86 cr250

[onformula1]

The HPP is only loud if they are not adjusted correctly because the exhaust gases push them in & out.

You can also tune the HPP valves for more low end with a few tricks, I also have 5-6 mods for more low end that are pretty easy to do.

The KTM is very impressive, but a good running CR even from 1986 will hang with it no problem once it is tuned.

[bkm]

That's pretty much what I'm looking for.

Sent from my SM-G900V using Tapatalk

[onformula1]

Ok, I am digging for my specs.

Did you put a stock head on it? or find out if that head was modded?

[bkm]

Ok, I am digging for my specs.

Did you put a stock head on it? or find out if that head was modded?

The stock head was milled a good amount, so much to where they had to run a thicker trx/atc 3 piece gasket to keep from having to run diesel lol. I put a box stock head back on it with oem head gasket. When I had the head off the ports are untouched with a fresh chromed bore and new piston.

[onformula1]

There are many things you can do to that motor for more low end, here are a few some require you to remove the head and/or cylinder so it maybe best to wait for a re-ring, you can re-ring those pistons 2-3 times with no issues and the power can be felt every time.

When you take off the cylinder head you will notice the spark plug is recessed in the head, which causes hot spots & detonation from the exposed threads along with cold fouling of the spark plug, which also feels like a jetting issue plus you will have quicker throttle response. The top of the head gets turned down on your lathe by 3mm. If you do this mod there a a couple of ways to chuck it up and one is very easy, let me know.

Ditch the stock reeds for LT Carbon Tech reeds- http://www.carbontech.com/motor/honda.html and don't use the factory reed stops, they block the Boyesen boost ports.

A reed spacer works well on this motor for more low end.

Fill the intake side of the transfer ports with epoxy to redirect the flow for more low end. (I have the exact specs for this, it is easy)

Use a 1990 CR250 head gasket for more compression and more low end without having to run race gas. They are .030 in. thinner.

Retard the ignition timing- all you have to do is file the bottom hole by 1mm using a rat tail file and rotate the stator plate counter clockwise.

I am not sure what size of carb you are running, but a 36mm gives a ton of bottom end. You can make a sleeve out off aluminum or Delrin for the carb you have.

A 6mm torque spacer made of aluminum at the head pipe works well for more low end, just use your lathe.

Make 1-2mm spacer and 1-1mm spacer for the clutch side of the HPP spring to shim it for more low end, now you have 3 settings to plays with 1mm, 2mm and 3mm by stacking the shims.

Let me know if you have any questions.

[bkm]

Wow, once again awesome info. Being a member of the inside clique sure has it's prevlidges. Lol

I'm running a boysen rad valve with carbon reeds. I also have a v-force 3 reed block I can use if you think that gain over the rad valve? I now remember you telling me about the 6mm exhaust spacer.

The carb is the Selvy tmx 38 that has been taper bored, and other than being rich and loading up at very low speeds, the throttle response is great. I also have a reed spacer from my atc sitting on the shelf I could try.

Head gasket is actually a 89 or 90? It is the thin single metal gasket.

I will do the ignition mod as well. I was going to pull the cover and check the weight locks, so this will work great.

I have a brand new bridgestone to put on the rear. The oem dunlop is getting bald and hard as a rock.

Thanks brother once again!

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[El Camexican]

Being a member of the inside clique sure has it's privileges.

Time to start using a secret symbol. Which do you prefer?

[onformula1]

I would stick with the RAD valve, but I would prefer the stocker with those reeds, but it is close, so no worries.

If you have a 38mm taper bored carb., then it is 38mm to probably 40mm ish, I would try a sleeve you can make one very easy with your talents, I loved the 36mm on a CR for low end, it's Awesome!

You have the good head gasket then.

The OEM rear tire was a Bridgestone M22 which was great at Carlsbad MX and asphalt and nothing else, so any modern tire will be a great improvement!

For the ignition mod, while you are in there you can file the opposite way way 1mm and have some fun playing around with the timing, advanced 1mm will rip your arms off..lol

A spark plug one heat range colder can be a nice improvement depending on the setup- BR9EG, give that a try, it works more than it doesn't.

Those bikes sucked sand and dust between the air boot and the air box and should be sealed with 3M weather strip adhesive. Twin Air make a great filter too.

The reed spacer works well on that engine.

[onformula1]

Time to start using a secret symbol. Which do you prefer?

Ask Ironchop, he is making the official stickers.

He came up with the- Trilluminati, I countered with 3Masons.

[bkm]

Time to start using a secret symbol. Which do you prefer?

El Tres Masons

[El Camexican]

I liked the 3Masons. Hence my new avatar. Can you come up a with a secret handshake?

[onformula1]

I liked the 3Masons. Hence my new avatar. Can you come up a with a secret handshake?

Sorry, I think I blew my creative load on the "3Masons" I do know a very hip young Mexican kid that fist bumps and then opens his hand and raises it up and yells... BOOM!

He is very well liked, great kid.

That's the pic I liked, I hope Ironchop approves.

[El Camexican]

I hope Ironchop approves.

If we can get him and a few others to join we may be able to get t-shirts made. What size is Barnett?

[bkm]

If we can get him and a few others to join we may be able to get t-shirts made. What size is Barnett?

Barnett who?

[El Camexican]

Barnett who?

Sorry, I meant Grand Master 666