Remove valve guides from 650?

absolutely correct;)

Great advice, larrycavan. By "valve job", so you mean valve lapping or the more involed process of having the valves and valve seats reconditioned at the machine shop?

I planned on doing the lapping on my bike, as there are only 14000 original miles on the engine.

ive never seen the reasoning behind just lapping valves.once motor warms up a little and things start to expand i dont see how its gonna make any differance,id say have a multi angle valve job done then you know its right;)

Thanks, wireman. Always appreciate responses, and hope you're not offended if I ask for a few more. :ohmy:

I'm wondering about other member's opinions on this subject, i.e. when valve seat repair/cutting is warranted. I wasn't able to do a compression check on the bike prior to teardown. The service manual describes the use of machinist's dye to check proper valve seating. Anyone use this method? Is valve seat repair a routine procedure, or does compression testing or the dye method indicate the need?

Doesn't seem that the local Kaw dealer would charge a great deal for vale seat repair, so I may be stressing over nothing, however I want to do this rebuild right the first time, coupled with not spending $ that's unnecessary.

Thanks all.

no problem.like neil bortz says believe absolutely nothing unless you can confirm it yourself!

Draman86, I did do the lapping with the dye before deciding to take the head to a machine shop to have the seats done professionally.

The reason I ended up going to the machine shop was that with the lapping, I was not able to get a good solid "ring" with the dye. There was too much pitting to correct with just a good lapping.

I called my local Kawi dealer and asked them who they send their head work to for machining. I went to that shop, and they charged me about $90 to grind the seats, valves, and hone my cylinders. In my mind, it was money well spent.

Thanks, wireman, for the positive attitude.

Skyman, I believe I'll check out my local machine shops. I had in mind that such a job (hone cyls, repair valves and valve seat) would be way more expensive than what you paid. By the time I buy the lapping materials/tools and test dye stuff, I could get the complete job for just a couple of more bucks.

Money well spent to go with the machine shop. I have a strong desire to do the best job I can with my bike. Plus, I like a well running bike and am not opposed to a bit of speed every now and again. :whistle:

The OEM valve jobs are adequate at best. They are not performance type valve jobs. You take a virgin KZ or J head with 5000 miles on it, do a good valve job on it and the motor will respond well.

Back in the days of the bad J cranks, we were replacing them a lot. Most bikes had several thousand miles on them. I'd offer the customers a deal on a valve job while the bike was apart and most opted to have it done. Many said the bike ran much smoother and stonger than it did new. Never had anyone come back and bitch contrary to that.

4V motors are even worse, especiall the early 4V Kaws. The seats chipped, the valve faces caved in....Throw away motors IMO.

JMO

I don't know about motorcycle heads, but of all (100's) of automotive heads that I have taken to machine shops to have the valves ground, not one ever lapped the valves.
Every single one said it was a waste of time to lap valves after grinding, but I never believed that so I did a test. Two identical Chevy 350's, same miles same chassis, etc, sent both sets of heads out to have the valves ground, got the heads back and I lapped the valves in one set while leaving the other set alone, installed new identical cams in both vehicles and bolted everything back together.
End result was the vehicle that I had lapped the valves in had noticeably more power.

steell wrote:

I don't know about motorcycle heads, but of all (100's) of automotive heads that I have taken to machine shops to have the valves ground, not one ever lapped the valves.
Every single one said it was a waste of time to lap valves after grinding, but I never believed that so I did a test. Two identical Chevy 350's, same miles same chassis, etc, sent both sets of heads out to have the valves ground, got the heads back and I lapped the valves in one set while leaving the other set alone, installed new identical cams in both vehicles and bolted everything back together.
End result was the vehicle that I had lapped the valves in had noticeably more power.

but they were ground 1st,lapping the valves will not substitute for a good valve job if the valves and seats are already borderline in my book;)

wireman wrote:

steell wrote:

I don't know about motorcycle heads, but of all (100's) of automotive heads that I have taken to machine shops to have the valves ground, not one ever lapped the valves.
Every single one said it was a waste of time to lap valves after grinding, but I never believed that so I did a test. Two identical Chevy 350's, same miles same chassis, etc, sent both sets of heads out to have the valves ground, got the heads back and I lapped the valves in one set while leaving the other set alone, installed new identical cams in both vehicles and bolted everything back together.
End result was the vehicle that I had lapped the valves in had noticeably more power.

but they were ground 1st,lapping the valves will not substitute for a good valve job if the valves and seats are already borderline in my book;)

Exactly. Lapping is the last step in the valve job process and NOT a substitute for properly cut seats and refaced or new valves. Different people have different theories on how to do a valve job.

If you've got a Serdi machine then you cut the angles all at once. I dont' have one so I use a Black & Decker seat grinder for the 45 so they're good and straight and then hand cut the inside and outside angles with hand cutters.

If you take your head to an automotive shop to have a valve job done, don't have them assemble it. Instead bring it home and thouroughly clean it. I've seen heads come back from shops full of grit and assembled.

IMO, it's good practice to have motorcycle people work on your motorcycle engine parts because they generally have the proper attitude to do the work correctly. Some automotive places treat your parts like they're going on a tractor.

I'm also not a big fan of bronze valve guides. I prefer the iron guides.

Wow. Great discussion, and I'm learning SO much as usual.

Now that I understand the issues concerning valve seating, it makes sense that lapping following machining would improve performance. Kinda' like sanding wood and progressing from coarse grits to finer grits for a smooth finish. Now I know what to do; have the valves and valve seats professionally finished by a shop experienced with BIKES followed by lapping at home.

You members are the BOMB. :woohoo: Thanks again.