1998 mountain srx 700 mountain riding and jetting

G

Gerryjackman

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Alberta
Hey guys I've never posted before and new to the forum world.

Have a question on a 98 mountain srx I have v force 3 reeds mbrp exhaust. I'm not sure what Gutting the air box means but I've heard guys say it I took the filter out and there is nothing at all below I'm assuming its gutted. I want to go to the mountain over Xmas an am wondering if this thing will give me trouble there without an altitude compensator? At home in Lacombe alberta were at 850 m and heading to revelstoke is about 400 off the mountains where we will be will be about 1500 m max. Basically I'm wondering what jets I should have in for the mods and riding elevation I'm new to tuning carbs and still trying to understand it also when I checked the plugs when I bought they appeared as so it is running very rich I'm not sure what's normal. Any help is greatly appreciated thanks guys
 
I am no mtn expert but dont THINK 650ft is going to make a big differance if your already set up good to go. Sounds like you might already be to rich though. The guys that would be able to say for sure are prolly gonna want to whats in your carbs currently to give suggestions. As far as "gutting" your air box, that has more to do with removing the inner plastic dividers. As in your "filter" on the very top of air box is intact, parts inside have ben removed.
 
The SRXs and SXs with their smallish 33mm flat slide carbs are not overly sensitive to altitude changes with their jetting. If your sled has been run in your area or into the Mountains already then it may be jetted properly already. The good thing is that as you go to a higher altitude the sled will become richer and lesson any chance of burn down.

2500ASL to 5000ASL is not a huge change.

If it were me...I would take the carbs off and clean them and check/record all the jetting specs.

Have fun at "Revy" its a great place to ride!

JM.02c

Bob
 
Right on I appreciate the help I will tear it down shortly and reply if there is any other information around I would greatly appreciate it thanks again !
 
Jetting for the mountains

Ok so I ripped it down and this is what I have


Carb 1 & 2:

Main Jet - 141.3
Pilot - 47.5

Carb 3

Main Jet - 143.8
Pilot Jet - 47.5

I have no idea if this thing has been in the mountains before the Carbs defintiely needed a cleaning so thats a bonus. Also when I bought this sled it came with a set of spare carbs and an altituded adjuster (possibly two diff kinds I dont know yet) its just the parts not installed what so ever but I have no idea how to install one of these things. Its a Holtzman and from what Ive read I beleive its an ataac and I may have the vari flow also I dont know. I went on there website and they do have installation instructions but there is two different ways im not sure what I have.

#1 Inside air box venting
#2 Outsied air box venting

On the spare carbs I have it has a tapped vacuum hose in the top of one of the carbs, but on the carbs Im using this doesnt exist. Also on the spare carbs the venting is different all the carbs join together and go to the top with one hose bib to connect to. On the carbs Im using they join together and vent directly below to the bottom of the sled.

I will try to upload pics shortly
To be honest I have absolutely no idea how to hook this thing up, but after reading it helped and basically firsdt off need to find out if this sled is inside or outside air box vented.
Another thing I noticed tearing down was alot of holes in the air box and a tiny chamber installed with a nut and bolt. The holes are mainly at the bottom. 5 - 3/8" size holes and 1 - 9/16" size hole, again I will try to upload
pics.
In the instructions for the holtzman compensator it did mention jetting at your lowest altitude and how this can greatly differ how this thing operates, one more quick note, the jets in the spare carb i have are
Carb 1&2
Main Jet - 147.5
Pilot Jet - 42.5
Carb 3
Main Jet - 150


Any help would be awesome Im suppose to be leaving for the mountains in two days, I appreciate everything you guys and look forward to joining with.

Thanks again Guys

One last thing I dont know where i found what jets i should use for my elevation how do I get this information any help? I tried searching the internet but no luck
 
Last edited:
I can't help you with the Holtzman altitude compensator as I have never used these.

The jetting you have in the carbs now look to have been changed for Higher Altitude riding.
The Yamaha jetting charts show the following for 0 F up to 4900':
Mains: 1+ 2 = 142.5...3 = 145
Jet needle clip = 2.5
Pilots = 52.5
Fuel screw = 2.0
 
First off, pics would help ALOT. The inside/outside air venting I would assume they are talking about a cold air kit. With no cold air kit your inside, with cold air kit your outside venting. If your not familar with the cold air kits they go between the hood and bezel, ends up drawing air from in front of the bars via foam mesh filter.
 
Not starting after revy trip

So I took the girl out to revelstoke ended up mountain it in a tree besides that it ran fine for hour or more after and now it won't start compression seems fine Nd has spark my guess is not getting fuel any things to check out first without tearing this thing down ?
 
or take a old pop bottle and fill it with hot water, pour it over the fuel pump by the airbocx on the clutch side, its likely frozen up
 
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