Author Topic: Engine parts that fit Xbr500  (Read 2049 times)

blew

  • Full Member
  • ***
  • Posts: 197
Re: Engine parts that fit Xbr500
« Reply #15 on: August 20, 2013, 10:26:12 PM »
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....

Propellor

  • Posts: 1187
Re: Engine parts that fit Xbr500
« Reply #16 on: August 21, 2013, 05:56:41 AM »
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
BEIGE is all the rage

blew

  • Full Member
  • ***
  • Posts: 197
Re: Engine parts that fit Xbr500
« Reply #17 on: August 21, 2013, 01:31:45 PM »
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.

guest1640

  • Guest
Re: Engine parts that fit Xbr500
« Reply #18 on: August 21, 2013, 08:49:56 PM »
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

guest1640

  • Guest
Re: Engine parts that fit Xbr500
« Reply #19 on: August 21, 2013, 08:59:52 PM »
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

Propellor

  • Posts: 1187
Re: Engine parts that fit Xbr500
« Reply #20 on: August 21, 2013, 09:42:09 PM »
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.
BEIGE is all the rage

guest1640

  • Guest
Re: Engine parts that fit Xbr500
« Reply #21 on: August 22, 2013, 01:02:14 PM »
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...

blew

  • Full Member
  • ***
  • Posts: 197
Re: Engine parts that fit Xbr500
« Reply #22 on: August 23, 2013, 09:23:04 AM »
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.

guest1640

  • Guest
Re: Engine parts that fit Xbr500
« Reply #23 on: August 25, 2013, 12:55:04 PM »
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

blew

  • Full Member
  • ***
  • Posts: 197
Re: Engine parts that fit Xbr500
« Reply #24 on: August 25, 2013, 06:51:40 PM »
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.

guest564

  • Guest
Re: Engine parts that fit Xbr500
« Reply #25 on: August 25, 2013, 08:32:23 PM »
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.

guest564

  • Guest
Re: Engine parts that fit Xbr500
« Reply #26 on: August 25, 2013, 08:42:02 PM »
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.

guest1640

  • Guest
Re: Engine parts that fit Xbr500
« Reply #27 on: August 26, 2013, 03:09:46 AM »
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...

blew

  • Full Member
  • ***
  • Posts: 197
Re: Engine parts that fit Xbr500
« Reply #28 on: September 11, 2013, 04:37:13 PM »
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.