not much power till it backfired!

[Guest]

Took the wifes' 81 450 out for a ride after work, now that I got all the wiring harness redone and working properly. Bike had little power, did want to go very fast at all. Couldn't get it past 40 in 5th gear, and lots of hesitation on take off. Had to turn up idle to get it to stay around 12-1300 at idle. Pulled back into driveway and reved it up to 6-7000 rpm and left it there a couple of mins. and the bike backfired a few times, let off throttle and bike idled past 2,000 rpms. Turned idle down to where it should be and took off on bike. Bike took right off and so much more power I had no problem getting up to 50-55mph. Still wasn't running perfect, but what a difference. Got home shut bike off and no juice wouldn't start. Just put in a new battery so I knew it wasn't that, and I had done a quick check on charging system not long ago and seem within range. Put battery charger on, and tried it after only 15 mins. and bike started right up! Will charge it some more and do tests later.Did pull plugs which are almost new and little black on them, cleaned and regapped, and turned carbs alittle leaner. Any ideas on what would make power appear after reving and backfiring? terrylee

[Dave8338]

Had the same think happen once many years ago. In my case (it was on a two stroker) there was a baffle loose in the exhaust that was partially blocking the pipe and the thing couldn't breathe. When it backfired, it blew the loose baffle piece to the back of the pipe where I could see it. Pulled the junk out and the bike never ran so well.

Just a thought. I your case, it may have been a jet that cleared a partial blockage and as the correct amount of fuel entered the lean cylinder, a nice kaboom was heard.

[Planecrazy]

If it WAS a blocked fuel passage in the carb then there's a good chance there's more sediment or buildup still in place. Take the carb apart and give it a good soak for 24 hours or so (there's a recent thread regarding the use of Pine Sol for this, instead of the more standard choices). I wouldn't be surprised if it ran even better once it's clean!

Regarding the electrical issue, you may have to do some more testing with a voltmeter to find the culprit, but it could be something as simple as a bad ground, etc.

Regards,

[Steve]

I really hope your sense of time is a bit distorted.

Are you kidding us? 6-7000 rpm, in the driveway, with no load on the engine "for a couple of minutes"?

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[Planecrazy]

I really hope your sense of time is a bit distorted.

Are you kidding us? 6-7000 rpm, in the driveway, with no load on the engine "for a couple of minutes"?

.

I'm hoping "minutes" was slang for "moments."

Regards,

[Dave8338]

I really hope your sense of time is a bit distorted.

Are you kidding us? 6-7000 rpm, in the driveway, with no load on the engine "for a couple of minutes"?

.

Noticed that as well. Hoping it was seconds. If indeed it was minutes, I feel that bikes pain, all the way to my toes.

[Steve]

I'm hoping "minutes" was slang for "moments."

Regards,

Me, too, but I just had to ask.

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[Allie]

..... a nice kaboom was heard.

Where's the Kaboom? There was supposed to be an Earth shattering Kaboom!

[terrylee]

Ok, maybe a moment or two, didn't realize it was that bad a thing, since you have to rev to 5,000 rpms to test elec.. Guess I won't do that again! Did a few quick test on elec. today and only got 12.2 with key off, only 11.8 with key on, 12.35 at idle, 12.9 at 2500 rpms, only 13.2 at 5,000 rpms, and then 12.4 with key off. Numbers don't seem to far off except with "key on" and at 5,000. Will do the rest of sator papers this week end and see what I get. Oh by the way the carbs. were just cleaned, soaked, new o'rings, ect. late this winter and this is first couple of times bike has been on the rode. Will take off again if problem occurs again, rode today and power was still there. Still seems to want to go "more", feels like something is holding it back. I did order a new oem petcock last night since I suspect that is part of problem. One on there now is old one off 850 and it doesn't fit real well, and seemed to run alittle better when just on prime. terrylee

[Dave8338]

Where's the Kaboom? There was supposed to be an Earth shattering Kaboom!

Nice grab, Allie! Is that the X-P 12 Space Modualtor he is aiming?

[tom203]

If it hasn't run much and old gas was sitting in carbs, why don't you try new gas, maybe a little Seafoam and ride it a bit. Sounds like your charging system needs work, so do those stator tests- don't go too far from home till you do!

[Steve]

Ok, maybe a moment or two, didn't realize it was that bad a thing, since you have to rev to 5,000 rpms to test elec. ...

Yes, you test at 5,000 for some things, but that should take about 5 seconds, 10 at most.

A couple of minutes is pure torture on an unloaded engine.

.

[Planecrazy]

Yes, you test at 5,000 for some things, but that should take about 5 seconds, 10 at most.

What was that, Steve? Five minutes? Ten at most?

(I crack myself up - LOL!)

Regards,

[terrylee]

Did but some new gas in it today and some carb. cleaner and yes going to have wife ride it around neighborhood as much as she can till I have time to go through stator papers. terrylee