Jump to content

Built RFS 570 won't cold start?

Recommended Posts

Any and all help will greatly be appreciated.I've got a thumper racing build 570 Big Bore Stage 5 cam,portedhead,oversized valves,overbored carb,dual spray  AP, jetting is close, a little rich. 15 hours run time on it. The problem is it will not cold start it turns over slow like the battery is weak sometimes it won't rotate past compression stroke. I'm on my second battery which is WPS lithium 180 CCA battery I'm on my second new starter my valves are adjusted correctly, once I get it started and it runs for even one minute I can turn it off and on 15 times it will always and very easily start if just slightly warm or hot but never cold. I'm dumbfounded.... I can't figure out why it's doing it maybe I need a good high torque starter I will appreciate any help thanks.

Edited by Jay Smith
I left something out

Share this post


Link to post
Share on other sites

What’s your jetting. Have you tried upping the pilot?
What pipe are you running? Any other mods to the bike?

Share this post


Link to post
Share on other sites

I would suspect the starter is not up to the task of starting your high compression big bore.  It probably doesn’t turn the engine over quick enough when cold to start.  I would just get used to kickstarting it for the first start of the day.  Also, perhaps your new cam is not set up for the auto decompression feature, which would make the starter struggle.

Share this post


Link to post
Share on other sites

I cannot remember my jetting right now I have stock header with HMF slip-on the Stage 5 cam does have the correct Auto decompression mechanism I tore the engine apart yesterday to inspect it and I'm pretty sure that it is functioning correctly I am currently looking into having a custom starter built maybe I just happened to have gotten two-week starters also full disclosure I've been reading this form for years this is my first time posting I wasn't sure if I done it right my machine is not a bike it's an 07 Outlaw 525 IRS

Share this post


Link to post
Share on other sites

I agree the high compression may be over taxing everything, have you tried kickstarting along with starter on a cold start. The starter has only so much output no matter how big of battery you go.

Share this post


Link to post
Share on other sites

I'm starting to think I should replace the starter one more time. But I've never heard of a starter going bad that it won't cold start a motor but it'll easily and reliably start it when it's slightly warm. don't think the compression has anything to do with it the auto decompression should resolve that issue I know there are a lot of guys that run 14 to 1 compression or more and don't have problems with OEM starters I'm at 12.5 to 1so i dont need race fuel.my ATV does not have kick start only E start I even made my own thicker gauge power wire thinking the factory might be too small and not allowing enough amperage to the starter I haven't been able to speak with Travis from Thumper racing he has recently had a few surgeries so understandably I haven't had any luck there I really appreciate the help by the way

Edited by Jay Smith

Share this post


Link to post
Share on other sites

OK., I have an 08 outlaw 525 S, Check your spark plug. What color is it? Color can tell you if you're jetted correctly. Mine was really rich with my yosh slip on so I had to change my pilot. The FMF slip on will let it breather better. The stock one is pretty corked up. Is your air filter stock? I know lots of questions. Just trying to help. Here is a write up on a outlaw from polaris riders

https://www.polarisriders.com/132-outlaw-general/25301-525-outlaw-hi-comp-head-cam-build-56k-beware.html

Edited by KTMForecon

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:


×