Valve float on z155ho

[twisties]

Hey everyone,

I was out riding my dpro160 on the weekend and was getting valve float really easily. The sound is horrible!
I am wondering if anyone knows of some stronger valve springs that will fit a z155ho to raise the RPM that valve float begins so that hopefully the rev limiter kicks in before float occurs... I hope that made sense...

Any help is much appreciated!!

Thanks guys

 

[nickv1980]

Really??? im able to pull a decent 10500 rpm on mine before she starts to bump ... the only time i really ever hear any float is when im wide open and the wheel is skipping off the ground higher up in the rpm range

 

[nickv1980]

forgot to add try these guys i think his name is jamie and very helpful always answered all my questions.

Classic Honda 50's Australia

 

[coolmodee01]

you might find thats a carby or cdi issue and not actually valve bounce these this dont have a limiter they just bounce the valves
but you can get HD valve springs i think

 

[twisties]

Ah I see.. well if it makes any difference me and a mate both have dpro160's and we were both having the same problem. The conditions were very slippery and they were revving out really quickly making a high pitch CHATCHATCHAT noise that was very different to a rev limiter. It sounded really horrible, like my engine was eating itself!

I read on planetminis that apparently these engines have a rev limiter around 12,100-12,300rpm. If that's not the case then I might just invest in an OORacing rev limiter..

 

[wogtaz ryder]

Mine had the same issue , was really annoying !

v2 head with 450 springs solved it

 

[nickv1980]

Im not having any problems with mine mate get yourself a cheap hour meter with tach . you'll be surprised how hard she's actually revving .

My tach shows max rpm , when i shut it down most of the time im changing at 8500 probably why i dont get alot of float .

Either your revving the pants of it and dont know it or its another issue

 

[DHZ_XR8cing]

The engines dont make any power that high up in the rev range so its pretty much pointless revving them that hard.
All that will happen is you will break stuff.

 

[wipeass]

i too get that valve chat thing on my dpro 160, it sounds very different to rev limiting!

 

[twisties]

Like I said earlier when riding in wet conditions or grass tracks the rear is very prone to sliding. Over the weekend I would be riding through some muddy areas and suddenly the revs spike big time and I'm getting valve float. Like I said, my mate that was with my on an identical bike was having the same problem, along with wogtaz and wipeass. In case you're wondering I've been riding for 5 years so I know how hard to rev a bike.

Anywho what I would really like to know is if anyone knows where I can get some HD valve springs for this engine. Any help is much appreciated

 

[DHZ_XR8cing]

If you have seen wotgaz ride you would understand why he gets valve float. he is a animal. lol
Contact this place. they may be able to help you out.
http://www.akunar.com
If that fails get a V2

 

[nickv1980]

okay AGAIN go to this WEBSITE : Classic Honda 50's Australia

If you dont have any clue what your after email jamie he can point u in the right direction

:beerchug:

I think even if u upgrade your valve springs and continually rape it at 10000+ rpms something else will give out sooner or later .

Good Luck !!

V2 is probably the go ;-)

 

[nickv1980]

The engines dont make any power that high up in the rev range so its pretty much pointless revving them that hard.
All that will happen is you will break stuff.

Funny you say that ^^ ive found that myself ... anything past 8500 on mine seems pointless the power curve starts to fall on its ass

 

[sean01]

yep, not enough cam profile for anything above that rpm....

the standard springs are fine for the cam its just that people think power can be made all the way till it goes bang...

 

[Kurlon]

Your bike doesn't have a rev limiter FYI...

 

[twisties]

okay AGAIN go to this WEBSITE : Classic Honda 50's Australia

I think even if u upgrade your valve springs and continually rape it at 10000+ rpms something else will give out sooner or later .

V2 is probably the go ;-)

I emailed him the first time you suggested that

V2 is probably getting a bit $$ for me, plus I'm content with the power I've got at the moment.

If you have seen wotgaz ride you would understand why he gets valve float. he is a animal. lol
Contact this place. they may be able to help you out.
AKUNAR MOTORCYCLE PARTS & ACCESSORIES THAILAND
If that fails get a V2

Thanks mate, I'll flick them an email.

Funny you say that ^^ ive found that myself ... anything past 8500 on mine seems pointless the power curve starts to fall on its ass

yep, not enough cam profile for anything above that rpm....

the standard springs are fine for the cam its just that people think power can be made all the way till it goes bang...

Yes I know, like I've said twice already as soon as the back tyre starts sliding the revs spike almost instantly. E.g. riding a friends grass track over the weekend in damp conditions, I go to pin it out of a corner in 2nd and suddenly there's no traction and the bike is going CHATCHATCHAT. It all happens in about 1 second so it's hard to avoid especially when you're not expecting it.
I know power isn't made all the way through the rev range, I was just trying to find a solution to prolong my engines life. I know of 3 other people with the same motor having the same problem, along with a few guys on planetminis.

Your bike doesn't have a rev limiter FYI...

Ah ok, everywhere I read I get different opinions, some say it does have a rev limiter but the bike will hit valve float before it gets to the limiter, and then others say it has no limiter at all...

 

[sean01]

you can address the float by adding extra spring shims under the spring.. not too many tho or it will coil bind and break/ stretch valves...

always roll the engine over first and make sure there is at least .060tho clearance in the spring on full lift...

extra shims can be bought from an engine reconditioning shop, you will need a sample tho...