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over-revved; stumbles & missing above 3500rpm
Posted: Mon May 05, 2008 4:35 pm
by Peter Meilstrup
Hi Folks,
So yesterday I pulled out to pass someone and screwed up a downshift,
going into 3rd when I thought I was going into 4th. The engine
overrevved and immediately lost power. Fearing the worst, I pulled
off into the nearest ditch. Nothing was obviously broken or leaking
on the outside. The starter was strong and the engine turned over
well but did not fire. All the fuses seemed okay. I pulled the spark
plug and it looked like usual (i have no idea how to read plugs.) I
brushed some gunk off of it and checked the spark, which was sparky.
After replacing the plug and looking over the pike to see if I had
missed a fuse somewhere, I tried the starter again and it fired up.
However it would stumble and miss above 3500 rpm and would pop on
deceleration.
I limped home in this condition. Halfway home I pulled off and turned
the engine off; it would not start again until I had repeated the
routine of pulling the plug and/or waiting around for a half-hour.
What do you think is going wrong? I have a suspicion but I wanted to
get some independent ideas from the list before I start taking engine
covers off.
-pm
over-revved; stumbles & missing above 3500rpm
Posted: Mon May 05, 2008 4:57 pm
by roncriswell@sbcglobal.net
I don't know. A friend used to take his to track day and continuously
over rev to 8 grand (he said). He asked me if I thought it would hurt
it. Probably I said. Last time I heard from him it was still running.
Criswell
On May 5, 2008, at 4:34 PM, Peter Meilstrup wrote:
> Hi Folks,
>
> So yesterday I pulled out to pass someone and screwed up a downshift,
> going into 3rd when I thought I was going into 4th. The engine
> overrevved and immediately lost power. Fearing the worst, I pulled
> off into the nearest ditch. Nothing was obviously broken or leaking
> on the outside. The starter was strong and the engine turned over
> well but did not fire. All the fuses seemed okay. I pulled the spark
> plug and it looked like usual (i have no idea how to read plugs.) I
> brushed some gunk off of it and checked the spark, which was sparky.
>
> After replacing the plug and looking over the pike to see if I had
> missed a fuse somewhere, I tried the starter again and it fired up.
> However it would stumble and miss above 3500 rpm and would pop on
> deceleration.
>
> I limped home in this condition. Halfway home I pulled off and turned
> the engine off; it would not start again until I had repeated the
> routine of pulling the plug and/or waiting around for a half-hour.
>
> What do you think is going wrong? I have a suspicion but I wanted to
> get some independent ideas from the list before I start taking engine
> covers off.
>
> -pm
>
>
[Non-text portions of this message have been removed]
over-revved; stumbles & missing above 3500rpm
Posted: Mon May 05, 2008 5:00 pm
by E.L. Green
--- In
DSN_KLR650@yahoogroups.com, Peter Meilstrup
wrote:
> So yesterday I pulled out to pass someone and screwed up a downshift,
> going into 3rd when I thought I was going into 4th. The engine
> overrevved and immediately lost power.
Valve float from overdriving the valve train, maybe slung your rings?
> I pulled the spark
> plug and it looked like usual (i have no idea how to read plugs.)
Can't read plugs with modern gas, it's always a light gray-tan.
> missed a fuse somewhere, I tried the starter again and it fired up.
> However it would stumble and miss above 3500 rpm and would pop on
> deceleration.
Maybe when the valve train was being overdriven your cam chain jumped
time?
> What do you think is going wrong? I have a suspicion but I wanted to
> get some independent ideas from the list before I start taking engine
> covers off.
Okay, first thing I'd do would be to take the cam cover off and see if
the valve train jumped time, and check the valve clearances while
you're at it. If that all seems okay, next thing I would try would be
a leakdown test. That should tell you whether you managed to burn some
valves while they were floating off their seats during the overrev --
if air starts coming out your exhaust pipe or carb horn, ya got a
problem, Houston -- you'll need a head job for sure. If instead air
starts hissing out of the crankcase because your rings aren't sealing,
again, ya got a problem.
Chances are it's just the timing chain jumped time, which can be
easily solved by setting the engine at TDC then lining up the marks on
the timing chain (you'll need to loosen the cam caps and take the top
timing chain cover off and take the cam tensioner off to re-time it,
but we're not talking major surgery). If it's more than that...
(shrug). We'll see, hmm?
over-revved; stumbles & missing above 3500rpm
Posted: Mon May 05, 2008 6:27 pm
by Peter Meilstrup
On May 5, 2008, at 3:00 PM, E.L. Green wrote:
>
> Okay, first thing I'd do would be to take the cam cover off and see if
> the valve train jumped time, and check the valve clearances while
> you're at it. If that all seems okay, next thing I would try would be
> a leakdown test. That should tell you whether you managed to burn some
> valves while they were floating off their seats during the overrev --
> if air starts coming out your exhaust pipe or carb horn, ya got a
> problem, Houston -- you'll need a head job for sure. If instead air
> starts hissing out of the crankcase because your rings aren't sealing,
> again, ya got a problem.
>
> Chances are it's just the timing chain jumped time, which can be
> easily solved by setting the engine at TDC then lining up the marks on
> the timing chain (you'll need to loosen the cam caps and take the top
> timing chain cover off and take the cam tensioner off to re-time it,
> but we're not talking major surgery). If it's more than that...
> (shrug). We'll see, hmm?
Yeah, jumped timing chain was my first guess too. Murphy's law means
this had to happen just days after I'd done the valve clearance check
anyway.
Thanks,
-pm
over-revved; stumbles & missing above 3500rpm
Posted: Mon May 05, 2008 8:00 pm
by Jeff Saline
On Mon, 5 May 2008 14:34:57 -0700 Peter Meilstrup
writes:
> Hi Folks,
>
> So yesterday I pulled out to pass someone and screwed up a
> downshift,
> going into 3rd when I thought I was going into 4th. The engine
> overrevved and immediately lost power.
SNIP
> -pm
<><><><><><><><><>
<><><><><><><><><>
Peter,
I'm with Eric on the valve train issues. BUT... And this is a huge
butt...
Running to high rpms under load is over reving but it's probably a bit
different than missing a shift and over reving.
At a smooth acceleration that goes to the limit and beyond you will
really be working on getting many rpms over red line.
Missing a shift and over reving with no load can get parts moving to way
higher revs before you can do anything about it.
You may have bent a valve just enough to cause it to stick a tad that
isn't noticeable at lower rpms but at higher rpms where the valves must
move faster the sticking shows up.
Best,
Jeff Saline
ABC # 4412 South Dakota Airmarshal
Airheads Beemer Club
www.airheads.org
The Beautiful Black Hills of South Dakota
75 R90/6, 03 KLR650, 79 R100RT
russell seat [was: concours regrets?]
Posted: Mon May 05, 2008 8:47 pm
by greg saunders
I agree, a Russell is the most comfortable seat out there. I put one on an old BMW R100RT and then put over 100,000 miles on that bike. The Russell was the best investment I ever made on that bike. Now I have a Russell on my KLR; this year I'm riding the CDR, next yeat North to Alaska all on the KLR and all because of the Russell seat. The Russell on my KLR is even more comfortable than the stock seat on my GL1800. After all that it isn't even ugly anymore.
Greg
St. Paul, MN
To:
DSN_KLR650@yahoogroups.comFrom: chris02@...: Mon, 5 May 2008 15:50:52 -0400Subject: [DSN_KLR650] Russell Seat [was: Concours regrets?]
I bought a Russell seat for my KLR. It's awfully spendy, but it worksfantastic. I can ride all day and not be hurting. It gets a little warm,especially when I wear my Aerostich, so I put a beaded cover on it in thewarm weather. It doesn't get in the way when standing, and offers differentriding positions (moving forward and aft). It's ugly, but it gets you there.YMMV,Chris-----Original Message-----From:
DSN_KLR650@yahoogroups.com [mailto:
DSN_KLR650@yahoogroups.com] OnBehalf Of Jake WilsonSent: Monday, May 05, 2008 12:46 PMTo:
DSN_KLR650@yahoogroups.comSubject: [DSN_KLR650] Re: Concours regrets?--- In
DSN_KLR650@yahoogroups.com, "David C." wrote:(a Russell on a KLR is just wrong) ~~~Sorta like tits on a bull?=:-) I've owned/ridden three different Russellseats, two of which were custom built to my specs. It is one hell of a seatno matter what you install it on but I bet if I had one on my KLR, my KLRwould see far more LD miles than it is currently gettingJakeReddick Fla.
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[Non-text portions of this message have been removed]
over-revved; stumbles & missing above 3500rpm
Posted: Tue May 06, 2008 12:14 am
by Jud Jones
--- In
DSN_KLR650@yahoogroups.com, "E.L. Green" wrote:
>
> --- In
DSN_KLR650@yahoogroups.com, Peter Meilstrup
> wrote:
> > So yesterday I pulled out to pass someone and screwed up a downshift,
> > going into 3rd when I thought I was going into 4th. The engine
> > overrevved and immediately lost power.
>
> Valve float from overdriving the valve train, maybe slung your rings?
>
> > I pulled the spark
> > plug and it looked like usual (i have no idea how to read plugs.)
>
> Can't read plugs with modern gas, it's always a light gray-tan.
>
>
> > missed a fuse somewhere, I tried the starter again and it fired up.
> > However it would stumble and miss above 3500 rpm and would pop on
> > deceleration.
>
> Maybe when the valve train was being overdriven your cam chain jumped
> time?
>
>
> > What do you think is going wrong? I have a suspicion but I wanted to
> > get some independent ideas from the list before I start taking engine
> > covers off.
>
> Okay, first thing I'd do would be to take the cam cover off and see if
> the valve train jumped time, and check the valve clearances while
> you're at it. If that all seems okay, next thing I would try would be
> a leakdown test. That should tell you whether you managed to burn some
> valves while they were floating off their seats during the overrev --
> if air starts coming out your exhaust pipe or carb horn, ya got a
> problem, Houston -- you'll need a head job for sure. If instead air
> starts hissing out of the crankcase because your rings aren't sealing,
> again, ya got a problem.
>
> Chances are it's just the timing chain jumped time, which can be
> easily solved by setting the engine at TDC then lining up the marks on
> the timing chain (you'll need to loosen the cam caps and take the top
> timing chain cover off and take the cam tensioner off to re-time it,
> but we're not talking major surgery). If it's more than that...
> (shrug). We'll see, hmm?
>
If it jumped time, you may also find you have bent some valves.