Quad Yamaha Beartracker

Sami23

Hi all, looking for some advice on my Quad. It starts fine with choke on but revs excessively, when I turn choke off it cuts out. What might be causing this problem ?

CJhaughey

Sami23 wrote: »

Hi all, looking for some advice on my Quad. It starts fine with choke on but revs excessively, when I turn choke off it cuts out. What might be causing this problem ?

Blocked jets after sitting for a while.
Remove carb, strip, and ultrasonic clean.
Rebuild and refit.

Sami23

CJhaughey wrote: »

Blocked jets after sitting for a while.
Remove carb, strip, and ultrasonic clean.
Rebuild and refit.

Thanks will have a go at wend if I get a chance. Your right it was parked over da winter

CJhaughey

Here is a good tip.
Next year, buy a 5 litre can of Aspen petrol and after emptying the tank.
Pour the 5 litres in and run it through the engine.
It doesn't have ethanol or any other crap that sludges the carb and will likely be fresh enough in the Springtime to start.

roadsmart

CJhaughey wrote: »

Blocked jets after sitting for a while.
Remove carb, strip, and ultrasonic clean.
Rebuild and refit.

Before you go to all that trouble try a can of wynnes carb cleaner, you can get it in halfords. 500ml of redex injector cleaner in your tank usually does the trick too. If it's been lying up all winter the petrol is probably off, fresh juice needed.

Sami23

Well lads, believe it or not I only got round to workin on the quad last w-end.
Anyway I took off the carburetor, stripped it all down, sprayed everything with carb cleaning spray and carefully put it all back carefully. Cleaned out fuel tank and put new petrol in.
Unfortunately the same problem exists. It starts easily on full choke but immediately revs very high resulting in the exhaust pipe getting red hot coming out of the engine. On full choke the accelerator works fine albeit pretty much full throttle
When I go to half choke or no choke the bike cuts out straight away.
Can anyone please suggest what the problem is or what I can try next as I have no idea as I was sure the carb clean would work.
Thanks

Flood

What is the condition of the boot, i.e the piece that marries the cylinder head to the carburetor?
The high revving can only be down to stuck throttle cable or similar.

Sami23

Flood wrote: »

What is the condition of the boot, i.e the piece that marries the cylinder head to the carburetor?
The high revving can only be down to stuck throttle cable or similar.

Hi Flood. It's a new boot that's on her and new spark plug too. The throttle cable is sound and working ok with full choke on but when I close choke she just cuts out.
I'm wondering would one of the small holes or inner chambers of the carb be blocked ? as I don't know what else it cud be ?

Flood

Are you sure you have the understanding of the choke correct, you are not mixing up choke on with off? The diaphragm/vacuum piston must be put back incorrectly and stuck open if the revving is uncontrollable and stuck revving itself. It cant be anything else.

Sami23

Flood wrote: »

Are you sure you have the understanding of the choke correct, you are not mixing up choke on with off? The diaphragm/vacuum piston must be put back incorrectly and stuck open if the revving is uncontrollable and stuck revving itself. It cant be anything else.

Ah feck ya of course I'm not mixing the choke up with the off switch.
Could it one of the small holes or chambers in the carb that's blocked I wonder ?

Flood

When you cleaned the carb did you not check were all jets were free? You have more than one issue, the high revving wouldn't be related to a blocked jet I would have thought.

Sami23

Flood wrote: »

When you cleaned the carb did you not check were all jets were free? You have more than one issue, the high revving wouldn't be related to a blocked jet I would have thought.

I did. I removed the 3 jets (main, idle and another small 1) and cleaned them.
All I can do is rip it again and clean I suppose

Flood

What is the history on the bike, did you buy it this way or was it running fine and suddenly acting up?

Sami23

Flood wrote: »

What is the history on the bike, did you buy it this way or was it running fine and suddenly acting up?

No it was fine when I bought it. Then it was left for a winter and started this cracked after the winter

Flood

Does the bike have the same traits now as to before you cleaned the carb?

Sami23

Flood wrote: »

Does the bike have the same traits now as to before you cleaned the carb?

Yes very same

Man of Aran

Possibly float or float chamber related issues?

Sami23

Man of Aran wrote: »

Possibly float or float chamber related issues?

Would ya recommend I order a carb repair kit and try that or go all out and buy a new carburetor ?

Flood

You better be sitting down when you hear the price of a new carb. Unless you have wear in the needle jet, needle jet holder and needle jet I dont see a carb kit solving your problem.
Is the throttle tick over wound up to the last or cable stuck?

Sami23

Flood wrote: »

You better be sitting down when you hear the price of a new carb. Unless you have wear in the needle jet, needle jet holder and needle jet I dont see a carb kit solving your problem.
Is the throttle tick over wound up to the last or cable stuck?

No throttle cable is fine and idle is not wound up.
Wonder wud it b anything to do with the diaphragm or needle coming down from it ?

Forgot to mention that when I did put it back together petrol was coming out from the overflow pipe at the bottom of the bowl so i had to take it apart again and the needle was slightly stuck so wonder would this b related to my problem.
By the way thanks for you advice and help so far cos it's so annoying I can't get it going

CJhaughey

Check the float valve is clean and the seat is clean.
If the fuel level inside the floatbowl is too high or low it will affect the way the engine runs.
I have found with modern fuel and especially after sitting over winter the crappy ethanol in fuel will deposit a kind of coating on the float valve. this can result in the valve sticking and either a low fuel height or an overflowing fuel height.
I would start with stripping the carb again and when you do so, check the float valve tip, it should have a black rubber pointed tip if its dirty or covered in a scum it won't seal properly and will cause flooding as the fuel flows in and the needle can't seal the valve.
Clean it thoroughly so the rubber tip is clean.
Next check the brass seat that the needle valve seats against, that should also be spotless and not full of gunge.
I find a cotton bud with some cab cleaner sprayed onto it works well, in extreme cases a little brasso dripped on to the cotton bud and polish the valve then spray with carb clean to wash it clean.
Make sure the pilot and main jet are very clean, run a bristle from a brass wirebrush through it to make sure its clean don't use steel as it will damage the jet and cause more issues.

If it won't run on half or no choke it sounds like the pilot jet is blocked.
The biggest problem is that all the little passages in the carb get a kind of varnish in them when left idle, when you put fresh fuel in, the varnish gets loosened and comes down and can end up blocking things like the float valve or jets, usually pilot because its so small.

Lidl have ultrasonic cleaners for 25 euro or so, its worth buying one and running the carb in it for a few runs to make sure its clean inside.

Sami23

CJhaughey wrote: »

Check the float valve is clean and the seat is clean.
If the fuel level inside the floatbowl is too high or low it will affect the way the engine runs.
I have found with modern fuel and especially after sitting over winter the crappy ethanol in fuel will deposit a kind of coating on the float valve. this can result in the valve sticking and either a low fuel height or an overflowing fuel height.
I would start with stripping the carb again and when you do so, check the float valve tip, it should have a black rubber pointed tip if its dirty or covered in a scum it won't seal properly and will cause flooding as the fuel flows in and the needle can't seal the valve.
Clean it thoroughly so the rubber tip is clean.
Next check the brass seat that the needle valve seats against, that should also be spotless and not full of gunge.
I find a cotton bud with some cab cleaner sprayed onto it works well, in extreme cases a little brasso dripped on to the cotton bud and polish the valve then spray with carb clean to wash it clean.
Make sure the pilot and main jet are very clean, run a bristle from a brass wirebrush through it to make sure its clean don't use steel as it will damage the jet and cause more issues.

If it won't run on half or no choke it sounds like the pilot jet is blocked.
The biggest problem is that all the little passages in the carb get a kind of varnish in them when left idle, when you put fresh fuel in, the varnish gets loosened and comes down and can end up blocking things like the float valve or jets, usually pilot because its so small.

Lidl have ultrasonic cleaners for 25 euro or so, its worth buying one and running the carb in it for a few runs to make sure its clean inside.

Thanks for that, I'll b giving it a go again this week.
Do you think it could be one of these jets being dirty that's causing it to rev so much when the choke is on fully too ?

CJhaughey

Sami23 wrote: »

Thanks for that, I'll b giving it a go again this week.
Do you think it could be one of these jets being dirty that's causing it to rev so much when the choke is on fully too ?

Check that the slide is the correct way round as well.
There might be a small marking on the diaphragm that shows the correct orientation.
If the pilot is blocked the engine will only run with choke, its being starved of fuel.
The reason you have choke is that when cold fuel will stick to the cylinder walls and the engine will be too lean to start, the choke circuit enrichens the fuel air mix so the engine will run correctly.
Did you blow the carb through with compressed air when it was stripped?

Flood

A blocked pilot would not cause it to be revving though.

CJhaughey

Flood wrote: »

A blocked pilot would not cause it to be revving though.

Correct blocked pilot won't cause the bike to rev.
I'd be checking the slide is seating correctly and the right way around, and float level.
Make sure the throttle cables are free and haven't unseated themselves.
Float height can be checked with a piece of clear tube connected to the carb drain hole and raised vertically, once the drain bung is open the pipe will fill to the same height as the float height.

Flood

What is a slide?

Sami23

Well lads, believe it or not I actually got her going again yesterday. I stripped the carb again to clean it and spotted a jet I had missed 1st time round. It was located deep in a hole between the main jet and the idle needle. I think its the pilot jet but could be wrong. It was fully blocked so she hadn't a hope of going right.
After putting her back together she actually started with no choke after a couple of years sitting there which pleased me.
I took her out of the shed and gave her welly down the fields for a while and she's goin mighty.

Only dodgy thing is she is a bit up and down on the idle revs. I got off to open gate and left her in neutral and she proceeded to race alot then return to normal then race again etc.
If I leave her in 1st with break on she ticks over perfect.
Wonder what might be causing this irregular idling ?

CJhaughey

Sami23 wrote: »

Only dodgy thing is she is a bit up and down on the idle revs. I got off to open gate and left her in neutral and she proceeded to race alot then return to normal then race again etc.
If I leave her in 1st with break on she ticks over perfect.
Wonder what might be causing this irregular idling ?

Check all the carb connections are tight and there are no leaks between the insulator boot between the head and carb.
Usually vacuum leaks cause hunting.
Try spraying some carb cleaner spray around the boot when the engine is running and listen for change in the revs.
@Flood slide refers to the sliding piece in the carb that moves up and down restricting airflow.
CV carbs have slides connected to the diaphragm, normal carbs have a cable attached to the slide.

Sami23

CJhaughey wrote: »

Check all the carb connections are tight and there are no leaks between the insulator boot between the head and carb.
Usually vacuum leaks cause hunting.
Try spraying some carb cleaner spray around the boot when the engine is running and listen for change in the revs.

Thanks haughey will do.

Sami23

Quick question. What type of engine oil is best for the Yamaha Beartracker, is ordinary 10w 40 car oil ok to use ?

CJhaughey

Sami23 wrote: »

Quick question. What type of engine oil is best for the Yamaha Beartracker, is ordinary 10w 40 car oil ok to use ?

You really need Motorcycle oil rated for use with wet clutches, JASO MA /
JASO MA2 spec on the label.
Car oil may cause the clutch to slip after a while.

The Sidewards Man

Motorcycle oil rated oil this is a new Charlie haughey.

CJhaughey

The Sidewards Man wrote: »

Motorcycle oil rated oil this is a new Charlie haughey.

JASO MA and MA2 oil is designed for use with wet clutches.
http://www.oilspecifications.org/articles/JASO_MA_JASO_MB.php