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Discussion Starter · #1 ·
Was out testing on the lake today for this first time with my sled since installing the 800 top end and having it dyno'd.


Seemed to be running pretty good....clutching off..BUT when running down the track you could hear it surging up and down. The farther you went (max 2000 feet) the slower the changes in sound got. (hard to explain) If you watched the tach could not see any variation. When riding the sled the surging was noticeable, but for the people standing beside as I went down they said they could hear it plain as day. The one thing is it seems to get better the farther ya hold WFO....possible not enough heat in the pipe????


Any suggestions ??
 

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Was out testing on the lake today for this first time with my sled since installing the 800 top end and having it dyno'd.
Seemed to be running pretty good....clutching off..BUT when running down the track you could hear it surging up and down. The farther you went (max 2000 feet) the slower the changes in sound got. (hard to explain) If you watched the tach could not see any variation. When riding the sled the surging was noticeable, but for the people standing beside as I went down they said they could hear it plain as day. The one thing is it seems to get better the farther ya hold WFO....possible not enough heat in the pipe????
Any suggestions ??[/b]
How's your circulation, coolant amount and water temp? You could have some air in your cooling system. Happened to me today, low coolant because we had the sled on it's side when I did the bearings. Took it out to do some runs and it was surging and running strange because it was getting hot. Check engine light came on. Added coolant checked circulation and presto back to normal. Just an idea for you. Which 8 kit did you put on?
 

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sounds like maybe fuel pressure not keeping up with engine?
do you have a gauge that you can monitor while riding?
 

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Discussion Starter · #4 ·
Coolant level and temp fine. Have a digatron with the coolant probe and everything there is where it should be. When it was on the dyno nothing strange showed up. Do not have a fuel pressure gauge but if that was the problem would think it would have shown up on the dyno. Seemed to be better when the pipe is hotter. I dunno just grasping at straws at this point. Have never experienced this before.
 

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what pipe are you using? i have a bikeman fat ass pipe and mine does the same thing until heat the pipe up and it goes away and runs great.


Was out testing on the lake today for this first time with my sled since installing the 800 top end and having it dyno'd.
Seemed to be running pretty good....clutching off..BUT when running down the track you could hear it surging up and down. The farther you went (max 2000 feet) the slower the changes in sound got. (hard to explain) If you watched the tach could not see any variation. When riding the sled the surging was noticeable, but for the people standing beside as I went down they said they could hear it plain as day. The one thing is it seems to get better the farther ya hold WFO....possible not enough heat in the pipe????
Any suggestions ??[/b]
 

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Discussion Starter · #6 ·
what pipe are you using? i have a bikeman fat ass pipe and mine does the same thing until heat the pipe up and it goes away and runs great.[/b]
I have the bikeman fat azz for the ported F7. So it sounds like it might be not enough heat in the pipe. I am wondering how to address this when I go to radar runs, where it is not an option to blast up the lake once or twice to get the pipe hot before doing the run. I don't think it would create enough heat warming it up on a stand. Maybe if a BMP rep is floating around you could chime in on this..
 

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Discussion Starter · #8 ·
get your pipe ceramic coated. that way it would hold heat in the pipe.[/b]

Just bought the pipe...guess maybe I should have got the ceramic version to begin with...can't really be without my pipe for another two weeks to send it out to be coated. Wish there was someone close here in ontario that could do it in a few days and I would consider it
 

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Just bought the pipe...guess maybe I should have got the ceramic version to begin with...can't really be without my pipe for another two weeks to send it out to be coated. Wish there was someone close here in ontario that could do it in a few days and I would consider it[/b]
Talk to Art before you run a coated pipe. He had issues with the ET9 (not sure on the 800) with the ceramic pipe as there was too much heat.....might not be the case with the 800 but worth a call.
 

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Discussion Starter · #10 ·
Talk to Art before you run a coated pipe. He had issues with the ET9 (not sure on the 800) with the ceramic pipe as there was too much heat.....might not be the case with the 800 but worth a call.[/b]
Ya I should. I had heard about those issues and thats why i went with the non-ceramic pipe in the first place. Still not 100% sure its the lack of heat in the pipe causing the surging...also not 100% if the surging is doing anything negative.
 

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to test the theory and get you by until you can get it coated, get some automotive header wrap and wrap the chamber with it.
this will be a cheaper, and less permenant way to try than getting it coated first.
 

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My friend said that his F was surging and the "surge" would change with engine Rpm and speed. After a little riding he said to try it out because it was really starting to piss him off. Before I rode the sled I put on his new spare belt and felt nothing. His belt the whole time. Can't say that this will fix you up but you two are using the same term--- "surge".

Flake
 

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Just bought the pipe...guess maybe I should have got the ceramic version to begin with...can't really be without my pipe for another two weeks to send it out to be coated. Wish there was someone close here in ontario that could do it in a few days and I would consider it[/b]
http://www.fireballcoatings.com/
don't know how long they would take but these guys are in southern ontario.
 

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to test the theory and get you by until you can get it coated, get some automotive header wrap and wrap the chamber with it.
this will be a cheaper, and less permenant way to try than getting it coated first.[/b]
Good idea. IMO I would not use it as a permanent fix, moisture can get in between the pipe and wrap and make is rust!
 

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You are running the Ported F7 pipe on a 800 Big Bore?????? Who's big bore? The F7 pipe is too tight for the 800 and 900 motors!!!If I read that wrong, and your sled is "cavitating" and not pulling rpm's then it sounds like it's too rich and you could lean it down a few #'s on the Boondocker...otherwise get the right pipe.
 

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Discussion Starter · #18 ·
You are running the Ported F7 pipe on a 800 Big Bore?????? Who's big bore? The F7 pipe is too tight for the 800 and 900 motors!!!If I read that wrong, and your sled is "cavitating" and not pulling rpm's then it sounds like it's too rich and you could lean it down a few #'s on the Boondocker...otherwise get the right pipe.[/b]
I tuned on dynotech's dyno with the ported F7 fat azz pipe. All was great at the dyno. So thats why I specifically got the ported F7 version and not the F8/F9 pipe. I am pulling rpms no problem...actually over reving..but thats just clutching that I have to figure out. While on the dyno we did some long 14 sec+ runs and according to Jim that pipe showed no signs of being too tight for my motor. CFM was right in line where it should be. I do have access to the F8/F9 pipe that I could put on...but after dyno tuning to good fuel management...seems like a step backwards to change pipes and start guessing again.
 

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700saber, if it is indeed your pipe that isn't getting hot enough, you could try getting one of those buttons off a 440 to let the pipe get hot, might help you for radar running...
 
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