Beginner RD250 project questions

[mlakritz]

the poet windows need to be radiused on cul a bit, no sharp edges.  as far as that bottom end, aside from the muck and rust nothing stands out, just check the rod up and down play and side to side.

so there is zero up and down play and a tiny bit side to side on each rod but i can't find my feeler gauge to measure accurately. it isn't much that's for sure, but not sure what the tolerances there should be or if there should be no side to side play at all.

[RDnuTZ]

do you have a manual? A lot of the spec stuff is covered in there. I never start motor tear down stuff without 1 -preferably a Yamaha branded 1. Makes life a lot easier.

[SoCal250]

RD250 & RD350 specs (this is from a tech bulletin for 1974 models)
Rod Clearance
Axial:  New: 0.8-1.0;  Max: 2.0
Side:   Min: 0.1;  Max: 0.3

[mlakritz]

do you have a manual? A lot of the spec stuff is covered in there. I never start motor tear down stuff without 1 -preferably a Yamaha branded 1. Makes life a lot easier.

no manual but am finding stuff needed so far online. i'm gonna just buckle down and research stuff when i am unsure and when i really run into a dead end, i'll ask questions here. if i keep asking everything in my head right now this thread will stretch forever so i'll try to be judicious when posting. i'm just caught up in the excitement of the project at the moment.

[RDryan]

you need a stud removal tool like the 1 Mark recommended some time ago. I used to struggle with removing using Primitive Pete methods as well until I saw Mark's, so I went to NAPA and got 1 of these and they come out easy (using Blaster does help too)

https://www.jegs.com/i/JEGS/555/W83203/10002/-1?msclkid=1e0b40afb9fa13619be7275c8384e7d7&utm_source=bing&utm_medium=cpc&utm_campaign=WP_US_Bing_Shopping_555_Hybrid_Category_Catchall&utm_term=4581664973605614&utm_content=555%20Products

I used it multiple times on various sizes and it's great.

Ok, I did it! special thanks you as well as Striker and Mark. That tool kicks ass I actually got it over at a Advanced Auto Parts nearby with a Spring discount and unbeknownst to me my credit card's bonus pts. paid for it.

Didn't use any heat just the tool, Blaster juice and patience. The stud closet to the oil lines and grommet that got singed from heat was the toughest. Gave that one about half a dozen blasts and tapping it like the side of the can recommends over twenty minutes. Another stud gave an audible crack when it broke loose, felt like something satisfying when folks go to the chiropractor. Really quite amazed at how well intact the studs came out looking as well. Simply tightened the tool to as close to the bottom of the stud with out contact on the threads and it really didn't seem to mark up the stud at all. I thought for sure looking at those tools online that it would gall up the stud to the point of whatever, good forbid I snapped it...my worst fears were all for not. Nope every stud came off looking great for a potential reuse.

F'n awesome is all I can say,thanks fellas. Still waiting for the Vito's wrist pin bearings till then struggling with a cheap harbor freight dremel too I acquired recently to chamfer the poet windows. They came somewhat chamfered but not all the way around.

[RDnuTZ]

That tool is a huge work/time saver. Well worth what they cost 

[m in sc]

sweet! if you have a die grinder,  I like to radius the ports with a small sanding drum (toostie roll) on a longer arbor. dremel can actually be trickier imho. 0.02

[RDryan]

sweet! if you have a die grinder,  I like to radius the ports with a small sanding drum (toostie roll) on a longer arbor. dremel can actually be trickier imho. 0.02

Well I couldn't agree more about the Dremel being tricky. I got a very small one for under 10 bucks yesterday at harbor freight. I think it's a neat little tool and I thought it would be quite easy to work all around those ports at preferable 45 degree angles but it wasn't. Definitely takes some skill and careful hand and eye coordination. I unfortunately tagged the cylinder wall a couple of times. I was using a cone shaped stone and although I had just it as far out of the holding chuck as I could it just couldn't easily do the work right. Would  be nice to be a longer arbor at least. I definitely would like to find a better tool.

I remind myself hey at least the tools and parts are cheap. I can afford the learning curve. 

[mlakritz]

So question on these Kveldvulf cylinders...the flanges that sit in the lower case are not a tight fit into the case recess, you can see they are almost 2mm smaller diameter than the stock cylinders. This can't be right, is it? Looking at them from the bottom it looks like there should be a sleeve that slides right into the recess that makes it the correct fit but given this is my first time in an RD top end I have no idea. Maybe this doesn't matter? But it sure seems like something is amiss on the fit here.

[m in sc]

are you sure you got them from the same seller?

mine fit very well 350 cyl to 350 cyl. comparison pic. the od of the sleeve is the same 250/350

[mlakritz]

are you sure you got them from the same seller?

mine fit very well 350 cyl to 350 cyl. comparison pic. the od of the sleeve is the same 250/350

Well, same seller in terms of the link from one of the other users in this thread, I couldn't find a direct link in your old thread. But if you look at every listing on ebay now, they all look like they are cast like this. It is not unlikely that they all come from just one factory, many different seller accounts are obviously the same seller/distributor. So I'm not sure what to think. Is it possible that that groove facilitates oil flow from side to side of the cylinder? But how can you not have a positive fit/connection with that flange and the case, even if the studs are what ultimately dictate the position the cylinder?

[m in sc]

there have been variations but from different sellers, i know this for a fact. there were indian ones and multiple chinese ones. i cant speak to yours directly. i have a set int he garage still new in the box, haven't even opened it. ill go open it in a bit and check them, they were bought recently just to have on hand.

[mlakritz]

there have been variations but from different sellers, i know this for a fact. there were indian ones and multiple chinese ones. i cant speak to yours directly. i have a set int he garage still new in the box, haven't even opened it. ill go open it in a bit and check them, they were bought recently just to have on hand.

I've sent a note to the seller, never know if that will be helpful but it can't hurt to ask. pic shows a rough measure the diff, 3mm+.


interestingly, after checking amazon, there are a few nonsense name sellers (of course) who show a cylinder much more similar to the stock and ones in the older post. sleeve is still thinner but no outside groove. it's amazon, i'll probably just order a set and check them out and compare. But a lot of these listings have no reviews and are pretty fly by night sellers so I guess you just gotta shop around until you find one that seems right and decide if you want to buy cylinders from a store/factory that also sells baby nasal irrigators and beauty products :-)
https://www.amazon.com/360%E2%80%9111311%E2%80%9100%E2%80%9100-Performance-Shockproof-Aluminium-1973%E2%80%911975/dp/B0BY9S2H75

[m in sc]

just checked mine. yup there's a difference. also can say, there's never been an issue on my bike so me, i wouldnt sweat it. 0.02

[John Ritter]

If you are still looking for heads I have a pair of R5 high compression and high torque that CC'd at 20.5cc each, $100. plus ship. All fins and chambers are good. Outer fins need rubbed on and then fresh paint.