Topic: 550 cylinder head valves

[BomberMann650]

Been searching for intake and exhaust valves for the 550.

Budget friendly alternative preferred

Kibblewhite and Honda oem are basically the same price. 
Vesrah doesn't offer a kit for 550's

And ebay had limited stock of jpn shop service spare parts nos

Recommendations

[Flyin900]

I don’t know what your looking at price wise for the good ones, yet the old adage you get what you pay for definitely applies to key motor components in my experience.

While you can normally recut the seats the Honda OEM valves are Stellite coated on their faces and tips, so lapping a worn valve is shade tree mechanics.

Vintage CB750 in Canada has the Kibble White valves and some Japanese made less expensive ones around
half the Kibble White price. They are a good seller from my experience, yet I cannot comment on the valve quality their offering for the less expensive items.

[bryanj]

Try 500 they are the same valves

[BomberMann650]

Both KPMi and oem valves are priced $45-50 per valve. 

Stumbled across ebay ads for shin nippon and fuji replacement valves.  Intakes only - $7/valve on the nippon parts.
As a company, nippon seems to make a valve for damn near every engine.  Probably a safe bet, if only there were a listing for the exhaust valves.

[Flyin900]

I saw that same seller in Thailand and be careful there. I have purchased a fake item from a Thai seller who was less than honest on their goods. Any real Shin valves would cost more than $7 a valve.

Four Shin Nippon real valves for my CL 77 were $120+ US for the set as an example.

A cam chain follower I bought for a CL77 was made of real cheap rubber that was very flexible unlike the original Honda one which was NLA. The seller claimed made in Japan and had a Honda logo and part number. 

Wasn’t worth returning, as the shipping cost would have been half the refund.

[Little_Phil]

Unless you buy genuine, how do you know that the valves have the correct hardness (stellite or equiv) coating which has been discussed so much recently?

[bryanj]

Trouble nowadays is even in a genuinr pack you cant guarantee its original

[Deltarider]

Maybe try Mitsubishi directly. A friend of mine runs a yacht service. Instead of ordering parts from Volvo Penta and various other manufacturers of marine diesels, he orders exactly the same parts from Mitsubishi.

[BomberMann650]

I'll heed the warning on the risk of fraudulent sales.

Did stumble across nos shin nippon exhaust valves from a seller in b.c.
They could've found the lot of em at a swap meet.  Price penciled on the box was $11.
Still had the old service shop inventory sticker too.  Neat no sequitur.

Delta, i would take your advice.  Though I have no clue how to reach Mitsubishi factory direct.

Will see how long I can hold out before caving into KPMi's demands

[MRieck]

I am sure I have some used OEM 550 valves that are in very good condition.....do you want to look?

[BomberMann650]

I am sure I have some used OEM 550 valves that are in very good condition.....do you want to look?

I appreciate the offer.  Though I have used oem valves already stashed in the garage.

Just not so sure i want to subject a used valve to land speed racing

Figured an unused service shop valve would be a middle route between used and kibblewhite.

[MRieck]

Years ago I had an repair shop old timer tell me "used parts are proven parts". For LSR I'd recommend a +1mm intake and have the seat/throat bored to .9 of the OS valve OD. Have done it many times and it works.

[BomberMann650]

Years ago I had an repair shop old timer tell me "used parts are proven parts". For LSR I'd recommend a +1mm intake and have the seat/throat bored to .9 of the OS valve OD. Have done it many times and it works.

Im a fan.  Your posts across this forum are bookmarked in my browser.  Like a practical guide for hobbyist port work

As far as oversizing the intake.  I don't know if its in the cards for this go round. 
Stubbornly doing it myself also means recognizing I don't have the adequate tooling to bore a new valve seat in the head.  Would also suck to find out the ims gentlemans express piston doesn't have the material to pocket a bigger valve!
Many local performance machine shops are motorcycle-phobic too.  Hopefully the recently acquaintanced family shop won't say no to boring the cylinders.

Would be curious to know if the oem valve seat can tolerate any biggening without wanting to drop though.
Found a sioux stone that might be about the right size to plunge into the bowl.

[MRieck]

Years ago I had an repair shop old timer tell me "used parts are proven parts". For LSR I'd recommend a +1mm intake and have the seat/throat bored to .9 of the OS valve OD. Have done it many times and it works.

Im a fan.  Your posts across this forum are bookmarked in my browser.  Like a practical guide for hobbyist port work

As far as oversizing the intake.  I don't know if its in the cards for this go round. 
Stubbornly doing it myself also means recognizing I don't have the adequate tooling to bore a new valve seat in the head.  Would also suck to find out the ims gentlemans express piston doesn't have the material to pocket a bigger valve!
Many local performance machine shops are motorcycle-phobic too.  Hopefully the recently acquaintanced family shop won't say no to boring the cylinders.

Would be curious to know if the oem valve seat can tolerate any biggening without wanting to drop though.
Found a sioux stone that might be about the right size to plunge into the bowl.

The seat does get thin but I have done it on many 550 heads including roadracing and LSR with no problems. If you want to go over 1mm OS intake you will need to replace the seat with another one with a larger OD. Kibblewhite sells them. The 750 is the opposite....I've put a 35mm intake on the stock seat no problem.
 

[BomberMann650]

Years ago I had an repair shop old timer tell me "used parts are proven parts". For LSR I'd recommend a +1mm intake and have the seat/throat bored to .9 of the OS valve OD. Have done it many times and it works.

Im a fan.  Your posts across this forum are bookmarked in my browser.  Like a practical guide for hobbyist port work

As far as oversizing the intake.  I don't know if its in the cards for this go round. 
Stubbornly doing it myself also means recognizing I don't have the adequate tooling to bore a new valve seat in the head.  Would also suck to find out the ims gentlemans express piston doesn't have the material to pocket a bigger valve!
Many local performance machine shops are motorcycle-phobic too.  Hopefully the recently acquaintanced family shop won't say no to boring the cylinders.

Would be curious to know if the oem valve seat can tolerate any biggening without wanting to drop though.
Found a sioux stone that might be about the right size to plunge into the bowl.

The seat does get thin but I have done it on many 550 heads including roadracing and LSR with no problems. If you want to go over 1mm OS intake you will need to replace the seat with another one with a larger OD. Kibblewhite sells them. The 750 is the opposite....I've put a 35mm intake on the stock seat no problem.
 

Thanks for the enlightenment.
Optimizing flow on stock valve size is probably the route I'll go.

The sum total cost of going to +1 valve might be better spent on improving aerodynamics.