engine tuning ntv600

[fenton]

i went out today on the bike and was very disappointed with the acceleration going for the overtake. I stopped at a cafe and had a chat with a few lads there one suggested fitting a turbo and or doing some engine work. what makes me grin is my nsr250 mc21 has 60 hp ! any input on how to get the best from the ntv very much appreciated

[Jake]

Fenton,

Apart from adjusting valves and carbs etc., I’d recommend fully synth Silkolene 5w40 oil and SplitFire spark plugs SF416C. Both come at a cost however….. A new air filter always helps…and 98 octane petrol. Some would argue that this defeats the purpose of the NTV being an economic bike to run. But Like you, I prefer improved throttle response, and it’s nice to feel the bike perform close to its potential…..

www.bellrockracing.co.uk/sparkplugs.html

www.splitfire.com/
b2c.oldworldind.com/b2c/catalog/

Also, try checking out Steve Beatty’s Hawk site and the MHP exhaust….

www.hawkland.de/beatty/mhp.htm
www.hawkland.de/beatty/HawkGT.html

Jake.

[fenton]

thanks for that. do the plugs and oil make that much of a deference ? everything i have read on the ntv motor says that it is in a state of mild tune do you not recommend getting the dremel out and doing a Little port work ?

[Jake]

Fenton,

It's lot less risky to begin by changing oil and plugs.... You can modify ports later if you feel it's needed.

But yes.... the Silkolene oil and SplitFire plugs make a noticable difference otherwise I wouldn't keep on using them. Don't just take my word for it, though, give it a go yourself and see what happens.... It certainly won't do any harm to the bike, but altering the ports could be irreversible if anything goes wrong.

Jake.

[fenton]

i did the oil and plugs this morning and went out for a ride the only way i can explain how the bike feels is gutless it is a bit better than last time but not much. i came back and cleaned the carbs and air filter went back out and it was a tiny bit better but still wouldn't pull the skin of a custard it gets to 65 70 then its just flat any ideas what to try next

[sheekbiker]

Hi Fenton,
What are you comparing the bike with, if you had say a Fireblade then it will seem gutless, I have the 600 Revere and all my mates are suprised just how well it goes.
I think the road test said 0 to 60 mph in 4.7 seconds and a top speed of about 105 mph.
Check compression on both cylinders is OK and that the valve and ignition timing are correct, what colour are the spark plugs should be light brown not white or black.
Is the fuel pump working OK the bike will run without it pumping but will starve at high revs, there is a fuel filter near the pump check to see that it's not blocked up at all.
Could it be that the clutch is slipping a bit or the brakes binding, try turning the wheels by hand to be sure there are no tight bearing in the transmission.
If that lot's OK then perhaps a previous owner has rejeted it for economy or something, can't think of any thing else at the moment.
Sheekbiker.

[Jake]

Mine has no problem running at 90 up to 112mph on the motorway…. And that’s with a fairly large National Cycle screen fitted. In fact on the motorway the bikes running at 90 mph for most of the time…. 80 feels too slow.

Maybe you should follow Steve’s example and try a Predator exhaust. It sounds like a worthwhile upgrade and I’m tempted to buy one….

www.growell.proboards49.com/index.cgi?board=tech&action=display&thread=1191250088&page=2

Jake.

[McF]

Did you see the recent post (I cannot quickly locate it I'm afraid) on poor power performance?
The problem was sticking slides in the carburettors. Solved by polishing them. You said that you had cleaned the carbs, so you have probably done this, but if not, perhaps that is worth looking at. I'm assuming that you have already cleaned the float bowl and jets etc.

Performance on mine is very good, even compared to memories of a CBR600 (granted, not in the same class, but it's not significantly worse). I regularly cruise at 80+ and it's not sluggish getting there; there's enough power left to bring a cheesy grin when I want to as well.

When I had first completed assembly, I had a problem with mine running on one cylinder, it felt sluggish, but still got up to 65-70 before I discovered a cracked coil and realised I should have expected more from it.

As suggested by Sheekbike, if the engine is fit, there's nothing slowing you down is there, eg brakes sticking slightly on?

[Jake]

Other things worth checking are valve clearances very 8000 miles or so, and carb synchronisation. Before this is done you’ll need a new air filter…. I’ve tried using K&N air filter-cleaner in the past, to clean old filters. But although it’ll get rid of most of the grunge, a cleaned air filter does not work as well as a brand new one. Wemoto sell pattern air filters at a reasonable price….

Also, see post below on poor power performance:

www.growell.proboards49.com/index.cgi?board=tech&action=display&thread=1192794041


Cheers,

Jake.

[fenton]

been round it today and i think the problem is that it has done 98k mite be time for a rebuild

[honda]

Having read all the postings I would advise having a good bike mechanic look at it. Someone mature with plenty experience. Unless it is blowing by and filling the airbox with oil or the crank is rattling around in it like a bag of bolts, both of which are easly seen/heard there is no need for a rebuild. There is more than likely a logical explanation which can be cured without a complete rebuild. Jets blocked, slides sticking, air filter blocked, exhaust blocked, poor or no spark to one or both cyl's, fuel starvation from tank, restrictor fitted, tight tappets, someone timing the cam's wrong?? All can be sorted without major expense.
honda

[norman]

Hello, when bought my NTV it would not pull above 4000 revs,pistons in the carbs were sticking, this is what McF mentioned. Gave them a good polish until they moved freely and now it goes like the clappers. Red lines in every gear no probs. Make sure the diaphrams are properly seated, one of mine was out of place when I took the top off the carb.
PLUGS ,OIL AND FILTER.AIR FILTER SORT OUT SLIDES AND DIAPHRAMS AND NOW THE OLD BUGGER FLIES, WELL MAYBE FLIES IS NOT ACCURATE FOR A ntv BUT IT PULLS STRONGLY UP OVER A 100.
good luck Norman

[McF]

Carb Diaphragms!
check they're intact too. I have a set of Carbs with badly split Diaphragms. Unlike my beemers, they're not user replacable. I found a place in Manchester that will do them for £34 each. Seems rather steep, but I blame Honda for making them a professional fit.

NRP
Unit 2 Station Approach
Victoria Station
Manchester
M3-1NY
www.NRP-carbs.co.uk

0161 832 8646

[pugs]

didnt realise how good these beastys are, handles like a dream, should have bought one years ago.going to respray mine at some time this year.mines an 88 one ntv600 revere

[RJ2Para]

I have a Revere 600 which also goes like stink, if you need an upgrade to go faster you may be better getting a sports bike.

If it is not broken ride it hard :-)