98 XCR 440 (Red Rocket) issues

Paulson · Mar 3, 2019

I have been having top end issues with this sled. I completely cleaned the carbs and the whole fuel system. Took tank off & cleaned thoroughly. Took fuel pump off & cleaned it thoroughly as well. New gas lines & filter. I have it starting on 1 pull in heated shop at an idle. runs great in shop but when I get out it doesn't have that power band so to speak & reach high rpm's.
- as I was cleaning the fuel pump, I noticed that just 1 of the small, round diaphram had a crinkle in it, it isn't perfect but it didn't appear to be ripped. I basically sprayed carb cleaner and completely got the pump looking like new again, it was all gummed/varnished up. Obviously I should put a rebuild kit in the pump but would that solve any high rpm issues? Starts & idles great..
- I've read about the primary clutch, if it isn't perfect, it may lead to no high rpm's? I don't have any experience in diagnosing clutch issues. Is there anybody that can give me some pointers as to what I could see with my eye for diagnosis?
Do I rebuild the clutch? I have a buddy who is parting out a '92 RXL 600 triple, can I put that clutch on it? would it work or is it a waste of time?

I've had this sled for 5 years now & only had good riding on it for 1 of them, its been having this high end bog issues and I've always thought it was the carbs, but I feel the carbs and fuel system is in perfect condition now but the issues remain. It was so darn much fun riding it that I want to keep this thing around. Not many 440's can keep up with 600's & this one used to..

Thank you to anybody with some insight toward putting these issues behind me.

BeartoothBaron · Mar 3, 2019

Doesn't sound so much like a fuel supply issue to me, although that's possible. With a bad fuel pump what you're more likely to see is it takes off like it should, then falls on its face and won't recover until you back off. If there's any question though, it's pretty cheap and simple to put a kit in it. If it's just not putting much power down, but doing that in a pretty consistent way, then I'd be thinking of other things. A broken or weak spring in the primary would tend to make it under-rev; a gummed up and/or sticky clutch would tend to cause erratic RPM response. What kind of RPM do you see when you hold it open? You want it to stabilize near the quoted peak RPM (7800 is pretty typical for older liquid-cooled twins, but can't say specifically on this one).

05rmksteve · Mar 4, 2019

Have you check and cleaned the power valves? Make sure the bellows are good and all the little ports are clear. Also make sure you have the proper ves spring. Does this one have the little black box with a turn dial on it for ignition timing? These motors where hard to tune get them just right and the ran tike a raped ape run them a little rich and they where poochie. So also check you jetting. And no the clutch from the rxl won't work properly. 2 different motor makes. Rxl is a Fuji motor the 440 is a liberty motor.

Paulson · Mar 7, 2019

More info

No black box with turn dial on it.
I haven't cleaned the reeds, I was told that they could be part of my problem as well. I've never done that before, any advice?
I took the belt off of it last night to check springs & primary one seems good, but when I turned the secondary clutch back a bit to remove the belt, the secondary has quite the tight/ sticky spot in it. I've never took a secondary off before, any advice? You think it just needs a cleaning? I saw videos on replacing the helix & spring in them, but it's there obvious signs if a helix is bad? Im thinking about tearing it down & just putting it back together & lube it up good, then take it for a quick rip.
2nd pull it just idles for me, good feeling there.
Thanks for any advice! Well appreciated!
Thanks

motodad383 · Mar 7, 2019

I had the same sled, and it was a blast to ride when running the right RPM. Had to be above 8200. All my problems stemmed from the Exhaust Valves. Dirty valves would drop RPM's to 7800 - 7400 and the fun would end. You didn't mention what RPM's you are running, but I would clean the exhaust valves, inspect bellows closely and install new springs. Hope this helps.

Paulson · Mar 7, 2019

I haven't taken it back out yet to check the rpms. I know it engages clutches at 4800. I'l have to do that soon. Hopefully tomorrow i'l be able to.

Paulson · Mar 7, 2019

I did clean the exhaust valves, I got them fairly shiny. The springs seem to have really good tension on that cover when I put it on in order to get that clip snapped back on..

BeartoothBaron · Mar 7, 2019

The secondary isn't hard to take apart as long as you have a heavy-duty snap ring pliers. A typical snap ring pliers isn't big and strong enough, and may just break. If the moveable sheave doesn't slide/rotate smoothly all the way open (which can be hard to tell if it's got a heavy spring in it), then you might have a bad bushing, helix, or buttons. One tell-tale sign is if the marks on the helix from the sheave opening and closing are inconsistent or if there's scoring on it. Could be just fine, but it's definitely worth looking over. If the bushing and buttons get too worn, it'll ruin the helix at a minimum.

sno*jet · Mar 10, 2019

sounds like clutches/belt. how many miles on it total? and how many miles since it was running like a top?

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98 XCR 440 (Red Rocket) issues

Paulson

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BeartoothBaron

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05rmksteve

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Paulson

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motodad383

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Paulson

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Paulson

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BeartoothBaron

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