xbr500 calf racer

[JOOLZ]

no problem

[db.engineering]

we did some work on a xr600 engine i think they are similar,  i have a couple of xr600 cams which are in good condition,on the carb side you buy a crf 450 carb they have pump jet and are fitted with hot start,you can make a manifold up to change from oval to round then fit  a xj650 carb rubber this brings it out straight ,do away with the air box and fit a filter ,this is what we did to a xr engine for twinshock motocross

[guest1512]

And there is also Mikuni TM 40 with an adapter for XBR.

[guest1540]

My xbr calf racer project is nearly finished so I'll post some pictures soon. Main problem at the moment is when I plug in my xl600 CDI unit and push the starter button - the 10 amp relay fuse blows? CDI unit number is MG2 CF476A. I thought this was a straight swap but it keeps blowing this fuse for some reason. Any views on this problem.

[JOOLZ]

Weird, does it kick over and start ok. Does the starter motor turn over at all or will the fuse blow without the starter turning. Have you got a good earth between the starter and the frame?

[guest1540]

Hi Joolz, I was hoping you would come to the rescue. The fuse blows as soon as the starter button is pushed - starter does not turn over. I didn't try to start her with the kick start but I presume the wiring is ok because when I refit the original CDI unit she fires up on the starter first time? There is a discussion about this problem on the GB500 site but the guy talks about removing a green/white wire to stop the fuse blowing. I can only find a green wire on the xbr loom from the CDI so Im reluctant to follow his instruction.

[JOOLZ]

I dont know what the problem might be. Kick it over with the xl cdi fitted to confirm the the cdi unit works and the bike runs ok.
Dont go removing wires without knowing what they do.  Read my current post on cdi boxs, on page 3 there is a diagram showing the pin outs and the corresponding wire colours.  I didnt encounter this problem on my XBR as the starter was knackered and I always kicked it

[guest1540]

Ok I'll try the kick starter approach tomorrow Joolz. Excuse my ignorance but where can I find your discussion on CDI units.

[guest564]

There is a 'boost' function on the XBR CDi that gives a bigger spark when the starter is engaged, it could well be causing issues on the XL CDi.

[JOOLZ]

Ok I'll try the kick starter approach tomorrow Joolz. Excuse my ignorance but where can I find your discussion on CDI units.

Its on the chatter general discussions page, open my post cdi box, open the link, and scroll down to page 3

[guest1540]

Good article Joolz but although the wiring details on page 3 correctly states that the unit has a 2 and a 4 pine connector, it then identifies seven different colored wires connecting to it?
I fitted the xl CDI and tried the kick start as you suggested - the engine fired up first time!!!. 
I would still like to use the starter though so I will have to figure out what is blowing the 10A fuse.

[guest1540]

I'm sure there is a real obvious answer to this but - can anyone explain how I upload photos?

[guest1540]

Bike finished and MOT'd this morning. Although the weather over here in N.I. has been wet and cold I can't help taking her out every chance I get. I love riding this bike - it's everything I hoped it would be. Ill post pictures in the project section.

[guest1540]

Can't upload photo's to the Project site - so here goes to this section???

[guest1540]

Can't upload photos - even one! Refused stating that the file size is too big??? Any advice?