Got the bike back from the shop today.... idle is smoother than ever.   I was on the freeway on my ride home alternating between 5th and 6th gears.

I noticed that if I was in either of those gears and I opened the throttle past half, I actually LOST power and speed.  In 5th I would close the throttle to about a quarter turn and all of a sudden I'd feel a bump of acceleration.

Anyone know what gives?

What did they do at the shop?

I have the exact same problem with my bike, going out 50+ mph and if I open it up to full throttle it stumbles untill I close it to about half throttle.

I have suspected that I am running lean and need to rejet, as well as a valve ajdustement may also be neccesary.

I had him set airbox and carb jets back to stock.   But this is a problem I before, I just noticed it more this time.

So the mechanic return the bike back to stock jetting?

I think that the stock air box is a good idea to put back on, but putting the jets back to stock will make it run lean...pull the spark plugs and see what color(colour for you Europeans ) they are.

They were bright white.   He pulled the box and carbs because my bike overheated and I told him to make the problem go away. the idle is much smoother now, and it seems to be behaving more nicely. Its just up at those top ends that it feels dead.  I was at 75 trying to accelerate and it just wasnt having it.

You need to richen up your main jetting.

Is that easily done?  And will that affect my idle speed?

Yeah going back to stock jetting is a bad idea....

The problem with stock GS bikes is the fact that they run lean, my guess is that your bike was probably jetted but was still lean, If you went back and replaced the air box, did you use a paper filter  or k&n drop in replacment, you will want the bike jetted with bigger mains.

The gurus will tell you what you  need to jet with and there is a table that tells you what you need to run, but If your bike is still lean as I suspect then it would be best to rejet.

Ugh.....

Well the matrix settings with the K&N Pod were lean.....  Now it has stock airbox with paper filter, and back to stock carbs.

This bike is becoming a headache.    

I may take it for a few more rides, feel out how bad it really is,. then I may ship them off to srinath.  But its a damned shame everything came out like this.

Talk to the mechanic, tell him your problem, maybe he will cut you a deal and do it again? :dunno:

Otherwise you can rejet yourself, really not that hard, if you want to wait I am going to do it myself with step by step picture instructions, but it isnt going to happen for about 3 months

Quote from: JCHUgh.....

Well the matrix settings with the K&N Pod were lean.....  Now it has stock airbox with paper filter, and back to stock carbs.

This bike is becoming a headache.    

I may take it for a few more rides, feel out how bad it really is,. then I may ship them off to srinath.  But its a damned shame everything came out like this.

I shipped my carbs to srinath...  he has a great turnaround time

I have great turn around time ... yea I can pretty much turn around in under 3 seconds ... but you're not gonna see your carbs back till next year se7enty7 ... cos no jets in the store, no stores open, no UPS truck comming anywhere except speeding down my residential street .... grrrrr ... and pretty much we are all screwed ...
Now JCH you were lean with the 147.5 (I dont think 1 size makes any real diff) and now its back to 100% stock and leaner now than before ... and you had them jetted by a guy that said the air filter was sucking air out of the carbs ... Some else is off in your carbs ... blind jet changing will not help your cause 1 bit and neither will rebuilding a carb whatever that is ... I told you we have to figure out before we start swapping parts ...
Send it to me ... if its something simple I'll fix it free ... you already have the pilots in ... send me the 147.5 mains or I could put 150's in ... Something else is off ... could be a float set low, out of synch, rip in diaphragm, some other kooky crap like air leak from throttle linkage or somehting that "scratch" had last year ...
Cool.
Srinath.

Well I'd just feel more comfortable sticking with the stock box and filter.  If anyone else wants the K&N Pod I'll sell it cheap (All it is is the pod, no documentation or lube or anything.)

However the jets I may do.  I'm going to give it a longer ride than I put it through today (45 minutes) to test it out and see what I have going on, and then I may send it to you to see if we can get it rejetted or find out what the deal is.

Are we sure that whatever the problem is is carb related?  The mechanic said there was no problems with the vacuum seal, whatever that is.

I just remembered one mroe thing......   both 5th and 6th went flat at 6000 RPMS.  Just wanted to add this in case this shed any light.  Thanks!

good luck, hope you guys figure it out

That is exactly when my bike does it, 6000 it starts untill about 8000, after 8000 i can crack it open again and it will start pulling. I highly suspect lean jetting, but my vavles need to be checked so it could be a combination.

Keep me posted JHC on what you do would ya?

OK flat at 6k ... does it feel there is no more rpm ... and it never climbs above that ... dead giveaway ... tiny rip in diaphragm ... hard to see, near impossible to see ... cos my hard to see rip make it die at 4500 or so ... else sounds like you have a funky ass vacuum leak wt one position of the butterfly ... never happened to me or seen one carb do that, but I believe Scratch has had that ... maybe he will chime in... or call him to this thread ... he had a silly leak of some kind in the throttle body ... If I recall ...
Cool.
Srinath.

It feels like once it hits 6rpms, its all it has (and this is at like less than quarter throttle)   Beyond that any additional throttle the bike actually feels like it loses power, like I've suddenly cut the throttle completely or something.. But its a noticeable deceleration.

Coll, Mine never gets above 6... except in 5th I seemed to get 6.5 once.   That just kind of sounds like a tpyical flat spot doesn't it?

SCARTCH!

Send it to me ... I'll fix it most likely free or cheap there is 2 good diaphragms left in my friends carb rack... might be time to buy the whole rack ... we seem to be eating diaphragms ...
Cool.
Srinath.

Srinath,   I'm leaving in 2 hours and won't be back until the new year, but as soon as I arrive I will take them out and send them of.

Anyone have any resources on how to do that?