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Hello everyone I have a 2007 crf105r with a complete fresh rebuild. New crank, piston, valves, cam and head was cleaned up. The problem I am having is the piston is hitting the intake valve when it comes to TDC. Idk what could be wrong I am almost positive the timing is done right but maybe if no one has any other ideas what could be wrong can someone just conferm how to do the timming.

I assume you have found this by turning it over by hand!

What brand of piston was used?
Is the piston the right way around? Seen it to many times not to ask.

i.e. Are the inlet valves hitting the exhaust cut-outs (assuming your piston has them)

Either that or timing is out or did you change the camshaft for one with more lift.

Yes I found this out by turning it by hand.
It is a Wisco piston
And I believe the piston is in right but I did try both ways
As for the cam its new but stock size

The piston should have Valve Reliefs cut into them , the LARGER is for the Intake side , the SMALLER is for the Exhaust side , make sure the Intake side is facing the REAR of the engine

At no point should the valves hit the piston , so either timing is off or the piston is very high compression , in conjunction with a cam with very high lift (aftermarket) , but something is definitely wrong , and do not try to actually start the bike till its fixed

As far as timing goes , you will have several marks that have to ALL line up at the same time , 2 are on the Ignition side 1 is on the Clutch side

The clutch side will be a large round plug in front of the clutch cover , it will have a Arrow on the case itself facing to the front of the engine , the Gear will have a dot usually , it needs to be aligned with the Arrow on the case .....

While that is in position you should also note the cam has the lobes facing rearwards about 2 o clock position when looking from the Ignition (left) side of the engine , at this position there are 2 slash marks on the gear (like this - ) , one on the rear half of the gear , the other on the front half , they both need to be level , so it will look like this (-o-)

The 3rd mark is the small round plug on the Ignition side , it will have several marks , but 1 of them should be lined up the the notch in the opening , if ALL these marks are aligned at the same time ,. then your timing is correct , if not then you will have to readjust the timing chain till they ALL align at the same time

It is a stock piston and stock cam so I am going to check the timing again when I get home and I will get back to you but is there anyway when the company cleaned up the head maybe they took to much off

What is the part number of the piston and cam you used?

I do not have the part number for the cam in hand. The problem I am coming up with now is that the cam gear can only get bolted to the cam one way because the bolts are offset and when bolted on it is impossible to get both the lines on the gear to be straight across while the cam lobes are at about 2:00

what is the part number for the piston you installed?

I don't have that on hand either lol I'm not home when I get home I will look for the part numbers

ok..post them when you have them.

OK np but does the thing about the cam gear not lining up when the cam is at 2:00 make any sense

The cam gear has an alignment mark towards the outer edge of the cam. This mark should be facing outward when the cam gear is installed correctly. Install the cam gear correctly first and then concern yourself with aligning the timing gears.

If you do not have the Honda Service Manual, set your tools down and get it before you proceed.

Ken

Ok can part number is 06140-kse-305 and position part number is 4915m06600

Interesting...the piston part number is correct for the 2007 150R. The cam part number is a 2009 version. I can't see it not fitting however. Has to be something with your installation/timing.