Engine rebuild
- Phil-VTwin
- Posts: 348
- Joined: Mon May 11, 2009 11:21 am
- Location: Olney, Bucks
Re: Engine rebuild
Ohhh i used to have that amount of play on a set of forged pistons, the piston slap when cold was loud but when warmed up and the pistons had expanded it was quiet as a mouse, apart from the 120dB exhaust!!
Ride Safe
Phil
Phil
- benny hedges
- Posts: 6110
- Joined: Sun Oct 18, 2009 5:09 pm
- Location: Warrington
Re: Engine rebuild
keep us informed how you get on with the pistons - i'd be interested to know what the valve to crown clearance is for obvious reasons, with standard cams and the (very expensive) moriwaki works of art.tony.mon wrote:
Secondly, I gave the cams to a local company who said they could do something but have had them for a couple of months and all I get is promises of "next week". So maybe I'll have to dig deep and get some Moriwaki's after all.
Either way, don't care 'cause I've just ordered the 11.5 to 1pistons from somewhere in California.
Only £103 wife-pounds, bargain.
Game on!
last time i looked they were about 500 notes!

You do not have to say anything. But it may harm your defence if you do not mention when posting something which you later rely on in quote. Anything you do say may be ripped to sh*t.
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- Posts: 280
- Joined: Sun Jul 25, 2010 3:32 pm
Re: Engine rebuild
Standard cams are:-
inlet open 20btdc
close 45abdc
Exhaust open 50bbdc
close 15atdc
These are pretty advanced timings for a road bike much more than most 4 cylinder sports.That's why it sups gas and has little bottom pull ,these cams don't work till over about 6000 rpm.I myself am a nippy rider but on A and B roads know I would be quicker on tamer cams.The XL motor makes over 100bhp which is a lot, it's timings are :-
inlet open 15btdc
close 30abdc
Ex open 40bbdc
close 5atdc
If I can get hold of some I,ll post results.Unless your going racing I wouldn't put in fancy cams.
inlet open 20btdc
close 45abdc
Exhaust open 50bbdc
close 15atdc
These are pretty advanced timings for a road bike much more than most 4 cylinder sports.That's why it sups gas and has little bottom pull ,these cams don't work till over about 6000 rpm.I myself am a nippy rider but on A and B roads know I would be quicker on tamer cams.The XL motor makes over 100bhp which is a lot, it's timings are :-
inlet open 15btdc
close 30abdc
Ex open 40bbdc
close 5atdc
If I can get hold of some I,ll post results.Unless your going racing I wouldn't put in fancy cams.
- benny hedges
- Posts: 6110
- Joined: Sun Oct 18, 2009 5:09 pm
- Location: Warrington
Re: Engine rebuild
thats what mines like, pulls your arms off over 6k but not much under 5
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Re: Engine rebuild
So is it best to ride the storm above 6k revs then? When I did my bikesafe course the cops said that I should be keeping the revs high. Im always worried that im gonna feck it up when I ride in 2nd and 3rd round the twisty sections of road. As you guy say though I guess its meant to be ridden with high revs.
When does the limiter kick in?? I take it its the to stop you over revving and shaking the bike to bits like the washing machine in the other thread.
Jazz
When does the limiter kick in?? I take it its the to stop you over revving and shaking the bike to bits like the washing machine in the other thread.
Jazz
Everything good is bad
Everything bad is good
Everything bad is good
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- Posts: 280
- Joined: Sun Jul 25, 2010 3:32 pm
Re: Engine rebuild
I bet a copper won't reckon much to you riding above 6K when he pulls you over.The Japs knocked this bike out in a hurry to nick sales off Ducati so a lot of development went out the window like the power characteristics so compared to other bikes it's a bit of hard work to ride well. The XL version which is a revolting mongrel actually had more time spent on it which makes it a better ride.Ride within our limits as this is one easy bike to get spat off.
- benny hedges
- Posts: 6110
- Joined: Sun Oct 18, 2009 5:09 pm
- Location: Warrington
Re: Engine rebuild
you will find it is a different animal between 6k & the red lineJazzscot wrote:So is it best to ride the storm above 6k revs then?
When does the limiter kick in??

that's where all the power is, lugging it around low rpm there's plenty of torque that pulls you around, but you're probably only making 39hp which sort of defeats the object of having a 100hp bike imo.
you will find it drops off above 9k due to the ecu (iirc) retarding the ignition timing to stop it revving (much) higher.
at 9.7ish- 10k it more or less kills the ignition, and you will notice a chronic misfire and loss of power.
try riding it hard to the limiter, on your favourite twisties - you will find it is very quick !!!
you won't kill it btw, if it was harmfull to the engine, mr honda would've set the limiter lower.
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Re: Engine rebuild
Jazzscot:
"When does the limiter kick in??"
Just take it to a race meet, then, in the campsite, after about 3 AM, start it and immediately wind the throttle back to the stop, cold engine and all.
Then you'll know what the limiter does, it makes the engine backfire and gets you a kicking.
"When does the limiter kick in??"
Just take it to a race meet, then, in the campsite, after about 3 AM, start it and immediately wind the throttle back to the stop, cold engine and all.
Then you'll know what the limiter does, it makes the engine backfire and gets you a kicking.
Last edited by tony.mon on Sun Sep 19, 2010 8:40 am, edited 1 time in total.
It's not falling off, it's an upgrade opportunity.
Re: Engine rebuild
Right, the rebuild is under way....
I started with this:

and then I took all these bits off:

and these bits:

And then I undid some bolts, and this happened:

Here's the other half:

And the main reason for doing this?

Lovely shiny 11.5:1 high comps.........
Just as a precaution I'm replacing the big ball bearing behind the clutch, which seems ok but I have a suspicion that it contributes to the graunchy clutch that some people have.
Next, gas flowing the heads ( once it's back together again, that is.....)
I started with this:

and then I took all these bits off:

and these bits:

And then I undid some bolts, and this happened:

Here's the other half:

And the main reason for doing this?

Lovely shiny 11.5:1 high comps.........
Just as a precaution I'm replacing the big ball bearing behind the clutch, which seems ok but I have a suspicion that it contributes to the graunchy clutch that some people have.
Next, gas flowing the heads ( once it's back together again, that is.....)

It's not falling off, it's an upgrade opportunity.
Re: Engine rebuild
Can't say I've ever noticed tbh. Concensus always has been the the Storm is an easy bike to ride.so compared to other bikes it's a bit of hard work to ride well.
Two bikes, still only four cylinders!


- benny hedges
- Posts: 6110
- Joined: Sun Oct 18, 2009 5:09 pm
- Location: Warrington
Re: Engine rebuild
tony.mon wrote:
And the main reason for doing this?
Lovely shiny 11.5:1 high comps.........
Next, gas flowing the heads ( once it's back together again, that is.....)
when you do this tony, please dont forget to measure the piston to valve clearance for us, with standard cams...
need to know if i can do this with my high lift jobbies, without kissing the crowns lol

You do not have to say anything. But it may harm your defence if you do not mention when posting something which you later rely on in quote. Anything you do say may be ripped to sh*t.
Re: Engine rebuild
A small post-script, my spare set of cams finally came back from the cam-grinder.
He's only had them since May!
Still, by taking a bit off the base circle he's achieved a half mm extra lift (11.6mm for both) and a smidgeon more dwell (255 degrees) and all for £108 all in, inc dropping them off on my doorstep on his way home.
I'll be assessing back-to-back performance gains or losses measured against standard ones in due course, on the dyno.
Looking at specifications for other types and makes of cam, I might be get best power from a reground inlet cam and standard exhaust, I'll have to play on the dyno.
But for now, on with the mains, big ends, hc pistons, and get it back together.
A few weeks- it's Dyno time! (want to get it built, installed and run in first).
He's only had them since May!
Still, by taking a bit off the base circle he's achieved a half mm extra lift (11.6mm for both) and a smidgeon more dwell (255 degrees) and all for £108 all in, inc dropping them off on my doorstep on his way home.
I'll be assessing back-to-back performance gains or losses measured against standard ones in due course, on the dyno.
Looking at specifications for other types and makes of cam, I might be get best power from a reground inlet cam and standard exhaust, I'll have to play on the dyno.
But for now, on with the mains, big ends, hc pistons, and get it back together.
A few weeks- it's Dyno time! (want to get it built, installed and run in first).
It's not falling off, it's an upgrade opportunity.
Re: Engine rebuild
Right- update so far:
bores honed, top crankcase half thoroughly cleaned and back on the engine stand.
But the more I look at the main bearing shells, the more I think that although they look ok, while I'm there I might as well fit new ones- they're not expensive.
I'd checked them on strip-down, and they looked fine, so I decided to re-use them. But now I'm having second thoughts- ship-spoiling ha'porth/tar equation.
So that's as far as I got today!
A bit of a false start, TBH.
But soon, soon......
bores honed, top crankcase half thoroughly cleaned and back on the engine stand.
But the more I look at the main bearing shells, the more I think that although they look ok, while I'm there I might as well fit new ones- they're not expensive.
I'd checked them on strip-down, and they looked fine, so I decided to re-use them. But now I'm having second thoughts- ship-spoiling ha'porth/tar equation.
So that's as far as I got today!
A bit of a false start, TBH.
But soon, soon......
It's not falling off, it's an upgrade opportunity.
Re: Engine rebuild

Phhhhhhhwoooaaaaaarrrrr momma
Cant wait for the results Tony.

I see myself as a sensitive intelligent man but with the heart of a clown that causes me to **ck things up right at that crucial moment........'Jim Morrison'
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- Posts: 54
- Joined: Wed Apr 14, 2010 6:07 pm
- Location: luton, bedfordshire
Re: Engine rebuild
interesting reading tone, nice pics too 
with your new cams what will the dynamic compression ratio be?

with your new cams what will the dynamic compression ratio be?