Ok in that case 0.25? Block/Piston are standard.

I am sure but I've got the right people here to help me so I am not that concerned.

Will I be giving up the convenience and performance of a Mikuni? I am thinking of ordering a VM28 for the RK and a smaller VM for the B.

Not sure and they aren't in great shape. I will have to compromise here and go for convenience over originality when it comes to controls and switchgear. I plan to install modern controls and switchgear on both bikes.

My mech said "Standard size bore/piston and brand new" and my friend who rode it said it was noiseless and smoother than his own RK. On Sunday's ride his RK had heating issues but mine had no such problems. I am reasonably confident this one isn't a dud and in any case I've got the right people to help me source pistons and maybe even sleeve a block (talking about Rajkumar and Rajendra from Chennai)

Will do.

The Mikuni isn't a straight fit for either bike. Quoting from a paper from another Yezdi/Jawa enthusiast from the old Jawa club (I think he's on this forum now if I'm not wrong)

'A Mikcarb (Mikuni) may be used on a Roadking or a Classic with good results after a few mods are done. The 2 carb studs need to be changed to longer ones and the carb cover will have to removed unless a good lathe shop can alter the carb top, to take the threaded part, so that the cover can be held in place. Either the carb from an Enfield Bullet, with the
smallest size jet [experiment with various combinations of jets and needles] or one from Radjoot 175 with UPSIZED jets and needle to get the mixture right, may be used.'

Personally, I'm not sure it increases performance at all. I haven't heard that it does. And I'm pretty sure, from all I heard, it isn't more convenient. You'll need to keep on fiddling with the settings.

The Jikov noticeably makes the bike more rev-happy and is the simplest (some would say crudest) carb ever. If you get a good one, you can just instal it and forget about it. Only, keep an eye on your mechanic every time you give your bike to him. Alternatively, a Pacco is completely hassle free and its relatively easy to get your hands on a new one.

There really isn't much switchgear required on the Type B. Only things are high-low beam and the horn. It has no indicators anyway I do suggest you try and get your hands on the original handlebar at least. Its a nice one.

Actually.... On taking another look at your Roadking, it doesn't have the original handlbar. Just take the one from your Type B (which is from the RK) and plonk it there

As for the bore, I wasn't referring to the Roadking. I was referring to the Type B. Do let us know what you see when you open it up. Considering the put-together nature of the rest of the bike, I do hope they haven't screwed up the bore..

As for oversizes, perhaps I was completely wrong but I understood a standard piston on any motorcycle to be considered 0. The standard boreXstroke of a Roadking cylinder is 70mmX64mm. Hence, the standard piston conforms to that. When a re-bore is done, the diameter of the cylinder increases and consequently, to retain pressure, the diameter of the piston has to necessarily increase too. The piston on a Yezdi increases in measures of .5mm. So first oversize is .5, second is 1.0, third is 1.5.

At least thats how I understood it..

Now, considering your extensive experience with all sorts of motorcycles, I'm wondering whether I got this theory generally wrong

As for sleeving... Please stay away from it. I have never yet come across a sleeved Yezdi bore and getting pistons for it will be impossible.

A simpler solution (if it comes to that) is to simply pick up a used block and plonk it in. You should be able to get one thats running a first oversize fairly easily.

I'm only referring to the Type B. It is very unlikely a 95 Roadking will require any engine work unless the previous owners buggered it up. From what you say, she sounds a beauty.

Cheers

Rahul

Getting the gasket for the Pacco carb took longer than I expected. In the meanwhile I also acquired:

1. New seat - Rs.1500
2. Front dome enclosure (minus headlight lens/reflector, speedo, ignition key and handlebar) - Rs.1500
3. Front fork seals
4. Cable set
5. Brake shoes
6. Clutch plates
7. Switchgear

Tomorrow we start the bike for the first time and then the rest of the work will proceed in earnest. It should be done by late evening and I get to ride it home. Will not be fixing the authenticity just yet...will wait till I acquire all the required parts.

Rather eventful Saturday!!

Reached the garage at 11:00 and sat around until 1:30pm before any work happened on my bike. Big Bore (Arun) was around for a while with his Shogun. I needed a bottle of water after all the drooling I did around his bike. I adore the Shogun design!

First things first the Pacco carb was cleaned and the bike was kick-started. The points were set and a dab of vaseline went on the cam before attention was turned to the front forks. The forks were JAMMED and put up a solid fight before we could open them, clean them out and replace the seals. So complicated compared to modern forks! This took a MAJOR chunk of the afternoon.

Front wheel hub was opened and the brake shoes and liner were cleaned. Re-installed the front fender and the wheel. Rear wheel was also removed and the brake assembly cleaned. Oiled the chain and put everything back together. Installed the new seat I had purchased, new hand-grips and a RHS mirror.

Filled in engine oil, front fork oil and petroil mix before going for a test ride. No problems during the test ride except for poor brakes. With all signals green I decided to ride the bike back home. 5Km from the garage and the bike makes a "kutkrr kutkrrr kutkrr" sound and switches itself off. I immediately pull in the clutch and pull over wondering if the piston had siezed. But the kick was still working and I could feel the piston moving. Kicked harder and she fired up again. Rode another 1/2Km before the same issue occurred again.

Parked up and called the mechanic who showed up, added more 2T oil and went for a test. Same problem but he says it is a gearbox issue. This will be sorted out tomorrow...

This was my first ride on a Yezdi and I LOVED it. If 13bhp feels this good I can't wait to sample the 16bhp of the Roadking!!

So the gearbox issue will be checked out and I'll post an update tomorrow.

I can't wait for the moment when everything gets sorted out and I can ride for as long as I want because I loved every minute of my experience today...

Hey Guru, i am glad you started the bike and took it home So finally all the patience paid off fruitfully See you around again soon at Mahesh Bhai's place.

Dude I couldn't take it home...see previous post. The bike slips gears and stalls every 1/2Km or so. Mahesh bhai took it back to the garage entirely in 2nd gear for 5Km. Siva Bhai is checking it out today and hopefully it will be roadworthy by the evening. Also the alignment of the two wheels is a concern - have to get that checked out too...seems like the rear wheel is too far to the right.

Glad you got it out and about even if it did end in some pain. Check the fuel line and the carb. It sounds like it died on you due to a fuel-flow issue or possibly because it was running too lean. Check the plug and see whether its sooted up. I really doubt its a gearbox issue..

13bhp vs. 16bhp: They're both very different experiences actually. The Roadking is very rev-happy and has a shorter stroke. Its much more responsive and so its great in-city. The Classic has a longer stroke, is less rev-happy but is beautiful to cruise on. Just goes on for miles and miles. Glad you enjoyed it

I had an equally nightmarish weekend working on my RK fork. Something seriously wrong with them. So I feel your pain man. Only more so.

Don't know if it has anything to do with it but do check the rear shocks. If they really aren't the original shocks, or simply one of them has been replaced (lots of jugaad tends to be the norm with these bikes unfortunately) then that could be the cause for it.

Happy times on your bike man

Btw, any news on the bore and piston? Have you opened it up?

Thanks Rahul...

So yesterday they decided to let the bike run on idle for an hour or so to see the effects. Bike kept idling happily for 2 hours!!

They did this in an effort to let everything lube-up, warm up and the bore to get cleaned up. First test ride after this the same problem occured and the bike shut down.

This isn't a fuel starvation issue because there is a mechanical "kutttkutttkuttt" sound before the bike cuts off. It will re-start right away so I doubt it is a bore issue.

The garage is closed today so I will get it opened tomorrow. I suspect the piston is expanding very quickly under load (when it heats up) and siezes. Once it cools down for even 30 seconds the bike runs normally again for a few minutes under load before this happens again. Outside of that I have no other explanation.

Assuming the bore is fine and this is not a siezing issue, can this be linked in anyway to the gearbox?



Issues aside I have found a scrap Jawa from which I can salvage:
1. Front fender
2. Tank (maybe)
3. Handlebar
4. Engine casing and maybe piston
5. Jikov carburetor (maybe serviceable)
6. Foot-pegs
7. Other bits and pieces

I've made an offer of Rs.500 for it as scrap value...lets see if the owner lets it go. Trouble is some people harbor "sentimental" value for all this junk and it makes it difficult for us to get our hands on parts we desperately need

Wow! If you get the bike for scrap for that much its totally worth it. In fact its worth a lot more.

However, very few of those parts will be usable on this bike (if you want it to be stock that is) since they differ slightly in design from the Yezdi. Of the ones you've listed

1. Front fender: I'm not 100% sure about this, but I believe the front mudguard of the Jawa has a flared bottom, while the Type B is straight.
2. Tank (maybe): This is quite obviously different with the Jawa being rounded as opposed to the squared tank on the Yezdi.
3. Handlebar: The bar is the same though the levers are different (Yezdi ends in a ball at the end while the Jawa is pointed)
4. Engine casing and maybe piston: Casing completely different. Its beautifully rounded on the Jawa while very squared on the Yezdi. I'm not even sure you can shoe-horn one on the other. I wouldn't try.
5. Jikov carburetor (maybe serviceable): Yup, this one is common
6. Foot-pegs: Different. Jawa rounded, Yezdi squared (like everything else )
7. Other bits and pieces: Which ones?

All told, its worth picking the Jawa up for scrap simply because its a STEAL. You might not be able to use the parts on this bike but it may come in handy in future when you find yourself a Jawa Internals for the most part could be used (gearbox and suchlike) though.

One the subject of seizing.. I'm no stranger to that since my Roadking came with a junk local piston. Seized it good and proper the first few times I tried to go over 80. Have since changed the piston and it runs beautifully. Its a bit different from the sound you describe though. The engine note rises from a beat to a high pitched scream (as the piston expands and causes greater friction in the bore) until it shuts off. You can feel the stress in the engine when that happens. I somehow doubt thats the issue from the way you describe it but, if it is, you're going to have to find yourself a good piston. And I hope to hell it hasn't damaged the cylinder.

These posts might shed some light on it for you as they describe my seizing experiences




Cheers

Rahul

@GS: Hope you dont buy that JAWA and end up REstoring that as well instead of keeping it donor
Good to hear about your Type B. Get it back to shape soon.

Is this Type B called Tank switch model?

Yeah...I am aware of the differences and some like you mentioned are visually obvious. All I know is that the front fender on this bike is similar to the ones I've seen on the B's that you find on the web. But I only had a quick look at it and I am not yet tuned to tell the differences.


Side panels, seat plate, shocks, Headlamp bottom half, shock bodies, maybe a true frame, clean papers so the engine/chassis number may come handy for a bike that doesn't have clean papers but is in better shape. Stuff like that.



I agree with this. If it had siezed it wouldn't have started up so quickly and so easily. Anyway my experience is only with the Yamaha 2-strokes and these are properly siezed when siezed (possibly due to the higher rpm operation). My bike may have a variety of issues. Best way to tell is to open it up and see whats what.

Incidentally I've found another single-owner B in great shape and being used daily by an elderly gentleman. I am heading over to check it out in an hour or so. If it looks good...I'll have it!!

Just spoke to the owner of the 1971 Jawa 250 and he has asked me to come over tomorrow because he finds it hard to believe that someone who rides a SUPERBIKE would be interested in his itsy bitsy historic monument. Well I am going...and I am going on the MT-01 and I am coming home with the keys to his Jawa come what may...

If the geezer needs a replacement 4-stroke then I am happy to buy him a low end Hero Honda or something as compensation. It is rare to find single owner bikes that are used daily by the same rider for 39 years!!

If this bike comes into my garage..fingers crossed...then I will have to make a few decisions.

1971 Jawa...
1980 B...
1995 RoadKing...

Awesome!Good luck..looks like youve been bowled over by YJ bikes

No.The first series of Jawa is the tank switch model.There's a small console on the tank.An ammeter is part of that console.1961-1962 Jawas came with tank switch.

They are like 2-stroke Enfield Bullets...whats not to love? Long stroke 2-stroke bikes are awesomely fun to ride!