Venom X22R 250 performance mods

[bogieboy]

nice.... sounds a lot like my cammed pocket bike did....LOL its really just a baby version of your x22... LOL

[JerryHawk250]

Originally Posted by bogieboy

nice.... sounds a lot like my cammed pocket bike did....LOL its really just a baby version of your x22... LOL

Yes it does sound bad azz. I'm also thinking of installing a offset flywheel key to increase the timing. either a 2 or 4 degree.

[MeatHammer]

I have read that the Hotcam is a drop in and requires no mods to the engine. What kind of performance gains could you expect by only swapping cams and not doing the port/polish and piston swap?

[JerryHawk250]

Originally Posted by MeatHammer

I have read that the Hotcam is a drop in and requires no mods to the engine. What kind of performance gains could you expect by only swapping cams and not doing the port/polish and piston swap?

With out increasing the compression ratio and opening up the ports you will loose low end power. The higher compression makes up for that.

[Chrisguga]

Any update on how that 18 tooth front sprocket is doing? Is it hitting the case at all? I wouldn’t mind buying one if it manages to clear the cover.

[Megadan]

Originally Posted by MeatHammer

I have read that the Hotcam is a drop in and requires no mods to the engine. What kind of performance gains could you expect by only swapping cams and not doing the port/polish and piston swap?

I wouldn't bother with a cam install without at least doing some work to the exhaust port. These heads, both CB and CG 2 valve engines, have pretty terrible exhaust ports. Putting a more aggressive cam without doing at least some port work would be like running a marathon race but only breathing through a straw while doing it.

Honestly, even if I weren't installing a cam, or raising compression on any engine these bikes run, I would still open up the exhaust port, as well as port match and smooth out the intake a little.

If you don't believe you are capable of doing your own head porting there is actually a shop in Missouri that will do pretty damn good port work for a pretty good price (Around $150-200). This is their facebook page. https://www.facebook.com/LFRPowersport/

You can see some of their porting examples. Corey Lansdown is who I talked to and he is a knowledgeable guy that does good work. Get in touch with them and see what they tell you.

As far as increasing the compression goes. Given the specs of the cam in question, I would want no less than a 9.5:1 static compression ratio to avoid losing low end power. Mid range and top end would perform just fine. It might not be quite the fire breather that Jerry is making, but it will have most of the benefits of the cam while also running cooler.

I am not 100% sure what the X22R CB engine has stock, but usually the OHC motors are around 9:1 compression. So, at the very least you could have the head decked 2 thousands (.002 inches, or .5mm) to bump it up to about where you would want it.

[JerryHawk250]

Originally Posted by Chrisguga

Any update on how that 18 tooth front sprocket is doing? Is it hitting the case at all? I wouldn’t mind buying one if it manages to clear the cover.

Never installed an 18 tooth. Even though an 18 tooth might fit, it will pass too close to the case for me. If you get too much slack in the chain and it decides to jump tooth you can plan on buying a new case.

[JerryHawk250]

Originally Posted by Megadan

I am not 100% sure what the X22R CB engine has stock, but usually the OHC motors are around 9:1 compression. So, at the very least you could have the head decked 2 thousands (.002 inches, or .5mm) to bump it up to about where you would want it.

The stock gaskets on the engines have a triple layer head gasket. Like the CRF230F guys you can separate the gasket and use one layer which will give you a .5 increase in compression ratio.

[Chrisguga]

Originally Posted by JerryHawk250

Never installed an 18 tooth. Even though an 18 tooth might fit, it will pass too close to the case for me. If you get too much slack in the chain and it decides to jump tooth you can plan on buying a new case.

Doh, wrong thread!

[JerryHawk250]

Originally Posted by Chrisguga

Doh, wrong thread!

That's what i figured. lol

[JerryHawk250]

Update. Bike has been parked in the shed since Tuesday night. When i got home Tuesday my my fan for my AC condenser unit decided to degenerate so had to take my truck Wednesday as it would of been a pain to carry a huge fan on the back of the bike so i took the truck. Not as much fun to ride as the bike. lol Turns out the supply house had the wrong fan so had to order a new one. Good thing i have a couple of window units for back up. Now it looks like we have rain for a few days. I need to ride. I need my fix. Well last night i went in the shed just to crank up the bike. Man she sounds bad azz. Gave her a few quick revs and all of a sudden the head lights go out. I just turned off the bike, closed the door and went back into the house. You know the saying bad things happen in threes? Well i wasn't going to touch the bike anymore cause i was afraid something else would go wrong. Hopefully it's just a fuse or connection. I got a few days to of rain coming so i have plenty of time to figure it out.

So yeah, not so much of an update but it's all i got at the moment.

[JerryHawk250]

for anybody looking to port there head, I ran across this thread this morning. Very informational and with pictures. https://thumpertalk.com/forums/topic...onsiderations/

[China Rider 27]

Originally Posted by JerryHawk250

for anybody looking to port there head, I ran across this thread this morning. Very informational and with pictures. https://thumpertalk.com/forums/topic...onsiderations/

When you did your head did you take a lot of material off the roof of the port over the valve guide? Shortening the radius?

[JerryHawk250]

Originally Posted by China Rider 27

When you did your head did you take a lot of material off the roof of the port over the valve guide? Shortening the radius?

Yes, I did pretty close to what that guy did in the link i posted. about the only thing i did different was i didn't do any work around the intake valve seat on the chamber side like that guy did. Also you have to be careful not to remove too much around the valve guides. It's pretty thin there. Look at the cross section the guy posted.

[Megadan]

Originally Posted by JerryHawk250

for anybody looking to port there head, I ran across this thread this morning. Very informational and with pictures. https://thumpertalk.com/forums/topic...onsiderations/

He did the same trick I did with the port floor around the short side radius on the intake. I widened that up on the right side of the port along the outer edge of the curve. That was the only real port shaping I did besides the port match at the flange.

As far as the thinner material around the guide. Where it is the thinnest doesn't really need much material removed anyway. Most of the material removal is at the bowl and especially next to the guides just leaving the bowl along the roof of the port right next to the guide.