MZ/MuZ Riders

Hi all, I have an 03 Baghira. I've had the bike for a few years now and it has performed great but now there seems to be an issue.

I get an intermittent stumble at freeway speeds. It doesn't happen all the time but when it does happen it seems to be when I am accelerating. Sometimes all is well, hit the gas and everything is fine. But the next time I try to accelerate, stumble. It seems to happen from about 60mph and up. Riding on the streets, all is well even accelerating hard at the lower speeds.

I decided to try the easy stuff first so I disassembled the carbs and cleaned everything out. I replaced some o-rings in the carbs that looked like they were cracking. I reset the float level and adjusted the mixture screw to about six turns out. Next, I replaced the spark plug and visually checked the plug wire for corrosion. Seemed fine.

Took a little test ride.... wow, got a bunch more grunt when accelerating. Felt quite optimistic that I might have fixed the problem... Got on the freeway and rode about 15 miles and all was well accelerates strong and no stumble. Turned around and rode home and the same problem came back.

The stumble seems like a hard stumble. I lose power and the bike coughs. I roll off the gas and then the bike seems normal. Power is back and all is well. The next time I roll on the gas to accelerate, I might or might not experience the stumble.

Any Ideas??
Help!
Jose Soriano

try changing the brand of gas your using
my rt125 and 660 traveller both do this
there seems to be some thing in the gas that makes it not want to burn proper
it has been a pain in th A for the last 4 years
i just figure it expensive crappy gas
once i cleaned the tank it was like it was full of OLIVE OIL
other than electrical problems its been the gas
for about 4 or 5 years now
and i have tried not to go to the point where i turn on the reserve
as its just like your running out of gas when i do
because of crud in the bottom of the fuel tank
Dave

Did you clean the filter on top of the needle valve ?
Clean the in tank filter, check for fuel flow.

Are you sure it is not an ignition problem ?

All the best,
Henri
http://moto-science.com/

I will try all that, Thanks!

I did fill up fuel after taking the carbs apart.

I forgot about the filter in the gas tank!

But opening up the fuel valve showed pretty good fuel flow (just by eye)

How do you access the filter on top of the needle valve?? Had the carb pretty much apart and I didn't see anything.

No, I am not sure its not an ignition problem... thats why I changed the plug and inspected the plug wire.

I didn't have time to work on it today but tomorrow, I was going to check wiring for anything loose. I'll add the filter checks to the list.

Henri, hey! Met you at the Glendale DMV. I was riding a Concours at the time. Great talking with you.

Jose Soriano

You might try giving Vance & Hines in Whittier a call (562-695-9626). I spoke to a mechanic there (his name might be Nate I'm not sure) he used to race Scorpions and sounded well versed regarding our 660 engine, Rob is the owner and is a good guy. You could also check with Pasadena Yamaha (626-577-3000) they are nice people (Kel is the owner). I've taken my 2001 Baghira to them for service and tires.
Good Luck, Ed

amahoser wrote: How do you access the filter on top of the needle valve?? Had the carb pretty much apart and I didn't see anything.
Jose Soriano

Hi Jose,
I was having similar problems.
My float valve filter looked like a lint trap. One side of the clog was loose and it could move enough to allow good flow, then cover the filter again and clog it up.
Here's the location:
Float valve:


Remove this screw and the valve seat twists out:


Here it is:


Be very, very careful and gentle when replacing the float retaining pin...
As you can see in Pic1, Stoopie (that would be me) managed to snap one of the holders off.
I was using a small pair of pliers to push it in the last few mm's and managed to bobble the carb body. The "grab" broke it off.
Luckily, I have a Tour I'm saving for "parts"...

Anyone know if that can be brazed back on?
BillR

Bill, I think you can Alu weld that and then file it down.

Hello Jose....

Yes, it's propably that filter on the needle valve....not ignition.
Check the valve adjustment too. Singles don't like out of spec valve adjustments.
Wash the tank out, there will be a lot of crud in there.
If that doesn't work...

Come over to my house in WLA and between my friend Steve
( an old MZ racer) we'll quickly figure it out.

All the best,
Henri
http://moto-science.com/
323-933-1366
skype shb777

hb7 wrote:Bill, I think you can Alu weld that and then file it down.
All the best,
Henri
http://moto-science.com/
323-933-1366
skype shb777

Thanks Henri.
I'll give that a try.
Bill

billr wrote: The "grab" broke it off.
Luckily, I have a Tour I'm saving for "parts"...

Anyone know if that can be brazed back on?
BillR

I have a spare carb body. If you want it, its yours. A bit grungy but it can be cleaned up. PM me if you want it and we can work out a deal.

Hoser

Thanks for the offer Henri.
Im gonna tackle it after work today. If I cant figure it out I might take you up on your offer!

Jose Soriano

She Lives!

Its been a heck of a few months with Baghira issues... First was a worn Clutch, a week after fixing that, I blew out a fork seal.... fixed that and a week later the battery died.... fixed that and then I noticed the rear brake was worn.... fixed that and then I get this stumbling issue. I know, I know... all of it is just simple maintenance issues but sheesh!

Hopefully thats all for now... I wanna ride my baghira!

Yep, it was the float valve filter... I cleaned that as well as the filter in the gas tank. Gas tank filter wasn't too bad but it did have some small debris around it. Never knew about the float valve filter. My Kawasaki Concours does NOT have float valve filters... Wish it did, every once in a while I get stuck float valves in that bike. Gotta be careful of hydrolock but the Baghira does not have that problem.

Thanks to all that responded.

Jose Soriano

amahoser wrote:She Lives!

Its been a heck of a few months with Baghira issues... First was a worn Clutch, a week after fixing that, I blew out a fork seal.... fixed that and a week later the battery died.... fixed that and then I noticed the rear brake was worn.... fixed that and then I get this stumbling issue. I know, I know... all of it is just simple maintenance issues but sheesh!

Hopefully thats all for now... I wanna ride my baghira!

Yep, it was the float valve filter... I cleaned that as well as the filter in the gas tank. Gas tank filter wasn't too bad but it did have some small debris around it. Never knew about the float valve filter. My Kawasaki Concours does NOT have float valve filters... Wish it did, every once in a while I get stuck float valves in that bike. Gotta be careful of hydrolock but the Baghira does not have that problem.

Thanks to all that responded.

Jose Soriano

Appreciate this thread and all the posts.

I drained the tank, pulled the tank and washed it out with soap and water. Rinsed it very well and left it to dry. I will rinse it out with fresh gas before I fill it (going to fill with race gas once for good measure.)

I'm going to pull the carbs again and clean that filter as well as see if I can find anything in the circuit that goes to that filter in the carb. Last time it had very little debris on it, and now having seen the tank filter (which had very little debris as well) I am worried those filters may not be the issue.

If anyone else has some tips I would appreciate any input. I have a paper element clear fuel filter to put between the tank and the carb in hopes that any other junk will never make it into the carb and to let me see if somehow air bubbles are causing an issue. (read something about that happening somewhere when people have to hit the reserve).

The people I'm going to be riding with next weekend are not going to want to deal with someone who can't go over 65 (speed limit is 65 on one road, but people go over 70mph all the time.)

Whilst you have the tank off and emptied why not seal it. Over here in the UK you can by a product called Pet Seal. Its a 2 part resin which you pour into the tank to coat the inner surface to seal any rust and pinholes. I have also used the resin from a fiberglass repair kit in the past, just remember to remove your fuel tap and plug the hole.

radiograf wrote:Whilst you have the tank off and emptied why not seal it. Over here in the UK you can by a product called Pet Seal. Its a 2 part resin which you pour into the tank to coat the inner surface to seal any rust and pinholes. I have also used the resin from a fiberglass repair kit in the past, just remember to remove your fuel tap and plug the hole.

What? It's a poly tank?

What? It's a poly tank
I'm still in the era of steel tanks, didn't realise the Baghira was plastic.