OzVMX Forum

Marque Remarks => Honda => Topic started by: MX? on October 28, 2009, 08:57:22 pm

Title: XL250 Motosport - Performance ideas/help
Post by: MX? on October 28, 2009, 08:57:22 pm
OK, sorry to bore you all with this............but. ;D
Looking for tips on the above, and hoping someone here may have some more specifics.
I want to keep the reliability but bump up the pony's a bit...... not looking for outright super performance.
So I spoke to Serco today about getting my 305 kit fitted, which is all good, but they don't have anything to do with cams any more.
They suggested Tighe or Waggott's for a re-grind of the cam and/or line bore to clean up the bushes any recomendations here? or other suggestions
Wanted to stick with standard type carb ( maybe upgrade to a 350 carb?)
What about valves, rockers etc? Is it really worth changing over the valves (different material or oversize)
Any and all ideas invited.  :)
Title: Re: XL250 Motosport - Performance ideas/help
Post by: lc4 on October 30, 2009, 08:14:40 pm
Do a search on Powroll I think they do or done a bore and stroke kit that would take the Xl out towards 400cc
Title: Re: XL250 Motosport - Performance ideas/help
Post by: matcho mick on October 31, 2009, 10:12:09 pm
grovel before the Griffith boys,bit of luck they might give you some tips ;D ;D, :P
Title: Re: XL250 Motosport - Performance ideas/help
Post by: cyclegod on October 31, 2009, 11:23:51 pm
Page #23 performance don't come cheap...

http://www.megacyclecams.com/catalog/catalog.pdf
Title: Re: XL250 Motosport - Performance ideas/help
Post by: MX? on November 01, 2009, 08:00:48 pm
Thanks for the replies. Spoke to Tighe Cams the other day...$170 to weld and re-grind the cam. Serco want around the same to fit liner and bore for the 305. Holiday down here tomorrow, so I'll try and get hold of Waggotts then. Sounds like it all depends on how wild the cam is, as to what other bits need upgrading? Hoping to get away with the bare minimum for a reasonable gain.........though I guess that'll go down the drain once the head comes off. ::)
Title: Re: XL250 Motosport - Performance ideas/help
Post by: jack82 on November 15, 2009, 07:38:23 pm
Thanks for the replies. Spoke to Tighe Cams the other day...$170 to weld and re-grind the cam. Serco want around the same to fit liner and bore for the 305. Holiday down here tomorrow, so I'll try and get hold of Waggotts then. Sounds like it all depends on how wild the cam is, as to what other bits need upgrading? Hoping to get away with the bare minimum for a reasonable gain.........though I guess that'll go down the drain once the head comes off. ::)


Keen to see how you get on with this as I've just picked up a shitbox in need of some serious lovin.I've been scouring the net looking for XL related stuff. So far I've seen 270 and 305 kits......and XLints high comp pistons and 298 kits.Unsure of which way to go but I'm tempted to try a high comp piston just to keep costs down. Any tips,contacts,parts suppliers etc for my rebuild much appreciated.

Checked out your thread on your bike build......you did a magic job on that mate......wanna sell it... ;D
Title: Re: XL250 Motosport - Performance ideas/help
Post by: MX? on November 15, 2009, 08:04:24 pm
G'day there Jack. Nothing happening yet, still trying to get on top of the house restoration.  ;D not to mention the nice new 15m x 8m garage........that I can't even move in at present. :(
I'm running a bog standard motor (Only has a pipe) at the moment, but have a bloody good time on it all the same. Hoping the small upgrade will supply a few more! Hope your going to post up the rebuild pics? I'll get onto mine sometime this year (not much left though now :o) soon as I tidy up the shed. XLint have some good (if pricey) gear.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: jack82 on November 20, 2009, 09:34:45 pm

The shitbox arrives home......

(http://v2-forum.com/photopost/data/500//0471.JPG)


Should have waited till I got a manual but could'nt help myself...... :)


(http://v2-forum.com/photopost/data/500//0042.JPG)


Now for some questions........I'm putting a 270 or 305 kit in it.....the stock carb is farrked.....What's a good replacement??.....was thinking a VM Mikuni but not sure what size??.....30/32ish ??

Also does anyone know where I can get NOS or good secondhand parts in Oz??

ANY info,tips or tricks related to the XL's would me much appreciated.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: LWC82PE on November 20, 2009, 09:48:28 pm
Have you been to the Oldrice website? lots of XL hop up articles there.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: fatboyracing on November 21, 2009, 07:45:29 am
If you are going for a bigger bore then I would go for say a xl350 carb or simular the VM Mikuni32/34mm would work fine also,in the pictures the old girl looks very original good restorer good luck

cheers
Fatboy
Title: Re: XL250 Motosport - Performance ideas/help
Post by: MX? on November 21, 2009, 03:47:02 pm
Looks similar to mine when it arrived......hope it costs you less than mine.  ;D
http://www.tiaromotorcyclewreckers.com/Nos%20Honda.htm (http://www.tiaromotorcyclewreckers.com/Nos%20Honda.htm) did have NOS Bassani pipes at one stage for a couple of hungy, also picked up a 305 kit for around US$90 delivered on Epay a while ago.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: Tim754 on November 21, 2009, 04:38:56 pm
Tips from one that has been there and enjoyed doing that to XL 250/350s . !!!!!Find an electronic ignition system!!!!!!! All the engine work in the world fails as the stock points / magneto system cannot handle the job, even a stock XL 350 side port in fresh condition is a fun competition machine but ohh the ignition will start to  break down, pop ,bang and fart dying as you near the end of a moto  leaving you pissed off with these fine four strokes. Change the boiled oil after every second heat..... ;) Having bushes or bearings fitted to the camshaft not just the soft alloy they sit/shit in is another tried and proven reliability mod.  Cheers Tim754. 
    Did I mention to change the oil after every second moto ???? After every race if it is a warm day.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: cyclegod on November 21, 2009, 04:58:44 pm
!!!!!Find an electronic ignition system!!!!!!! All the engine work in the world fails as the stock points / magneto system cannot handle the job, even a stock XL 350 side port in fresh condition is a fun competition machine but ohh the ignition will start to  break down, pop ,bang and fart dying as you near the end of a moto  leaving you pissed off with these fine four strokes.

Any suggestions or real world practcal help and/or links to finding an electronic ignition that fits and works would be gratefully received.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: sudman on November 21, 2009, 05:07:03 pm
I have a XL350 that I race in vmx in kiwi land & they are a lot of fun, 36mm carb on the 305 motor is the best option 32mm on all but stock 250 works as well, CDI is a good option which I am currently fitting, but if you fit Honda points not after market & run them at 12thou they work fine as I did all of last season in that trim with no problem, but when you put the compression up you will need a bigger spark, they also love bigger pipes, I run 1 5/8 header & free flowing muffler put that with a bigger carb & the stock engine will give you about 20% more power every where.

Happy thumping
Title: Re: XL250 Motosport - Performance ideas/help
Post by: Tim754 on November 21, 2009, 08:37:09 pm
Cyclegod  I had a couple of NOS Martek electronic set ups,that I found in an old wreckers. Both sets never missed a beat even on the 420 at 13 to1 unfortunately both were destroyed in a shed fire. Lozza may be able to set you on a good path. Cheers Tim754
Wish I still had them as they are the same set up as used on SL125 ::)
Title: Re: XL250 Motosport - Performance ideas/help
Post by: LWC82PE on November 21, 2009, 08:53:35 pm
I wonder if something like this would work and eliminate the points on the XL

http://cgi.ebay.com/ebaymotors/Yamaha-TT-XT-HL-500-points-conversion-module-AHRMA_W0QQcmdZViewItemQQhashZitem1e592394d6QQitemZ130344522966QQptZMotorcyclesQ5fPartsQ5fAccessories

http://www.youtube.com/watch?v=yvZJXU52AaY

Dynatek www.dynaonline.com also make a points conversion module. i know www.serco.com.au use to sell them

http://www.dynaonline.com/skins/products/accessories/Dyna_Boosters/
Title: Re: XL250 Motosport - Performance ideas/help
Post by: VMX247 on November 23, 2009, 05:52:10 pm
http://ozvmx.com/community/index.php?topic=6503.15

bit of CDI info  8)
cheers
Title: Re: XL250 Motosport - Performance ideas/help
Post by: sudman on November 23, 2009, 06:33:15 pm
Points can work well take look at this link

http://www.motorcycleproject.com/motorcycle/text/sohcign.html

This is a local option for you, I think the SL125 6Volt kit will fit.

http://www.motorcycle-ignition.com/motorcycle_ei_kit.htm
Title: Re: XL250 Motosport - Performance ideas/help
Post by: Tim754 on November 24, 2009, 08:36:09 pm
Thanks for locating that site for me Sudman That is the kit I was wanting for my SL125, but could not locate "Piranha Systems"  as they had changed.  Just a note SL100/125s run battery/points ignition systems ,"SL 250 / 350 "are points magneto/points. Cheers Tim754
 TYPO error above should read  "SL250 /XL350 singles" OK sorry I am old and the Viagra is working backwards and my dog does not eat aardvark meat and....
Title: Re: XL250 Motosport - Performance ideas/help
Post by: jimson on November 24, 2009, 09:18:16 pm
Tim does that mean I don't need a battery in my SL350 if I run it without the lights.jimson
Title: Re: XL250 Motosport - Performance ideas/help
Post by: Tim754 on November 25, 2009, 05:26:43 pm
Yes "SL350 twins" are a 12volt battery ignition set up too, We used to run a total loss system changing over and recharging the battery after each race.  OPPS ARRR!! I see a typo in my post above, The "XL350 singles" do NOT need a battery as they are magneto points. The Genuine Honda workshop manual for the XL350 even shows your how to remove the lighting and other gunk for track racing.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: misfit on November 27, 2009, 12:29:55 am
so would that apply to the xl250? how would you go with running a headlight without a battery?
Title: Re: XL250 Motosport - Performance ideas/help
Post by: jack82 on November 27, 2009, 12:02:40 pm

Cheers everyone for all the helpfull info.......... 8)

Have started pulling the motor down......head off no worries but can't get the barrel to budge......given it a flogging with the soft hammers but no luck........any suggestions??

Also found a Bassani pipe that's listed for a K1........will that fit a K0??.....same head??

Title: Re: XL250 Motosport - Performance ideas/help
Post by: Tim754 on November 27, 2009, 04:52:21 pm
Headlight will work on the 250... Just keep blowing a heap of globes. Sort of lighting keep battery, no lights toss it.
Bassani Same pipe K0/K1 according to my old sales pamphlet.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: lc4 on November 29, 2009, 10:11:30 pm

Cheers everyone for all the helpfull info.......... 8)

Have started pulling the motor down......head off no worries but can't get the barrel to budge......given it a flogging with the soft hammers but no luck........any suggestions??

Also found a Bassani pipe that's listed for a K1........will that fit a K0??.....same head??



Pipe will fit , however KO and K1 barrel and heads are different also KO barell  is bolted to crankcase with 2 x 10mm bolts.
Looking at the photo it appears you have a KO fitted with a K1 exhaust.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: MX? on June 26, 2010, 11:52:14 am
Ok, bit of an up date post;D
How's your XL coming along Jack?
I've now got hold of a new barrell that has 305 bore, so that's going to save relining and boring (I hope)
Also just bought what sounds like a good complete head in the US and getting it shipped straight to Xlint Performance there. They'll do a MegaCycle 127-40 cam, hard faced rockers with HD springs/alloy tops.
Idea being I'll end up with a swap over set or mix'n match set.
What I'm not sure of at present is whether to buy the you beaut camsprocket or file out the existing one....is this a good idea?
The end result with luck, will be a performance lift that's relative to the speed of my wallet empting. ::)
Title: Re: XL250 Motosport - Performance ideas/help
Post by: Slakewell on July 08, 2010, 07:25:58 pm
You can get a real 40 HP from the 250 bottom end any more than that and the standard frame bends and fall apart so why bother.
The rear wheel weighs something like 12 kilo's and is ok to replace if you keep the power just under 40. A YZ wheel weighs 4 kilo's Power is good but weight is equal for performance. Get the weight around 100KG and power around 40 and you can win if your up to it. 
Oh fitting 77 XL fork tubes into the standard bottoms gives a full 7" instead of 5" of fork travel. 
Title: Re: XL250 Motosport - Performance ideas/help
Post by: firko on July 08, 2010, 10:35:36 pm
hen I built my Champion framed XL350 i searched high and low to find the lightest wheels. I settled on a Bultaco Mk8 back wheel which worked fine except for one inbuilt flaw. The Honda 4 stroke transmission isn't the strongest on the planet so to soften the blow from rough treatment the factory used that 12kg cush drive back wheel that Slakewell described for good reason. I couldn't figure out why I kept breaking transmissions until another Honda XL racer pointed out the lack of cush drive in my Bully back wheel. I sold the bike not long after but if I was building an XL Honda racer today I'd avoid MX style non cush back wheels and look for the lightest cush wheel I could find. Yamaha DT 250 wheels are two or three kg lighter than the Honda and I'd imagine the 125/175 wheel lighter again.

For ignition I used the CDI from a CT110 posty bike and it gave absolutely no trouble. Slakewells right about the stock frame. Start pumping serious HP into it and they turn to plasticine, especially the swingarm. That doesn't mean the cstocker doesn't cut it as a race frame. For average use they're reasonably light and handle pretty well. The forks are basically the same as CR250M Elsinore units
and if you fit a 350 swingarm to the XL250 and use 1" longer quality shocks, you'll be surprised how nicely the old XL handles. The stock XL front wheel is pretty light and stops really well but you could use a Yamaha unit like I did.
The XL Motorsport is a very underestimated race vehicle. If built properly aiming for weight saving rather than big horsepower you will have a bike that's more than competitive with most pre 75 2 strokes.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: MX? on July 09, 2010, 07:18:58 pm
I want mine to be as close to XL as possible, so I'll be keeping rear wheel. I did break the front down tube of my old XL175 years ago...but that poor thing got jumped and mono'd constantly. ::)
I have got the 350 S/arm on and am really happy with the handling, I can generally more than hold my own on corners and twisty bits, but REALLY lose out on acceleration out of corners and on the straights. Don't really know what sort of power increase to expect from a cam and 305 bore. It's meant to give quicker response and better low/mid range.
Title: Re: XL250 Motosport - Performance ideas/help
Post by: bazza on July 09, 2010, 07:32:06 pm
moded my 305 motor-use a 36mm mikuni round slide with needle shrowd cut to half size and smooth as
Title: Re: XL250 Motosport - Performance ideas/help
Post by: holeshot buddy on July 09, 2010, 07:46:54 pm
my xl was out to 320 had a inch and three quarter tuned manderal pipe
38mm mikuni ported and flowed head  hot cam
lightened engine and frame
still ran points standard swing arm and cush drive :o
and was faster than a kitted 420xl  ;)
lighter engine with less inertia and more revs
much quicker through and out of corners
i won that many races and titles on this bike
it was lots of fun shouldnt have sold it :'(
Title: Re: XL250 Motosport - Performance ideas/help
Post by: bazza on July 11, 2010, 04:16:18 pm
used HONDA points in my XL bigbore since 1991-only time played up i put aftermarket points in
PS i run a 74 CR coil
Title: Re: XL250 Motosport - Performance ideas/help
Post by: jack82 on August 02, 2010, 06:41:26 pm
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Quote
quote author=MX? link=topic=10343.msg137594#msg137594 date=1277517134]
How's your XL coming along Jack?

Slooooooowwly........... :-[..........been busy with other stuff but will be back in the shed next weekend.

I got her going though and did a few laps of the paddock......feels hellishly slow after riding the XR650R...... ;D

I'm on a tight budget so she'll be a bit of a roughy.

I'm just gunna remove as much weight as I can off it and run it stock for a while.Thinking about pulling the magneto rotor off (it looks like it weighs a ton) and running a small battery and total loss ignition.Hopefully that'll allow her to rev up a bit quicker without losing too much bottom end