14:1 Venom wont start

[IMSROLL450R]

I am having a friend put a piston in my bike and after everything was done it wont start. I has an HMF slip on, HRC kit, and now the new piston. What should the jetting be? Any other things to look at??????

[chad502ex]

around 185 main.

i'd bet your decomp. is not set correctly.

good luck.

[IMSROLL450R]

Originally posted by chad502ex
around 185 main.

i'd bet your decomp. is not set correctly.

good luck.

A fellow you may know by the name of CHINO is doin it for me and we couldnt get it to run last night. He knows a whole lot more about it than me as he has done it to his bike a couple of times so I just probably get in his way. Hopefully we can figure it out I really want to see what this VENOM will do!!!!!!

[IMSROLL450R]

the bike is an 06 by the way......

[chad502ex]

Originally posted by IMSROLL450R
the bike is an 06 by the way......

oh ok, yea Chino...

well let us know when all is alright

[IMSROLL450R]

He worked on it for 8 hours yesterday and still no fire. We are gonna put a new plug in it tonight and if it still doesnt fire I dunno what to do. It doesnt even try to run as it is now.

[Chino886]

Yep, put 8 hrs in on a bike and it did not want to fire, but plug is old.

I took the top end apart, rechecked everything, then put it back together.

I adjusted the valve clearances, the intake valves were so tight I coud not get the smallest feeler guage in there. It now has a 1.30mm shim in both intakes............the smallest one in the HotCams shim kit is 1.20. The ones I took out were 1.68 mm.

I am going to check the plug for spark tonight with a new plug! I will also do a compression check again!

I rebuilt my complete motor the second time in less than 8 hrs............
:mad: :grr:

[IMSROLL450R]

Originally posted by Chino886
Yep, put 8 hrs in on a bike and it did not want to fire, but plug is old.

I took the top end apart, rechecked everything, then put it back together.

I adjusted the valve clearances, the intake valves were so tight I coud not get the smallest feeler guage in there. It now has a 1.30mm shim in both intakes............the smallest one in the HotCams shim kit is 1.20. The ones I took out were 1.68 mm.

I am going to check the plug for spark tonight with a new plug! I will also do a compression check again!

I rebuilt my complete motor the second time in less than 8 hrs............
:mad: :grr:


I smell a challenge.............

[Chino886]

Originally posted by IMSROLL450R
I smell a challenge.............

Or a bonfire! :devil:

[sandmanblue]

Originally posted by IMSROLL450R
I am having a friend put a piston in my bike and after everything was done it wont start. I has an HMF slip on, HRC kit, and now the new piston. What should the jetting be? Any other things to look at??????

First off a 185 main is WAYYY too rich - Try a 175 max. The other HRC jets should be fine, but you might want to richen the fuel screw a bit. Also, turn up your idle to help start it.

You should be setting the decompressor by compression testing, not clearance. Set it so that you get about 65 - 70 psi with the throttle all the way open when cranking.

Having to change the shims that much concerns me. If you have the same cam in there and all you did was put in a different piston, something is not right. Are you sure the cam timing is okay?

Also - what is it doing? Cranking fine but not lighting up? How long has it been sitting, what about the fuel? Spark? Leaks around the carb/intake/head?

[Chino886]

Originally posted by sandmanblue
First off a 185 main is WAYYY too rich - Try a 175 max. The other HRC jets should be fine, but you might want to richen the fuel screw a bit. Also, turn up your idle to help start it.

You should be setting the decompressor by compression testing, not clearance. Set it so that you get about 65 - 70 psi with the throttle all the way open when cranking.

Having to change the shims that much concerns me. If you have the same cam in there and all you did was put in a different piston, something is not right. Are you sure the cam timing is okay?

Also - what is it doing? Cranking fine but not lighting up? How long has it been sitting, what about the fuel? Spark? Leaks around the carb/intake/head?

Yeah, I think the valves were way out of wack to begin with. It concerns me to. The Decompressor is being set with the compression guage. The fuel is fresh, I have my 06 running on the same batch of gas. I am going to start trouble shooting this bizniggle tonight as I have spent way more time on it then I should have.

My bike is gettting pretty ticked off at me, as is the Mr. 50!

[speedfreaksguy]

Sounds like the intake valves are wasted. You can shim them to get it fired up but they will need to be replaces or they will tighten up again, FAST. I am assuming this is an 06 or 07 with stock junk ti valves. I see it happen with the bike motors all the time.

Chino, you really need to check lash and record it before you tear any motor down. That way changes can be made before putting everything back together. In this case, you could have pulled the valves while you had the head off.

[Chino886]

Originally posted by speedfreaksguy
Sounds like the intake valves are wasted. You can shim them to get it fired up but they will need to be replaces or they will tighten up again, FAST. I am assuming this is an 06 or 07 with stock junk ti valves. I see it happen with the bike motors all the time.

Chino, you really need to check lash and record it before you tear any motor down. That way changes can be made before putting everything back together. In this case, you could have pulled the valves while you had the head off.


Thanks for the reply!

I tried to check the IN valve lash, but I could not reach the smallest feeler in there. I will mess with it some more tonight.

I am thinking that the IN valves are not sealing properly after I pulled them.

[Chino886]

Well some more fun tonight!

I checked for spark, it was good!

I checked to make sure pilot circuit was good! The pilot was a 42 pilot (it was supposed to be the HRC pilot).

I pulled the head off when I could only get it to attempt to start and I think the intake valves may be the problem, what do you guys think!

http://i138.photobucket.com/albums/q272/chino886/DSC00596.jpg

http://i138.photobucket.com/albums/q272/chino886/DSC00598.jpg

http://i138.photobucket.com/albums/q272/chino886/DSC00597.jpg

http://i138.photobucket.com/albums/q272/chino886/DSC00595.jpg

[IMSROLL450R]

What a turd. Im gonna owe Dave about 50 hours worth of work.

[speedfreaksguy]

Were you having any issues before it was torn down (hard to start)?. Was anything else changed besides the new piston??

It's hard to tell the condition of the valves from your pictures. I would guess that the intakes are hammered because of the .00 lash. You need to pull the valves and inspect.

You really need to replace the valvetrain components at the same interval as the piston (considering all stock components). At least, you should replace the valve springs (in. $8ea and ex. $5ea) especially when racing and running an aggresive cam profile.

[Chino886]

Originally posted by speedfreaksguy
Were you having any issues before it was torn down (hard to start)?. Was anything else changed besides the new piston??

It's hard to tell the condition of the valves from your pictures. I would guess that the intakes are hammered because of the .00 lash. You need to pull the valves and inspect.

You really need to replace the valvetrain components at the same interval as the piston (considering all stock components). At least, you should replace the valve springs (in. $8ea and ex. $5ea) especially when racing and running an aggresive cam profile.

IMSROLL450R could answer the question about starting better. When I pulled the head off, there were substantial deposits on the piston (sand, grit, etc). Upon have the head off, I shot some brake cleaner around the combustion chamber, which cleaned it up to where it is now, I am assuming that there were substantial deposits in the valve contact area.

I will be pulling the valves out tonight and take more pics. All components in the head are stock. He did note that before tear down he thought it was running good............

He is running the HRC cam, the stock piston. I think we could solve the problem with new valves, springs, and a valve job! Once that is done, one kick and vrooom!

:devil:

[IMSROLL450R]

Originally posted by speedfreaksguy
Were you having any issues before it was torn down (hard to start)?. Was anything else changed besides the new piston??

It's hard to tell the condition of the valves from your pictures. I would guess that the intakes are hammered because of the .00 lash. You need to pull the valves and inspect.

You really need to replace the valvetrain components at the same interval as the piston (considering all stock components). At least, you should replace the valve springs (in. $8ea and ex. $5ea) especially when racing and running an aggresive cam profile.

The bike ran fine before we did all this. I never really had a problem starting it except maybe when it was really hot it took a couple kicks. I would probably say that it does need new valves but hopefully we can use the stock springs again as its gonna get more expensive than I had hoped for the piston swap.

[chad502ex]

is this running now?:confused:

[Chino886]

Originally posted by chad502ex
is this running now?:confused:

No, the head is going to get inspected for valve seat damage and wear.

I did not have the time to take the valves out.

Can the valves be cupped and not leaking?

[chad502ex]

Originally posted by Chino886
No, the head is going to get inspected for valve seat damage and wear.

I did not have the time to take the valves out.

Can the valves be cupped and not leaking?

sure..

[Chino886]

Originally posted by chad502ex
sure..

and would the cupped vavles affect performance?

[IMSROLL450R]

I really hope this head work is what it needs. Im really excited about seein what this Venom will do.

[chad502ex]

Originally posted by Chino886
and would the cupped vavles affect performance?

absolutely, especially below 0.25D of the valve where low lift flow occurs twice in the lift cycle for curtain development.

this is not the reasoning why the engine will not start imo.

[IMSROLL450R]

Originally posted by chad502ex
absolutely, especially below 0.25D of the valve where low lift flow occurs twice in the lift cycle for curtain development.

this is not the reasoning why the engine will not start imo.

I have no idea what you just said.:)