Help! I lapped titanium valves

[JefaunTe250]

So I've been doing a full rebuild on a blown 2007 Te250, got to the valves and decided to go through them. Pulled them apart, inspected them, yada yada yada.

My big concern now is that I went and lapped the valves with a lapping tool and grinding compound. When I finished and moved to the next step on the workshop manual there is a big bold disclaimer saying that "the valve can not be ground. If the valve is damaged replace the valve."

How screwed am I? I'm assuming the note is because they're titanium, not certain what it really is for.

Where can I get new valves for the 2007 Husqvarna Te250 if I can't use the titanium ones anymore?

 

[Dirtdame]

Did you actually grind the valves or just use them to lap in the seats?

 

[JefaunTe250]

Did you actually grind the valves or just use them to lap in the seats?

I lapped them in the seats. First time rebuilding valves so I'm a bit clueless on what I'm doing. Because of that, I did it very lightly and only lapped them once compared to the 2-3 times that most manuals/guides were saying I should to get a good contact surface. That said, I've clearly removed material from the valve. I can measure how much material with a height gage, might do just that.

 

[Dirtdame]

This video explains what happens when you lap a coated valve. You will need new valves.

View: https://www.youtube.com/watch?v=M45wrq0Nv_c

 

[JefaunTe250]

This video explains what happens when you lap a coated valve. You will need new valves.
View: https://www.youtube.com/watch?v=M45wrq0Nv_c

Yeah I think I screwed myself lol. Measured real quick and found I removed 0.001" of material from the surface. Mostly carbon build up I'd assume, but the coating thickness is 0.0002" rounded up.

So now I need to figure how to get new valves.

 

[glangston]

https://www.ebay.com/itm/194710017020?hash=item2d559f13fc:g:a1YAAOSwOZlhXBc2

 

[JefaunTe250]

https://www.ebay.com/itm/194710017020?hash=item2d559f13fc:g:a1YAAOSwOZlhXBc2

Appreciate the link there, I did come across those; they're a set of 4 steel rather than the standard 2 steel/2 titanium.

Info for future readers who stumble into this issue...

After some research it seems that the TE runs the steel exhaust valves and titanium intake valves stock. If you want to run all titanium you have to get the TC's ECU to allow for the higher rpm. If you want to run all steel you need to change your springs to accommodate the change in weight on the intakes.

So I did end up finding a good source for these parts and other Italian husqvarna components! I'll post later in the thread who this is if they follow through with parts on the order.

 

[glangston]

Great you found what you needed. I had an 08 TE with an Athena kit and really liked it….then got a ‘12 and still have it.

 

[JefaunTe250]

Great you found what you needed. I had an 08 TE with an Athena kit and really liked it….then got a ‘12 and still have it.

I actually did go with an Athena kit as well! Ups the cylinder from 76mm to 83mm.
Stock displacement is 249.5cc, the kit takes it up to 297.58cc.

https://www.athena.eu/en-us/big-bore-cylinder-kit-83-mm-300-cc-P19487.htm
P400220100002 is the part number for the Athena big bore kit. Comes with the cylinder, piston, and all needed gaskets for the top end rebuild.

Really looking forward to buttoning it up. I started this rebuild because I lost compression and when I tore the top end apart found heavy scoring in the cylinder + bad piston rings.
Looked into ordering a new piston bored one size up and found that the stock cylinder is plated. If you have it bored over to the next size for a rebuild you have to have the cylinder replated.

If anyone decides to go that route the piston PN's are:
ProX - 01.6336.a, 01.6336.b, or 01.6336.c
Wossner - 8650da, 8650db, 8650dc
(a is standard bore, b is one size up, c is two sizes up)

Athena also sells a standard bore kit that comes with a fresh 76mm cylinder and piston.

I've also found aftermarket rubber components for the fuel/air delivery system, replaced my air box stuff since the rubber was heavily degraded
https://www.claussstudios.com/store...jDc20yucZefnbYGjRpIzEwqLFCJELCKUiE3czBZLMmNTI

I found every single Husqvarna workshop manual (1970-2019) archived at the following location: http://docs.husqvarnaoutlet.com.cdn.wavenetworks.com/repair manuals/

 

[glangston]

I actually did go with an Athena kit as well! Ups the cylinder from 76mm to 83mm

https://www.athena.eu/en-us/big-bore-cylinder-kit-83-mm-300-cc-P19487.htm
P400220100002 is the part number for the Athena big bore kit. Comes with the cylinder, piston, and all needed gaskets for the top end rebuild.

Really looking forward to buttoning it up. I started this rebuild because I lost compression and when I tore the top end apart found heavy scoring in the cylinder + bad piston rings.

Looked into ordering a new piston bored one size up and found that the stock cylinder is plated. If you have it bored over to the next size for a rebuild you have to have the cylinder replated.

If anyone decides to go that route the piston PN's are:
ProX - 01.6336.a, 01.6336.b, or 01.6336.c
Wossner - 8650da, 8650db, 8650dc
(a is standard bore, b is one size up, c is two sizes up)

Athena also sells a standard bore kit that comes with a fresh 76mm cylinder and piston.

I've also found aftermarket rubber components for the fuel/air delivery system, replaced my air box stuff since the rubber was heavily degraded
https://www.claussstudios.com/store...jDc20yucZefnbYGjRpIzEwqLFCJELCKUiE3czBZLMmNTI

I found every single Husqvarna workshop manual (1970-2019) archived at the following location: http://docs.husqvarnaoutlet.com.cdn.wavenetworks.com/repair manuals/

Is your bike injected? My ‘08 was so George (Uptite) had to piggyback the Athena ECU into the stock ECU. It finally worked and he was able to input values for the 3 fueling stops. They were prettydifferent, around 125 for the top number. Not sure if the Athena requires re-jetting carb.

 

[JefaunTe250]

Is your bike injected? My ‘08 was so George (Uptite) had to piggyback the Athena ECU into the stock ECU. It finally worked and he was able to input values for the 3 fueling stops. They were prettydifferent, around 125 for the top number. Not sure if the Athena requires re-jetting carb.

No actually my 2007 has a Keihen 37mm FCR-MX, I haven't buttoned everything up quite yet but my assumption is not to mess with the carburetor.

I'm not too familiar with it but all the other forums I've read on this bike with the Athena 300 kit say that they didn't have to touch the carburetor. One way or another I don't think it'll be too bad, just a bit of testing and swapping jets from the JD kit if it isn't dialed proper

 

[glangston]

The FCR MX on my Beta has run pretty good from sea level to 10,000 ft. Solid.

 

[JefaunTe250]

The FCR MX on my Beta has run pretty good from sea level to 10,000 ft. Solid.

100% agree, my FCR-MX has been all over. My bike is jetted for 6-7000 feet and I haven't touched the jetting in years. I did remove the fuel filter on the carb vent tubes and routed two up/two down. Rode it down at sea level with no issues, all I have to do is adjust the air/fuel mixture screw slightly and it does just fine at 14000 feet.

I also wanted to add a bit more information about this valve thing for future readers! It took me so long to find the parts for these valves because I was searching in English. Attached a screenshot showing what you really want to search for to find them

 

[JefaunTe250]

100% agree, my FCR-MX has been all over. My bike is jetted for 6-7000 feet and I haven't touched the jetting in years. I did remove the fuel filter on the carb vent tubes and routed two up/two down. Rode it down at sea level with no issues, all I have to do is adjust the air/fuel mixture screw slightly and it does just fine at 14000 feet.

I also wanted to add a bit more information about this valve thing for future readers! It took me so long to find the parts for these valves because I was searching in English. Attached a screenshot showing what you really want to search for to find them

One last thing to mention, if the valves ever do become completely unavailable you can still get them! Del West made the OEM valves for the Cagiva era Husqvarnas. I reached out to them, they still have the part prints to make the valves on custom orders. Attached the screenshot from my conversation with them.

 

[Hurky]

Same happened to me years ago with a Yamaha WR450F, I was changing to a new cylinder and piston and decided to clean and lap the five valves just to get things done properly ... well, I did the exact opposite as I lapped the vales without knowing about the thin superficial coating I lapped away.... I didn't try to run that cylinder head as I've found out I did a mistake and supposedly they don't last very long without the hardness. So I decided to get 5 new valves, not cheap... and I send the head to a machine shop to have the seats cut so they get a fresh finish for the new valves. All went fine and bike was running strong.

Cheers !

 

[JefaunTe250]

Same happened to me years ago with a Yamaha WR450F, I was changing to a new cylinder and piston and decided to clean and lap the five valves just to get things done properly ... well, I did the exact opposite as I lapped the vales without knowing about the thin superficial coating I lapped away.... I didn't try to run that cylinder head as I've found out I did a mistake and supposedly they don't last very long without the hardness. So I decided to get 5 new valves, not cheap... and I send the head to a machine shop to have the seats cut so they get a fresh finish for the new valves. All went fine and bike was running strong.

Cheers !

I'm kinda tempted to button it back up and ride it once or twice then check the valves again, it would be interesting to see how much that coating really effects longevity of titanium valves. That titanium stuff is harder than you'd expect but still about 20% less than steel.

I totally would if I had an extra head gasket. Waiting a few weeks for these valves to come in instead :P

 

[JefaunTe250]

Valves, valve guides, springs, and a few gaskets came in today. Really excited to put things together! Need to press out the old guides & press in the new, ream out the guides for the new valves, cut the valve seats, and check my contact patches.

Shoutout to Edgar Carreira at CGmotos in Portugal, he was a solid source for these valves when everyone was telling me they were made of "unobtanium." Definitely recommend reaching out to him for any Cagiva era parts, he seemed to have great sources on everything from the engine to plastics.

 

[JefaunTe250]

Status updates! It's been about two weeks since I got the parts in. I got the valve guides installed, was simple enough. Threw the cylinder in the oven at 350°F for about 20 minutes then hammered them out with a drift. Hammered the new ones in the exact opposite way while things were still hot. Checked them all with calipers out of curiosity and found they all stand about 10mm +/- .02mm high from the boss the spring rests against. Right after that I ran a 5mm reamer through all the guides by hand with some tap fluid to clean them up. I haven't gotten a whole bunch done since I've been busy and waiting on a valve seat cutting kit to come. I have it now, so planning to go at this tomorrow evening after work and see if I can get everything cut proper.

I've been looking at the workshop manual. Manual says to do a three angle valve job. Cutter sizes called out to do the job are the 20°, 45°, and 73° cutters. I have managed to get my hands on a Neway cutter set, pretty good stuff but those cutters aren't in the set. The angles I have in the kit are 15, 31, 46, 60, 70, and 75. So, it's time to do a 5 angle job I'm thinking. Hypothetically the 3 angles are already cut and are dictating the inlet and outlet flow profiles. Cutting the two additional angles should improve flow but not have a dramatic effect. To be fair, I just put a 300 kit on this 250; increasing flow to account for the higher displacement in the cylinder sounds like a good idea to me.

The 45° and 46° conundrum is one that I'm struggling to wrap my head around. I imagine the engineers designed some tolerance around the valve seat angle. I measured my new valves with an OGPScope; intake measures 45.1450° and exhaust measures 45.3186°. Cutting with the 46° cutter produces negative interference, which is exactly what you want over positive interference (doesn't leak). I also read a bit saying that the 46° valve seat is cut against 45° valves specifically for the interference fit so they wear in a proper seal faster without having to grind the valve seats with a lapping compound. I'm rolling with it.

Anywho, the stock valve seat flow profile is 20°->45°->73°. I'm taking it to 20°->31°->46°->60°->73°. I have to take the 46° cutter, cut away material to get a clean seat, then lap with "blue" and figure out how big my contact patches are (caliper measurements likely). if the "blue" transfers too high on the valve I will have to cut with the 31° cutter, too low is the 60° cutter. Highly doubt I'm going to nail exactly the contact width first cut without touching up anything.

SO, TLDR; I've never cut valves before, I have no clue what I'm doing, and I'm gunna wing it tomorrow evening. Fingers crossed.

 

[JefaunTe250]

Welp, I took a shot at cutting the valves the first night. Spent about 4 hours making lots of mistakes on my first go at it. I was frustrated because I would cut then lap and check my contact patches on the valves themselves and the contact patches would look right but the valves were all sitting at weird heights in the cylinder.

Slept on it, looked over the manual again. Went at it again today and this time focused on dialing in the diameter of my 45° cut per the manufacturer's spec. That made a world of difference! Dial in your diameter first (called out as diameter "B" in the workshop manual, then cut the other angles to narrow your patches ("A") if you do this by hand. Don't get impatient. Grab a sharpie and mark up the seat, cut until the sharpie is gone, measure after each cut, remark. A pair of calipers will get you close, I went overboard on measurements.

Specs per the manual for a 2007 TE250 are to have a contact patch width of 0.9-1.0 [mm] and diameter measurement taken at the top of the 45° cut of 24.6-24.65 [mm] on the exhaust valves.
I manage to dial mine into 0.97116, 0.98652 [mm] and 24.63927, 24.60498 [mm] on the exhaust.
Intakes call out for 0.9-1.1 [mm] "A" and 30.1-30.15 [mm] "B", my intakes landed at 1.08670,0.95946 [mm] "A" and 30.13710, 30.14650 [mm] "B".

So I'm on the top end of the tolerance, but still in spec. Not gunna overthink it too much, the valves seat so dang pretty now. I am concerned with the quality of the contact patches though, under a microscope those carbide blades look like they've left some nasty scarring on the valve seats. My plan is to lap them with the old valves to try to knock down all those peaks that the cutters introduced. I'll post images of the results to show people what lapping with old valves does to the quality of the seat.

 

[JefaunTe250]

So, I followed the advice of the interwebs and lapped my valves to "establish a good contact surface" because well I was curious about why people say you should lap valves after cutting seats. The exhaust I lapped with the new valves because there isn't a coating on the stainless steel, no big deal. Intake I lapped the seats with the old intake valves to avoid removing the coating from the new titanium valves.

The first thing I noticed was that lapping the valves immediately brought things back out of spec. I precisely measured everything again, but am focusing on one of my exhaust valves below...

Contact patch width "A" (0.9-1.0 [mm]) and diameter "B" of the port measured at the top of the contact patch (24.60-24.65 [mm])
Pre-lapping dimensions: A=0.98652 mm, B= 24.60498 mm
Post-lapping dimensions: A=1.20773 mm, B= 24.68702 mm

So, the first thing you notice is that by lapping I have 100% removed material from the valve seat. The contact patch is wider and the diameter is enlarged. I had to go back and recut my top and bottom angles for the contact patch width to bring things back to spec. I also took a minute immediately after lapping to take pictures under a microscope of the surface of the valve seat and valve itself, which are attached to this post.

The one thing you notice when looking under a microscope is that the lapping process definitely knocked down all those peaks the cutters left behind. I'm noticing the valves themselves feel much better seated even though before they felt great already! So, I think it wasn't really necessary but definitely would help if you're looking to really get things perfect. I think I went overboard.

I'm really excited to button everything together, I have a few more pieces to go on this bike. I did strip it down completely to the frame and have documented everything I've done, not far from the finish line though.