General tips needed
 

So I bought a 2005 Roketa DB-27a the other day, top end already removed.

I'm going to buy a full gasket set, piston rings, and valve assemblies. Is there anything else I need to look for while its disassembled?

The only reason I'm buying the valve assemblies is when I got it, one of the valve springs were missing. I can't find anywhere to buy just the springs, so I'm just buying the whole set.

Everything else looks really good, the bore looks good(haven't had a chance to measure it yet), still can clearly see the cross-hatch on it. Piston looks good, timing chain looks good, as does cam. Of course, I'll check measurements to know for sure.

Other than that, the body looks good, suspension is good. Haven't checked to make sure but I believe the previous owner removed the switch for the electric start, which doesn't really bother me.

Any good resources for these bikes? Good places here in the states to buy parts?

EDIT: What bikes are parts interchangable for this one? I've heard XR200R's are the same?

The XR200R is similar, but not the same. The bore and stroke is different, as is the top end. Clutches, gears etc are probably all the same.

Not sure where to buy parts like valve springs in the States, so hopefully someone else will chime in.

Correct me if I'm wrong, but if I don't mind kicking, I can remove the starter, and battery completely can't I? The bike has no lights

That's a very timely question; I just posted something similar today:

If you have an AC version (if you can start it without a battery, that is a good indicator), then yes, you can run without the starter also. You'd need to figure out how to plug the starter hole.

I have a '96 XR250R, and I really wish it had electric start.

Thanks for the info, I guess I'll leave it on. No point in ripping things out that may make the bike not work when I'm not sure it will work in the first place, lol.

I have a shop manual from a XR 200 I found online, looking through their crude pictures, it looks exactly like the Roketa.

Any idea where I can find some specs on the roketa engine so I can check clearances and such? I know the bore * stroke is different, mainly using the manual to make sure of the parts/position of parts.

Its a completely different beast putting this thing together when I didn't take it apart!

If your Roketa is OHC, then the top end will be the same as an XR200R; I was thinking of the OHV pushrod version. The bottom end on the left side will be different because of the starter.

If you provide us with the number that is stamped on the engine, we can try to decode it, although they're not always 100% accurate. Look for something like 63fml.

I think I remember someone uses xr valve springs. Where are the pictures.

Just use photobucket.com to upload them.

Ill get some pictures up tonight or tomorrow. Tonight if I can find one of my digital cameras, tomorrow if I have to use my phone( no flash).

I'd just about swear xr springs will work. Other than the bore ad stroke the manual seems identical to the roketa. Ill also get the engine number in a bit.

I'm excited to get this thing running. Last bike I had was a 80s model Suzuki dr100 I pulled out from under scrap at a friends barn. He said it had been sitting in the weeds for 10+ years and I could have it for free. A little tinkering and got it running. I think after it was all done I had $15 plus gas in it. Ran it hard till it died. Clutch would stick if you used it so had to just rev it up and drop it in gear and hardshift it. Of course sprockets were almost smooth, had a bad oil leak. But ran like a champ until my friend borrowed it and didn't put oil in it. Siezed the motor good, lol.

This bike I plan on making nice and keeping it that way! But hell, the gas tank on the Dr was just a 5 gallon gas tank strapped to the frame and a petcock tapped into it. Couldn't take that thing to serious!

EDIT: Alright, pictures are up, took pictures of everything as it sits right now.

See them here: https://picasaweb.google.com/1042146...at=directlink:

Couldn't find a number stamped on the engine anywhere. How long is the number and where is it located?

Looks like like an OHC motor to me. I believe that xr springs and parts will work.

The smaller valve is the intake, correct?

Seems I'm missing the wrist pin too. Looks like it would be easier to get a top end rebuild kit.

Anyone have ideas where to find one for this motor? I'd hate to get one for a xr seeing as I wouldn't be able to use the piston or rings.

Another question, I know these bikes aren't built that well. I"m going to replace bolts all over the place, loctite everything, and gorilla glue it for good measure.

What can I do to make it more withstanding? Beef up any welds? Add any braces? I don't go jump triples or anything. Just fields and woods for me. I think the worst "jump" I have where I ride the most is where the field slopes down at the top of the hill, usually get air for about 5-10 feet and drop maybe 2-3 feet. Nothing hard at all.

Occassionally I go to a friends track where there are slightly more harsh jumps, but still nothing worse than a 5' single that if hit right you'll land on a 5 foot decline on the other side, with no more than 2-3 feet of air.

I'd be more than happy to stay away from my friends house with this bike if it just won't handle it.

It looks like there is a smooth section under the shifter that might contain the engine number. If you can measure the wristpin hole diameter, I'll see if I have a spare that matches. Measure your remaining spring as well; give me the free height, ID and OD and I'll see about a match for that as well. What is the true diameter of the piston?

https://lh4.googleusercontent.com/-Y...0/DSCF4838.JPG

Stay away from the track.

Alright, here we go.

The wrist pin is there so no worries. Although it is missing a circlip! Why couldn't the guy keep all the little pieces, lol.

Tell me if these measurements sound way off, without my tools here(conveniently, my friend is on vacation, and my stuff is locked in his building!), I'm having to make due with what IS here.

Spring Height: 1.734", OR 44.04mm
OD:1", 25.4mm
ID:.734", 18.64mm

Piston actual diameter:2.671", 67.84mm
Cylinder Diameter: 2.703", 68.66mm (it is in complete round)

Ok, I dismantled an old XR200R head, and my measurements are pretty close to yours.

Mine is 45mm vs your 44.04
Mine has an OD of 26.6mm, vs your 25.4
mine has an ID of 18.8mm, vs your 18.64.

There is also an inner spring, and it is 39mm long with an OD of 17.65mm and an ID of 12.3mm. There is also a steel shim under each spring to prevent galling at the spring seat.

My spare piston is a 66.5mm. Too small for you.

It looks like an XR spring would do the trick. I can also spare a circlip. Do you want me to send this stuff to you? If so, send me a PM with your address. BTW, the small valve is the exhaust.