Author Topic: 8000 @ 65MPH??????? WTF!!!!!!!!!!!!!!!!!!!!!!!! (Read 2266 times)

I Zombie · « **on:** July 01, 2009, 08:18:20 PM »

Ok I need some major help here.
Finally got most of the major bugz worked out of my 78 750k. Runz good, idlez decent (not sync'd yet) 40mpg city, ect. My new issuse is really high RPM'z @ highway speedz. Where do i start looking for my problem, as far as i know the sproketz are stock, tirez are 110-90-19 front & 130-90-17 rear. Gearz were nerve off the shaft during the rebuild so they should be in the right order?

It seemz that if I keep it under fifty I can hold a decent (?) 5000 RPM.
Where should I start?
Can the carbz make this happen?
Do i have bigger problemz somewhere else in her?
Any thoughtz, help, idea would be great.
I'll do my best to give more detailz as needed.

d_soles · « **Reply #1 on:** July 01, 2009, 08:20:35 PM »

Well, to sound like a jerk, have you tried shifting into 5th gear?

Seriously, either you're having some serious clutch problems, your gears aren't stock, your sprockets aren't stock, your gears are in the wrong order (is that possible?), or you aren't actually shifting into fifth......but, hey, I've never owned a 750.

Doug

I Zombie · « **Reply #2 on:** July 01, 2009, 08:24:55 PM »

Yes I was in 5th. Trust me i was thinking the same thing, but i've tried 3 timez last weekend all with the same result. It'z alwayz pos the PO was in it, looked untouched when i cracked it open for new gasketz & sealz, but what do I know.

jmckinne · « **Reply #3 on:** July 01, 2009, 08:40:52 PM »

I'd say clutch first. Adjust the engagement - a little goes a long way remember. They usually start slipping at the higher RPMs.

Adjust your engagement then set your cable play to match the new setting.

Sam Green Racing · « **Reply #4 on:** July 01, 2009, 08:54:26 PM »

Zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz wake me when u figurez it.

Samz.

BobbyR · « **Reply #5 on:** July 01, 2009, 09:09:24 PM »

I have a stock 78 and 5000 is about 70 mph so you are high already. You either have non stock sprockets or one hell of a clutch slip. It would not be carb synch since your carbs are all opened together via the solid bar linkage.

andy750 · « **Reply #6 on:** July 01, 2009, 09:12:29 PM »

Not to be the spelling police or anything but its quite challenging when you cant read your text clearly....too many z`s. Spelling more clearly might a) make you sound more educated and b) get you more replies as I am sure more readers will take the time to read your post. Just a thought.

And as for your high RPM problem. If agree with the previous poster and check your clutch. Either that or the tach/tach cable is not working correctly.

Good luck
Andy

CBJoe · « **Reply #7 on:** July 01, 2009, 09:31:50 PM »

Quote from: Samcr750 on July 01, 2009, 08:54:26 PM

Zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz wake me when u figurez it.

Samz.

Zmart Aleck

Sam Green Racing · « **Reply #8 on:** July 01, 2009, 09:56:55 PM »

Did you mean Aleckz ?

Sam.

Sam Green Racing · « **Reply #9 on:** July 01, 2009, 10:00:31 PM »

Sorry Zom, joking apart....It's either got a 10 tooth front sprocket in there or your clutch is slipping, probably the latter.

Sam.

I Zombie · « **Reply #10 on:** July 02, 2009, 06:29:25 AM »

Thank you all, looks likei'm starting @ the clucth & going from there.
I'll try to wath the "z" bad habit i picked up along the way.

cb650 · « **Reply #11 on:** July 02, 2009, 06:32:17 AM »

Come on guys he waz juzt akzin a ?

d_soles · « **Reply #12 on:** July 02, 2009, 06:35:59 AM »

Sometimes it's best to just slow down and type. Think about it first. Generally, kids in my generation are very bad at this, resulting in a lot of typos, misspells, horrible grammar, bad punctuation, and substituting symbols for words. Typing (and talking) like that is not going to get you a lot of respect or answers. At least try to "act" educated. Hell, I do, and I haven't even started college yet (I'm 24). Typing is not difficult, neither is speaking proper English. Also, not everything needs to be "shortened". Typing out a full word is fine. If you don't have the time or the patience to do that, you probably shouldn't be working on bikes like these, and you probably need to do a little introspection.

Okay, rant over.

Doug

mlinder · « **Reply #13 on:** July 02, 2009, 06:36:45 AM »

Zombie, please go ahead and count the teeth on your sprockets, just to make sure.
When you are buzzing along at highway speed, and you open the throttle, does the engine speed up without any real acceleration from the bike itself? does it feel like the bike speed is catching up to the engine speed when you crack open the throttle?

bryanj · « **Reply #14 on:** July 02, 2009, 06:53:34 AM »

One other possibility is either the speedo or tacho playing up. Does it sound like its doing 8,000 revs and/or are you passing everything (Doing more than 65)

I Zombie · « **Reply #15 on:** July 02, 2009, 08:14:56 AM »

Oh yes, she's screamin along.
That was my first clue to a problem. Yes i will double check my tooth count. The PO was pretty abusive, i.e. blown out fork seals, loose neck bearings bald rear tire glazed brakes ect........
God only knows what all he did to get it to pop wheelies & what not.

Sporkfly · « **Reply #16 on:** July 02, 2009, 08:35:42 AM »

Quote from: I Zombie on July 02, 2009, 08:14:56 AM

Oh yes, she's screamin along.
That was my first clue to a problem. Yes i will double check my tooth count. The PO was pretty abusive, i.e. blown out fork seals, loose neck bearings bald rear tire glazed brakes ect........
God only knows what all he did to get it to pop wheelies & what not.

If he was popping wheelies you might want to look into a clutch kit. Blown fork seals would have resulted from coming down hard off of wheelies, and chances are he was (being an amateur and) playing the clutch to pop the front end up.

How many miles are on the bike? It might be a good idea to just replace the clutch pack either way.

I Zombie · « **Reply #17 on:** July 02, 2009, 08:52:56 AM »

She's got about 26,000 on her. When i had her apart for the new gaskets & seals everything was in spec & justed need to be cleaned up & reassembled. I didn't pull the clutch apart or off for that matter, so it could be close to toast.

I Zombie · « **Reply #18 on:** July 05, 2009, 07:20:43 PM »

Quote from: Samcr750 on July 01, 2009, 10:00:31 PM

Sorry Zom, joking apart....It's either got a 10 tooth front sprocket in there or your clutch is slipping, probably the latter.

Sam.

How does 15 front & 42 rear sound?

mlinder · « **Reply #19 on:** July 05, 2009, 07:27:10 PM »

That's not stock, but still wouldn't cause 8k rpm at 65 in 5th. More like 2nd.
Something isn't right. Either you've got a slipping clutch or the gearing on your tach or something is wrong.

Tretnine · « **Reply #20 on:** July 05, 2009, 07:28:30 PM »

could be all of the above both sprocket, clutch, and fork seals. Might have changed the sprockets to get the front end off the ground, screwed up the clutch getting it off the ground and blew the fork seals bringing it back down. Just a thought.

I Zombie · « **Reply #21 on:** July 05, 2009, 07:30:04 PM »

Played with the clucth today, didn't much time on it, but we'll see if it helps

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Author Topic: 8000 @ 65MPH??????? WTF!!!!!!!!!!!!!!!!!!!!!!!! (Read 2266 times)