XR200 performance

[lazza]

Hi all, I have a XR200 RC and it goes "ok" but i took my mates 2002 XR200 for a ride last night and his xr seems to have a whole lot more instant power than mine. Other than the fact he has a extra gear on his bike is there any other major performance item that the later xr200 has over the earlier models ? cause they look like similar motors but his performs way better and we are using the same sprocket ratio's. Just wondering if things like a later carby would give my bike a bit more get up and go like his bike etc. Personally i'm guessing its cause he has a 6 speed box but thought i'd ask anyway.

cheers

[scott411]

the RC was a much more pwerfull motor (4 valves and twin carb) but do not have the greatist reliability record, honda droped that motor and went back to the older 2 valve motor,

[barty5]

i thought the RE was the first twin carb?? (hand gernade)

[merv]

You've got something screwy here because all XR200s have six speed gearboxes including the RC which was around a 1982 model. The RE was the radial 4 valve and that was 1984 and short lived because of its problems.

My belief is the RB, RC and RD models were the best they built and they came standard with very little restriction to the motor so should be every bit as fast as a 2002 with better suspension to boot with longer travel. The later ones like a 2002 need the airbox opening up to make them go and your mate has probably done that. The only other thing is maybe your bike is just getting tired because it is no spring chicken

[xwhatsit]

The only other thing is maybe your bike is just getting tired because it is no spring chicken

I'd agree with that. It's 20 years older than your mate's bike; especially on a dirt bike, things like rings and a worn-out cylinder bore would be taking their toll. Valves too. My engine is a similar design from the same era (XL250S/XR250 from 79-82), and they're very prone to cam pitting apparently (although I haven't suffered this).

No idea if the XR200s were so susceptible to it, but the XR250s from that era (pre-RFVC and RFVC) had massive issues with cracked cylinder heads. Interestingly enough they would keep on running for years and nobody would know the difference until the top-end was taken off, but I would expect that would cause power loss too.

One last thing, doing some common maintenance can help. Buy a new OEM Honda air-filter (call Econohonda), keep the chain in pristine condition, set the valve clearances. You're probably doing all that anyway but I reckon there's no point in spending money on upgrading your bike until you've got it's original potential maximised.

[Paulus]

No idea if the XR200s were so susceptible to it, but the XR250s from that era (pre-RFVC and RFVC) had massive issues with cracked cylinder heads. Interestingly enough they would keep on running for years and nobody would know the difference until the top-end was taken off, but I would expect that would cause power loss too.



Excessive fork flex (check for tyre marks on the fork legs), frame cracking, swingarm cracking, poor cam chain tensioner design, fragile kickstart ratchet were some I can remember. I had my XR200RC (82 model) back in about 84 and it already had all those problems. I hate to think what one would be like today. Have fun with it.

[lazza]

Thanks for the replies. My RC is the 2 valve single carb model and i should maybe of mentioned that i don't expect my 25 year old XR to perform as well as my mates 5 year old XR was just more curious about the difference between the two engines as they both look "similar" externally but i'm guessing internally they are probably stroked different etc ? Whilst i'm on the subject is there any common tricks of the trade ( such as air box mods, carby mods etc ) that used to be done to the early XR200Rc's back in their day ? not talking about anything radical here just wee tweaks maybe :-)

[Buddy L]

more air in the air box is a good start, so clean filter and see if their is anyway to get more air in their.
As for the carbie im not the one to answer but maybe try lifting the neddle up one notch and maybe going one size bigger for the main jet. but don't take my advise just yet.

[xwhatsit]

At a guess the newer 200 would be faster due to the usual things that come with modern technology; improved combustion chamber design (different bore/stroke ratio too), higher compression (?), four valves instead of two, perhaps a more aggressive/carefully tuned cam profile which can be allowed due to better valve springs, better tolerances due to better machining allowing a higher red-line.

I know Wiseco et al make plenty of high-compression and larger size pistons for the 250 motors of that era, perhaps you can get them for the 200 motor as well? Look on eBay, they often have new-old-stock of those.

People always say `just buy a bigger bike', but I reckon they're missing the point :D

[lazza]

Out of pure curiosity I grabbed my mates workshop manual and compared stats between the two engines, surprisingly the 2002 engine has same sized valves, bore and stroke, same valve lift, same timing and same gear ratio's as my 1982 XR ( and yes i stand corrected, last night i went for a drive and i do have a 6 speed box in my bike not 5 speed the difference between 5 and 6th sound almost identical so my mistake there ). Anyway.. i did notice one difference was that the later XR's have a 2mm larger venturi in the carby so one day i might put his carby on my bike and see what, if any, difference it makes :-). I don't expect to make gold out of brass but a mans gotta tinker with something :2thumbsup

[Buddy L]

i remember the look on mums face when i found out that XL75cc that i learnt to ride on hand more then 1 gear, dad was happy but mum wasn't. then i found out it had 3 gears, soon made up for lost time in the quest to break the sound barrier.

[Motu]

As Merv says,your bike should cream the 2002,the early models had more power and better suspension.Get a black motor and do a top end job with a new piston and Wiseco cam,better exhaust and sort the carb.

Sounds like your bike is just a piece of shit.

[lazza]

well i wouldn't go as far to say its a piece of shit and based on the fact that its still going "ok" after 25 years as a trail bike i still give it a big thumbs up. Anyway as a extra question..... My bike had the cam chain replaced on it about 2 months ago prior to me buying it off my mate and i noticed it starting to rattle again so did the usual procedure of undoing the adjuster nut whilst the bike was running to tighten the chain and when the tensioner is loose the chain starts to get quieter but when i retighten the adjuster nut up again it goes back to sounding loose. Is there a common senario to the adjuster systems not working correctly on these motors ? IE : the angled adjuster bushes wear out, the guide rails stick/ break or whatever ?
And secondly, can i undo the cam chain adjuster nut on the gearbox completely and remove the angled bushes and plunger rod that sit underneath it to inspect them without upsetting the cam timing etc ? thanks in advance