Beginner RD250 project questions

[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.

Have you used this to remove a cylinder stud? With the bottom end still in the bike? I would think the engine being in the bike would help to hold it in place but I am nervous that I could do greater harm ruining the stud trying to remove it. I looked at the tool reviews and one them said that it's possible to shear off the stud there by necessitating to drill it out and retap it.

Do I really need to remove the studs at all? I do think it makes sense to use the longer 350 studs but I just have a bad feeling that at least a couple of these studs are really stupidly stuck and although a tool like this may work OTOH if it doesn't and the engine is already out of the bike that's one thing by all means drill and tap em out. However maybe I am just making a mountain out of a mole hill?


PS- I did split these cases sometime ago not really knowing any better and thought it a good idea to replace the seals and gaskets, I also put a Vito's crank in it. That was about 4 thousand miles or so ago. I never bothered to remove the studs as they seemed fine as is except one of them was like finger tight and had some balled up threads so I replaced it. I can say they are not loctite in. Just been there a long time. I do have a funny issue trying to read the oil level ( oil level reads like an inch or so over the upper level when cold) like it doesn't return very well,I suspect from the crankcase to the clutch cover side and I assume there may be some  excessive Yamabond obstruction causing this but I don't really know. I think maybe I used too much of it, quite possible I did, I know I put on surfaces like the cylinder base gasket that don't require it. Well once the engine warms up and I run it for like a minute, the oil level reads proper upon a recheck and I just always measure out what I put in the bike which is what's specified.  Just pondering a worst case scenario should I have to perform surgery but I do think that's a last resort. As much as I would like to right the wrongs of my past repair work.

[Striker1423]

Either that Jets tool, or the clamping puck style.

https://a.co/d/cuEJHyn

I have this similar tool and I got all of the nasty gt750 studs out with it.

My RD I caveman double nut and heated them. Then gave up and got the tool.

If you decide against it you have to run the nuts without washers on the short 250 studs.

But since you started, hit the actual stud with your torch and get it pretty hot, then soak it with penetrants. Then crank until it comes off. It'll let go eventually with the old heat juice method.

[m in sc]

ive pulled the studs w the motor in the bike before. 

[RDryan]

Either that Jets tool, or the clamping puck style.

https://a.co/d/cuEJHyn

I have this similar tool and I got all of the nasty gt750 studs out with it.

My RD I caveman double nut and heated them. Then gave up and got the tool.

If you decide against it you have to run the nuts without washers on the short 250 studs.

But since you started, hit the actual stud with your torch and get it pretty hot, then soak it with penetrants. Then crank until it comes off. It'll let go eventually with the old heat juice method.

Yeah when I was hitting the studs with heat the longest I had the torch on one was about 20 to 30 seconds. I gave up as soon as I started burning the oil line/ square three holed grommet. Interestly I got one more stud out last night before going to bed, all the exhaust side studs are out but all the intake side studs are just too cozy there. I guess I can try what you suggest, I did order replacement rubber bits. If I run it the remaining 250 studs minus washers, those washers only give about 1/16" extra threads.

When I was putting heat on the studs I directed the flame to the stud meets case. I thought it better to get the case warm there but maybe it just takes longer to warm that extra surface area?

I dunno the tools are cheap enough in price but what is the better stud remover?...the one you recommend that looks like a socket or the one that RDnutz recommends?

ive pulled the studs w the motor in the bike before. 

Yeah well it does make sense in more ways than one. I just felt like if I was in a different situation with the cases split then I would be more brave. I am so nervous about wrecking the studs or just case if that makes sense. It does seem like that stud removal tool maybe the way to go though.

[RDryan]

Well I gave it another go with the heat on the stud. Did a better job covering flammable parts nearby and really put the heat to one stud till it was glowing red for a second or more. Took the heat off and immediately went at with the double nut method and it still wouldn't budge. Gave a few squirts of blaster and tried a second time, mind you I soaked it with blaster last night before bed and same thing, won't budge a bit. The only movement I get is the nuts wanting mash each other and the only give feels like in their threads so I back off.

I dunno what to say except the same scenario goes thru my mind,If I plan on more engine work like say a crank replacement or even just replacing crank seals  then OK I'll go to town with the stud remover tool. However those removal tools just look like they may very well work but with a good chance at ruining perfectly decent threads on the studs that in theory may well be OK to use as is.

So let me as this I think I am going to chance it with the shorter 250 studs that are stuck in there. I'll just not use the washer for that extra bit of threads that would give me. Is it ok to not use the washers? I guess I just have to me mindful of frequently checking torque values? The heads seem like they got more than enough material to em. I don't think the nuts would seize up on them, which I could just put a bit of anti seize on them?

I wish there were longer nuts with more threads knowing that folks would do these 250/350 conversions.It is interesting to figure out just how much thread depth you really need to keep it all together given all the vibration.force of the engine running. I know I had to retorque the nuts occasionally as a stock 250 but I also never checked them often enough.

[RDnuTZ]

I had several damaged Yamaha MX & YZ case halfs laying around to practice on with that stud extractor tool. Patience is a virtue here. I've typically soaked a stuck bolt or stud in PB Blaster or similar and walked away instead of hitting it right away. When I come back to it, I lube it a little more and begin trying to loosen - but I also go a little in tightening direction too just gently working back and forth to see if it moves at all either direction. Once I can tell it is actually loosening (instead of weakening and ready to snap) I give it some more Blaster and walk away and keep repeating this process over time. Haste makes waste 

[RDnuTZ]

I'm also wondering if shortening the head hold down bolts a little instead of ditching the washer could work? I haven't gone out to the shop and measured anything but just brainstorming (or farting) a little from a distance.

[m in sc]

look you can run them as is, ypu don't need to swap them. however it makes it easier to clean the top of the case. worst case is you helicoil the case. these studs see 15-20 ft lbs of torque so not a big deal. I've never had the stud tool fail me, ever. I literally just stripped 3 sets of rz cyls and had to pull all the studs out a few mos ago,used that tool and none were damaged. bit of oil,  hit it with my Dewalt nut runner and they all zipped right out

[RDryan]

I'm also wondering if shortening the head hold down bolts a little instead of ditching the washer could work? I haven't gone out to the shop and measured anything but just brainstorming (or farting) a little from a distance.

Yeah I tried putting the 350 cylinder and head on and tightened it up just finger tight and I think I counted a bit over three full thread turns now without the washer I'm guessing over four turns. Mind you that's not even fully tightened to torque value spec. I did measure out about an inch of thickness where the studs pass thru on the head.My heads being what they are a mismatched compromise of functionality,value and aesthetics...if I had the means I would be tempted to take quarter inch cut off the top of the stud holes just to get the nuts to suck in deeper and I don't think it would hurt em. It would just make them more unique for my top end build. Of course not the right way to do it and sooner or later one may need to just replace a stud anyways. Those studs that are stuck are the original 50 year old parts,doesn't surprise me they like being at home there. FWIW

look you can run them as is, ypu don't need to swap them. however it makes it easier to clean the top of the case. worst case is you helicoil the case. these studs see 15-20 ft lbs of torque so not a big deal. I've never had the stud tool fail me, ever. I literally just stripped 3 sets of rz cyls and had to pull all the studs out a few mos ago,used that tool and none were damaged. bit of oil,  hit it with my Dewalt nut runner and they all zipped right out

OK good to know I think I will just run it with em. It'll be easier for me, I'm kinda lacking in tools as I don't even have an impact wrench never mind the stud remover tool. Just as an aside when I pulled the cylinders off there was road sand etc, inbetween them.  I should've known( but really have very little experience with engine building), I was careful not to get that stuff in the crank, cases but I think there are so many variables that can just go wrong with this build anyways that for one reason or another I may very well do more than I bargained for. Gotta at least try to keep it on a budget I still feel bad about boogering a few rubber bits with the heat but live and learn.

I did watch one video of a fella on you tube.He used propane gas and laid flame on the stud for what seemed like a minute and half with a few pauses and used candle wax and the double nut method. It was an exhaust stud and the head was outta the machine. Not sure if there is an advantage to candle wax vs. penetrating oil but it looked good.   
 

[Brad-Man]

You might also freeze the studs with aerosol freeze spray before trying to remove...

[mlakritz]

Bringing this back around a bit to the cylinders themselves, is the only place to source them from Ebay or Amazon? Are there any US distributors? I'm generally not one to take a chance on Ebay/amazon stuff these days unless as a last resort. I do see US manufacturers of the piston and rod kits needed for the 350 top end (Wiseco etc). And then just asking again, does the crank require a rebuild/refresh at that point to handle the extra power? This bike has 12k generally well maintained (as far as I can tell) miles on it. I don't have a clue as to how much the lower end would need done to it to be fresh and ready to run a 350 top end. I just assume at this point refresh the bottom too? But if people tell me it is ok to use the bottom end as is and just need some fresh pistons and correctly sized wrist clips, I wouldn't be unhappy going that less labor intensive route. But it does seem like doing it right requires refreshing the lower end. Ideally I would love an ordered to-do list of all the basic things your should do when doing an RD engine restore so I get it right the first time as well as can spec out the budget more accurately. I do seem to be able to pull that list together though from a number of posts here.

[Guygrrr]

For stubborn studs, if there's access, I like gronking down on the stud in my vice and using the case to get more leverage and torque the stud out.

[m in sc]

if you don't know the age of the crank seals, change them and the bearings are worth a look. mileage really means.. nothing. I had a 5k mile motor with cranked and dead crank seals  a few yrs ago, condition of crank itself is ? unless you inspect it. My 70 r5 just got a new crank at 27K. it was still running fine but was def time.   so, its a case  by case situation.

Me? at this age on a (previously) stock bike is minimally do the crank seals if the crank is quiet. 

also, you need wrist pin bearings (wider) from 250 to 350. and no, just get the ebay cyls, they are fine, the link is in the post i put up before.  No one else is carrying them as far as i know.

[mlakritz]

if you don't know the age of the crank seals, change them and the bearings are worth a look. mileage really means.. nothing. I had a 5k mile motor with cranked and dead crank seals  a few yrs ago, condition of crank itself is ? unless you inspect it. My 70 r5 just got a new crank at 27K. it was still running fine but was def time.  so, its a case  by case situation.

Me? at this age on a (previously) stock bike is minimally do the crank seals if the crank is quiet. 

also, you need wrist pin bearings (wider) from 250 to 350. and no, just get the ebay cyls, they are fine, the link is in the post i put up before.  No one else is carrying them as far as i know.

all excellent info, thank you! it sounds like you can simply put the 350 pistons on the 250 rods with a wider wrist pin and bearing, that seems almost too easy.

the key i've found so far is be sure to make progress every day, even if it is just a little bit. no different than any big project but daily progress adds up quick on a motorcycle as long as you avoid going too deep down the rabbit hole. easier said than done sometimes, it is motorcycles after all.

so i read your thread m in sc on those cylinders, seems like they require quite a bit of prep to be ready or maybe optimal...is there a shop or machinist here that you recommend to prep them the way you did? followup, looks like HVC Cycle in Nebraska is sort of one stop shop for all engine things RD.

and what do you know, ebay has them right now with a coupon you can apply for $30 off so they come in at $161 +tax. https://www.ebay.com/itm/284771396485




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[IR8D8R]

Crayons work better on steel studs in aluminum than penetrating oil if you are using heat. The wax doesn't evaporate as easily. The oil just burns off. Use several heat cycles on them to let the wax get down as far as possible into the threads. Some people say metallic crayons work better. At least silver is a better match on aluminum.

IR8D8R