1999 MM 700 mild bog between 5000-6000rpm

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kimoaj

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Hi guys!

My brother in law just purchased a 1999 MM 700, yesterday I got to test it a little and I was amazed by how hard it pulled, but I also noticed a mild bog between 5000-6000rpm.

Not a serious bog, if you run at 5000rpm and give it full throttle, it will jump straight up to (clost to 9000rpm) and pulls good. But if you stay between 5000-6000rpm it feels kind of lazy.

Could this be a jetting issue?.
I haven`t checked the carbs on it yet.

The guy who sold it said he had jetted it for 500meters of altitude.

I don`t think it`s a false air bog because I can barely notice it, but still it`s annoying.

If the jets are changed I think I will get the stock jets and turn the fuel screws back to stock setting, and go from there.


Any opinions?:)
 
Hi guys ! Thanks for the replies!

03viper159: OK thanks for the tip, but can that little needle really affect an engine so much?. Isn`t those needles kind of hard to remove?.
Maybe the previous owner fiddled with the needles, who knows.

gild: what can cause wrong-backshifting?. I checked the wear buttons on the secondary, looks ok.
 
sounds like the ole reed spacer problem to me...Does it gurgle ?..put spacers in!
 
Yammy, is that how the reed spacer problem sounds? :).
Nah it doesn`t gurgle, runs nice elsewise.
Are the spacers aftermarked or does Yamaha make them? . Cost?.
 
yes indeed , they have a midrange bog. Thats what the reed spacers do , they take that low end ,midrange bog out! You have to purchase them thru after market distributors , such as pioneer performance.or some do the reed notch, but I personally dont think thats the way to go, weakins the reed cage and is prone to breakage from vibration.
 
OK yammy thanks for the help.. I will do some more research. Maybe I`ll take the carbs off tomorrow and check them.

So the MM is known for having a midrange bog?. It seems OK from 2000-5000rpm, then boggish between 5000-6000rpm, and then it screams.

I`ll keep you posted.
 
My 97 MM 700 Has that same exact problem. Ok to 5,000 RPM, But that 5,000 - 6,000 RPM bogs not terriable but its noticable and then it goes after 6,000.
 
I did the spacers and notch and have no burble or bog on my 00 700. The spacers alone did not take out the burble by itself but after I did the notch it's totally gone.
 
snow_guy that sounds cool!. How much did the spacers cost?.

I checked the jets on the MM, 42.5mains and 45idle jets.
I kind of forgot this thread since I`m now working on recovering the sled from a dive under the ice !!.

But it`s nice to know that there is s cure for the bog.
 
kimoaj said:
snow_guy that sounds cool!. How much did the spacers cost?.

I checked the jets on the MM, 42.5mains and 45idle jets.
I kind of forgot this thread since I`m now working on recovering the sled from a dive under the ice !!.

But it`s nice to know that there is s cure for the bog.
Click to expand...

I think I paid about $25 for the spacers from a local supplier, I've seen them for quite a bit more too so check around.
 
I never noticed any bog mid range. But I put spacers and reeds from bender when I bought their pipes in 2000. the only bog I ever had was right off idle at 10k ft. it was a lean bog I put in 50 pilots and it was fixed.

I think MPI sell reeds and spacers.

what is the NOTCH you are doing to the reeds? must be on the stock reeds.

thanks
 
Reed notch

No, the notch is done in the reed stopper, not the reed itself. As far as reed spacers and the notch go, "They do the same thing. This mod and the reed
spacers unblock the intake port for a straighter flow into the case on the top side of the reed stopper (Notch goes Up)." This is taken from the tech pages under engine mods/Reed Stopper Notch.

I put the spacers in when I added on triple pipes. Haven't ever felt it bog. I sometimes ride my brother's '97 MM 700 and I feel the bog all the time. He doesn't have the spacers in. Man is it annoying. It's worth the time and money. I think I only paid about $20 for the spacers but there is a link on the technical pages for plans to make your own. Look under engine mods/reed spacers.

Bruce
 
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