'84 engine numbers

[TRP]

Over the winter I bought an '84 WR 250. It was not running, and in some pieces, but not a total basket case. The previous owner told me he bought the bike used at the end of '84, rode it several years until blowing it up rather severely, and then in the process of collecting rebuild parts he came across someone selling a complete WR motor from the same year. So he bought that motor, rebuilt it with the new parts he had, and ran it. Not long after, it developed a no spark issue and he parked it. That was about 1991. It sat in the same corner of the garage until this winter, when it went into my van, along with a tangle of parts in boxes. The ignition was Motoplat, and indeed there was no spark, and nothing simple like a broken wire. One of the boxes contained the SEM system, and rather than dig deeper with the Motoplat, I just stuck the SEM in and tried it:a fat spark! The PO is a machinist and car restorer and very serious mechanic. Noodling around the motor, I got the idea that he did a pretty thorough job on it. It has good compression, no signs of stupidity in the form of chewed up bolts and gasket goo etc, and after a carb clean, it fired right up. I decided not to take it apart, and instead did a mostly cosmetic tune up. The bike looked kind of beat to hell, but actually it was well looked after in the areas that mattered.

My rambling story boils down to a simple question: can one tell by the engine number if it is a WR, CR, or XC? It has the 2089 prefix, but this is too general to know. I'm not going to take the jug off and examine ports at this time. The motoplat ignition makes me wonder. I've only been able to ride the bike around parking lots so far. I know the bike is supposed to be pipey, no low end, etc. But it totally rips, and pretty much right off the bottom, in my opinion. It's not a tractor like my Maico 400, but definitely not high strung either. It has lower gearing than standard, which can make a difference. I'm really happy with the deal, I liked buying it from someone who knew what he was doing, but 1991 was a long time ago for all of us! Is it possible I have a non WR motor?

I'm including a pic of the bike in it's current state, which isn't to say I'm done with it yet. The goal is simply to make it look good again and be functional for CC races, not to go all out on it (although I'm a great admirer of the ones who do!).

Todd

 

[Kartwheel68]

2089 is correct for an 82, 83, or 84 air cooled 250WR or 82-83 250XC.

 

[visiteur1948]

 

[silverstreakNZ]

checking gear ratios might tell you something . but not which cylinder it has

 

[Bigbill]

The 84/250wr had cr Ported ac cylinders. Extra ports over the standard wr porting. To me it’s the best 250wr ac bike husky ever put together. She has a lot of spunk when she’s running correctly. She’s no bigbbore but fun to ride. The 430 wr ac is like a tractor plenty of grunt. Now things change with the 86/400wrx. Wicked fun ride. Unfortunately after riding the bigger bores my 250’s got parked. But the ‘84/250wr is a different 250. I’d look into that having a motoplat ignition. I think the moto plats came with the xc’s larger flywheel over the SEM.

 

[TRP]

When I first checked the serial numbers, I thought the CR's were also in the same group as the XC and WR's. But posting the numbers makes it plain as day, it must be an XC or WR. Think I'll dig into the motoplat and try to figure out what the problem is and then see which one I like more. I know the SEM's have reliability issues, but having lights and the potential for heated grips is kind of neat. Looking forward to getting it out into its natural habitat!

 

[1982 XC 430]

An easy way to tell if its got the 84 250 Cylinder is to remove the Exhaust and look up the Exhaust Port. On either side of the port there should be some cast in holes that lead to extra exhaust ports. These have a tendency to fill up with carbon so You might have to look closely .

 

[Kartwheel68]

The 83 CR had those ports also.