250-500cc Is WR300 racing head a good choice?

daft question why didnt you measure your squish band then remove your existing head annd get that skimmed by a machining shop, or are the domes completly different?
have they no just supplied you with a std head with 2 thou off the clearance?

The 300 head isn't flat like most 2T heads. You can't just mill it. RB Designs can do it as well as I'm sure other reputable machine shops with the experience. I didn't want to be without a head for a couple weeks, so I just bought the hi comp head.

yes mate not much differance i checked the volume of head that came off my bike in liquid form with my thumb over plug hole filled upto the top of ridge the head off bike =approx 43ml ,,,hi-comp =38ml pictues of head and drawing

Measure both like this. My stock, racehead and black edition all have same dimension for squish

i see, is the actual height of the new casting the same? i was just fuiguring out where they have lost the thickness im assuming rather than a new casting pattern they have shaved the whole lot down so decreased the volume in the combustion chamber. interesting pics thank you that has shown alot

The differance in the dome width same depth slightly deeper on std head

I have a WR300 with the race head etc and have been toying with the idea of changing it to more MX. I have taken it on a couple of supercross tracks recently which obviously it isn't designed for. I have also been looking at a TC449 but am very concerned it would have similarities to a G450X. So the dilemma is convert the 300 or buy a 449. I love the 300 so I am tending to lean towards a conversion.

I don't ride supercross tracks, only fast natural terrain, and some woods, so for me, it seems like it would be perfect... and completely different. We don't have displacement classes, so I'm battling 450's every weekend on my 150. A little more power wouldn't hurt.

Do the math on the bore/stroke. 5 ml is a substantial difference.

i`m about to put the new 0944 head on my bike but have hit a snag finding the torque specs for the head bolts, what tension do you guys use for them?

google wasn`t helpful but i`ve found the 10ft-lbs for the engine mounts to the head, sound about right?

15.5,16 ft lbs

thanks!, time to put it back together and test it out this afternoon

Well?

bloody fantastic, well worth the price,
took a little bit to find a happy place with the jetting ended up 1&1/2 turns richer and also went from 95 to 98 octane fuel, more power everywhere, really impressed.

it was a pretty good climber before but now,well lets say i caught myself laughing mid way up a seriously ugly hill, picked a less than ideal line, lost momentum and gave it more gas from very very low revs,it just gritted its teeth and got moving again,no clutch or anything needed. much much stronger now

they really should have made the the high comp head standard issue when they built the bikes, it now has the power i expected the bike to have when i bought it

only downside so far is it seems to want to stall a little bit easier at idle,not a big issue in my book, also seems a bit less forgiving of rear wheel lock ups. makes sense with added compression.

pretty sure it was a bit easier to start too, 2 kicks from cold today, used to take 7 or 8.

I concur.

I experienced the same thing. I turned my idle up a little more than normal and it seemed to help. I refuse to get a Rekluse.

dam those wretched auto clutches, get a high quality cable, i got a venhill one and my one finger clutch is back (360) looking into carb but may have to sell a kidney for one.. for a few years the tm38 will be fine still it aint broke dont fix it..
may have to skim my head an reprofile it to get better compression if it makes asmuch differance as you state.

ol mate has a recluse on his 250 and is really getting into how it works. its a lot better than he thought it would be

I put one of those race heads on my wr300 and had to remove it after a couple of rides, it wanted to rip the bike outta my hands in the tight single track!!! but if your desert racing or hill climbing it will get the job done !

{Old thread, I know, apologies for that..}

Hi all,
I came across reading about that race heads and gave it a try asking several european Husky dealers without success, all responded the same: No stock and fabric had this p/n discontinued...

So, anyone knows if it's still possible to get this somewhere ? Maybe someone reading this tried the race head back in the days and didn't like it and is willing to sell it ? Would be great to find one in Europe avoiding the import taxes...

By the way, will 95 or 98 RON octane fuel suffice or does this heads need race fuel ?
I suppose the kickstarter will go a little harder with this head ?

Regards.

You can do the same thing by finding someone who can dial in the squish on your current head. I didn't notice much if any difference with kickstarting.

Well returning to this topic, I gave up searching for a new head cause I couldn't find no one... But yesterday I came back to this idea and I really want like to try this head in my bike. Maybe I should post in the Classifieds section for a used head...

Regarding to dial in the actual head, I know someone that has the equipment to do it (CNC, lathe etc.) but he is no engine mechanic, he doesn't know the details about squish etc... If I could give him precise instructions what to do ... but I can'. Is it enough to remove some material from the flat surface area and top of the ring to compensate ? Or is it necessary to also adjust the squish band ?


Regards.