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My new SR500 engine review - fark!

Discussion in 'Bike Reviews, Questions and Suggestions' started by QuarterWit, Feb 9, 2010.

  1. Hey guys, the bike is running! There's a bit of a backstory here about some problems I had before it went for a rebuild... https://netrider.net.au/forums/showthread.php?t=107740&highlight=SR400 All engine work was done by Carl, from Cafe Racer at Wattle Flat, in NSW. http://www.caferacer.com.au/content/index.htm He does a lot of work on VMX and some road racing SR's as well. A good go-to guy for squeezing extra horses out of most things it seems!

    Anyway, here she is... there's a few additions to the bike in the past couple of weeks but here's a visual.


    (Note: all speeds are relative for a 30-something year old dirtbike engine. Your ZX6R is faster, CBR1000, GT1400R etc. I'll gladly give up those pissing contests before they start!)

    So basically a few nights ago a mechanic who was helping me with the electrics dropped off the bike. He wheeled it out of the van with a stern look on his face. When she was sitting in my back yard he said; "We need to have a chat about a problem you might have..."

    Ah... shit.

    The timing is off, he said. He can't start it, and two other blokes at the workshop couldn't start it. For shits and giggles he said I should throw a leg over and have a shot. Using exactly the same routine as I did with my 400 I held in the decomp, pushed the kicker all the way. Decomp off, kick it until it reaches TDC. Decomp and push just past, raise the kicker again and with a pathetically weak half kick it barked into life and settled into a nice steady idle. Timing is perfect

    "I've lost my knack" The mechanic said while cupping his mouth to light another cigarette. Kick starters seem to be the best anti theft device and the bike's still as easy to kick as it ever was.

    I'd taken it to this guy because he does a fantastic job with electronics. He'd redone my loom, tidied everything up and neatened my idiot lights. Also fixed a problem with the key and sorted the mounting of that. Everything was plugged and looking sweet and he'd fixed many things that I'd gotten lazy with over time. I found him through another guy who has done some work on my frame, and was also bloody good. It seems once you find somebody who you trust it's best to ask for recommendations and you'll soon be tapped into a really good bunch of guys who know what they were doing and really care about the job that you put in front of them.

    But the exciting bit was the engine was finished, and running beautifully. My bike was a late model SR400 that was just about the self destruct when I gave it to Carl from Cafe Racer in Sydney. This all might sound like a bit of paid advertising... but I couldn't be happy with the donk in the SR510 (?) now. And I'm not receiving cash, kickbacks or headjobs from the guy either, just to be clear!

    He'd done the following...

    Donor Crank pressed apart, flushed washed, new pin and pressed together and trued. Cases heated and main bearing removed. New cam fitted, Carillo Rod, Oil Pump rebuilt. New camchain and tensioner, Donor Head bead blasted (Thanks for the head donation Dave!) and as it was an XT valve was cut down as well as both valve seats cut. Ported. Yamaha Hi-Comp piston. Tested and jetted FCR39 Keihin carb. Exhaust fitted...

    ...And various other bits and peices.

    So it was a considerably different beast to when it left me, a weak but free-revving 400cc thing chewing it's head apart. Carl said the bike now pulled double the rear horsepower over the standard and after riding it a couple of hundred k's in the last few days... it feels like more.

    It pulls amazingly from just about anywhere. The power is virtually instant and the most fun, without doubt, is the 0-80kph start from the lights where the thing just climbs through the revs and you're thundering along in second gear without even thinking about it. I've done some highway riding and in fifth it'll sit at round 3500rpm at 110kph beautifully. There's so much power available from here as well. I'll have to find some controlled circumstances to really give it some stick when it's broken in.

    But the best bit about the power is it's around-town usability. It's respectable and still fun to let the engine sit low in the rev range and just plod around some tight turns, and it feels very traditionally SR500-ey. But come to overtaking that car, nailing out of the apex of a corner or just blowing off stunned looking fully sik boys in the WRX's at the lights and the whole thing just... gah. I can't really describe it!

    A few of my mates have ridden it in the past three or so days as well. One, a die-hard motorcross Honda nut was nothing short of amazed and how much poke it had from anywhere. As an interesting comparison he'd ridden a DR650 the day before and said that it absolutely shat all over it and you couldn't even compare the two. My SR is probably lighter, and has better tyres... but it's still an impressive showing for a 30 year old SOHC twin valve four stroke air cooled shitbox that one motorcycling journalist said "Couldn't pull a fat kid across greased Lino". He also was really happy with the jetting. He said he always had problems getting his motorcrosses running sweet with the Keihin and my bike was perfect. Wahoooooooooooo!

    The exhaust is also very interesting. It's definately got a rather fruity tone. Stew, I think I could give your Conti a run for the money in the volume stakes! What's cool is that when riding along at a normal RPM it's no louder than my old Peyton place 400 exhaust. But give it a bit of throttle and it changes into a really deep staccatto roar. Absolutely beautiful. When MattB took it for a ride tonight he stopped in the middle of a parked tunnel to rev it for a few minutes.

    It's a completely different bike to the stock 400. It pulls amazingly well, is as easy to start. Given my time again with the bike I'd have done the suspension first (Which I did do) but rather than faffing about with cosmetics I should have done the engine straight away and worked the bike around that.

    I suppose the best analogy for the engine that I can think of is comparing it to old big block V8 powerplants. It's simple, straightforward and has a bit of engine noise and a distinctive tone. There are plenty of other powerplants that are quicker, quieter and can do things at one hundred million RPM effortlessly from the factory... but there's something about opening the throttle on the bike and being thrown back into my seat and feeling every distinct thump turn into a strong ripple of torque and power as the rear rises, eyeballs water and testicles crawl into my guts. It's not GSX1300R lightspeedfast but thumpingobnoxioustorqueyevillaughreartyrechewing fast of the traditional variety.

    F'n love it.
  2. Very nice! A 'well proper' motorbike.
  3. Nice write up, I wonder why more people don't get a bike they can use. As much fun as it is riding a 300kmh missile IMO it is crazy to have once for the street.

    Gimmee a bike I can wring the neck off without tearing up my licence.

    Oh and cafe racers just look so f****ingg cool!
  4. Chairman will read this and then go stand in his shed and stare at a certain dust-covered motorcycle...
  5. I like! good stuff there. Singles FTW
  6. It's no good. I have to give the DR lump to a good singles tuner.............
  7. I rode this thing last night, and it's quite possibly the best street SR in the country. It just flips you out! Grant Roff / Groff, an SR Club member and enthusiast, wrote recently in TW that the SR lacked both the traditional Brit torquey thump, due to such things as its light flywheel (more simply, I think, because it was really just a dirtbike engine in a tarted up body) and yet that it wasn't fast either - a failure on both counts. QuarterWit's bike now has both! It thumps along with heavy low pulses at slow speed, and then when you shift at 7000rpm (the stock SR red-lines at 7 - this just keeps going!) it roars and tears away. And it's so very responsive! QW has the high beam switch on the right, and as I was flicking at it I accidentally gaved the throttle a slight pull. It snapped my neck back and absolutely lunged! Riding it in first is an exercise in utter pleasure and attention-getting.

    I've been riding around on my Hornet 600 solely at the moment, which by comparison makes an SR feel like slow dripping mud in the power stakes. Taking off from the lights on this SR, however, I really didn't feel much difference.
  8. Careful Pat, I hear those DRs like to blow third gear apart!
  9. Damn straight! The more I ride other singles the more I think they're the most fun on the roads.

    Twins are pretty neat though!
  10. i dislike 4's unless they are big and tuned for torque like a bandit 12 or something.
    twins... im not really sure, plenty of torque but they occasionally need a rev and they don't seem to like to like it verry much

    but proper big singles... no need to rev. wheel lofting rumbling fun is had from idle and theres no need to speed.

    Id love to have something like your SR one day. my next second bike will probably be another big dr. most likely a 650
  11. Slick, feel free to take her for a spin anytime you like mate. Just don't bin it!
  12. Very nice bike you have the QuarterWit. All your hard work seems to have finally paid off and enjoy riding the thing.

    Sorry for the noob question I'm new to riding but what are you referring to when saying single? Is it a single cam? And why is this better then a twin or 4's?

    Are they easier to maintain?
  13. cheers mate, i'll take you up on it!

    If you treat it nice you might get a spin on the modern day cafe racer (or eric buells idea)
  14. Sounds like a deal mate, I'll send you a PM later.

    Resmen, it's a single cylinder. They can come as DOHC, four valve things as well. Singles tend to vibrate, have fantastic torque and excellent acceleration at all road speeds. They require a bit of attention to the engine, solid oil changes and things like that but the reward is they are usually really simple things to work on with comparatively few moving parts.

    They're also easier to hot up. Only one carb, vs four on other bikes, one rod, less porting to be done etc etc.

    They can also vibrate like mad... Annoying on long long rides but you get used to it after a while. All part of the charm.
  15. Hmmm that's very interesting actually. Are there still many current single cylinder bike manufacturers or is this more of a thing of the past.
  16. That is one Seriously good looking SR
    Doesn’t really look much like an SR any more…
    But then again My old one was the tamer half sized cousin
  17. Nah, there's still heaps of them mate - 90% of offroad bikes are still singles. KLR's, DR's, CRF's, KLX's, WR's etc. The newer ones with lighter flywheels and rev their tits off (CRF450 and the like) have shocking service intervals because they're so stressed. Bigger stuff like the DR650's are sweet because they just chug along happily. If you're new to riding it might be worthwhile to give one a go - it'd be a very different behaving engine to the CB.
  18. I've always liked the simplicity of the SR, yours is a very nice one QW!

    It's a shame that they are very overpriced for what they are in todays market, but that's the way the cookie crumbles I guess.

    Good work I say.
  19. Beautiful bike QW! I'd love to have one of those in the shed!
  20. For a good, non-intimidating introduction to the breed, I recommend scoring a test ride on a DR650. Forgiving engine, light (for a road bike) and adequate chassis and an electric start make it an easy bike to like. Loads of tuning bits from the US make it an easy bike to turn into a ripsnorting monster.

    I like mine a lot. So I'm about to bugger it up by attempting to fit it with EFI.