braindead1684
Member
Just did a rebuild on the 700 Red head, new (used) crank, new crank seals, re-used OEM pistons with new Rings gaskets (all three layers on head).
Everything was running good but after a few miles I noticed if i creep up on 6000rpm the motor breaks up (misses, stutters).
If you give it some good throttle at 5k it will blast past it and you wouldn't even notice.
Several things we noticed.
When we checked the oil pump cable it was at 26mm we turned down close 20-21. This was done after the throttle was set however the idle was adjusted afterwords.
I assume adjusting the idle then tweaked the free play on the throttle as it is at 3.5mm instead of 1-2mm.
We pulled the carbs and the bowls are clean main are clear, needles show wear.
All three needles are the same (i thought specs called for a different needle in #1?)
The wear i speak of is that 1 needle the clip falls off the other grooves are fine just the #3 clip location doesn't hold the clip in place.
1 more needle is loose but it doesn't fall all the way off, and then another of the needles holds nice and tight.
Carbs are all stock other then possibly the needle (all three needles have the same markings)
Now for the questions?
Would excess oil cause the sputter.
Could a worn needle move enough to cause this problem?
Should all the needles be the same across the three cylinders?
Everything was running good but after a few miles I noticed if i creep up on 6000rpm the motor breaks up (misses, stutters).
If you give it some good throttle at 5k it will blast past it and you wouldn't even notice.
Several things we noticed.
When we checked the oil pump cable it was at 26mm we turned down close 20-21. This was done after the throttle was set however the idle was adjusted afterwords.
I assume adjusting the idle then tweaked the free play on the throttle as it is at 3.5mm instead of 1-2mm.
We pulled the carbs and the bowls are clean main are clear, needles show wear.
All three needles are the same (i thought specs called for a different needle in #1?)
The wear i speak of is that 1 needle the clip falls off the other grooves are fine just the #3 clip location doesn't hold the clip in place.
1 more needle is loose but it doesn't fall all the way off, and then another of the needles holds nice and tight.
Carbs are all stock other then possibly the needle (all three needles have the same markings)
Now for the questions?
Would excess oil cause the sputter.
Could a worn needle move enough to cause this problem?
Should all the needles be the same across the three cylinders?
shaggyzr2
Active member
replace your exhaust donut between the pipe and manifold. if it's worn out it will make it run like that. I just replaced one on my buddys sxr 700 last week, it was doing the same thing.
A couple of bucks
VIP Member
That donut can be gotten at most any muffler shop. Slather it up w/ Permatex Ultra Black when you put the pipe and springs on.
braindead1684
Member
Donut didn't look bad, i can probably permatex the current one. At idle i did not notice any exhaust leak however i would imagine at 6k it could develop one.
What about the needles, I am most concerned about the clip not wanting to stay on.
My local dealer just closed up so I will have to order them if needed.
What about the needles, I am most concerned about the clip not wanting to stay on.
My local dealer just closed up so I will have to order them if needed.
super1c
Super Moderator
http://www.totallyamaha.com/snowmobiles/aaTECH/ReedNotch/Reed_Notch.htm. reed spacers or reed stopper notch will help clean that up if not already done.
shaggyzr2
Active member
It might look good but does it fit tight? That needs to be a tight seal.
the larger the gap the less oil ..the smaller the gap the more oil.
worn needles will cause problems
all needles are the same on those sleds
worn needles will cause problems
all needles are the same on those sleds
A couple of bucks
VIP Member
braindead1684
Member
Thanks guys i dropped those needles back in it and will mount the carbs back on it tomorrow and see how it sounds/runs after re-adjusting throttle and oil cables.
I will get new needles this offseason and take care of the donut at that time, probably about to get the last snow down here so don't want to monkey with too much at this point.
I will get new needles this offseason and take care of the donut at that time, probably about to get the last snow down here so don't want to monkey with too much at this point.