First time crank replacement

[RD350NL]

Hi all

I am planning on replacing the crank of my 352 aircooled rd250 engine (350cc top end) because the current crank is shot. Planning on installing a Vitos crank. I have never done this before but I have experience with top end replacement etc.

Can you share tips, dos and donts? Is there a detailed manual available?

I will also replace the seals. Tips for this are also appreciated.

Thanks so much!

[RDnuTZ]

HI, I am just curious here if there is any specific reason you are choosing to go with Vitos crank for your 1st install? I am getting ready to do my 1st install (2 actually) on USA air cooled 1973 RD250 and 1974 RD350. I have pulled apart a couple motors over the years but never rebuilt at this level. I liked the way Vitos are updated design and I also found HPR on eBay as well. Some of the more experienced guys on here have good results using both vendors. I bought 2 of the HPR versions and have not installed yet but they look very well done and were less $ (almost $90 each for me) so figured if I mess something up or crank isn't up to expectations upon install- it hurts less financially than 2 Vitos at this time

I'm not expecting issues other than my own learning curve and am planning another build of backup engine that will probably have a little more HP and will use a Vitos for that 1.

[1976RD400C]

Seal orientation and don't forget to install the clip on the gear side to lock it in place.

[m in sc]

^^ this.

I'll be curious about the HPR ones. i saw them but wasnt sure

[RDnuTZ]

thought you mentioned you used HPR before? Turns out the business is a crank builder and has decades of experience.

Here's a link to where I bought on Ebay with pictures of actual crank like I received. Notice difference between labyrinth seal on these and Vitos:

https://www.ebay.com/itm/364763626086

[m in sc]

i'll be honest, the only diff on the lab seal i can see is the vitos one is anodized black. also, IMHO, the vitos rods look better/beefier. lastly, the vitos rods use japanese bearings. I'm not saying there's really any major difference, but it was a consideration. I've used a similar one, was an LC crank though, and it was 7? years ago for the lightweight. and its been great.

[RDnuTZ]

good eye on the labyrinth seal    I had never seen a black 1 before and didn't know if it was rubber, plastic, etc. HPR has Taiwan bearings (a step up from Chinese IMO) I DO like the design/construction of the Vito's crank best, but my 2 coming builds will have nothing more than common bolt on mods and few miles/hours ever to be ridden so HPR should be fine with my expected limited stress on them.

[gargantua350]

Yeah I put a Vitos crank in my mine.  The lead weights fell out of the old crank and locked up the motor.  This was a few years ago and it's been problem free ever since the install.  I didn't know there was another crank manufacture for the aircooled RD. That's good to know.