500i Hot Start Problems & Solution

[vision976]

Jaunroberts: Is that your 500i on a fork-mounted chainsaw carrier? I am impressed! Did you custom fabricate the saw carrier?

I built a rack for my snowmobile so I could carry the 500i, a 60 inch peavey, a gallon of gas and some bar oil during winter to remove deadfalls across the trails.

Sometimes in the summer I'll find a big deadfall across a hiking trail and I'll backpack the 500i with it's 32 inch bar to the location.

And yes, you are correct that "winter" gas usually has more volatiles to facilitate easier starting, which may contribute to some vapor lock problems. I don't know at what temperature winter blend gasoline boils compared to summer blend gas, but I have seen gas boiling in all of my chainsaw tanks, during extended cutting periods on hot summer days.

It seems the ultimate solution, is to let the saw cool down enough to start.

 

[juanroberts]

Nice. I am aching to try out snow biking.

I use the Bill Dart rack which is the cheapest and most versatile. In Baja I instead use the rack to carry extra gas on the longer days. You can get the rack here:
https://billdarttrails.com/product/accessories/chainsaw-mount/
Here are the specs on how I mounted it:
https://www.thumpertalk.com/forums/...nsaw-carrier/?do=findComment&comment=15826614
I run a 28” bar because any bigger and I run the risk of it hitting the dirt when my front suspension bottoms out.

Ride on!

 

[vision976]

Bill Dart makes a great fork rack for a good price!

While I have a 20", 25" and 32" bar for the 500i, I generally run the 20" because most of the downed timber in these parts are less than 20". I find the 32" bar makes the saw nose-heavy and I get tired of muscling it around in a full day of cutting. The saw balances great with either the 20" or 25 inch Stihl ES series bars in place.

I have 3 KTM's: a 2018 350 exc-f, (first one I bought in 2019), a 2020 500 XCF-W which I turned into a snow bike with a Yeti conversion kit, and a 2021 Six Days 500 EXC-F, which I have modified and am extremely satisfied with. I had the Six Days suspension (front and rear) modified to lower it so the balls of my feet could the ground, (it was re-sprung for my weight, too). I removed the reeds in the induction tract, removed the restrictor plate on the back of the muffler, and fitted the machine with an Athena Get aftermarket ECU to increase the power.

I enjoy riding the Six Days way more than the 350 EXC-f, not because of the power difference so much, but because the bike is less tall and fits me like a glove. The suspension tweaks really made a difference in riding comfort and maneuverability.

I spend more time on snowmobiles in winter than on the snow bike, because most of my snow buddies own sleds, and not snow bikes. Always best to ride in a group, whether on sleds or snowbikes, to help with the inevitable "stuck" problems that can occur.

I did ride the snow bike last March a fair amount: I could feel the difference in engine power between the modified Six Days and the stock XCF-W, despite them being the same basic 500 cc engine. The Six Days just rips compared to the stock XCF-W. The snow bike conversion kit I used, removes the stock KTM induction airbox; gone are the reeds and air filter. In its place is a velocity stack and a loosely woven cloth bonnet cloth which isn't restrictive at all.

I contacted Taco Moto about getting an Athena Get ECU for the XCF-W and will order one shortly, and install it for next season, as it will reap the same power benefits as obtained on the Six Days.

The stock XCF-W tank is only about 2.4 gallons, so I've purchased a 4 gallon "Plan B" tank from C3 Powersports in Canada. The removable tank fits perfectly on top of the Yeti snow track, way forward to keep it near the CG of the bike. Very nice, quickly removable extra fuel solution.

Snow-biking is way easier than learning to do than it is to learn to carve turns in deep powder on a snowmobile. The learned motorcycling skills translate well from dirt/street to snow.

The snowbikes side-hill effortlessly, where keeping a sled traversing on a steep side hill is a major balancing effort that wears one out.

As they say - Ride On (And keep the shiny side up!)

 

[glock37]

When coming out of cut let saw return too idle for a few sec before shutting off
Saw remembers the last thing it did
If you shut it off right after full throttle your trying to start on full throttle

 

[singinwoodwackr]

Nice. I am aching to try out snow biking.

I use the Bill Dart rack which is the cheapest and most versatile. In Baja I instead use the rack to carry extra gas on the longer days. You can get the rack here:
https://billdarttrails.com/product/accessories/chainsaw-mount/
Here are the specs on how I mounted it:
https://www.thumpertalk.com/forums/...nsaw-carrier/?do=findComment&comment=15826614
I run a 28” bar because any bigger and I run the risk of it hitting the dirt when my front suspension bottoms out.

Ride on!

Ever think of adding a scabbard to that? I’ve adapted a small bungee to the scabbard to keep it tight regardless of position.

cool setup!

 

[singinwoodwackr]

In my limited experience with the 500i I’ve discovered that a basic muffler mod or adding the WCS or Egan plate opens the exhaust enough to greatly cool things down, even in 100* temps. I haven’t had an issue since.

 

[juanroberts]

Ever think of adding a scabbard to that? I’ve adapted a small bungee to the scabbard to keep it tight regardless of position.

cool setup!

I never have. I ride with a few riders that do and they love them. It would help keep dirt from clinging to the oiled chain. Somtimes branches grab a tooth and it rocks it into my fork, so its not a bad idea. And with the MS500, I have to be very careful when I load it so the chain’s teeth do not hit the rack because of the large 28” bar. A sheath would help with that. Can you post pictures of how you attached yours to the mount? One of my considerations is that sometimes I run a small saw, or no saw at all. So a large sheath would be too much on those days. By the way, I painted the airfilter cover on my MS201 white so you can hardly tell I have a saw when I ride with it as its mostly white now, like my bike.

Thanks.

 

[juanroberts]

In my limited experience with the 500i I’ve discovered that a basic muffler mod or adding the WCS or Evens plate opens the exhaust enough to greatly cool things down, even in 100* temps. I haven’t had an issue since.

That is good to know. I have not heard much about the Egan but it looks similar to the Bark Box. Then there is the Performance SS Dual Port Muffler Cover with tubes. This guy says the Bark Box was significantly louder, as in double ear protection loud, with no noticeable performance difference:

 

[singinwoodwackr]

I never have. I ride with a few riders that do and they love them. It would help keep dirt from clinging to the oiled chain. Somtimes branches grab a tooth and it rocks it into my fork, so its not a bad idea. And with the MS500, I have to be very careful when I load it so the chain’s teeth do not hit the rack because of the large 28” bar. A sheath would help with that. Can you post pictures of how you attached yours to the mount? One of my considerations is that sometimes I run a small saw, or no saw at all. So a large sheath would be too much on those days. By the way, I painted the airfilter cover on my MS201 white so you can hardly tell I have a saw when I ride with it as its mostly white now, like my bike.

Thanks.

This bungee is shot but you get the idea.
There are better scabbards out there; this is just a cheap plastic one.

 

[singinwoodwackr]

That is good to know. I have not heard much about the Egan but it looks similar to the Bark Box. Then there is the Performance SS Dual Port Muffler Cover with tubes. This guy says the Bark Box was significantly louder, as in double ear protection loud, with no noticeable performance difference:

O yea, it is way louder. I did a basic mod on my first 500 and it was a little louder but nothing like the bark box, lol
no idea on the Egan

 

[farmhard]

I was cutting at about 5700 ft, so over a mile high, but I don't know what difference the elevation would make in terms of hot start difficulties.

How is the computer adjusting the stochiometric ratio in these? Sounds like it's running hot with improper timing to me. What is the compression reading hot vs cold?