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1995 Monster 900
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Discussion Starter · #1 ·
Hi, I'm looking for some suggestions on how to get my bike starting. It's a 1995 900 Monster that hasn't run in 3 years.

I've checked valve clearances and put new belts on, new spark plugs NGK DPR9EA-9 and set gap to 6.4mm and new battery is fully charged.

Checked sparks visually and both have a spark. I also checked the coil primary and secondary resistance - the secondary are slightly out of spec - H is 16.4 and V is 16.5 - manual says they should be 10.8 to 16.2

Cleaned the carbs and jets - they were clogged and very dirty in fact inside of carbs was full of a gritty substance.

Attached vacuum hose from manifold to the fuel pump and attached another vacuum hose with a sealed end to the other manifold as my bike doesn't have a vacuum petcock (I added a manual petcock).

Put some petrol into carbs through the fuel line so there should be some in the float bowls.

I've tried starter fuel into the air filter area, as well as into the carbs and also into the cylinders (where spark plugs go) and I get a brief attempt at starting then nothing.

When I've seen videos of people using start fluid, the engine starts up and runs for a few seconds then dies, mine barely fires.

So what next? I'm wondering if the spark has enough spark and maybe I need new coils or spark plug leads?

Or maybe the carbs need a full rebuild or even replacing?

Anything else that I should try?
 

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So what next? I'm wondering if the spark has enough spark and maybe I need new coils or spark plug leads?
You can remove the spark plug, insert it back into the ignition cable, turn out the lights touch the spark plug threads to the head and crank it. You should be able to see the spark visually bright and blue. That's one way to test it. The other option is that you have no compression as in a broken piston ring or piston. If that was the case, the engine wouldn't have strong pulses when it turns over or much air shooting out of the spark plug hole. It would just sort of spin.
 

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1995 Monster 900
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Discussion Starter · #3 ·
Thanks @CheeseSpeed - I just tested the spark and the vertical is a bright blue and with a fast repeating spark. The horizontal looks weaker and doesn't repeat often but battery is drained now (so will recharge overnight).

I can feel compression on both cylinders and both feel the same to me which hopefully is a good sign the pistons are OK.

One other thing that could be a factor, the bike had an aftermarket rev counter added and I read somewhere that this can cause a problem with spark on whichever ignition control the rev counter is wired into. I didn't get a spark at all on the horizontal spark a few days ago and the rev counter was conntected to that ignition control. I removed the live wire but I've left the earth and signal wires connected to the control. I'm not sure if that could be causing a problem re weak infrequency spark?

I'll try removing rev counter eath and signal wires from the horizontal ignition control and try again when the battery is charged.
 

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put new belts on
Those belts need to go on the exact same way they come off. You don't just pull them off and put the new ones on, you have to keep the position of the stroke exactly the same. Note how this guy marks it:

This is going to be a hard start. Prime the cylinders with ATF to free up any stuck rings (let sit for 24 hours). You need to run the starter motor with spark plugs pulled for a bit (minutes not seconds) to get oil up and through the various oil galleys and pumps. Then dump a teaspoon of fuel down the spark hole to 'prime' the cylinder. Then replace spark plugs and run your test. This is a high compression twin... a lot harder to get this motor turning over than the videos with inline 4s you've probably been watching people do test starts.
 

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1995 Monster 900
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Discussion Starter · #5 ·
Those belts need to go on the exact same way they come off. You don't just pull them off and put the new ones on, you have to keep the position of the stroke exactly the same. Note how this guy marks it:

This is going to be a hard start. Prime the cylinders with ATF to free up any stuck rings (let sit for 24 hours). You need to run the starter motor with spark plugs pulled for a bit (minutes not seconds) to get oil up and through the various oil galleys and pumps. Then dump a teaspoon of fuel down the spark hole to 'prime' the cylinder. Then replace spark plugs and run your test. This is a high compression twin... a lot harder to get this motor turning over than the videos with inline 4s you've probably been watching people do test starts.
thanks @DucatiM900owner - I watched a few videos re the timing belts and was very careful marking everything before taking the belts off and putting on the new ones.

I couldn't workout why I was initially getting a weak intermittent spark from the horizontal compared to vertical - and then the horizontal stopped sparking altogether.

I've also got some inconsistent electrical issues i.e. the horn worked briefly now doesn't - only 9v getting to the horn.

And one job I thought would be easy, the oil change didn't happen as the oil nut is completely stripped on my bike so I couldn't get it undone.

So I've got the bike picked up by my local bike shop (I've used them before with other bikes and my scooter) and I'm getting them to check all the electrics and try and get it started. Hopefully I'll be up and running soon - I really want to ride this bike especially as we're getting into our Spring and Summer here in Sydney.
 
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