Jump to content
Sign in to follow this  

2011- Stalls after full throttle

Recommended Posts

Just finished rebuilding the top end. Replaced OE piston with 13.8 : 1 Vertex and replaced valve seals and springs with new spring seats, retainers and collets. Everything assembled by the manual with proper torque specs, cams timed, etc.

 

I started it and let it warm up before riding it and everything sounded good.

Bike starts and runs smooth but it will sputter and stall after a full throttle run as if it is running out of fuel. It will start right up immediately after and will not have any problems riding around easy at partial throttle.

 

I installed a Vortex ignition a couple of weeks ago at the same time I installed a Rekluse and I tried it out a couple of times before starting the top end rebuild and it all worked fine. I used it on the all around power setting since the engine was stock. I started the bike today on map 4, torque setting high comp, and then tried map 5 to see if that helped but still have the same problem.

 

checked all connections and fuel line and everything appears to be good. I wanted to spend some more time on it but it started raining so I'm taking a break. I figured it would help to get some ideas from you all before just going in circles and getting aggravated.

 

Thanks in advance.

 

Share this post


Link to post
Share on other sites

The rmz250 motors don't get along well with hc pistons. Are you running race fuel? Could be too rich also. If it is humid or raining it can create a rich condition. I have had that happen before at speed with high rpm. Try more air or turn up idle. Those are my thoughts.

Edited by perkybewbs
  • Like 1

Share this post


Link to post
Share on other sites

I agree with the perkster.. I installed a HCP on my 2013, had to take it out 13 hrs in.. it was making nasty clacking sounds. Thought the motor was gonna grenade

Share this post


Link to post
Share on other sites

I didn't get to mess with it today but I have nothing planned for tomorrow morning and I will try adjusting the fuel a little. I was a little hesitant to try the HC but I figured if it was set up right with a good map it would work out. Hopefully I don't end up regretting that and wish I just got the 270 kit. 

 

The weird part is that it runs smooth with good power while accelerating. It doesn't start to cut out and stall until I let off. I went through all 5 gears WOT and it didn't start to sputter until I let off. Then it won't come back to normal until I shut it down or it stalls then I restart it. I can keep it running with working the throttle back and forth but it wants to stall. 

 

There is no noticeable drag or weird sounds at all. 

 

Thanks again for the replies and I'll post up what I figure out if I get it to work right. 

Share this post


Link to post
Share on other sites

Yeah if you're going to run mod run the big bore or cams or both + port cleanup. I've heard through the grapevine that they don't like high compression and it was verified by jay clark on a racer x tested video. They did a comparison of a hc and standard compression rmz build. High compression pistons don't last very long either maybe 20 hrs if your lucky. Cams are a good way to get more hit off the bottom but your motor will sound like a model T engine or in other words rattling a pile of shit.Try running some u4 or something oxygenated and maybe lean it out a little bit. Otherwise I would probably swap it out. I don't like the rattling sound personally.

Edited by perkybewbs
  • Like 1

Share this post


Link to post
Share on other sites

Like I stated earlier, I installed a HCP in my 2013 and it only lasted about 13hrs then it started making some crazy top end noises.. I was so worried to even start my bike.. went to a wiseco oem compression piston and BAM back to normal

Share this post


Link to post
Share on other sites

Like I stated earlier, I installed a HCP in my 2013 and it only lasted about 13hrs then it started making some crazy top end noises.. I was so worried to even start my bike.. went to a wiseco oem compression piston and BAM back to normal

I'll definitely keep a close eye on it and swap it out way sooner than I did the stock piston and Ill go back to stock compression. I planned on having the head work done at the next piston change, port, new valves, etc. and ill use a standard comp piston. I've heard about Fast heads. Anyone else I should check out for getting the head rebuilt with new seats, valves, and porting?

 

Thanks for the replies.

Edited by JohnnyB24

Share this post


Link to post
Share on other sites

Well its still a mystery to me as to why the bike was cutting out but I started out this morning by removing the tank and double checking all the electrical conections and fuel line connections. I had already applied dielectric grease before but went ahead and added more before putting connectors back together. All connections were clean and appeared to be normal so I put it all back together and started it up, stuck a screw driver in my pocket and went down the road figuring I was going to have to make some fuel adjustments. Well, the bike ran perfectly and I couldn't get the issue to replicate itself even once. Go figure.

 

Hopefully it isn't a intermittent problem that will pop up again next time I drive out to the track. 

Share this post


Link to post
Share on other sites

Yeah if you're going to run mod run the big bore or cams or both + port cleanup. I've heard through the grapevine that they don't like high compression and it was verified by jay clark on a racer x tested video. They did a comparison of a hc and standard compression rmz build. High compression pistons don't last very long either maybe 20 hrs if your lucky. Cams are a good way to get more hit off the bottom but your motor will sound like a model T engine or in other words rattling a pile of shit.Try running some u4 or something oxygenated and maybe lean it out a little bit. Otherwise I would probably swap it out. I don't like the rattling sound personally.

 I thought about doing the stage 1 cams but that is the first time I have heard that it will make the engine sound like it is falling apart.

Edited by JohnnyB24

Share this post


Link to post
Share on other sites

I had all my head work done by John stallworth at JsrPerformance in witchita Ks. He has built 5 of my motors already. They are so fast and smooth power. Everything he does in InHouse. From replating to full transmission treatments.

Share this post


Link to post
Share on other sites

Yeah it's like when you put a cam in a car. It will make the motor in the car motor sound differently. I have never ridden a bike with a cam but have heard a few running. Maybe a stage 1 would be alright. They just sound super loose rattling like that, like your valves are out of spec or something or a high hour motor. That's a personal thing maybe wouldn't bother you. I hate to be a douche but I've heard tons of people say seat time is the best mod. With the big bore you might lose top end. Every mod will give you something and detract another. Cams will also only give you a bottom end hit. 250s are kind of slow but If you push them hard you can go fast. The right exhaust system will give you more top end power. Not sure what else you could do to get more. I don't really care about bottom end hit too much on a 250..

Share this post


Link to post
Share on other sites

Yeah I hear you about seat time. I've been trying to put in as much as possible and invested time and money into lessons and it's payed off. I have a lot more control than I ever had.

I felt It was time for a top end refresh so I figured why not go for a little extra power. The bike is fast enough in most cases just a couple of jumps that I felt a little extra boost would give me a better launch and easier to clear certain jumps. You know, out of a turn and up hill. I was having to hit it with everything I could get out of third and loading the suspension on the face and still barely making it.

Probably doesn't help that I'm 180 without gear. I've even transitioned from lifting heavy to light weight workouts and a ton of cardio. Even when I lean out I'm still close to 180. But anyway like I said the 250 is fast enough probably 99% of the time and definitely still has more speed potential than I'm capable of in most situations.

Share this post


Link to post
Share on other sites

Yeah I hear you about seat time. I've been trying to put in as much as possible and invested time and money into lessons and it's payed off. I have a lot more control than I ever had.

I felt It was time for a top end refresh so I figured why not go for a little extra power. The bike is fast enough in most cases just a couple of jumps that I felt a little extra boost would give me a better launch and easier to clear certain jumps. You know, out of a turn and up hill. I was having to hit it with everything I could get out of third and loading the suspension on the face and still barely making it.

Probably doesn't help that I'm 180 without gear. I've even transitioned from lifting heavy to light weight workouts and a ton of cardio. Even when I lean out I'm still close to 180. But anyway like I said the 250 is fast enough probably 99% of the time and definitely still has more speed potential than I'm capable of in most situations.

For sure, sounds like you did need a little bit of low end hit. Hope that hc piston works out. I would try using c12 or u4 something like that. I hate when people tell me that on here it comes across douchey. I don't need anyone on the internet to tell me to get seat time haha. Were all doing this for fun considering 99% of us will never be champions. But yeah man I put the full ti yoshimura system on mine and it's pretty awesome on top. It makes the bike totally different. Now it's awesome. I don't really dig the headshake though. As far as mods go, port polish/clean up is good to go too and a ecu or remap system like the PIM 2 or the power commander box other dudes are running here. Ac717 runs one and he says it's pretty awesome. Unfortunately I haven't had the cash to get one yet. Good luck man.

Share this post


Link to post
Share on other sites

 I hate when people tell me that on here it comes across douchey. I don't need anyone on the internet to tell me to get seat time haha. .

Haha no worries man. It's sound advice to give even if it sounds like a default cop out. I know there are a lot of people who just want their bike to be faster than their buddies bike even though they overlook how much speed they will gain with good form and suspension tuning and practice, practice, practice.

 

I'm not usually big on modding out engines but I did get an exhaust pretty early on with this bike because it just felt and sounded so choked up. I got the mega bomb and RCT 4.1 and I feel like it did more for the bottom and mid range but its been so long since I rode the stock exhaust so who knows.

 

I did spend some cash last summer on getting the suspension re-valved and it was night and day difference.

The head shake is not as bad now but still there sometimes. I also did the old poor mans stabilizer trick by tightening down the steering stem a little more and I think that helps too. I read that in MXA. I just keep an eye on the bearings and so far no issues, I usually check them and add a little grease whenever I take off the forks. 

 

I just got the Vortex ignition so I'll have to play with it a little. I wanted something that I could adjust as I did more mods to the engine so I wouldn't have to get the stock ECU reprogrammed every time. I did find a reprogrammer for the stock ECU but it was almost as much as the Vortex anyway.

Share this post


Link to post
Share on other sites

Haha no worries man. It's sound advice to give even if it sounds like a default cop out. I know there are a lot of people who just want their bike to be faster than their buddies bike even though they overlook how much speed they will gain with good form and suspension tuning and practice, practice, practice.

I'm not usually big on modding out engines but I did get an exhaust pretty early on with this bike because it just felt and sounded so choked up. I got the mega bomb and RCT 4.1 and I feel like it did more for the bottom and mid range but its been so long since I rode the stock exhaust so who knows.

I did spend some cash last summer on getting the suspension re-valved and it was night and day difference.

The head shake is not as bad now but still there sometimes. I also did the old poor mans stabilizer trick by tightening down the steering stem a little more and I think that helps too. I read that in MXA. I just keep an eye on the bearings and so far no issues, I usually check them and add a little grease whenever I take off the forks.

I just got the Vortex ignition so I'll have to play with it a little. I wanted something that I could adjust as I did more mods to the engine so I wouldn't have to get the stock ECU reprogrammed every time. I did find a reprogrammer for the stock ECU but it was almost as much as the Vortex

anyway.

I had that done with my suspension and it's still pretty wobbly but I can't complain too much. It's a trade off..if you want to turn you shake going straight and if you want to go straight you can't turn. It's a good bike. Pretty close to perfection with a couple of minor add ons. I could've bought one of those grenades, I mean Hondas. Yikes.

  • 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:

Sign in to follow this  

×