[700SRX]

Hello everyone.

I have a 98 700SRX
When going through deep snow WOT it backfires and starts losing power.

When I bought the sled I was told 1 of the cylinders need to be changed.
Somebody else told me the reeds are no good.

I have yet to get thing thing into my shop for testing.

Any idea's on the symptom?

Thank!

 

[ditchpicklebrad]

When I bought my 98 ZR600 had same problem. Mine turned out to a reed issue. I did not do the work. I talked to several local riders and a few techs. I met one of my local dealer techs after he got off work on a Sat. He rode it and said the same thing. He had my sled back in a very short time and now gets all my work. There are good techs out there but I suggest find one that rides. He was very aware of how I wanted it to work. Good luck.

 

[p057]

it out the exhaust or carbs?

 

[ditchpicklebrad]

It was out of carb. I believe the reed was cracked but to sure anymore. As i said i did not do the work.

 

[700SRX]

it out the exhaust or carbs?

It's out the exhaust. Yesterday I took it on the lake and went wot and passed my buddys that were already doing 85 mph lol it's fun.
I had no issues until after a half hour of riding I turned around and the rpms dropped and it started doing it again and I couldint get past 40mph

I'm like wth it runs great sometimes and then turns into a slug and then clrears up and runs great again.
I did a compression test btw this is a pull start I did it with the engine cold and I got 60 psi on 2 holes and 30 on 1 hole.
I'm new to this engine but not new to diagnostics of engines. Could this be my issue? or that and the reeds?

Thanks for any input

 

[Yamaha440]

DID you do it at WOT? You should have 110-120PSI in each. You might need a new top end.

 

[700SRX]

Probably most likely ^^^^^
it's got 2000 on the clock and I really don't know the life expectancy of these 3 cylinder water cooled 2 strokes.
It's weird.. it runs great and then feels like its got a plugged fuel filter or something.

But I guess I'll just suck it up and order up 3 pistons and rings for it.
Should I replace the sleeves to if it has them?

 

[Yamaha440]

You might be able to use a flex-hone on them if the taper and out of round don't exceed factory limits. Not hard at all to do. Then get STD. pistons and rings. (don't forget wrist pins, needle bearings, and circlips)

 

[chrisrx700]

Probably most likely ^^^^^
it's got 2000 on the clock and I really don't know the life expectancy of these 3 cylinder water cooled 2 strokes.
It's weird.. it runs great and then feels like its got a plugged fuel filter or something.

But I guess I'll just suck it up and order up 3 pistons and rings for it.
Should I replace the sleeves to if it has them?

The yamaha 700 triples are very reliable, bulletproof engines. My '99 srx 700 has got 12,200 miles and climbing, never had the engine apart. Might be due for a rebuild soon, but she still goes good.

 

[700SRX]

Could this be from lack of maintance?
I know the po bought it new and never really did anything to it except change the plugs.

 

[RJ Gleason]

No, the problem is in deep snow, it is plugging the exhaust.
Make or buy a deflector plate (goes in front of the outlet) and that will solve the problem.

 

[700SRX]

You know I never even thought of that.
Today I took it on the lake and most of the snow was so frozen it never broke through and it ran great!
I did 110 mph with it and holy crap it's fun.
then again it started acting like it was running out of fuel.
Brought it back to the shop and just went over everything under the hood and just found the lines on the fuel filter were loose. Like I could easily pull them off lol
So it could have been sucking air in the lines. I'll see how it go's next sunday.

Thanks guys for your advise.

Edit: oh yea and I'm going to fab up a deflector plate. Thanks Gleason

 

[rainbro]

Your compression readings cannot be correct either, maybe a bad guage. I doubt it would run at all with readings so low.

 

[yamadad4]

you can get an oem style deflector from either a 2000 or newer mtn max or the 03 and up mtn vipers. under $20, make a big difference. also spending some time sealing the exhaust components will help as well, especially the outlet through the bellypan.