Hitchcocks Forum

So, TEC bike parts now offer a performance Camshaft for the Himi.
https://www.youtube.com/watch?v=GHoqvbAnvEo
Promising 4 extra horses(20%) for £200
No retuning requried.

I'm a skeptic, but I'm taking a punt on this one, Here is my logic.

A 400 should be able to make 40bhp. For example, CB400X @ 45bhp.

The Himi is a long stroke, so it can't rev as high.
It's a low compression engine to deal with 70-80 octane fuel.
And it's a thumper.

But still that shouldn't add up to 21 lost horses.

All the Dynos I have seen show that exhausts, filters and even ECUs have a minimal impact on power production.

So the usual performance suspects seems over specced for the actual performance we get, and "upgrading" them does nothing

This makes me think it was designed to be better and then held back, most likely for emmissions.
Low compression, Longstroke engines are known for slow incomplete burns. This makes me think unburnt Hydrocarbons.

PAIR systems help with those at low RPM, not high, where peak power is produced.
Cats do nothing.
You can only lean a mixture so much before Aluminium starts melting.

The only way I can think the engineers could improve hydrocarbon output, is to remove any valve overlap and delay the opening of the exhaust valve. Which would reduce performance in high flow situations.

That is a huge amount of supposition on my part.
Anyway, money where my mouth is, I'll give it a go. If it feels like I need to drop a tooth after on the motorway I'll mark it a win.

I'd get your bike on the dyno, before and after. Let us know how you get on, dyno run print outs etc. It will be interesting to see where this extra power is made.

I have recently found out about this camshaft - let us know how it performs.

I have already gone up one tooth on the gearbox sprocket and it has no problem pulling that in a srandard state of tune, so perhaps with the camshaft you will be able to go up another one - is there room?

Good luck.

Hitchcocks do their own cam which gives same increase on performance and keeps the decompressor which with my battery drain I would rather keep

RocketRR wrote: ↑

Wed Jun 30, 2021 12:29 am

Hitchcocks do their own cam which gives same increase on performance and keeps the decompressor which with my battery drain I would rather keep

Do they, I looked but couldn't find one? Would be my preference to keep the decompressor if they plus of course support our wonderful hosts

Trev.

Our hosts Part No 90133 or 90134- stock due in September.

https://accessories.hitchcocksmotorcycles.com/43815
https://accessories.hitchcocksmotorcycl ... head/44747

Thanks Andy, I couldn't find it as didn't scroll down far enough to see the 'out of stock' items. I'll see how much that and the plate is and, unless they're silly money, will order them up. I already have a 'performance' air filter (just cos I had to replace the original as I flooded the airbox) so may look at whether I can mod the filter plate myself meantime.

I would be nice to see a noticeable increase in usable performance and, from the charts, this should definitely be noticeable

I was lucky enough to get one so will update when fitted.
Also bought a 16 sprocket and the airfilter.

RocketRR wrote: ↑

Fri Jul 02, 2021 1:52 am

I was lucky enough to get one so will update when fitted.
Also bought a 16 sprocket and the airfilter.

Thanks, will be interested to see how you get on.

I have a performance air filter (only as flooded my Himmy and needed a replacement for went for long life) but tried the LexTek silencer and couldn't really tell any difference apart from didn't like the exhaust note so took it off again. I use my Himmy more for off than on road so important I don't lose any bottom end to gain top end but a bit more overtaking capability wouldn't go amiss

Changing the cam will not do much without tuning the head/increasing compression etc, etc.
You can't compare a this bike with a Honda or whatever - different animal altogether.