Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: guest1640 on August 09, 2013, 02:40:04 AM
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Hi all
Subject xbr500 engine upgrade to 600cc
Bike xbr500 1986 Australian model without kickstarter.
From what read and other research the barrel from xl600 with the 589 case stamp on it fits with machining cases and changing conrods or gudgeon pins. Add an extra gasket at the base and avoid starter problems from high compression
I would like to have the kick starter as a back up and possibly remove the starter for weight issues, as it will end up a project cafe. Have started collecting parts and now have a XR600 on offer for low price and will be good for some parts lime a lighter fly wheel and clucht baskets and the like.
Main question does the xr barrel fit without mods?If not what mods would I need:ie: cases machined, piston shaved, conrod exchange etc.
Need to keep xbr cases for registration.
Any input much appreciated. Project on the back burner. Divorce is a bummer...
Stu Aussie xbr fan...
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Typo....
Corrected...
From what read and other research the barrel from xl600 with the 589 case stamp on it fits WITHOUT machining cases and changing conrods or gudgeon pins. Add an extra gasket at the base and avoid starter problems from high compression.
Stu
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Correct, 589 barrel and an XL conrod and piston and thats it. The only cases that need machining are from very early model XBR's
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Thanks for the input Joolz. Good to see someone with yr knowledge willing to share. Thanks mate.
XR600 Engine is still in bike and going cheap for $200 au. Minus carb and exhaust. Do the side covers for cases fit and does the rocker box(diesel mechanic) fit the head or am I best to source a XL top tappet cover? Aussie xbr models didn't come with kick starter, hence no decompression lever/cable on the cover...
Have read that the xl600 cdi unit enhance a spark. Bike I have is needing a stator, so I thought I might upgrade. Any info appreciated. Cdi and stator combo? Will eventually rmove battery for weight... Road registered bike...
Any exhaust tips for a two into one exhaust system also appreciated as it's still got to get me to work on any given day the sun is out. He he most of the year here.
Oh and can I have the shirt off yr back. Just kidding. Thanks for yr help...
Come n ride sometime...
Tyresforbikes.com.au
Stu
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Yes the rocker cover will fit ok, the right had clutch casing will fit but the alternator cover wont as the crank is longer in the XBR
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My xbr has an XL 600 barrel and piston and two base gaskets.The compression is HIGH.With hindsight,I would have fitted three gaskets.The electric start cannot turn the engine over when cold,but will occasionally turn it over slowly when hot.I always use the kickstart.Out of curiosity I've tried bump starting it downhill in third,and the back wheel stopped dead.I suggest you fit a kickstart and a decompressor.
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Thanks guys. This bike is going to be bitsa from all over.... Kick start shaft n gears from Germany, kick starter from UK, barrel xl600 from central Queensland,flywheel, covers and rocker cover from sunshine coast QLD, piston n rings from USA and the list goes on.
Trying to upload a pic from my phone but it's not working. Think I need a hammer...
Blew you've got me thinking about cutting out a spacer plate that I can paint.
Joolz is there any other heads that the xbr cam will fit? Xl600, xr600
If so. I'm thinking the combustion chamber might be larger and might not need so many base gaskets.
Have been quoted $450au for a cam grind and hard facing. Seems fair...
Slowly getting all the bits together for a build.. Sadly I don't think I'll be tacking it until summer. Least I can ride the stock bike in the mean time.
Stu
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Hi.
Sounds like you're having fun!
Does anyone readily know the compression ratio you end up with just using one gasket? And what is the engine capacity? Anyone ever done a dyno run?
Cheers.
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Hang on. My last post might sound daft.
I've been comparing specs of xbr500 and xl600 and the site I looked on gave the bore and stroke as 75x100 for the xl600. Is that the wrong way around?
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With 11.6:1 compression my starter would work reliably except first thing in the morning when I needed to use a boost battery.
The bore and stroke is 100 x 75 for an Xl600R, its most definitely a short stroke engine.
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Yer fun watching my bank balance get smaller. Thinking it will be worth it though. Love riding it stock, so I can't wait for a bit extra umph in the back wheel. Recently my stator has failed and trudging through posts found a few comments about fitting the xl600 cdi but not much on generators.
Hoping someone on here can enlighten me on getting a bit more poke out of the spark. It's seems like a weak spark but that could normal. And if there's an aftermarket stator that fits.
Not much knowledge on the cafe set up with smaller batteries and the like. So any info appreciated.
Undecided on carb set up. Thinking the kehien 40 or 42 flat might do but it's seems there's a leaning toward the minkuni. Any thought on that please...
Cheers
Stu
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It may be that your alternator can be repaired. The wire coming out of the coil often breaks due to vibration. A very careful soldering job will fix it, but must be covered with shrink tube. As far as I know, the spark gets stronger as the engine gets going, since it's driven straight off an alternator coil.
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One wire on my xbr stator wasn't working.I tracked it down to a bad soldered joint on the stator itself.All 14.5 volts are there now.Yippee.
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?...........The bore and stroke is 100 x 75 for an Xl600R, its most definitely a short stroke engine.
Ah. That explains my confusion. I've double checked and the site in question definitely had it the other way around. It was only when I realised the xbr500 stroke is 75mm that I realised they might have it wrong.
Which brings me back to a question I was going to ask before I was sent off on a tangent....
When you guys say the compression is phenomenal when doing the xl600 conversion, are you leaving the xbr500 head on?
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I used the 500 head on my bike.
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Rhinoman's post has got me thinking (that could be dangerous).My bike's compression should be lower than his,so perhaps I have a dodgy starter motor.I will investigate....
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Rhinoman's post has got me thinking (that could be dangerous).My bike's compression should be lower than his,so perhaps I have a dodgy starter motor.I will investigate....
TBH, it was everyone talking about phenomenal compression and yet the xl600 is quoted as lower than the xbr500. But if the xbr500 head is kept, that would possibly explain the leap in compression? In my very simplistic (read dangerous!) way of looking at it!
Presumably you'd effectively also build in an increased squish area by default?
Cheers
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From what I've read,all the 600 conversions keep the 500 head.I wasn't looking for extra performance (I have other,bigger bikes),I did it because the original 500 barrel and piston were damaged and I found a cheap good 600 barrel and piston on ebay.
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From what I've read,all the 600 conversions keep the 500 head.I wasn't looking for extra performance (I have other,bigger bikes),I did it because the original 500 barrel and piston were damaged and I found a cheap good 600 barrel and piston on ebay.
I've made a mischief and clicked the logged icon instead of "quote" on yr last post Blew.
Necermind. It's the same for me. The stock bike I have is only 39k old and apart from a small timing rattle on warm up and a little clutch slip in top gear when I'm really pushing her, the bike is sound.
So the 600cc upgrade is wanting( because I'm a overweight pig) but not in any rush. Hence why I
started this post.
I'm working from a phone because my ex took the whole office with her. @*#¥ch. Anyway, that's a whole other post.I'm only assuming but I think any combination of xl600 barrel head and cover can be mixed up and matched with the xbr Parts. From memory, i think some of the xl series came out with twin carbs and some didn't .
Sooooooo. I'm thinking that to get the best out the xbr case n crank ( as I need them for registration) is to use the barrel and head from a single carb xl and covers from another mother. And fit the big bore kit for the xl to stretch the capacity to the limit. Use an xbr hot cam and a decent carb and exaust and few extras like heavier clutch and the like and I shouldnt ever have to complain again. Transport laws stop me from a dominator 650 changeover otherwise I'd just do that and be done.
Please tell me anyone if I'm barking up the wrong tree and if so, with tree should it be.....
Stu
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It may be that your alternator can be repaired. The wire coming out of the coil often breaks due to vibration. A very careful soldering job will fix it, but must be covered with shrink tube. As far as I know, the spark gets stronger as the engine gets going, since it's driven straight off an alternator coil.
Thanks for the tip but checked out and not the case this time. Think I'll have to go internal. It can wait. My rides are less than hour during the day so I've rigged up a plug that sits under the side cover unde the seat and I'm just putting the bike on charge for a couple of hours when I get home. Doesnt need much if I don't ride with the light on...
Stu
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I don't know how swapping the various parts from an xl600 compares to what you would get from a production line xl600 but the quoted peak power and torque figures are virtually identical to the xbr500, albeit lower down the rev range. Therefore easier accessed. Plus, of course, quoted peak power/torque figures tell you nothing about the actual torque curve.
A final drive ratio change may be needed to get the best out of the mod?
I'm sure there's more to it in practice than my simple take on things.
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I don't know how swapping the various parts from an xl600 compares to what you would get from a production line xl600 but the quoted peak power and torque figures are virtually identical to the xbr500, albeit lower down the rev range. Therefore easier accessed. Plus, of course, quoted peak power/torque figures tell you nothing about the actual torque curve.
A final drive ratio change may be needed to get the best out of the mod?
I'm sure there's more to it in practice than my simple take on things.
Yes I wouldn't mind seeing a few comparative graphs. Especially of a motor with the mod to compare it with stock.
I'm only following the advice of people who have done the mod on here and other sites like this a several phone calls to a couple of clued up Honda dirt bike gurus here in OZ( albeit reluctant to share too much but very helpfull) and the common thread of excitement is that these motors love higher compression however you get it, and if you can afford to add a cam, carb and exhaust in the mix and a few other tweaks with ignition and clutch and gearing. You get a very light exciting bike that although it's not isle of man material, will make for a great little weekender with that wicked thumper sound. That's what I want anyway...
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I don't know what difference the 600 conversion makes,because my bike was knackered as a 500 when I bought it.I suspect its less keen to rev out than the 500.I tried a 16 tooth gearbox sprocket,but it was happier with a 15 tooth.As to performance,standard bar the 600 barrel/piston,open the throttle in top and it pulls straight up to 95 or so,sometimes 98.Drop into fourth and rev it to the red,then change up and it pulls just over the ton.Sitting upright.I don't know how that compares with a standard xbr.It's good fun on twistier roads,where you can rattle along at 70 to 80 all day in top,but it gets out of breath over 95 on straight roads.It's more about torque than top speed.
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Not sure if the 500 does those figures for me. But I weigh 95kg. I've had a bit of clutch slippage in top of late too, so reluctant to push it. I'm hoping a new carb and exhaust that breaths well will see the ton achievable but so far I've only hit 145km and want to keep what clutch I have before I pull it down.that could be another few months yet. I love the torque in these single engines and would like a bit more top end but like you say, it's a matter of gearing and the right mods.
Back to the subject though.
Has anyone used an alternate head to the xbr on the xl600 barrel?
What piston do you use Blew?
Stu
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I bought a standard XL 600 barrel and piston,flat top piston apart from a small raised edge.I suspect the bigger piston makes it less rev-happy,but it certainly pulls well.
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Has anyone used an alternate head to the xbr on the xl600 barrel?
I had an XL600R head on mine for a while but not with a starter motor fitted, I had two 34mm Dellorto carbs on it so its not easy to make a direct comparison between the two heads, I don't recall there being much difference in the combustion chamber size though. All my stuff is in storage while my garage is being built (took two years to get that started!) so I can't check right now.
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I bought a standard XL 600 barrel and piston,flat top piston apart from a small raised edge.I suspect the bigger piston makes it less rev-happy,but it certainly pulls well.
I ran a Wiseco piston, its almost exactly the same weight as a 500 piston so it keeps its balance quite well. A 0.5mm step works out at around a 5% reduction in CR if my maths is correct.
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Has anyone used an alternate head to the xbr on the xl600 barrel?
I had an XL600R head on mine for a while but not with a starter motor fitted, I had two 34mm Dellorto carbs on it so its not easy to make a direct comparison between the two heads, I don't recall there being much difference in the combustion chamber size though. All my stuff is in storage while my garage is being built (took two years to get that started!) so I can't check right now.
Have sourced a reasonably priced XR600 bare engine that I'll pilfer a few bits from and hoping the head is usable being a single carb set up. I'm told the rocker covers fit and the rfvc motors cams all run in the same bearing journal configuration. So I'm hoping I can use the head...
Won't find out until I strip motor andcompare heads.unless anyone on here has info. Having trouble finding the old xl single carb head. Not wanting to spend on a twin carb set up. Would like to keep the original headout of the equation if possible but will use if I have to. I'm not entirely certain of the history of oil changes, so the head might need work anyway.
I'm reading 55hp or more from these motors with right mods and looking forward to starting the job...
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As a follow-up to my earlier post on starter motors,I stripped mine and found dodgy brushes.With new brushes fitted,the starter has had a new lease of life.It starts the engine every time when warm,although I feel happier kicking it when cold.