Engine rebuild

[sirch345]

I can second the bike likes to rear its head, were following tnny on my bike and she still tried to lift after changing to 4 at 100.

Its a bloody animal compared to mine

-I have created a monster

Today I stripped and rebuilt the clutch to stop it slipping, used original Honda plates but with less wear than the set in there before.

Sorted!

While I was there I refitted the -4 degree Factory Pro ignition advancer, and removed the quieting gear on the primary drive.
No extra noise to speak of, and it feels strong, as ever, the dyno will tell its story in due course.

Tony, did you get around to what I was saying about doing in the last post of mine (re checking at what degrees the valves open and close etc) to see how they compared with the standard cam openings and closings

Chris.

[tony.mon]

The reground cams were based on a standard set, and so the lobe centres were the same as standard.

I think I'll leave the reground ones in for now, not an amazing gain form standard but I like the "power-band" effect, and funnily enough they seem to be giving better fuel economy.
I'll have a play with the customised airbox and see if I can get ram-air to work before I go back to other engine parameters.

TBH I've got a bit bored with pulling the engine apart, and I'm back to being just a little afraid of the engine, rather than being bored waiting for the next gearchange.
So that'll do for now, engine-wise, I'll see what gains can be had from intake and exhaust mods.

[sirch345]

The reground cams were based on a standard set, and so the lobe centres were the same as standard.

I think I'll leave the reground ones in for now, not an amazing gain form standard but I like the "power-band" effect, and funnily enough they seem to be giving better fuel economy.
I'll have a play with the customised airbox and see if I can get ram-air to work before I go back to other engine parameters.

TBH I've got a bit bored with pulling the engine apart, and I'm back to being just a little afraid of the engine, rather than being bored waiting for the next gearchange.
So that'll do for now, engine-wise, I'll see what gains can be had from intake and exhaust mods.

Tony, I'd be well pleased with the results you've already achieved. I just thought it may have been worth checking the opening and closing times (that sounds like a pub doesn't it ) of the valves, seeing as you seemed to be a little disappointed with the dyno results. I can understand though you don't want to be pulling it apart anymore, you've certainly done more than your fair share of that

Those dyno figures are definitely not to be sniffed at

Chris.

[agentpineapple]

i'm well impressed with what you have achieved tony, do you have any plans in the future for maybe doing work privately on other peoples bikes, if so pm me mate i would be very interested in putting some work and money your way, and once again well done buddy............

[tony.mon]

So far the best power increase seems to be from high compression pistons, which can be bought for about £250 plus rings, assuming your bore is not too worn and a rebore is needed.
To fit these the engine needs to come out, it's possible with it in the frame but so awkward it's easier to pull it out, rebuild it and reinstall.

Then race cans and carb setup, on a dyno for correct fuelling, and maybe an aftermarket air filter.
That gets you about 112-114 BHP, including a significant boost to torque.

I can build a supplied engine for about £250 labour, but you'd also need to cost for at least two new head gaskets, manual cct's and four big end bolts, plus whatever bearings you needed.
This would include fitting manual CCT's, reseating valves, and reshimming, which would mean the equivalent of the major service, so would only need riding for a while.
If it were my engine I'd automatically fit new mains and big ends, and always the large bearing behind the clutch, as I believe that it is the main cause of grabby clutch syndrome.
If you need a donor engine, I have one, we can agree a figure if you want it.

If you want more, then it gets expensive, Yoshimura or Moriwaki cams, head work, and maybe a full system.

Have you considered just buying an SP1 or 2?

[Billinjah]

Do you make manual ccts? Do you buy into the fact that they are no good as they need to back out at certain revs?

[benny hedges]

manual tensioners may not be the 100% ideal, but are a far better option than a failure resulting in bent valves and worse.
the front cct is a weak point on the firestorm. do whatever you feel is best!

[Billinjah]

I'm trying to find details of the stopper mod the search throws up thousands of results lol was going to do this in the meantime. I've used manuals on all of my 4t enduro bikes and never had an issue so I'm happy to use them.

[tony.mon]

Do you make manual ccts? Do you buy into the fact that they are no good as they need to back out at certain revs?

Never had a good explanation as to why this is necessary?
Any ideas?

[sirch345]

Do you make manual ccts? Do you buy into the fact that they are no good as they need to back out at certain revs?

Bill, I know from many hours of R&D (many more than I care to admit ) on the Firestorm CCT's that the standard CCT's do adjust themselves at certain revs. So manual tensioners will always be a compromise on the original by having the tension set the same throughout the rev range, but have the added advantage of never letting go, unlike the standard non-modified ones, which I can see is very favorably for piece of mind

I'm trying to find details of the stopper mod the search throws up thousands of results lol was going to do this in the meantime. I've used manuals on all of my 4t enduro bikes and never had an issue so I'm happy to use them.

I've now added a separate post in the Workshop Knowledgebase accessible in the Workshop Section for the fail safe (stopper mod) CCT mod, so in future it's easier to find.

HTH's

Chris.

[tony.mon]

Latest update.
Fitted a four-row SP1 oil cooler, to assist with cooling the engine and oil now that it's running hotter than standard.
More power= more heat.

SP1 cooler:

It looks curved in the photo, but is straight and the same length as the Storm one.
The RH fitting is angled slightly to the outside; the standard one is straight, but it fits ok if you use flexible hoses:


The lines on the SP1 are larger diameter than the Storm, which has 10mm external, the SP1 has 12mm diameter, as far as I can tell.
That means that the holes in the cooler are larger, too:

But it seals ok with a washer and O-ring.
Because the bracket holes don't line up for now it's held on one by only one bolt; I'll make up a bracket next time it's apart.
It'll do for now.

I had the lines made up by Pirtek, using and cannibalising the original solid Storm lines and end fittings.
£100 inc mild steel fittings, so they'll need to be painted when I have a minute.
Looks ok, though:



Swingarm next, but not until after Wales trip and trackday at Brands Hatch on 1st June.

[mik_str]

I did the same thing a while back (changed to larger cooler). Mine was sourced from a Honda EX400 ATV but it looks identical to the SP-1 unit (right own to the angled inlet). I kept the stock lines but got a rad shop to straighten out the inlet so it mounts perfectly to the stock lines. I ran it the first three years with tie-wraps to hod it in place (along with rigid lines which obviously do their part also) but recently built a custom bracket (had some aluminum plate lying around and some time to spare....) for it. I made a guard for it (keep the critters and rocks away) from aluminum mesh but it`s a fairly tight weave and restricts airflow more than I`d like so I will be replacing it shortly with a more open mesh I have left over from the front air vent project.

Given the VTRs propensity to run hot (especially when modded), it seems to be a wise move.

cheers

[tony.mon]

UPDATE:

I was made redundant recently, and so last working day was yesterday.

Good news is that i have found another job (actually typed another position first, but I can't give away opportunities like that ) and it doesn't start until Monday 26th March.

I'll use the bike for the commute for a while, so it needs to be on the road and ready by then.

But that gives me a week to do a full engine strip-down and rebuild.
Last winter's rebuild was using a donor engine that had a lot of wear on the front cylinder; the piston wasn't a good fit but I went ahead anyway as I wanted it back on the road.

But since then i have acquired a couple of spare engines, one of which is low mileage but has a gearbox problem; jumps out of second.

So I'm going to strip the engine out of mine, and rebuild it using the high comp pistons (possibly swapping them round, front to rear, to equalise wear) but using the donor crankcases, crank, and rods.
I'll move across the gearbox from mine, as it's known good.

Clutch? I'll use the Kevlar plates I have, and make up a best set form the metal ones, and use the least-worn parts form all, based on AMcQ's experience I may fit a new top hat sleeve and bearing while I'm there.
I'll leave the hybrid hydraulic/cable conversion on for now.
Obviously any bearings, seals and other parts get renewed along the way, although if the mains and big ends on the donor engine look OK I'll leave well enough alone.

I am currently running heads that I've gasflowed myself, and modified cams, which I'm tempted to put back in for now, but have a set of spare heads fitted with four exhaust cams- minor differences, but apparently beneficial.
I plan to change the valve timing slightly, 5 degrees advance on the inlet and a little more on the exhaust as I want t bit more overlap. It'll further ruin fuel consumption but should increase power a little, but before I get to that stage I'll revisit all of my notes about cam timings for Mori, Kent, and a couple of other cam mnfrs, to see what they've come up with.
And I'l have to set it up on first on a rod and pistonless upper engine case so that I can see into the barrel and check clearance between valves during the rotation of the engine.

I reckon that's a week's work, and I'll try to get it finished in time to get Dyno work done on Friday with the MWR filter.

Best get started, then.

[sirch345]

Good news on the job front, well done nice to know you got that positon

Interesting to hear what you're hoping to do with your VTR engine. That sounds like that could be more than a weeks work, but seeing as you need it for commuting no slacking

Chris.

[seb421]

Aye well done on the new job! that's a worry off the shoulders

and my god your going to be a busy fecker till the new one starts, nothing like a bit of time off ey tony

saying that i do enjoy some time spent in my cramped garage with the heater and radio on and as many brews and biscuits as i can sink