost. Your tooling looks very good.

[gravmax88]

$90 for a twin
Prices are on the contact details page on website..... now that you have the correct web address....... sorry about that

Graham

[graham]

If the twin is an RDLC, there are good quality aftermarket conrods available (Long brand from Japan) at less than $90 a cylinder. I tend to not use the supplied bearing/cage assembly as better quality ones are available just over $20 each.

I have stripped 6 LC motors recently, (I bought a job lot of stuff from a wrecker up north) and although several rods had play, the integral crank pin/web was ok in all the cranks..... a surprise..... Aftermarket mains (SKF C3 type) without the pip can be used on three of the bearings at less cost than koyo OE type, and the OE type used with the retaining groove on the other.

I have several new sets of genuine Yamaha rods for the rz series...... I also stripped 3 RZ motors recently and on two of them the crank had spread on the outer flywheel side.... a common problem it seems with a big over-rev and heavy flywheel seeming to be the cause. Maybe this would be a good reason for a tig location weld on this side when extreme use is anticipated.

All the crankpins on the RZ's were also in good condition, a very good indication of the quality from Yamaha, unlike a recent aftermarket crank I recently stripped with worn pin surfaces on both sides with relatively low mileage.

Graham

[2TInstitute]

As President of the Anti Crank Welders Guild of Australia I cannot condone the use of a welder on a crank I'll send a few for your opinions

[graham]

Its the only way to keep a KZ1000 or GSXR1100 roller bearing crank together under drag racing loading..... not a "correct engineering" way to do it I agree, but its a practical way of allowing high loading to exist and be reliable, whereas to not do it would encourage failure.

The spreading apart of the webs on the RZ's I have seen is exactly the same fault that occurs on the 4 stroke roller cranks in drag racing. The Banshee racers in ths states typically use welding (3 small tig welds on each outer journal) to keep their hotrod units together, using basically the same crank as the RZ

So really I do agree, it would be nice to not have to weld but in a practical world, it seems to be an effective means to keep it all together under extreme loading. I have ground away the welds on a KZ1000 drag crank three times and had it re-welded again for the 4th time with good results. (Nitrous bike with agressive jetting)


Graham

[2TInstitute]

What's the best way to speak to you your mobile just goes to message bank??????

[DOC03]

Graham, you wouldnt happen to have a spare set of 350LC cases in good nick from that job lot would you ??
Or maybe a complete motor ?
Pete

[graham]

All were 250LC as far as I know, so if the numbers are the critera, probably not, but I do have some spare 250 ones........

You got me thinking...... a couple/3 of the motors had the cylinders off so I will check the numbers and get back.....

Graham

PS if I don't answer my phone, just leave a message, I will get back. email is best for me, I check 2/3 times a day:

crsallora@gmail.com

Wow I got it right this time.......

[2TInstitute]

After a short conversation with Graham he's now the 2SDU forum crank guru. Crazy not to send your crank to him

[graham]

Peter, I have a set of 350 cases......

email sent.....

Graham

[Jeram]

Looks Good...

can you 'balance' single cylinder cranks to a customers specs?


I too used to have my GSX1100 dragbike cranks welded...
then the Aussie dollar got better...

suddenly Falicon Billet cranks became affordable.

[graham]

Jeram, I have done a few single cranks, mainly for the single cyl 250 National Superkart class where KX250's and YZ250's are reved up to 10.500 or so.

We only changed the balance factor 3-4% or so....... from 64 to 68% from memory, and it made a bit of difference..... esp when using the older style wiseco pistons which were a bit heavier....

It is quite straight forward to do, I have the good scales and quite a bit of the Mallory metal. The only problem is where you may want a quite dramatic change in factor, I get a bit worried over reliability when I start removing or adding too much material, esp the security of the weights over a long period. The best one I did was a TZ350 E or F model and we added some alloy stuffers on the inside of the crank cheeks, and drilled blind holes behind the alloy for the weights.

Yep, I agree the Falicon crank is by far the best solution......The aussie $ is almost $1.09US at the moment too.....

Graham

[Jeram]

Graham

I might have a job for you, because I am a bit frustrated about a crank problem and I cant find a solution.

Im rebuilding the CRM250AR (single cylinder 2stroke) (see honda section of this site for info, pics and video

my rod has vertical movement, so the big end bearing and rod and washers needs replacing...

Mr Honda however doesnt want to sell me individual parts.
he wants to sell me a complete crank for $700 !

so I have gone on a quest looking for rods and bearings that will fit on my crank. but have had issues because the crm has a 25mm crank pin whereas most dirt bikes have a 24mm crank pin.

solution 1

Run a KTM300 connecting rod with a KZK 25 x 31 x 17 big end bearing.

problem: the only good quality bearing in that size is a honda OEM K25x31x17, and the only KZK25x31x17 is made in china which scares me off a little.


solution 2

send my crank to you...
weld up the pin holes, rebore the crank pin holes at 24mm
get you to rebuild my crank with a KTM crank pin, KTM bearing and KTM rod

solution 3

got any other ideas????



any help apreciated... If you think you can solve my problem Ill send my crank up to you..