450 FSE 2004 starting issues


New member
Hi all,

I spent time stripping and cleaning the callipers, new seals, pads etc... Changing the bars, tyres and just getting it ready to ride.

As a matter of course I carried out a compression test it was just above 100psi, further investigation revealed it had suffered a dropped valve and they had left the piston in. The barrel looked like it had been sandpapered and the rod had about 2mm vertical movement on the pin (it had worn through the case hardening).

I've spent circa ?800 on new rod, piston, nikasil bore, gaskets, bearings etc.

I have a good spark and after checking the injector - what looks to be a good fan spray. I have now the diagnostic lead and have re-set the tps. The CO trim is see to 0. The sensors all appear to be reading correctly (guzzidiag)

The fuel is new and so is the plug. I have 2 relays on order and my next steps are to check the value clearances again.

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So tonight I checked the valve clearances and the exhaust valve, with the decompressor, was now .3mm over size!

I also wanted to check out the starter motor. I could see a rubber bung in the casing where the DRZ positive terminal usually exits and could see where a hole had been drilled in the rear of the casing - after reading a few of the threads off here I recognised the mods to be a DRZ starter with a modified casing. It didn't look in bad condition and just needs a clean up and a set of brushes.

The new relays are also here, I've ordered the V23074A1001A403 in replacement for V23074A1001A402 - I picked up the A403's for just over ?5 delivered from RS where as I struggled to find a supply of the A402's in the UK. They should be suitable as the gasgas doesn't require the middle pin (4).
So now I know why the valve clearance had been increased so much - it hadn't! Turns out if you check the clearances on the back of the cam on the exhaust decompressor cam the decompressor is in the right position to hold the valve open a fraction (as it should during starting) - lesson learnt!

After a recheck the shim is too big by 0.08 so I'll sort a new one out tomorrow.

Next step is to have the injector checked for flow rate and new filter fitted.
Not much progress tonight, I should have the shim tomorrow and the bits for the starter motor.

When I was building up the top end last night to check the clearances I sat the chain back on the sprockets. I was reading through the small amount of literature I have on the engine and I noticed something I'd not seen before. When timing up the crank to cam position there is no marks on the flywheel. This makes things difficult but I set it at TDC and set the cams with 3 on the inlet pointing up and on the exhaust cam 2 pointing up. I counted the pins as 15 which is correct also. Then I realised the arrows were also pointing to specific pin positions I.e the exhaust cam number 2 arrow points at the left pin on a complete link and so does the number 3 arrow on the inlet.

I basically got it a link out - unfortunately I don't know the timing condition before I stripped it other than it was at TDC & I had 15 pins between the vertical cam arrows - chances are I got this wrong last time.

Question is was it wrong when I bought it? I'll never know now but I do know with its dropped valve it had been touched at some point.

So when it goes back together tomorrow I'll make sure it's correct! Injector should be back from cleaning in a few days and then I'll try to fire it up again.
Top end built back up again - re-shimmed and timed (correctly this time!) and starter motor built back up with a Honda brush plate (identical to the gasgas one).

I've sent the injector off also to be cleaned, filter changed and new seals so that should be back early next week.
Hi, no I cleaned it through myself, took out the air bypass screw and cleaned also and replaced to 3 1/2 turns out from fully in.

Does anyone have a base setting for this?

Back on the engine timing - I'd not come across a 'wasted spark' concept before on a bike. As you time the engine up on TDC, and as the gasser runs a flywheel position trigger, the ignition system has no way of knowing its on the ignition stroke so basically it fires every stroke. Helps to recover any unburnt fuel I suppose on the exhaust stroke.
That's great, thanks for the info. The throttle stop has definitely been touched as the yellow paint is missing from the screw - I'll check the values plus set the air bypass back to 1 1/2 turns out!
Ok so the injector came back today and the flow rate has increased marginally with the clean - they run a before and after - it's increased by about 3% and the spray pattern is now back to as new.

After tank back on and everything coupled up I hit the button - it now fires on no throttle but not enough to coax it into life. After a little more cranking and an open throttle it started up and ran well. Releasing the throttle it sat on a nice steady idle.

I turned it off and after 4/5 attempts on an open throttle it started and ran again well.

I bought it back into the garage as it's still missing it's chain and other bits and bobs and realised I hadn't yet set the air bypass screw to 1 1/2 turns. I hooked up to Guzzidiag and the throttle voltage was 530mV.

Yngvim - do you have the setting range for the throttle - is 530mV too high?

I've reset the TPS but didn't have the time to run the engine again this evening.
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530mV is way too low.
I recommend using volt meter cause guzzidiag is not accurate, it jumps 20 mV.

First loosen the screw which had the yellow paint to fully close the throttle blade.

Next step is to adjust the sensor on the side of the throttle body so you get minimum 351mV, write down your voltage.

Next you add 290mV to the voltage you wrote down, if you had 355mV, 355+290=645mV.
290mV equals 6,5 degree opening on the throttle blade.

Next you screw in the hexagon screw until you have added 290mV and reach your calculated number.

Last step is to use the program to reset the TPS

Hope this will help so you can start her up on first push and without touching the throttle.

Sent from my LG-D855 using Tapatalk
Thank you for explaining - I was struggling to understand the link even with google translate!

So using the multimeter the value from the tps was 320mV. I slackened off the two screws and by some slight movement it jumped up to 360mV.

I then wound the throttle stop back out again to get 650mV.

I hooked up guzzidiag and reset the tps using the 'actors' feature but now the column on the right hand side is showing the throttle as 'between' when on closed throttle. If I open the throttle fully it's showing as being on the stop as it did before.

Previously when the throttle was closed it would register the throttle was on the stop. Should this be of any concern Yngvim?

I ran out of time again tonight so didn't get chance to try it but I will again tomorrow.

Many thanks again for your detailed help Yngvim!
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This is what it looks like when I connect my 2004 450fse to IAW Diaguploadfromtaptalk1446217609188.jpguploadfromtaptalk1446217631547.jpg

I tried to set TPS with IAW Diag but I can't see if it changed anything.I did use another program to set the TPS when I was figuring out how to get her running properly.

Just try to start and see what happens, maybe there is some auto learning functions if using IAW Diag doesn't work to reset the TPS.

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Thanks for that extra info - I'm never sure that the tps reset on guzzidiag works as I can't see any change to the values - what other program did you end up using?

I did however disconnect the yellow and blue lead yesterday to put it into race map mode - changing too many things at the same time is never good!!

I opened the bypass to 2 1/2 turns and started it again (on full throttle as when on 0 throttle it wouldn't kick into life) it ran nice and idled evenly.

Id like now to successfully reset the tps so it knows it's on its closed throttle and it registers its position in the text.
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I used MDST software, I was able to borrow it from my dealer.

Maybe next step is to contact Bern and see what he can do with Guzzidiag.

As I understand it we are setting the TPS not resetting it

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Well I took it out yesterday to go find some local lanes. It's been on the optimate but not been started for about a week.

I followed the general rule to key on, listen to the pump prime, then open the throttle for 5 seconds, close the throttle and hit the button - it fired into life like a dream!

I jumped on it and headed out, pulling up at a few road junctions I let it drop onto idle - absolutely perfect.

I found the first lane, not tricky but over grown, first gear just above tickover, the gearing was a little tall but it handled well and didn't feel too heavy. It turned into grassy ruts which it handled nicely, only slight complaint was its a little bit stiff on the suspension.

Back on the road and it goes well, really well, a quick run through the gears and 60mph comes quickly.

I stopped it a couple of times whilst opening gates, every time I patiently followed the same startup regime, and it rewarded me by instantly firing into life.

I spent just over an hour playing before heading for home, I was cold and it was raining, but the satisfaction was immense!
Hope it ran reliably for you ! Can't help with the engine / fi, but I had success with having http://proracing.co.uk/ do the fork shims to work better in our native mud than the Spanish rocks they are set up for. Sounds like we ride some of the same greenlanes.
I have a problem where my '05 FSE stall at idle and when starting to accelerate sometimes. Have checked everything and nothing helps.
I went to my GasGas dealer and he saied that '05 FSE had two different voltages when adjusting the TPS. At the moment i have added that +290mV but he said that on some bikes it was smaller voltage. So i tried today that +170mV what should be for FSE400 and i must say that at the moment it seems to work better. So my question to Yngwim is, do you know about that voltage situtation on '05 bikes? What happens if i leave the TPS with +170mV for now?

EDIT: Made a little 18km test ride with +170mV and the bike didn't stall and it feels better than before, butt-dyno would tell that theres more torque than before....

EDIT 2: Made a second test ring and this time managed to get bike really hot and it started to stall on tricky stuff and sometimes when trying to accelerate from small revs....maybe screw the bypass screw out a little bit to increase the idle??? And it's harder to start when hot and stalled.... Could it be faulty TPS? But why all those things start to happen when the bike is really hot?
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