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Rumbleguts
09-10-2008, 12:00 AM
Anyone done the xr400 choke plate replacement (Ballards)?
If so, how did you stop the screws from vibrating out? (Loctite, burr thread ends over)
I am thinking about doing the mod or even just removing the old choke plate (if the bike will start easily enough without it).
Thanks.

nifty
09-10-2008, 11:05 AM
I did it with the ballards plate 2 weeks ago.

Old link explains it in detail

http://www.dirtbikeworld.net/forum/showthread.php?t=17162&highlight=pushbike+speedo

Easiest and fastest is taking out the subframe ( sounds a lot bigger job than it really is.)

I would have to say, DON"T WASTE MONEY ON THE BALLARDS ONE. I did it, and spent ages trying to get it right. Their plate is about 1mm smaller all around, and it allows the plate to come slightly more closed than original. This then means the choke lever goes too far on the little cam on side of carby and jams choke ON until you get a stick/screwdriver,long skinny finger, and push the cam back down.

I fixed it by hammering the plate to flare it, then filing it back down to correct size. Rang Ballards, but they really weren't interested in rectifying the fault.

I locktited the screws, but am going to take the carby all the way off and punch the end of the screws. You can only do that by putting the punch down through from the front of the carby, because the screws face forward when the plate is closed.

Also, the Ballards one is aluminium, and about 3 times the thickness of the standard s/s one. Didn't like the look of the big thick edge when the plate is open, so filed a tapered adge on both the leading and trailing edges to make them less likely to cause "turbulence" in the carby.

In hindsight, I would just take out the old plate, go get a piece of scrap stainless the same thickness, and cut/grind/drill my own - you'll have to do almost the same amount of work with Ballard's one anyway to get it to work.

Rumbleguts
09-10-2008, 12:36 PM
I did it with the ballards plate 2 weeks ago.

Old link explains it in detail

http://www.dirtbikeworld.net/forum/showthread.php?t=17162&highlight=pushbike+speedo

Easiest and fastest is taking out the subframe ( sounds a lot bigger job than it really is.)

I would have to say, DON"T WASTE MONEY ON THE BALLARDS ONE. I did it, and spent ages trying to get it right. Their plate is about 1mm smaller all around, and it allows the plate to come slightly more closed than original. This then means the choke lever goes too far on the little cam on side of carby and jams choke ON until you get a stick/screwdriver,long skinny finger, and push the cam back down.

In hindsight, I would just take out the old plate, go get a piece of scrap stainless the same thickness, and cut/grind/drill my own - you'll have to do almost the same amount of work with Ballard's one anyway to get it to work.

Great info nifty, just what I was after!
I think i will try just removing the old plate and see how hard it is to start. if it becomes too much of a problem then I'll do as you suggest and fashion my own plate and use the original screws.:grinning-

Just400
09-10-2008, 02:17 PM
Can I ask whats wrong with the original Honda choke plate?

nifty
09-10-2008, 04:54 PM
Can I ask whats wrong with the original Honda choke plate?

The original has a small spring loaded flap the opens for some reason..........think it's in case of backpressure into carby????? The spring/hinge work hardens and comes apart, letting the bits through into the engine, running the risk of valve, piston, bore damage.

nifty
09-10-2008, 04:58 PM
Great info nifty, just what I was after!
I think i will try just removing the old plate and see how hard it is to start. if it becomes too much of a problem then I'll do as you suggest and fashion my own plate and use the original screws.:grinning-

The original screws were punched as well I think. They may not be real flash to try to re thread back in ( don't wanna strip the thread in the butterfy shaft) I just took one down to the local fastener place and got about 4 ( because I always lose at least one before getting home) I think they are 2mm x 12mm - check first though). Got allen head ones- are easy to hold on the end of an allen key to start installing.

nifty
09-10-2008, 05:02 PM
Great info nifty, just what I was after!
I think i will try just removing the old plate and see how hard it is to start.-


I reckon it might be a bitch when cold. Prob easier, while you have the sub frame off to make the new one up and fit it in the one go.

Just400
09-10-2008, 05:05 PM
How many XR4s have had their choke plates come loose and damage an engine? wondering if I should do mine - 2004 model HRC throughout with about 7000ks all done on dirt.

nifty
09-10-2008, 05:19 PM
How many XR4s have had their choke plates come loose and damage an engine? wondering if I should do mine - 2004 model HRC throughout with about 7000ks all done on dirt.

No idea. Could be an urban myth.:laughing- there are threads on it on Thumper Talk, and I've seen pics somewhere of the broken plate and aftermath, but can't remember where. If it CAN happen, then it WILL happen to me.:laughing-

Rumbleguts
09-10-2008, 08:20 PM
The original screws were punched as well I think. They may not be real flash to try to re thread back in ( don't wanna strip the thread in the butterfy shaft) I just took one down to the local fastener place and got about 4 ( because I always lose at least one before getting home) I think they are 2mm x 12mm - check first though). Got allen head ones- are easy to hold on the end of an allen key to start installing.

OK, thanks again nifty.

Kero
10-10-2008, 12:23 AM
What happened with mine was the little spring broke and the backfire flap wouldn't close, causing hard cold starting issues. On a previous one kick bike.
Thats what got me to investigating the problem.

Also with the spring broken the flap is free to ...... well, flap.
I imagine it wouldn't take long to then fatigue and break. I caught mine. Lucky.

Never did find the little bit of spring, either.

Anyway, I made this.

http://i20.photobucket.com/albums/b249/KeroseneCowboy/Chokeplateshut.jpg


Worked great for years, until I made this.


http://i20.photobucket.com/albums/b249/KeroseneCowboy/000_0622.jpg