Jump to content
Sign in to follow this  

No bottom end after new valves and high comp piston

Recommended Posts

Guys,

Some of you already know that I recently had new Ferrera Valves and a JE 13:5:1 piston installed in my 2004 CRF450R. The bike is running like a monster on the top end, but my bottom end is suckin terrible.

My current jetting is 158 MJ, 42 PJ, stock needle in 2nd clip, RedBeard AP Mod. I have a Dr. D full pipe too. Moving the needle clip from the 3rd to the 2nd clip seemed to make it better that last time I was fiddling with it.

The problem I have is, I used to pull 3rd gear through a lot of turns on our local tracks and get great drive and response from the motor. This is effectively running a gear tall on purpose, which I never had a problem with. The bike doesn't bog, it just seems slowly to rev up, then the power snaps on hard -- almost like a 2-stroke does.

Any ideas?

ben

Share this post


Link to post
Share on other sites
Guys,

Some of you already know that I recently had new Ferrera Valves and a JE 13:5:1 piston installed in my 2004 CRF450R. The bike is running like a monster on the top end, but my bottom end is suckin terrible.

My current jetting is 158 MJ, 42 PJ, stock needle in 2nd clip, RedBeard AP Mod. I have a Dr. D full pipe too. Moving the needle clip from the 3rd to the 2nd clip seemed to make it better that last time I was fiddling with it.

The problem I have is, I used to pull 3rd gear through a lot of turns on our local tracks and get great drive and response from the motor. This is effectively running a gear tall on purpose, which I never had a problem with. The bike doesn't bog, it just seems slowly to rev up, then the power snaps on hard -- almost like a 2-stroke does.

Any ideas?

ben

Hi Ben , i did not ever like the drd pipe for the type of power it made ,---but however --you liked it before so ---i would have to question your jetting ,

i assume you are running 91 pump ----most of the main jets i have been ending up with lately on the r's on pump have been 162 165 now with our weather ,

and i generally use 3rd or 4th clip on that 04 needle ,----

i could be wrong but it seems alittle two lean,----

do you have an area where you can get it pinned in 5th and start going up on the main and notice the improvement ?

GUY at canyon lets me use the sand drag strip at the car track for jetting runs and you can get the correct main and needle clip rather quickly with 10 15 runs .

but that thing now with a fresh top end should be great coming off the corners ,

---where are you riding this weekend ?

Share this post


Link to post
Share on other sites

Hey Kelstr,

Thanks for replying so quickly. My plan is to ride COP on Sunday morning. It would be real cool if you could spare a few minutes to help me out.

I'm going to bring out the stock exhaust too and maybe give that a try now again. It should be mentioned that I got the Dr. D back when I was new to the 450 and my riding was fast beginner level at best. I'm at least a fast novice now, if not a slow intermediate. So I may have out grown the Dr. D, and I'm willing to submit if that is the case.

ben

Share this post


Link to post
Share on other sites

Checking the timing is easy enough. I'll do that on Saturday while I'm changing the oil and cleaning the bike up. I was real careful when putting the bike back together. I even made sure the arrow on the crank was lining up perfectly with the arrow on the case before throwing the cam back in. So I'm not sure that is it or not. Worth checking for sure because of the other symptom I'm experiencing....

The other thing the bike is doing right now is it is hard to start when I first get to the track. It will kick over fine, and fire up within the first few kicks, but it is rough to idle and wants to die. After the bike is warmed up, it runs fine though and kicks over perfectly. (although I used to be able to start it in gear and now I have to put it in neutral).

ben

Share this post


Link to post
Share on other sites

That bike should scream now with that piston, bottom, mid, and top! Like Burned said, check your timing, you'll probably find it's off by one tooth. Even if it looks like it's dead on, move it one tooth one way and try it. If problem gets worse move it the other way one tooth.

Share this post


Link to post
Share on other sites

Sounds like the cam timing is retarded by one tooth.

Share this post


Link to post
Share on other sites
Sounds like the cam timing is retarded by one tooth.

I really hope it is that simple. Hopefully I can hook up with Kelstr and get it sorted out this weekend.

ben

Share this post


Link to post
Share on other sites

Sounds like the cam timing may be retarded by a tooth. I can't remember what jetting we had in the bike before you did the top end, but that Dr. D generally needs a pretty lean main jet to run well. I'm going to SW Saturday night so I won't be able to help you on Sunday. Did you put a new cam chain in when you did the top end?

I would try advancing the cam one tooth even if it looks right. After you advance the cam a tooth, turn the motor over slowly to make sure that things aren't ramming into eachother and start it up.

Share this post


Link to post
Share on other sites
Hey Kelstr,

I'm going to bring out the stock exhaust too and maybe give that a try now again. It should be mentioned that I got the Dr. D back when I was new to the 450 and my riding was fast beginner level at best. I'm at least a fast novice now, if not a slow intermediate. So I may have out grown the Dr. D, and I'm willing to submit if that is the case.

ben

If you didn't have the same issue right before the rebuild, I doubt you have "outgrown" the Dr D. Like others, my guess is that your cam is off by a tooth. However, you might also check to make sure that your hot start isn't sticking a bit, I found mine doing that this past weekend after I stalled it and used it to get going again :ride: If it's sticking, I can see where it may make it a bit difficult to start when cold and I would think it would hamper the bottom end a bit due to it running leaner than normal, just a thought :thumbsup:

Share this post


Link to post
Share on other sites

I cleaned the carb thoroughly before putting the bike back together. I did remove the hot start too. I'll check it, but I don't think it is sticking. You are right about that maybe being an issue.

ben

Share this post


Link to post
Share on other sites

after listening to your other complaints on hard starting , rough idle and all i would half to agree with these guys and say you really do need to quickly check you cam timing,----ill bet its off a tooth just like they say :applause:

i am going to caynon for sure on sat and i am going to try and make the old lady stay for sunday and not go to speedworld ,

she thinks she rides speedworld better and she just does not ,

so you and i can hook up and see whats going on :thumbsup:

but Check your timing real quick if you have time, --if not we can correct it at the track if need be :ride:

Share this post


Link to post
Share on other sites

I'll tear it down on Saturday morning and check it. I hope to see you on Sunday regardless.

ben

Share this post


Link to post
Share on other sites
double check your cam timing.

this is right for sure. its what i had happen. DON'T USE THE MARKS ON THE RIGHT SIDE OF THE MOTOR FOR CAM TIMING!!!!!!! The flywheel is easier, better, but a bit messy. Make sure to apply pressure on the chain tensioner after you adjust it to see where the arrows are

Share this post


Link to post
Share on other sites

Does anyone think I may have done some harm to the motor or valves runnning the bike like this?

ben

Share this post


Link to post
Share on other sites
Does anyone think I may have done some harm to the motor or valves runnning the bike like this?

ben

If it still runs you are fine. The only thing that could go bad is if you send a valve into the piston. If it's still running then that didn't happen so you are golden.

Share this post


Link to post
Share on other sites
If it still runs you are fine. The only thing that could go bad is if you send a valve into the piston. If it's still running then that didn't happen so you are golden.

Word! :thumbsup:

Share this post


Link to post
Share on other sites

Hey Ben, ---i tried to tell the old lady that we were staying at canyon for both days and she started yelling at me --( which she does all the time anyway :applause::applause: )-----

so i might be at speedworld on sunday---(hopefully not )

but speedworld is only 8 miles from canyon anyway,----but just give me a call saturday afternoon ( 480-926-1984 ) my cell works at the track--kinda ----and lets make sure we meet up at the correct track :thumbsup:

i am still hopeing to stay at canyon !! :ride:

Share this post


Link to post
Share on other sites

I'll be working on the bike Saturday. I want to work on it in the morning while it is still cool outside. Plus I need to help a friend work on his bike as well.

COP is a pretty sure thing for me on Sunday. I have other friends coming as well.

I'll give you a call on Saturday to let you know how it went and if I was able to get it working right.

ben

Share this post


Link to post
Share on other sites

Ok, got the motor apart this morning to check the timing and the valve clearance. Timing was off by one tooth.

I also found that my intake valves are already tightening up.

Left measured .003

Right measured .004

I've got a friend picking up the correct shims for me this morning and I'll button it up hopefully before lunch.

Should I expect new valves to break in and tighten up a bit like this, then not tighten up for some time?

ben

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  

×