450R Carb Questions

[Blodg]

I received my 450R carb from ebay in the mail today. I have read all the old threads and have about everything figured out but one thing I didn’t see discussed: Mine came with the full hot start cable intact. The standard practice is to insert the hot start plunger and guts and then seal it off. Having the full cable would it still make sense to just put the plunger in? I am thinking another option is maybe I could just cut the cable off above the adapter and not have to seal anything? Or I might just leave the cable attached and wire tie it to the frame somewhere and then if there is ever a reason to use it on another quad the hot start could be useful.

Also when I disassembled to clean I somehow dropped the splash ring that sits around the main jet. It has to be laying in my barn somewhere but I didn’t see it anywhere, is it really needed (older carbs never had one)? I guess I could order one when I order the 450R fuel line. Any advice on either? Thanks.

I kind of want to install the carb when I get the fuel hose to try it but winter is here and I won’t be riding much if at all. I may just wait since I will be tearing the motor apart this winter for a bore/cam/piston/HD studs/HD cam chain.

[CJM]

Ya need the ring, float wont work right without it.

You must make sure to block off the hotstart, if you dont the carb wont work right and you will have issues.

[Blodg]

It has the full cable attached so if I leave it intact I won't need to block it off or seal it.

Thanks for info on the ring, I just looked $6 something at sevicehonda so if I can't find it I will order one when I order the fuel hose.

[CJM]

If that cable should move at all then it wont seal.

be smart, seal it up or you will be chasing problems.

[Blodg]

Oh I see what you are saying. I would assume it would be fine as the cable has very good tension from the spring and it sits that way in the 450R. But to your point if it was sealed then it can't move and would elminate the potential for an issue.

[Blodg]

I got my 450R carb modified and installed a few days ago. Have had it for a month now but I only have a little time to work on it between helping coach my son's basketball team and other kids activities. Anyway's, I have the '04-'05 and it has an off-idle bog when I snap the throttle open in 1st or 2nd gear. In the midrange and top end it seems to rev quicker and pulls quite a bit harder than the stock carb. With the stock carb I was running the airbox lid and now have it removed so I am feeling the effect of the the new carb and having the lid off.

I swear I remember reading an old thread where someone with the same problem modified the actuator for the accelerator pump but I searched and searched and couldn't find it. The bog and AP tweak is a common problem on the FCR carbs but I have the '04-'05.
- stock motor with HMF slip-on, Uni filter, lid off
- 162 main
- 48 pilot
- fuel screw 2 1/2 turns out
Starts good, idles great, no popping on decel (was popping bad with stock carb), midrange and topend seem very good but need to tune out the bog. Any suggestions?

I thought I had a method to adjust the f screw and was going to try to turn it out farther to see if it helped with the bog but I couldn't get it. I will have to mock up a tool or loosen the carb. I was guessing the 162 main might be a little rich but so far it seems to pull hard all the way through.

[Thumpin440ex]

I took a pair of needle nose pliers, gently tweaked the accelerator pump lever just a bit, so it would squirt fuel just a bit sooner, it solved the bog. Also remember the engine is not going to be able to rev as fast while under load as it will with out one.

John

[hondaREX]

I had the same off idle bog. Open up the accelerator pump. Hard to describe but there is a square plug in a round hole. Clean all the small gaps between the round and square plug. Use one bristle from a wire brush then blow air through the gaps. Clean the bore that the accelerator diaghram shaft goes through. And you should be good. Huge difference after I did that. Good luck.

[hondaREX]

OP. Is #30 what you are missing? And CJM, if it is, isn't that not needed? I believe I removed mine.

[hondaREX]

Dumbass, I forgot the image.

[CJM]

Yes thats number 30 and yes you need that for the float to work right.

[Blodg]

Originally posted by hondaREX
OP. Is #30 what you are missing? And CJM, if it is, isn't that not needed? I believe I removed mine.
Yes #30 is what I was referring to. I never did find the one I dropped but I took one out of another carb I had after I checked to make sure it was the same part number on the Honda schematic.

Thumpin440ex, thanks for the info as that is what I thought about slightly bending the accelerator pump lever but couldn't find it anywhere when searching.

[CJM]

Where the shaft of the accelerator pump meets the arm for the carb. Bend the arm slightly so its resting on the shaft of the accelerator pump.

[hondaREX]

Ok. I just thought i remember removing something from inside the bowl, like a plastic deflector or baffle. Very good. OP, let us know what makes it better.

[Blodg]

I worked on the 450R carb some when it was warm over the weekend. When I removed the side cover of the carb it looked like the lever arm was already touching the AP shaft. I went ahead and bent the arm down a little and test rode and still had the bog. I bent it a little more and still had the bog. I bent it a little more and still had the bog. At this point I have pobably bent the arm 1 or 2 mm and it is pushing on the AP shaft before I move the throttle so I decided to go the other way. I bent it back so there was a gap between the arm and the AP shaft and the bog definitely got worse than it was with it pushing on the shaft. I put it back to just touching and am back to where I started and still have the off-idle bog.

I need to remove the air boot and watch what is going on with the AP squirt when I snap the throttle. I started wondering if maybe the AP wasn't working at all but the bog was worse when I backed the lever off so it is doing something. I cleaned the carb when modding it for the 400EX but never did pull the AP and diaghram off so maybe I better check that when it warms up some (working in a barn),

[JOHNDOE83]

Theres a 90% chance you need a bigger pilot jett, your bogging from being to lean.

Like I said 90% chance its the pilot being to small, after that the other option is the needle position.

If its determined that your pump is squirting properly, its deffinetly running to lean.

Check out the FAQ section on jetting and carb tunning at www.jetsrus.com

[CJM]

Agreed, Id up to at least a 50 pilot.

[hondaREX]

Did you take apart the AP and clean it like i described a few posts back? I had what sounds like the same bog and after i poked/cleaned the AP with a wire, it was a night and day difference. I went back and forth with my pilot and needle before i did this and the AP was just jacked up with condensation and corrosion.

[Blodg]

hondarex, I have not had a chance to remove the carb and dissamble the accelerator pump yet. I wanted to try tweaking the lever arm first because obviously that was a little easier than removing the carb. But yes that is my next step and I should have done it when I originally had the carb apart to clean, move the needle, sand the ridges for the zr adapter, and drill the side vent.

Thanks rex, cjm, and johndoe for the advice.

[hondaREX]

Im telling ya, its going to fix it. I was advised SEVERAL times to clean it thoroughly, i thought i did but i skipped the AP. As soon as i opened it up, i knew it had something to do with my problem, turns out it was the only problem.

[Blodg]

REX, off-topic but I have a question for you. Can you see a difference in your temperate dipstick with the spal fan on and with it off under normal riding? Also, what temp does it normally run at? I am debating on whether I want to buy the dipstick or not, it would be nice to be able to keep an eye on the operating temp.

[Stickman400]

I've got a temp. dipstick on my 400 and I let it idle for about 10 minutes in my shop and the oil got up to about 230 or so and then I turned the fan on and it brought it down to 200 within 3 or 4 minutes. Average is 200-250 depending on how hard you are riding and what the ambient temp. and humidity is outside. Normally mine runs around 230 or 240 in 70-80° with normal riding (road riding, fast/slow trails). I'd say get it, it's a very nice way to make sure your not running then engine too hard when the oil gets hot.

[hondaREX]

I agree with Stick, get it, its a good piece to keep an eye on things. I have never sat and tested it at idle but a few times ive stop when it wasnt on and watched it go down after i turned it on. I think i run in the 190 range, while riding with it on. When and if i see 250, i forgot to turn the fan on. I usually just run the fan constantly so i dont forget. I ride mostly trails, and try to go as fast as the trail lets me to keep air moving over the engine. I also have air shrouds, im not going to say they are cooling a whole lot but they HAVE to direct more air over the whole engine and through the cooler/fan than not having them.

But im pretty sure im running 190. Remember, my motor is...was bone stock. Ill find out where i run this summer. Ill be running a 407 11:1, HC stage 2 and full sparks exhaust so temps should be different with that setup.

[Blodg]

Tonight I removed the air boot and watched the AP squirt and it looked OK but was kinda bouncing off the bottom of the carb opening. I was expecting it to squirt all the way out the end of the carb. I then removed the carb and removed the accelerator pump and cleaned everything. The diaghram looked in good shape but the AP bowl was gunked up a little. I wiped the gunk out and blew carb cleaner through every opening and put it back together.

After cleaning I watched the AP squirt again and it didn't look a whole lot different but was a little stronger. The spray was still hitting the bottom of the carb opening and then bouncing out the opening. I was not sure I had accomplished a whole lot but when I warmed her up and took a test ride it was definitely much better. I thought I noticed a bit of a bog still when punching it off idle in 2nd gear but on further thought it was more likely a slight loss in bottom end as would be expected with a bigger carb on a stock motor. I only rode for five minutes but don't think there was any bog when punching it off idle in 1st gear. It definitely pulls harder in mid and top end than with the stock carb and airbox lid on.

hondaREX, you were right! Thanks for the help from everyone. I am still planning on doing a piston and cam yet this winter but wanted to see what it felt like with just the carb upgrade. I am also thinking about doing +1 a-arms, front shock revalve & dual rate springs, steering stabilizer, and +2 axle which would make the quad about perfect for my needs.

[CJM]

Told ya, clean the carb lol.

Glad you got it working good!

[Blodg]

CJM, actually it pisses me off that I didn't take the AP bowl off when I cleaned everything originally. I am pretty anal about that kind of stuff and can't beleive I didn't do it the first time. When I told my wife that it fixed it she even said she was suprised I wasn't more thorough as she says with me being a nerdy engineer that I am anal about everything, LOL (yes there may be a Freudian slip there:D).

[CJM]

You guys had it easy too! When i got my carb off ebay it looked good on the outside but due to ethanol fuel use it was disgusting inside and no amount of carb cleaner and scrubbing took it off. I had to buy a special carb dip and that cleaned it off super well.