How to test a scooter crank

[@h2omechanic]

Glad I saw this. I heated my case to put mine in. I did have to use a dead blow to even it up. But while I was doing it I did take notice that the rod/crank pin being offset would be what's taking the load. I have a dial indicator & before I finish my build although it is assembled,I'll check the shaft and make sure it's TRUE. If past 3-4 thou , I'll call yall for a new 1

[@Scooterswapshop]

thanks

[@matthewnorris203]

I appreciate how thorough you guys are. I just spent $465 on your website and I think it’s because I can see from your videos how things really work and I want to do it, too!

[@Scooterswapshop]

Thanks for the support! I’d like to think the videos give people confidence to do their own work :)

[@AllLifethingschannelyt]

Great demo of this I have a Chinese scooter and crankshaft went bad after 4300 miles

[@Scooterswapshop]

sounds right that's alot longer then I would have guessed!

[@FremontidaeScott]

Hey Brandon. You can true a crank, mate! MX shops can do it quick, work backlog notwithstanding. You can do it yourself, too, but it's a PITA without the right tools. Of course, not worth it with an OE or POS crank. Also, people need to use crank pullers like Brandon does. No pounding to center, not even pulling *back* to center is ideal. When you're pulling them it's best to leave a bit on the side you start first. Then when you're bringing the cases together, do a bit at a time when you get close, when the dowels start to seat. When you're pulling, you're looking to pull the case closed with the crank centered. If you pull the case one side first, then the other, you often wind up needing to center the crank a bit. But once those bearings are on the journals, and those bearings are seated in the case all the way, even if you use a puller you're putting stress on the main journal. That could spread the webs at the opposite side of the main journal. And always check true before installation! So it definitely pays to go slow and use the right tools. But don't chuck a good crank if it's out of true.

[@Scooterswapshop]

we never would spend time truing a crank or wasting the time on that unless it was a $500-1000 setup just replace it not worth the risk

[@FremontidaeScott]

@@Scooterswapshop yeah I'm talking to the peeps who don't have the $ to buy a new crank if they have issues with their decent crank. Makes no sense to pay the man hours to have y'all do it. Most MX shops are set up for this though, or you can DIY even though you will be chasing your own tail for awhile, maybe a long while. Not really risky for the integrity of the crank, though. They get trued and balanced at the factory to begin with. And of course ppl pull a crank apart to swap conrods, but that's a shop job. No harm in nudging the main journal square, though.

[@pcorpion]

Great video Brandon as always would it be possible to make a video of pressing in a crank and also pressing in crankshaft bearings into the engine cases . Thanks!!!

[@Scooterswapshop]

I have one already. We use crank pullers you don’t want to use a press

[@pcorpion]

let me know the title of the vid so can access it . @@Scooterswapshop

[@eamonnmckeown6770]

Moving away from Genuine for food delivery to a Kymco. 125 to 250. The Buddy crank on the driven side is toast. Put a used good variator plate on for a temporary fix and it lasted a little while. Really don't want to break down an engine in the late fall cold so off it goes for free to someone else. $130+ for a new factory crank w/o the connecting rod isn't bad but with $500 for the Kymco so why bother.

[@OnlyLifts.]

Is 10mm crank on a vertical minarelli engine enough(with malossi or polini piston bearing) for a sport polini AC cylinder(around9-10hp)? Is 12mm more robust?

[@Scooterswapshop]

As long as it’s a new quality crank the pin doesn’t really matter

[@dougbrittain3021]

So why/what causes OEM crankshaft failure when you go over 70cc. Does the journal bearing fail?

[@Scooterswapshop]

The stock Yamaha cranks are weak normally that bearing fails. Typically you see it when the bike is spinning a higher rpm.

[@bp-tuningaeroxlc-dd6474]

Can you make af video like this abouth Doppler crank .... SR1 and Endurance ...

[@Scooterswapshop]

some day

[@jimmy-zc1qs]

How good would you say a reinforced original crank will be over a normal original

[@Scooterswapshop]

Aftermarket cranks rarely fail

[@jasonsmith1714]

Hi With variator on i turn it by hand and has some movement then locks. Is this correct or should it move freely?Not sure but have ordered a new belt. Thanks

[@Scooterswapshop]

not quite understanding.

[@FremontidaeScott]

Necro reply, but it should turn freely. If it's binding after a new install, you're probably too tight to one side or the other.

[@solopomodoro5853]

Is malossi sport any good? Iam not racing, but want acceleration to be good. Onnshould i buy malossi mhr?

[@Scooterswapshop]

Call the shop Paul will set you up to go fast!

[@Tizzy_p]

My crank won’t turn the full 360 locks around 300 degrees why? I will change it anyway but why

[@Scooterswapshop]

ITS BAD?

[@Kyle_gallegher]

I just want to see a full case split for a 90 cc minarelli so I can get some ideas for my daughters kasea 90

[@Scooterswapshop]

not a motor we have here but we split that style of motor in many videos

[@Kyle_gallegher]

@@Scooterswapshop well anyhow it looks like I can do a 43 to 45mm crank swap. I see these addly cranks all over I hear good things about. Seems relatively str8 forward on these to split cases and remove bearings from case. I will invest in the tools as well.

[@dongerramarco9617]

my crank fell in a bowl of gasoline how do i lubricate it again? can i just install or do i need to buy a new one?

[@Scooterswapshop]

Gasoline is a lubricant.

[@dongerramarco9617]

@@Scooterswapshop ok thanks for the knowledge dropped, i will cherish it it my future work Thanks a lot

[@oliverfuchs4357]

Why so difficult? Use heat and cold!And if you try to rebuild an engine,use malossi,polini or yasil.

[@Scooterswapshop]

What’s so difficult?

[@oliverfuchs4357]

@@Scooterswapshop The way you want to install things, with heat and cold they just slide .

[@Scooterswapshop]

There’s lots of methods. I always freeze my bearings, but I’m not a fan of getting cases super hot. To each their own.. it takes longer to heat a case then it does to lightly press in frozen bearings.

[@oliverfuchs4357]

@@Scooterswapshop In the european countrys there is a general rule of getting around 120--140 degrees celcius on aluminium cases,Bearings maximum minus 30 degrees celsius. In Long travel engines we also do not use plasic case bearings,as they whreck like nothing when a Viton bearing starts causing lean runs.Another thing is that in this way you also reduce the Axial strain on the Rollerbearings themselves.

[@Bidalotroxi]

my bidalot crankshaft has 0.08mm of play and 2fast over 0.03mm

[@Scooterswapshop]

gotcha

[@nokia26300]

jiso and rrgs is 1 company.the are popular here in philippines.

[@vendivelangelo402]

San po may shop ng jiso pang dio

[@nokia26300]

@@vendivelangelo402 try mo kay deka.6th ave caloocan

[@Scooterswapshop]

Great parts but they’re not great communicators

[@nokia26300]

@@Scooterswapshop it suck to have language barrier.

[@FremontidaeScott]

Ohh, I thought he was saying Jasil.

[@penelope6504]

Mini stroke is only good if it’s full counter all metal

[@Scooterswapshop]

Most vintage high end Vespa cranks built to handle way more power than dio are half counter. Polini and stage6 make half counter too. Half counter helps with bottom end. There’s pros to both designs