VTR 250 won't rev out

[Tony]

I have a VTR 250 that doesn't seem to rev out as high as it should. It's a bit hard to tell where it revs to as there is no rev gauge.

But in second gear it begins to mis at high revs. (havent tried reving it out in other gears yet - but it's likely that it will have the same problem)

It has new plugs, fuel filter and air cleaner.

I suspect the carburettors.

I am guessing the carburettors need a strip and clean. I doubt they have had this since new.

I've done a bit of mechanicing on car and two stroke carburettors and but I am not gain to tackle these until I have watched someone else do them first.

I want someone with experience with this engine and these carbs. Can anyone recommend a good Honda mechanic in West Auckland?

I want a guru. (Preferrably someone who will let me watch over their shoulder)

[SupaCross Cycles]

sounds like your main jet

[NOMIS]

I have a VTR 250 that doesn't seem to rev out as high as it should. It's a bit hard to tell where it revs to as there is no rev gauge.


I want someone with experience with this engine and these carbs. Can anyone recommend a good Honda mechanic in West Auckland?

I want a guru. (Preferrably someone who will let me watch over their shoulder)

Take it to wild west Honda in New Lynn. and ask If you can watch,

[Tony]

sounds like your main jet

Nomis, I am guessing you are right if it's not something in the electrics. If it was electrics I would expect it would mis under load in higher gears at lower revs - which it does not.

How hard is it to clean the main jets. Is there anything I need to be alert for (Flying springs, etc!)

Is a fuel cleaner likely to help?

Have you had any personal experience with the mechanis at Wild West Honda? Are they good guys?

[Patar]

what's your top speed in second? I can get up to about 80-100 in second so if you're trying to push it past that you're likely hitting the limiter.

[FastBikeGear]

what's your top speed in second? I can get up to about 80-100 in second so if you're trying to push it past that you're likely hitting the limiter.

Patar their is a big difference between 80Km and 100km (20%).

Do you know whether it is 80 or 100 you are hitting in second?

[MSTRS:Me]

Which gear it is in should have nothing to do with it. Symptom suggests one of three things...
1. Starving for gas...blockage in the fuel line or jets?
2. Problem with electrics/coil(s)
3. Revving too high and hitting the limiter (if VTRs have such a thing)

[FastBikeGear]

Which gear it is in should have nothing to do with it.)

Thanks for your help your suggestions look pretty good but my first step is determine if I am actually getting full revs. My year VTR has no rev gauge. If I knew the top speed in second or third gear I would be able to confirm this.

[MSTRS:Me]

A rev counter is not required to know if it's doing what it ought to...Take it to a Honda shop. A mechanic can 'bench test' it and you shouldn't be charged for an opinion thusly gained.
And are you Tony or Wobblyas? Or both (frowned upon)

[FastBikeGear]

And are you Tony or Wobblyas? Or both (frowned upon)

Father and son

[Badjelly]

My year VTR has no rev gauge. If I knew the top speed in second or third gear I would be able to confirm this.

Your manual should be able to tell you your gear ratios and your sprocket sizes. You can measure your wheel size. A few quick calculations and you're sorted! You can probably find a calculator application on the WWW.

No rev counter?! The last bike I had like that was a Honda CB100, ca 1971. But it had markings on the speedo to indicate the speed range in each gear.

[MSTRS:Me]

No rev counter?! The last bike I had like that was a Honda CB100, ca 1971. But it had markings on the speedo to indicate the speed range in each gear.

VTR 250 1998?-2000 do not have a rev counter

[FastBikeGear]

Your manual should be able to tell you your gear ratios and your sprocket sizes. You can measure your wheel size. A few quick calculations and you're sorted! You can probably find a calculator application on the WWW.

Bad Jelly thanks for the good suggestion. Here are the gear-speed-rev charts I have come up with for the 2002 VTR 250 using the listed gear specifications and an on line calculator.


Theoretical speeds:

@ 11,500 red line
1=2.733 =60km/h
2=1.800 =92km/h
3=1.375=120km/h
4=1.111=148km/h
5=0.965=171km/h

@ 10,500 (max horse power)
1=2.733 =55km/h
2=1.800 =84km/h
3=1.375=104km/h
4=1.111=135km/h
5=0.965=156km/h

@ 8500 (max torque)
1=2.733 =45km/h
2=1.800 =68km/h
3=1.375=89km/h
4=1.111=110km/h
5=0.965=126km/h

Calculated with:
Primary drive ratio 2.821
Front sprocket 14 (I also saw 15 on one spec sheet)
Rear sprocket 41

I pasted stickers on the speedo that corresponded to the red line and road tested - Voila I am definitely getting full revs. I guess the sound of the V-Twin just had me fooled into thinking it was reving lower than it really was.

[koba]

Actually back to solving the problem here...

Clean the carbs out, esp the main jets.

Anyone can do this, its very easy you just need basic tools, make sure you have decent screwdrivers.

Here is how to do it, from memory, after I've been drinking!

I'm thinking of an '86 VTR but shouldn't be that differend for most models.
The reason for the detail is that thae carbs are a bit of a bastard to remove, esp if its old and the rubber boots holding them on have gone hard.

Take the fuel tank off being careful not to scratch it or spill fuel.
You will have to disconnect a fuel line or two - set tap to off! aswell as the fuel guage wires and probably a drain hose.

Take the plastic bits of the airbox off and you should have an alloy tub kind of thing that is connected to the mouths of both the carbs.

Undo the clamps (underneath) that hold the carbs on (should be four hoseclamp things to undo)

Now the hard part.
Get a sturdy screwdriver and lever the carbs off with it.
You want to get the screwdriver in between the top of the rubber boots and the engine side of the carb. there should be a sturdy tab kind of bit to push on.
Be gentle and try not to damage the boot.
If you alternatley move each carb up a wee bit at a time you should get them off nicley.


Pull the bottom off each carb, careful the screws are soft.

It will look a bit like this but a different shape.

Pull the jets out one by one and opke the holes with a still nylon brush bristle or somthing else that wont enlarge the holes from you poking it in there.

Put it all back together.

Good luck.

[FastBikeGear]

Many thanks Koba.