45-50MPH top speed.....

12658 Views 22 Replies 13 Participants Last post by Yazman, 10 mo ago

Laurenda

Discussion Starter · Jun 30, 2010

I am having an issue with a 2002 Honda Rebel I just purchased for my girlfriend. I can't seem to get the bike above 45-50 mph. When I got the bike a couple of weeks ago, it wouldn't idle without being on choke, so I figured I needed to do some carb work. I pulled the carb and the bowl was orange with crud. As I had figured, the low speed idle jet was clogged. So I cleaned the jets and the bowl, drained the tank, ran some seafoam through it and soaked the carb in it. Reassembled, put a new air filter on it, new plugs, and it idles perfectly, and starts most of the time without choke at all. The bike runs great; however, it seems like there's some sort of governor on the bike keeping it from getting to top speed. In the lower gears, it revs and pulls as well as I think it should be. ( I have never rode a rebel, so I have no comparison) I have read that people are gettin 70-80 mph out of theirs, but my top is 50 with a tailwind. It seems that between 3/4 throttle and full, there is no difference in the speed or sound of the motor in 5th gear. The throttle cable is pulling the throttle completely open (at least I can't move it any more with my hand, and it looks wide open from the side of the carb.)

Does anyone have any ideas as to why this bike that runs so well, and starts way better and quicker than my Harley would not reach its top speed?

I don't know the history of the bike, and I am not sure if there is a way to govern the speed in the event it was used in a MSF course. I am not sure if they even do that.

Even at the slow speed...it sure is fun to ride. Sorry for the long post, but I am out of ideas and could use a little help. By the way, I weigh 180lbs, so I don't think I am too heavy for the bike.

Thanks for your help,

Mark

1 - 20 of 23 Posts

Guba

· #2 · Jun 30, 2010

The procedure to adjust idle is...

turn the pilot screw out 2 3/4 turns from being seated

adjust idle speed with the throttle stop screw (big knob on the bottom right side) to 1400 +-100rpm

adjust pilot screw to obtain the highest rpm's (in/out)

readjust the idle speed w/ throttle stop screw

turn pilot screw in until 50 rpm's drop

readjust idle w/ throttle stop screw.

This is from the Honda manual.

If you don't have the idle set correctly, that could be the problem. You'll need a tachometer, that is unless your ear is perfectly calibrated. Mine isn't. Hope this helps Mark.

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J-Adix

· #3 · Jun 30, 2010 (Edited)

It sounds like you may want to re-jet your carb. After adusting your choke and idle if the problem persists start getting bigger jets. I had a similar problem. After I put on a K&N pod filter and some shorty mufflers it was running way too lean and I couldn't run the bike without the choke almost all the way on. It would die out if I had the choke less than 1/2 way on, or if I twisted the throttle too quickly, even with the choke all the way on. Also it would sputter and almost die out whenever I was taking off from a stop, or if I went past 1/2 throttle. I switched my stock jets; #35 slow & #135 main, to #40 slow & #140 main, and it ran way better. I can now turn my choke off after it warms up, and I can twist my throttle as fast as I want. The only issue I'm having now is that it's still sputtering after I pass 3/4 throttle, topping me out at about 60-65 mph, so I'm gonna put in a bigger main jet to see if that solves it. I'll probably do that next week, and I'll post my results.

bufbills

· #4 · Jun 30, 2010 (Edited)

hi , im a new rider, so take this for what its worth. i bought an 02 rebel last week. i weigh 250(so no, your not too heavy) and couldn't get it over about50 - 55 without it screaming like it was going to blow up. after adding air to the rear tire to the correct air pressure, adjusting the sagging chain, and adjusting the valves, i'm able to get 70+ mph easily, without it screaming in pain. i think that all of those things were holding it back. now it runs smooth and much faster. there is a great video link on this site for valve adjustment that anybody could follow and even if none of those things are your problem, they should be looked at anyway. good luck!

JunkyardDog

· #5 · Jun 30, 2010

If you can't get it over 45-50 you definitely have problems. I would say the most likely cause is in the carb somewhere, or possibly the throttle linkage is out of adjustment. But others have brought up other good possibilities, and they are also worth checking out. I seriously doubt there is any kind of "governor" on it.

I get about 70 mph out of mine, and have hit an indicated 80 (actual 75) the Rebel speedometer is hopelessly optimistic, with a slight tailwind and tucked in. I usually cruise at an indicated 60 mph (actual 55.7 GPS), to leave some room on top. I don't believe in running any 4 stroke engine at wide open throttle for very long at the time. Jerry.

flitecontrol

· #6 · Jun 30, 2010

Could the orange crud in the carb bowl be fine rust? If so, you'll probably need to clean the tank. Install an inline fuel filter if there isn't one already, and clean the carb again. Sea Foam is great on gas varnish and residue, but won't affect rust.

Laurenda

Discussion Starter · #7 · Jun 30, 2010

Well......

I guess I am going to have to tear down the carb again....It just confuses me that the bike runs and idles so well but I am not getting top speed. I would think that if I had a carb problem, it would sputter at wide open from either not getting enough gas, or too much. There's no miss in the motor at all. If it seems to be idling well, and running well, I am not sure how adjusting the idle will give me 20 more mph. BTW, the pilot screw has a tip on it that doesn't let me turn it all the way in or out. From my limited experience, when I have carb problems, the bike would run poorly, in either upper or lower RPMs, but in this case, it seems to run just fine. I tried running it without the air filter in case it was starving for air, but there's really no difference in top speed.

Reading some of the forums, these are also the issues I have considered

Clutch plates.....but the motor doesn't whine in gear like the clutch is slipping

CDI......Someone had mentioned that could be a problem, but I have no way of checking that nor do I know how.

Transmission- It shifts well, and I don't want to even think about if that could be the problem.

I am with you guys that I suspect the carb. But short of buying a new one ( which may not be out of the question) I am not sure what else to check. Do you think the needle or the accelerator pump could be the culprit? I didn't disassemble those. I haven't checked the compression yet; although, if the bike is running well and idles, I can't imagine that I have low compression.

Thanks for your help. I have never run into a carb problem where the bike runs well and just doesn't hit top speed.

As simple as it may be, I will check the chain and the tires just to rule it out. Sometimes it's the simple stuff that gets overlooked I suppose.

Like I said...I have limited experience with these motors, so I could be overlooking something really basic.

Thanks again for all of your help,

Mark

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fastpakr

· #8 · Jun 30, 2010

I agree that this doesn't sound like an idle mix issue. I'd install a fuel filter and pull the carburetor one more time. Do you have access to an ultrasonic cleaner? That can find and clear debris and gunk that you'll never get with just compressed air and liquid cleaners. Main jet looks good? How is the float height?

flitecontrol

· #9 · Jun 30, 2010

X2 on the ultrasonic cleaner. I believe Jack ( http://rebelcatalog.com/) has a carb cleaning service. He's gonna be unavailable until July 10 though. Have you looked in the tank to see if there is any rust? A rusty tank will mess up a clean carb over and over. Lots of ways to clean a tank. Do an internet search and find one you like. My personal preference is using The Works toilet bowl cleaner because it is cheap ($1.25/bottle), available at Wal Mart, and easy to do. Easy disposal; just strain it through a coffe filter when you're done, and use it to clean the toilet bowl!

Laurenda

Discussion Starter · #10 · Jun 30, 2010

Good ideas everyone

Does Jack do a full carb rebuild in addition to cleaning? I wouldn't mind having it completely done by someone who actually knows what they are doing. If not Jack, is there someone you would recommend I send the carb to other than the dealership whom I really don't trust?

Thanks,

Mark

flitecontrol

· #11 · Jun 30, 2010

Laurenda said:
Does Jack do a full carb rebuild in addition to cleaning? I wouldn't mind having it completely done by someone who actually knows what they are doing. If not Jack, is there someone you would recommend I send the carb to other than the dealership whom I really don't trust?

Thanks,

Mark

I believe he will do whatever it takes to fix your carb. Just talk to him when he gets back. But first, look here: http://www.hondarebelforum.com/show...sembly-reassembly-1743.html?p=32247#post32247

It really isn't hard to do, and has been done by folks with no previous carb experience, like me! I would offer to do it for you but don't have an ultrsonic cleaner, which I really think is the absolute best way to clean them. But carbs were cleaned by soaking (ONLY the metal parts) in carb cleaner and blowing out with compressed air for a long time before ultrasonic cleaners came along.

Another option is here: http://www.carbworx.com/ I have heard many good things about him on another forum, but have no personal experience since I do all my own wrenching.

socalmarcus

· #12 · Jun 30, 2010

Just throwing it out there - does it have stock gearing?

fastpakr

· #13 · Jun 30, 2010

Jack is a great option for the cleaning. You can't get better customer service at any price.

Out of curiosity, where are you located? Perhaps there's somebody on the forum that lives nearby and could give it a second pair of eyes.

JunkyardDog

· #14 · Jun 30, 2010

I have heard nothing but good things about Jack and carbworx, though I have never used either of them. I have cleaned hundreds of motorcycle carbs, and only had problems with 3 or 4. One of them was on my '94 XT225. The carb body had a hairline crack in it I couldn't see till I checked it with fluorescent dye. I got a replacement carb at a salvage yard for $20, and just used the main body, after a thorough cleaning. It worked flawlessly, and still does.

Overall, cleaning a carb is a very simple thing. but there are a couple of things that can mess things up. One is something like what happened to my XT carb, a crack or plugged up tiny passage. The other thing is putting the carb back together wrong, and that has happend to me (a trained and experienced mechanic) a couple of times. Once I remember while installing the diaphragm, spring, needle and slide, I got a spacer in the wrong place. I was absolutely convinced that is where it went, and took the carb apart and put it back together several times the same way, before finally getting out the manual, and realizing what I was doing wrong. Worked fine when I got it together right. Jerry.

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jboy

· #15 · Jun 30, 2010

I'm 170lbs and can get mine to 80-85. There's definitely something wrong.

Guba

· #16 · Jul 1, 2010

Is the puke tube drained?

shadetree

· #17 · Jul 6, 2010

try cleaning the petcock first. if it had rust dust in the carb it it will have it there also.

sludge2112

· #18 · Jul 6, 2010

I don't think accelerator pump. Don't they just temporarily richen the mixture during rapid throttle movement? Tire pressure is a good possibility as tire diameter could change significantly and effect the final drive ratio. However, it would feel really squishy in the twisties if it was that far off. Check your plugs. If the mix looks to be on target, maybe a larger jet. If it was fuel flow, like plugged pet cock, it would sputter for sure.

shadetree

· #19 · Jul 8, 2010

not necessarily sputter but cause a lean condition under the heaviest gear ratio load range.

JunkyardDog

· #20 · Jul 11, 2010

Before jumping at things, it wouldn't hurt to eliminate a few things first. Are the tires at the proper pressure? (the pressure shown on the sidewall) Is the chain adjusted properly? Do both wheels spin easily? Could the brakes be dragging? Are you sure you sure you have it all the way into 5th gear? Have you verified the gearing by actually counting the teeth on the sprockets? Someone could have lowered the gearing. Not likely but possible. CDI is also not likely, because I don't believe the Rebel has a built in rev limiter. I agree it doesn't sound like the clutch, but it might be worth checking out. Is the cable adjusted properly, with about 1/8" free play in the lever? Does it have a sufficient quantity of 20w50 oil in the engine? Have you checked the valve clearances? Does it make any unusual noises, like maybe a loose cam chain? What do the plugs look like? Does it seem to accelerate up to it's top speed ok, or is it sluggish just off idle? Does it sound like it might be misfiring at top speed? Is the throttle cable opening the carb all the way? Are the throttle cables adjusted properly? Does it seem to be running rich? Is there a strong exhaust smell? have you thoroughly checked the choke? With the complicated "enrichment circuit" that the Rebel has in place if a simple butterfly choke, there are several things that can go wrong with it, and a couple of parts are prone to breaking, especially the plastic (plastic?) threaded connector that screws into the carb body.

My first "guess" would be the carb, but the problem with guessing is that it can cause a lot of unnecessary work, and in some cases, wasting a lot of money replacing perfectly good parts. Better to try and narrow it down as much as possible before buying anything Jerry.

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