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davidw2155
05-11-2009, 11:29 AM
I just finished my winter rebuild (I know its almost summer…). I installed a Stage 1 Hotcam and a 450R carb. When I was installing my cam I snapped off two of the three long head cover bolts that bolt into the cylinder (I had a thead on here about it, thanks to everyone who helped with it, http://www.exriders.com/vbb/showthread.php?s=&threadid=391278). So to fix this I had to pretty much take the whole top end apart. Anyways, now I’ve finally got it all together and ready to run and its running like S***. It doesn’t help that my battery is completely dead and I have to jump it every time I start it because my battery won’t hold a charge, but that’s not the problem.

I haven’t jetted the carb yet because to do that I really need to have the cam broken in so I can drive it around and go through the whole RPM range. So I was trying to break in the cam this weekend, I figured the jetting on the 450R carb would be close enough to correct to run, its got stock jetting for the 450R. So I was running it, and it was idling really, really, really high and I couldn’t adjust the carb to correct idle, no matter what I did it would continue to idle really high. The main problem was, and, I don’t know if this was a consequence of idling high or incorrect jetting, but this thing was running H-O-T!!!!!. It was running so hot in fact that it melted my clutch cable that was run between the headpipes…after 30 minutes!!!! I have ran this thing in 100 degree plus heat for hours and never had that problem before the cam and the carb.

I’m just trying to figure out what all I need to do to get this thing running right. I know that running hot means that its probably running lean, so I’m going to order some jets today (And I guess an new clutch cable…) and hopefully play with all that a little this week. But I really don’t know why its idling so high. Has anyone else ever had trouble tuning their 450R carbs or had their quads run super hot after a rebuild like this?

Any info or advice would be greatly appreciated.

dang400ex
05-11-2009, 11:46 AM
Someone help this guy out.....he's a noob!!!

BigLuke
05-11-2009, 11:55 AM
JET YOUR CARB! Thats prolly why its running lean and hot. List some info on what youve got done, jets, exhaust, intake so on so we can help more.

dang400ex
05-11-2009, 11:56 AM
I agree....we need more info

davidw2155
05-11-2009, 12:05 PM
I'm running a White Bros. E2 silencer, the 450R carb is running Keihin 50 slow jet and 170 main. Got sparks timing key, hotcams stage 1 cam.

dang400ex
05-11-2009, 12:09 PM
I think the high idle you are experiencing is due to the size of your slow (pilot) jet. I would down size to around a 42 or higher...my $0.02

BigLuke
05-11-2009, 12:39 PM
Yeah down size the pilot jet to 42 like dang said. A 170 main shouldnt be to small but Im running a 220 in my 450r carb on my 416. Might try a 185. I also had trouble with my idle when I first installed it the idle screw was a beotch to turn so I took it off and adjust it at the lever now.

BigLuke
05-11-2009, 12:40 PM
what kind of compression you running?

davidw2155
05-11-2009, 02:36 PM
I'm just running stock piston, bore, and compression. I'm gonna run by the Honda shop later and buy some jets so I can play with it a little. Do you all think that the jetting is what is causing it to run so Hot?

BigLuke
05-11-2009, 02:43 PM
could very well cause it, you might check your main again cause when I got my new 450R carb it had a 118 main in it (crazy small).

davidw2155
05-11-2009, 03:04 PM
Was it a Keihin jet? If so a 118 is crazy small, I'm gonna buy a 48 slow jet and 175, 180, 185, and 190 main jet to play with.

BigLuke
05-11-2009, 03:10 PM
Yup factory Keihin jet. I bought the carb new at my local Honda dealer and it was jetted that way from the factory.

davidw2155
05-11-2009, 03:21 PM
You mean a 42 slow jet? You need to research your sizes a little more before you post, my $.02.


Originally posted by dang400ex
I think the high idle you are experiencing is due to the size of your slow (pilot) jet. I would down size to around a 142 or higher...my $0.02

dang400ex
05-11-2009, 07:24 PM
I dont know where you got that quote...read my post. Obviously Bigluke understood what I was saying...

davidw2155
05-12-2009, 09:42 AM
Ok, thats cool, just change it so you don't sound dumb...

Anyways, what size slow jets are all of your running in your 450R carbs, I've read everything from a 42-52!!

BigLuke
05-12-2009, 12:24 PM
Ive got the 52 if Im not mistaken.

davidw2155
05-12-2009, 04:34 PM
I think I'm going to stick with my 50 and just bump up the main jet to about 185 and see if that will make it run cooler, as for the high idle I guess I'll keep messing with the carb...Is it possible that the idle adjustment knob on the 450R carb is broke? Anyone ever have that problem? Thanks.

dang400ex
05-12-2009, 07:29 PM
Bump for help needed quickly....some others surely have an opinion of whats wrong.....c'mon guys!!!

BigLuke
05-13-2009, 07:33 AM
I had a prob with my idle adjustment, I just took it off and adjust idle at the cable.