Jump to content

'16 Sxf 350 spluttering when hot

Recommended Posts

Anyone heard of this problem before?

 

10-15 mins into a race it'll start bogging and spluttering when revs are fairly high, only doing it when it's hot hot.

 

Just had new piston fitted and valves are spot on, fuels all fresh and good, not sure if it could be blocked injector? But thinking it'd splutter straight out the gate

 

Thanks

Share this post


Link to post
Share on other sites

What coolant are you using? It may be getting so heat soaked that it's bogging because it's so hot. Does it boil over? 

it could be an injector problem but i've never heard of problems with it on the 16's. 

 

Does it do it when the bike is cooler? or just when it's in the trail getting hot? 

Share this post


Link to post
Share on other sites

Could be boiling gas.

My 16 FE 450 has problems with gas in the tank boiling when the bike gets hot.  It's very concerning and the bike runs like crap in this mode. 

You may want to remove the gas cap (very slowly) next time this happens and take a peak.

Replace the gas cap vent tube with a clear plastic tube and you may see gas boiling up into the tube.

Do not replace the stock vent tube with a one way vent valve - my tank almost blew up like that (it was epoxied on).

Boiling gas causes problems with the fuel pump and everything else downstream.

Please do report back if / when you get this figured out.

B

  • Like 1

Share this post


Link to post
Share on other sites
34 minutes ago, SafetyMeet said:

Could be boiling gas.

My 16 FE 450 has problems with gas in the tank boiling when the bike gets hot.  It's very concerning and the bike runs like crap in this mode. 

You may want to remove the gas cap (very slowly) next time this happens and take a peak.

Replace the gas cap vent tube with a clear plastic tube and you may see gas boiling up into the tube.

Do not replace the stock vent tube with a one way vent valve - my tank almost blew up like that (it was epoxied on).

Boiling gas causes problems with the fuel pump and everything else downstream.

Please do report back if / when you get this figured out.

B

I remember hearing about that problem with the old rfs motors, It happened on your 450? what were you doing when it happened? Sounds scary :/

Share this post


Link to post
Share on other sites

Riding in utah desert single track about 85 F, slow hard terrain, lots of clutch, stopping frequently to ride my buddies bikes over obstacles.  Shorty vent tube with one way valve blew off and gas sprayed like a geyser for several minutes .  You could see the tank pulsating as it absorbed heat and released pressure (this was with the IMS 3.1 tank).  We were able to get off the single track and return to camp on dirt road, so it was ok after that.

It had the EU map with TPS set appropriately when this happened. 

Since then I reverted to stock tank, shielded tank with DEI heat tape, t-stat delete host kit, manipulated the radiator louvres to force more air through the radiators.

the bike still gets hotter than I think it should but I have not boiled gas again.

  • Like 1

Share this post


Link to post
Share on other sites

Thanks for replys guys this 350 is so frustrating seems to be a different problem every week at the moment!! I'm running a shorty one way vent cap, it's been on for about 20 hours though? Il get some clear hose for this weekend and see what's going on.

I'm in the uk so it's eu bike and the outdoor temp about 70.

Runs perfect then it's like a switch goes and then bam different bike lol

Share this post


Link to post
Share on other sites
What coolant are you using? It may be getting so heat soaked that it's bogging because it's so hot. Does it boil over? 
it could be an injector problem but i've never heard of problems with it on the 16's. 
 
Does it do it when the bike is cooler? or just when it's in the trail getting hot? 

Putolene coolant mate just had fresh put in! Not using any at all and no not boiling over.

Starts doing it about 3/4 into a 20 minute moto

I thought injectors but surely it'd be missing straight out the gate not when it's warm :/

Don't know if this is relevant but had a brand new sticker on my ti 6 silencer and it totally melted it turning it black, so seems it's running too hot?

Share this post


Link to post
Share on other sites

Just ordered a fuel filter for it see if that sorts it out!! Bikes 30 hours old and it's not been changed yet oops!!

Share this post


Link to post
Share on other sites

Are you getting a flash code at the fi light?

Just thinking/guessing that one of the sensors might not be connected or bad?

Share this post


Link to post
Share on other sites

Nope all good! Checked the connectors and wd'd them but still doing it, il put 2 way breather back on and change fuel filter and hopefully she'll be good! Be chopping her in for a yam next week if not hahahha

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×