ZR 700 cant get out of its own way = SAD - Snowmobile Forum: Your #1 Snowmobile Forum

csdwarf11 · 02-27-2011, 05:58 PM

Alright, my dad has a zr700, we bought it about a year ago and when we got it, it ran great and had no performance issues.

it all started on out UP north trip last year on the last day of the trip. it just started doing this.

It now has a horrible bog, let me explain.

This bog seems to be at random times, it almost seems like its cutting out on one cylinder.

the sled will not move itself, it will just sit there revved up to like 5000 rpm and not even atempt to move, i check the clutches and they look like they are in the correct positions(fully shifted down).

when you keep the speed up on trains it has good power ,and on a tar road covered with snow, the sled pulls to 80+ mph no problem.

i havnt yet found a clue to why or when it bogs, the carbs have been cleaned the clutches seem to operate fine.

it seems as though the snowmobile is getting to much gas, or not enough gas.

I just dont know

any ideas to fix or test would be greatly appreciated, we got a good 36" of snow and its going to start melting fast, probably only another month

thanks!

DnD800 · 02-27-2011, 11:58 PM

Try plugs if you haven't, also try using the choke to see if it helps or makes it worse (make sure chokes aren't sticking as well), and a compression test probably wouldn't hurt either. If using the choke helps then your lean and of course if it makes it worse your rich. What year 700?

csdwarf11 · 02-28-2011, 06:57 AM

choke makes it worse, or not better.

Ill check the chokes.

its a 1994 zr 700.

i dont have an accurate compression gauge, so i cant give you a real number, but the pethetic attempt of a gauge i do have (old school hold it in the sparkplug hole) shows that its even compression in bolth cylinders, about 95(not accurate).

but all my other sleds( they all run) have 80-100

The sled has 2600 miles ish

catpride · 02-28-2011, 07:13 AM

sounds like ya need new plugs or check the wiring if the tps isnt bypassed yet, do it, if that doesnt help check your oiler you might be set to be coming in to early and fowling the plugs and then burning it off at higher rpm, does it smoke alot?

csdwarf11 · 02-28-2011, 07:20 AM

I changed the plugs, and it temporary fixed the problem.

i take the plugs out and wipe them off and blow them out to fix it when it bogs. OR i just let it idle and rev it up a little and wait.(it seems like its flooding out)

it doesnt smoke alot normally, but when its boggy. i got frustrated and pined it, and then the oiler kicks in full at like 5000rpm and then it smokes alot.

when its in its bog state, it seems normal and responsive at lower RPM's

1500-5000 ( the clutch engages at 4000)

but it just bogs after that, like BOOOOOOOOOGGGGGGGGG

and wont even move.

could TSS do this? im not sure if its bypassed, i think it is though.

thanks

**kccats** · 02-28-2011, 07:29 AM

Could have a weak set of reeds! Problem is the reeds are Under the jugs?

catpride · 02-28-2011, 07:31 AM

yes it can, I would check that first, and then go to the oiler, are plugs soaked with gas or oil? if its gas you may just need to clean carbs again stuck float dumping gas in, or as someone else said check the chokes pull them out and clean make sure they slide good and arent sticking, you might also want to drain tank and clean filters or replace make sure the tank isnt full of stuff, you may clean the carbs but if the tank has old gas and residue and other particles in it you will just keep having problems

csdwarf11 · 02-28-2011, 07:35 AM

i think ill clean the tank, adjust the chokes down and clean the carbs again and try it.

i dont think this engine has reeds, if it does there base reeds that are under the cylinder, because theres no reed cage.

i don't see anything on babbitts that shows there reeds, i think its just a straight forward ported engine? isnt it?

i think its carb to, because it always seem like it shuts down on 1 cylinder.

but would the sled at least be able to move itself with 1 cylinder.

thanks!

catpride · 02-28-2011, 07:55 AM

yes it is reeds and yes they are under the cyl in the case.

csdwarf11 · 02-28-2011, 07:59 AM

could that be the problem? the bog issue started mid ride last year when we were up north.

the sled starts awesome, first pull on cold days, and it will idle all day long, it just will get into this state of mind were it whats to be dumb

.

i think it would be an awesome snowmobile, but its being a huge pig, and it sucks having all the weight of a 700 when you are only making power half the time and the other half you could just have a 5hp brigs.

**RJ Gleason** · 02-28-2011, 11:10 AM

No-one mentioned testing the stator.

csdwarf11 · 02-28-2011, 11:56 AM

do you think it could be the stator? theres a tutorial under the how to's should i just follow that?

1-adjust chokes down

2- test stator

3- if stator checks out, rip my engine apart to check the reeds?

anything else? i dont have much experience with CDI ignition, all the experience i do have is bad, it never seems theres a proper way to diagnose it. it always requires swapping parts with working parts.

thanks

**RJ Gleason** · 02-28-2011, 12:19 PM

Yep, just follow the tutorial vid by Blain1.

csdwarf11 · 02-28-2011, 02:03 PM

is that a symptom of a stator on its way out? bog? random performance and random horrible bog.

man, if the stator tests ok, im going to make a video of this, ive seen nothing like it.

its sad, its the sled(pretty big sled) with one of those little 50cc portable rotatiller engine on it.

then you open up the cowling and see these two masive heads sitting there with 700 stamped on them, and these 2 huge expanstion chambers.

if i wasnt so frusterated, id laugh.

DnD800 · 02-28-2011, 03:10 PM

Quote:

Originally Posted by csdwarf11

is that a symptom of a stator on its way out? bog? random performance and random horrible bog.

man, if the stator tests ok, im going to make a video of this, ive seen nothing like it.

its sad, its the sled(pretty big sled) with one of those little 50cc portable rotatiller engine on it.

then you open up the cowling and see these two masive heads sitting there with 700 stamped on them, and these 2 huge expanstion chambers.

if i wasnt so frusterated, id laugh.

Personally I don't think it is but it's not to hard to check. If it does it all the time I would lean towards carbs/carb settings or compression. I have seen where people clean carbs and adjust but not do it 100% right and going back after to find something they missed although round slides are pretty easy to clean/adjust.
If it's intermittent I would lean toward electrical, coils, plug caps, bad/loose grounds, stator. It sounds like weak spark or just way to much fuel on the low end if using the choke makes it worse. Always better to try the easy stuff first though.
I know my sons ZL440 had a horrible bog at the low end and after adjusting the air screws (a lot) it was like a different sled. Needless to say but I'm not a fan of ethanol fuel.

catpride · 03-01-2011, 06:44 AM

you have hit the nail on the head with that one, ethanol has caused a lot of problems in the small engine world, its been a dealers or mechanics best friend. Im kinda going through the same ordeal with my 700 its very finnicky when it comes to fuel, it likes mid grade-high test and fresh clean fuel, even a season old, it doesnt like it.

DnD800 · 03-01-2011, 11:37 AM

Quote:

Originally Posted by catpride

you have hit the nail on the head with that one, ethanol has caused a lot of problems in the small engine world, its been a dealers or mechanics best friend. Im kinda going through the same ordeal with my 700 its very finnicky when it comes to fuel, it likes mid grade-high test and fresh clean fuel, even a season old, it doesnt like it.

I just found out about this stuff (Star Tron Enzyme Fuel Treatment - HOME) and am going to give it a try in all my cars, sleds, and bike. People are reporting 3-4 mpg increase in vehicles, bikes, and sleds are running better although they don't see the mpg increase like "auto's". Figures out to be roughly .05 per gallon to use as 1oz. treats 16 gallons so it's cheap enough to try IMO.

smokingcrater · 03-01-2011, 01:00 PM

Startron doesn't work... Its been EPA evaluated and the mpg claims are NOT TRUE. Unless you count better MPG's from less weight in your wallet.

rgoers · 03-01-2011, 01:27 PM

There's a GREEN bottle version of Sta-Bil made just for 2-strokes and crap-in-all (ethanol) fuel. That's what I use.

DnD800 · 03-01-2011, 03:02 PM

Quote:

Originally Posted by smokingcrater

Startron doesn't work... Its been EPA evaluated and the mpg claims are NOT TRUE. Unless you count better MPG's from less weight in your wallet.

Well I figure it can't hurt...I have been on a lot of forums (cars, bikes, boats, 4 wheelers, snowmobiles, etc....) and maybe it doesn't work with fresh gas or under certain conditions but I have gas sitting in somethings for a month or so and my vehicles aren't getting any newer. In theory it works great....and as far as the EPA....I would believe a 5 year old over them not to mention the EPA wants to add more ethanol to the gas we use now. I find the EPA's testing to benefit them and who ever is paying them. Last I read EPA is trying to ban it....sounds kinda funny to me.