I'm not into spending loads of money to get a few HP increase. Been there done that sort of thing years ago with older models. I also read enough of others problems on 600s when you go for all that extra compression and supposed hotness. Don't think I need it as I'm not a Hare and Hound, Enduro,MX racer anymore. My bikes run well enough as is with the CRF450-X mufflers on them and I sure as heck aren't spending $300 odd on a set of bigger headers. Best cheap mod you can do for an XL600 is swap the header over from an XR600(wider diameter) and throw a CRFX muffler on it.Carbs,,mmm,,The twins are already adequate and better than the CVs on the later models,,. Also without swapping a single carb head over to an early model 600 (mine are all twin carb) there hasn't been a part produced yet to allow you to fit a single carb to a twins head. You know anyone who makes one then let me know as I want at least 3.
sr2,
Jun 17, 7:01am
At the risk of adding petrol to the flames, as much as I like the old school air cooled Honda's if you're chasing performance why not just buy a CRF450!
helpless,
Jun 17, 7:10am
Simple answer for me with any modern MX type bike is my age and money. (Been there done that) I like dual purpose so I can ride road or head up the beach or into some dirt or forest if I so desire as we did 20-30 yrs ago on XL/XR.I don't need or want to be trailering bikes about to there riding areas. All those modern bikes while being powerful and all that just cost way too much to maintain and are to much of a single purpose machine.,,Reliability and cheapness,,Go older.
wilgil,
Jun 17, 10:37am
And here was I pretty happy with the standard power output from my old DRZ400E.
wrong2,
Jun 17, 2:16pm
imagine what it would go like with a decent extractor then 70 Hp is entirely doable from an XR500
Honda themselves did it with their dirt trackers. mine topped out around 60 - but that was the first serious engine hotting i ever tried
no power is made below the piston - EVERYTHING comes from the head
the standard CRF450 are perfectly fine , but they (the 450's) are like the first ever 4 strokers with a serious tune from the factory
muzz67,
Jun 17, 7:08pm
""70 Hp is entirely doable from an XR500 "", bet it never lasts long enough to get off the testbed! No-one in our VMX circle got over 55 without building a grenade. If its not the rod, its the clutch or box that lets go.
sfw4,
Jun 17, 7:27pm
RFVC Radial four valve combustion
sfw4,
Jun 17, 7:31pm
Back in the day the 82 XR500RC was "da shit" anyone who owned those was the man and rich. I owned a TT500 alloy swingarm back in the day, Everyone was doing the straight pipe on them, very noisy in a built up place and the throttle off sound was massive. Hard to come by now days if the seller isnt dreaming
muzz67,
Jun 17, 7:40pm
The TTs locally often run a straight pipe and are not as loud as expected, our quess is that the 2valve head is restictive. Try an XR500a with similar pipe and they are increbibly loud,, 4valves etc.
wrong2,
Jun 17, 7:59pm
their main problem was oil supply
i ended up going thru half a dozen engines - standard they are fine , tuff like the 250. hotted they eat everything. gears big ends cams rockers
the HRC stuff that americans were able to access was incredible - flat track gets big crowds over there & HRC jumped into it in a big way
wrong2,
Jun 17, 8:01pm
Prolink
the 500 was a total hotrod - its was basically the same size as the 250. i inherited my A model from my brother when he scored an RC.
helpless,
Jun 17, 8:33pm
Yep.I think we can call it a day and say the RFVC aren't crap.Wrongs Wrong.who could dispute it with a name like wrong. Getting back to reality ,,You are dead right Muzz.XR/XL single shock not vintage enough,,To me that stinks,,they run unitrak Yamahas etc in that game.,Someone's obviously fowled up somewhere and's been cutting their losses ever since.
wrong2,
Jun 18, 2:40pm
dreams are free -
Honda had it right to begin with - & then stuffed up the ultimate tuning ability with RFVC
they fixed it by reverting back with the Almighty 650R's release - im sure you notice its absence in the 450's as well. its because they wanted some real power capability - as opposed to a marketing stunt ala RFVC
& the login was carefully selected to give muppets something to try & poke fun at btw - lets me know who they are
wrong2,
Jun 18, 9:52pm
^ its surprising how weak the standard tune is on the 650R- its like they were scared of giving the public too much & deliberatly neutered the cam & choked up the breathing (airbox & exhaust) - stocker riders have no idea of the rocket that sits beneath them
with a near max cam & 12:1 they are incredible (is also with a flatslide & a proper extractor) . the head is quite decent standard & the valves are almost ok for the standard bore
its too much for trail riding (& the 450's are perfect for that) - but on the gravel its the thumper ive always wanted
sfw4,
Jun 18, 10:19pm
TT 500 same engine but with elec start!
sfw4,
Jun 18, 10:22pm
ok. hands up who been thrown or broken ankle by not getting TDC right ay! lol TT's were baddd if you got it wrong. Massive kickback! XR500 had AUTO decompression cable.
Did anyone hear that TT500's wont be given a warrant even tho they came out of Factory with no blinkers! apparently you gotta install them now. Put batery in as CDI cant power blinkers
helpless,
Jun 19, 7:13am
They are a bit heavy,,They aren't slow.,,and yes TTs had horrible kickback as do 600 Hondas should the Valve/Tappet gaps be to tight or you attempt using throttle when starting them. Throttles a big no-no on RFVC 500/600.turn the idle knob up a turn.prime it with 5-10 kicks through using no throttle with the hand decomp.get it to TDC then kick it.Return idle to normal once it's running.
muzz67,
Jun 19, 9:42am
Yep, they are heavy. Suggest you head along to a Classic MX event , you may be surprised how well they cope with 250 2strokes of the same era. ie CR/YZ/RM 250's. Able to get a holeshot occasionally through smooth power and traction. Never come last!
wrong2,
Jun 19, 9:43am
well at least in the case of the XR - they were basically the same as the 250. the weight difference was minor
angelab,
Jun 19, 12:32pm
GB 400 was a bore & stroke to the GB 500. 500 to 600 was stroke only. I bought a Wiescoforged 600 XL piston and White Bro barrel sleeve for my GB 500 at 85000k as it was the same price as new honda std rings. K&n and alloy supertrap, Barnett Kevlar XR600 clutch pack and CR250 clutch springs. Speedo cable broke again at 96000 k so who knows!. Never any head troubles, have held it 500rpm thru redline for an hour in top. If the fuel is not stale I can start it with my hand, they need full travel of the lever but speed is not as important.Excelent decompressor. Wife has a GB400 also bought new and its had 2 camchains only in its 67000k. I certainally have nothing bad to say about the Rudge Four Valve Copy. My one is far more fun than the Guzzi 1000s I had .I have owned 1/2 doz bikes since but now back to the GB only while I build a family friendly car for fun. Vaughan
trogedon,
Jun 19, 1:51pm
There is a German company that gets 70hp out of the TT engine. Its bored to 660ccs but still an old 2 valver. New they had 35hp!
trogedon,
Jun 19, 1:52pm
SR kick start only. Its a real motorbike!
trogedon,
Jun 25, 7:37pm
Ummm.you've got that wrong. Take a TT and turn it into an SR for a better looking bike.
muzz67,
Jul 30, 4:53pm
Yep,, TT a better engine,, actually got bearings in the head for cam and got an oil filter too. XR500 engine basically an upscaled 250 , but the oil capacity was unchanged sadly. Very important to run very good quality oil, and overfill about 200-250ml.Still prefer the XR to ride tho,, TTs are SOOOO heavy!
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