XL250 Motosport - Performance ideas/help

[LWC82PE]

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/

[VMX247]

http://ozvmx.com/community/index.php?topic=6503.15

bit of CDI info 
cheers

[sudman]

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

[Tim754]

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....

[jimson]

Tim does that mean I don't need a battery in my SL350 if I run it without the lights.jimson

[Tim754]

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.

[misfit]

so would that apply to the xl250? how would you go with running a headlight without a battery?

[jack82]

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

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??

[Tim754]

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.

[lc4]

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

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.

[MX?]

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.

[Slakewell]

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. 

[firko]

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.

[MX?]

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.

[bazza]

moded my 305 motor-use a 36mm mikuni round slide with needle shrowd cut to half size and smooth as