Engine Help

[450Rfutureracer]

Ok everybody I have been having a rough time with my 06 ER lately, I adjusted the valves and got everything running fine then went out to Sunday Creek to race and the quad was running great till Sunday and it started to be hard to start, I went out to practice and couldn't get it to start unless pulled (new battery this year also) so I brought it home and tore it down and started running through and found out that was only running 30 psi compression with the decompressor arm all the way off, so I ordered a new top end kit from Wiseco with a 13.5:1 piston and just installed it today and still can't get it to start, checked compression and only got 5 psi with decompressor arm at spec, so we started checking valves and they were tried getting them into spec, exhaust ones dead on but the intake we couldn't get right, used the smallest shim from Hot Cams (1.20) and couldn't get the feelers in. So were thinking the valves are done. Also don't know if you need to change jetting for high compression. If anyone can comfirm this or provide any help I would greatly appreciate it. Thanks everyone.

[brewster426]

Possible bent valve or one seized up..just freashin up the head and see what you come across. Not sure about the jetting. Possibly fatten it up some. Not sure though.

[TitanMotorworks]

your intake valve faces are cupped. Valves have to be replaced. cause by dirt. Most likely your running a K&n air filter. If so i recommend changing back to foam filter or you'll replace valves more often. Rule of thumb is alway check valves when doing a top-end rebuild

[eastside 400]

Yea its def. your valves, the 06+ bikes use Ti intakes that have a coating, once the coating wears off the valves suck up into the head very fast, shimming works for a very short amount of time before they suck up again. The real fix for this is to put copper beryllium seats with Ti valves on the intake side of the head. Or if you want a cheaper way, install SS intake valves and get a valve job, but make sure you get a spring kit since the SS valves are heavier. Also, check your exhaust valve guides because they are most likely shot as well. Typical honda head problems, not always caused by dirt, i use clean filters every ride or moto if needed and i still tear up valves pretty quick.

[DnB_racing]

as far as your jetting question: changes like- bore, stroke ,high compression,porting, only will change jetting slightly not anything major as changing intake or exhaust,

the fuel air mixture is controlled by the carb for fuel and intake and exhaust for air, that being said changes in flow will allow more MITXURE in and out, and pressure, volume and temp changes will have a affect on the chemical make up of that mixture,

any single change of any of the internals, will be similar to small elevation or temp changes, however if ALL changes are done, obviously you are adding small changes for each modification. meaning a bigger change in jetting

[fomospede]

the valves are probly the culprit
but i was having a hard time it was the cdi
also have seen the tps give people struggles at the start

as for the valves turn the head over sitting level all assembled and pour some wd40 into the combustion chamber if they are leaking it will seep thru and make it obvious where the prob is

[DnB_racing]

Originally posted by fomospede
the valves are probly the culprit
but i was having a hard time it was the cdi
also have seen the tps give people struggles at the start

as for the valves turn the head over sitting level all assembled and pour some wd40 into the combustion chamber if they are leaking it will seep thru and make it obvious where the prob is the tps is almost useless for the carb.. its needed for efi. Ive ran with it disconnected before for 2 years and never even noticed, it will help with aftermarket cdi but the stock cdi has little effect from the tps.

I can almost guarantee its not the tps

[rollie]

i just had this problem last week, it IS your valves. i didn't have time to get new valves/seats so i got a new head/valves piston and cylinder and it runs great now, don't get nervous either new valves and seats aren't very expensive

[fomospede]

Originally posted by DnB_racing
the tps is almost useless for the carb.. its needed for efi. Ive ran with it disconnected before for 2 years and never even noticed, it will help with aftermarket cdi but the stock cdi has little effect from the tps.

I can almost guarantee its not the tps

not knowing his build it had to listed
it is easy to verify its not an issue

[450Rfutureracer]

Thanks for all the help everyone!! It did turn out to be the valves, we did a test by shaving a shim down to get the valves in check and we got it started!!! The valves need to be done asap to avoid any other problems but don't know much above doing valves on these heads. I read in the service manual or somewhere that there is a titanium coating now is that on the head or valves or both? So does it sound like I need new valves and new seats? Anyone got a price range on what all this will run me if I have someone do it?

[TitanMotorworks]

just new valves, you can recut the seats

[450Rfutureracer]

What's everyone recommend for valves? I don't plan on putting in oversize ones.