The repairs begin Yamaha RD250 Disaster
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- เผยแพร่เมื่อ 28 พ.ย. 2024
- In this update we take some parts to a local engineering shop and send others for a romantic week away in Paris for repair, only for them to go missing
I'M LOOKING FOR A GEAR CHANGE LEVER for my 250D, please let me know if you have one I can buy - Thanks
www.nsmoteurs.fr - Crankshaft Rebuild
www.snr81.com - Cylinder rebore & machining
Your project is coming along nicely. Looking forward to the next video. Work safe in the garage. 😊
Thank you, just taking it slowly
Hi, new to the channel but want to say what's probably already been mentioned. This sort of failure looks like a detonation issue. I would check the timing very carefully., it should be 2mm BTDC. Also check for air leaks and main jet size. I assume you have up jetted with those expansions on? Beautiful looking bike. Hope all goes well with it.
Hi thanks for your advice. I’ve made a leak down test kit and I will static and strobe set the timing when I rebuild the engine.
well done , thanks for the update - looking foward to the next episode and a new format ?
Thanks for commenting. I'm going to try something different to see what the reaction will be. It will still be about motorcycles
All the best
Thank you
If you have electronic ignition, then blowing on one side is very unlikely to be timing. The strip down showed the other side undamaged, there would be some marks. An air leak through a seal, or even a small particle of debris in the carb from the tank will lean it out and cause this kind of damage. Just a fleck of rust or dirt in the main jet will do it.
I graduated in 1977 and my father cosigned for a Kawasaki KZ650 custom. I rode the bike many many miles and had quite a few friends that rode motorcycles. I never touched the two strokes. Except to ride a friends once in a while.
every one of them that I knew that had two strokes went to premix. Every one of them had some kind of story with the oil pump failing ,something block the lines or ran out of oil. And most the time it would lock the engine up and they end up putting a flat spot on the tire. It cost them so much money every time that happened. And it happened so quick even if a light came on you could do nothing about it. As much money and time as you put into that bike I would recommend going to premix, but jmho.
Thanks for your comments. The head always says four stroke is the sensible choice. I started riding on two strokes , they can be difficult to live with I agree, but on that one occasion where everything is working in perfect harmony they touch your soul.
@@RepairandRideout I'm sorry my comments weren't really about what type of bike. It was more worrying about you going through this again by trusting the oil pump.
it would lead to issue on bearings for a Suzuki GT 185/250 as premix would not get there. Also you need to jet up to allow for oil in petrol as that would make the mix weaker
That's very true, I will be testing the output from the pump or go to pre-mix. Sorry I didn't mean to wax lyrical about 2 stokes @@flyer5769
That’s the way to go 👍🛠🏍
When bottom half built and you come to tighten that nut at right crank end. Haynes manual will suggest couple wood blocks on top of crankcase. Pass a good fit round bar through small end holes like a 3/8ths socket bar extension. Rotate crank in direction nut tightens bar then sits on woodblocks that will lock engine wont hurt conrods. The nut on Lc 350 tightens to 47 ft-ib. Yours looks identical to 350 lc layout so i rekon the nut goes to same torque but check ya good ole haynes manual. Crank lovely all new parts bleddy ansome. Ya rebuild will start soon. Dont forget ya squirty oil can to wet bearings gearbox etc never assy dry keep crankcase mating surfaces dry clean as it needs a sealer applied to mating face. All new seals too especially outer crankseals most important. Make sure pegs on mainbearings locate into cutouts in crankcase when c/case halves go back together. Enjoy. Phil the dood
While the Haynes manual does contain that procedure, you are stressing the connecting rods, big end bearings and the crank, by doing it that way.
An alternative method is to jam a cloth rag in primary and clutch hub gears to lock things up to torque primary on the crank. This avoids putting torque on the crank, bearings, or connecting rods. When finished, hand rotate the crank to release the rag.
Either way will work, your choice.😊
Yamaha says do not jam a rag into crank pinion and clutch basket ring gear as the input shaft ie the clutch shaft could be distorted out of alignment. Yamaha makes mention of either whilst engine in frame place engine in gear apply rear brake and loosen or tighten crank pinion nut. Or if top end removed and engine is on the bench. Then a close fitting round bar through the Conrod small ends supported on wood blocks will suffice to work on crank but. Conrods mighty strong in the vertical. They have to deal with piston weight forces from 1,250 rpm to 8,000 rpm in a blink and back again.. those pistons probably quadruple their weight at speed. I'm 60 years of age and have worked with engines - car and motorcycle workshops since the age of 16 but mostly motorcycles. I've probably built more engines than had hot dinners in my working life as a motorcycle mechanic. For a number of years I even had my own motorcycle workshop until workshops were to be re developed. If in doubt please consult Yamaha UK mitsui sales and technical information. Phil the dood
@@PhilipHarrington-n1h Phil,
Interesting insights based on your years of experience. You are correct about the connecting rods being strong in the vertical plane. The Haynes manual details the procedure you advocate, which is fine. Ditto, Yamaha UK.
Following your advice, I am looking at the Yamaha USA Factory Service Manual for the 1985 RD350 YPVS RZ350. On page 3-11, Yamaha details the following procedure:
"CLUTCH ASSEMBLY and PRIMARY DRIVE GEAR
1. Place a small piece of rolled rag, or a small piece of soft lead between the primary gears, and remove the primary gears securing nut and washer."
Figure 2 is a photograph showing a rag jamming the primary gears.
So, I guess we can agree to disagree.😉 Yamaha says so.
Either way, work safe.
Glad you got some good service from a previously unknown engineering shop - it's nice when things go like that! As an aside - are you using a different camera? The picture quality of this video isn't brilliant and far worse than your previous ones....YT only gives the option of 360dp. Maybe just a setting on your editing software?
Thanks for commenting. Yes really chuffed with NSMoteurs. Sorry about the quality, it's filmed and edited on my iPhone as usual and looked fine before I uploaded it. I am getting a new camera for Christmas!
Hi thanks for your advice. Still no word on when the barrels will be ready. I’ve got the clutch basket holding tool, will that work to lock the engine when I tighten the nut?
All that is wrong with that bearing is a particle of aluminium from the blown piston, has found its way into the bearing race, and is causing the clicking, and rough feeling. Removing the top end, cleaning out the crankcases with solvent and compressed air, then rebuilding with rebored top end, is all that was needed.
Hi thanks for your message. Perhaps I’ve gone ott with the rebuild? I didn’t want to take any chances
@@RepairandRideout Never a good idea to rebuild a crank, without needing to, as every time its built the pins fit less tight. Only do it when needed is the best idea.
@Repair & Rideout
Hi buddy i love France local Ciders organic wow very nice . How long have you lived out there ?? iwas there this year in Northern Normandy . Fantasitc bikeing area .
I cant wait to hear that bike running . The RD250 is such a nice bike and back in the 70s i couldnt afford to buy one not many people could around Lancashire . Most guys had GT250s or went stright upto the GT380. Does anyone know where i could buy an expansion exhaust pipe for a AP 50. Thatnks for your stream mate 👍👍👍👍
Thanks for your comment. Wow AP50 the nemesis of the fizzy, quite rare these days. I’m in the south of France near Carcassonne been here 19 years