2st balancing

[Ktm181]

Who does it? what sort of cost? what are you finding as far as performance changes?

have a good one,
Kt

[Mick D]

I think one of the main problems is that there are so many lame jobs performed.

I have been bought many crank failures over my days. Build above .005" run-out as well as a lot of worse super woeful ones.

All Manufactures specify a rebuild of below .002" run-out.

Another common stuff-up, is accidentally changing the reciprocating mass by using different(brand) weight pistons and different weight(wall-thickness) gudgeon pins. And different weight rod kits.

Manufacturers occasionally got it less than satisfactory, occasionally.

If you have the above right? you will have a "very good thing" anyhow.

If you then want to optimise, you can adjust slightly the static resting point of your crank.

I have seen a few on here recommend "franks cranks", all satisfied consumers




 

 

[firko]

While the crank 'run out' can be a problem the main problem is the compromise balance factor on most mass produced cranks. I've sat and watched Frank Stanborough check a number of cranks of a number of different makes and you'd be blown away to see how far they're out. Franks Cranks has done crankshafts for a number of racers on here including seriously fast blokes like Dean Burt and every single one of them can't believe how smoother their engine runs. Slakewell has just had Frank do his 250 and 495 KTM  cranks and I watched him do the 250. There's a bit of work and a lot of Mallory heavy metal used in the process but I guarantee that you'll love the improvement it makes to your engine....two or four stroke. The costs vary according to the amount of work involved but if you factor in around $200-$250 you won't be shocked by the bill. I won't build a motor any more without getting Frank to balance the crank .

[Slakewell]

Some bikes need it more than others like a 440 Maico really needs it. These days with miss match parts etc its harder for the average guy to do it. In the old days I would do it myself in the lathe. These days I get Frank to do them.

[Mick D]

That's a good wrap, for sure.

I would like to send him a couple of cranks, pistons and rod kits.

Could either of you guys give me his postal address or contact details please?

Cheers

[Ktm181]

thanks guys, Mr Stanborough it is then! 

Mick- 19 Mathew ave,Blacktown (just off Resevoir Rd if you know it?) Ph. 9621 5604.

Kt

[Mick D]

Cheers, thanks Kevin.

I just had a brainwave, save on heavy postage, they could be dropped off by me or someone on the way to of from CD

Are you going to CD Kevin?

[firko]

Mick I just sent you a PM with his number as well .

[Mick D]

Thanks mate, I also appreciate the tip you gave me as well I am humbly all ears, Thank you.

[Mike52]

I sat down and learn't how to do this and it is interesting.
Did my 240 husky as it vibrated bad enough to send your feet to sleep.
Ended up a completely different engine no more vibrations and it now revs a lot freer.
Could not believe how far out it was .

[firko]

Top: The 350 square barrel crank destined for my 360 oval barrel Maico
Bottom: Slakwells 495 KTM crank.
You can clearly see the heavy metal additions opposite the crank pin,

                                                                                   
                                                                                   
                                                                                   
                                                                                   

[OverTheHill]

done lots of cranks over the years but alignment is different to balance & in saying that--i've never balanced or changed the balance factor of a crank as such as i don't really understand it. So far as truing goes i just press em up getting as near as i can with a steel ruler then in the lathe with the good end [usually the drive side]on a centre & the mag end supported by the tail stock chuck set up the mag taper just before the keyway because 99 times out of 100 the thread on the mag end will be bent from some harry smacking shit out of it to remove from the cases. Bit fiddly & better on v blocks or rollers as have to bugger around taking out & putting back in the lathe to alter. always end up within a safe range though but sometimes end up with a 'problem child' so compromise a bit. Some motors vibrate when put in different frames for some reason. My de-stroked mudbug 100 bucket racer has an RD200 twin crank [well one side crank] 46.5 stroke so i could overbore to a yamaha 52mm piston & is silky smooth as luck would have it. Some smaller cranks i've just put together in the vice [biggish vice] with a feeler blade beside the conrod, pressure the vice then pat the wheels & it'll sneak up little by little till nipping on feeler blade, then between centres in the lathe etc to true up. Cheers.

[OverTheHill]

just thinking--i made a heavy steel band to go around our honda rs125 roadracer many years ago as has a soft tin cover by memory & think CR's are the same & avoided damage when trying to true it up. truing up can go in all directions & might have to knock around on the pin or squeeze opposite the pin or spread opposite the pin. Villiers used to have a soft petal plug to knock in once you had trued the crank up which must've spread it just a bit to [be sure to be sure trick], never did one but saw it done in the "60's. Think the plug had to be drilled out to dis-assemble it then being a bobweight type crank i remember the foreman smacking a wedge in opposite the pin then somehow smacking the pin with a solid big punch & it slowly separated.

[OverTheHill]

just saw a mint looking kawasaki H1 500 on 'trademe' nz--have a look under classic & vintage [thought they were Mach111's but never mind], & bought back memories or nightmares of when i rebuilt a crank in the mid "70s, got it right but wasn't easy & never did another. Bike was same model & colour too. Remember using a DT1 eccentric/accentric 8mm screw to get the gearchange to centralise over the drum pin so as to pick up the next pin, worked good.

[HuskyPete]

Getting the correct balance factor in your crank is the best money you spend, everything is just so much smoother.