FrenchPaddy
11-02-2023, 04:44 AM
Hey all -Looking for a bit of advice/guidance from those that have done this.
About to rebuild my old 86 350x with a sandblast and chassis Gusset kit so was thinking about doing some performance upgrades while I am at it.
The suspension has been leaking and I'm sure the caliper pistons and swing arm bearings etc are all full of water etc so she is long due a freshen-up
The Bike is easy to start, Choke on, and 2 or 3 kicks and away. power is good through the rev range and probably enough for me under most case scenarios - although I have a plan to move to a place with more land in the future.
The bore seems to be OK so it's kind of a shame to open it but I got an inkling to fit one of those 10.25:1 pistons or more while the motor is out. the OEM compression seems more catered for Poor quality fuel which is not the case anymore
And one might say it would be a shame not to do the valve guides while in there. which leads to the question of porting too...
On the local free ads, there has been an EX400 pumper carb sitting for ages at 50 euros and I reckon 30 or 40 would buy it, it's a genuine one, seems to be missing a plastic cover or two but appears complete and the seller says was operational.. This is France so old stuff like that does not tend to rush off the shelves like it would elsewhere. People just buying new Polaris stuff with all this new borrowed money
The question is would a brand-new EX400 pumper China Carb off Amazon be better than a used and probably abused OEM EX400 Honda carb. Have tried the search but there is little info on the subject- only what people have managed to interchange between the 2. Seems one also needs the ultra-rare EX400 intake boot as well to run the pumper carb or have I got that wrong?
I have also read that there is a plug-and-play CDI upgrade .. was it the XR400? confused now as a lot of threads about XR250 / XR650 cdi and swapping flywheels etc.. surely some extra advance would be no harm on high comp better fuel.
Presently it's on standard EU exhaust ( no spark arrestor) I have a slip-on Supertrapp that seems to have about 6 discs ( was supplied with the bike unfitted ) There is also a cheap EX400 stainless header on EBAY UK which seems can be made fit easily enough. But I have no idea if it was standard or upgraded on the EX400. or even if there is a change in inside diameter over the 350x system.
Performance camshaft.. Not sure that is something I 'need', The grunt off the bottom is lovely, and without a Cdi curve to follow/ bigger valves proper ports, you surely never going to get that V-tec, yo
Final thought. E85 ethanol is available at the pump pretty much everywhere here at about 0.80c a liter.
Been running an old Saab turbo wagon on it, Big 760cc injectors dosing it in, and still melts a piston every few months :lol:
With that 12.1 piston, the trike would easily handle E85 but would need to be jetted waaay more and once again the whole goal of E85 is to run wild ign curves as it's equivalent to 105 octane, Was just an idea but for all I use it she can stay on 98 gasoline. would be a nightmare to set up and then it can never handle STD gasoline again without major backpedaling
OH yea and my kickstart pedal is starting to show signs of stress fracture. these don't seem to be available anymore. before I go welding is there a better solution?
Any thoughts or recommendations on what I should do or not do based on the above? Those who say leave it well alone will also be listened to!
About to rebuild my old 86 350x with a sandblast and chassis Gusset kit so was thinking about doing some performance upgrades while I am at it.
The suspension has been leaking and I'm sure the caliper pistons and swing arm bearings etc are all full of water etc so she is long due a freshen-up
The Bike is easy to start, Choke on, and 2 or 3 kicks and away. power is good through the rev range and probably enough for me under most case scenarios - although I have a plan to move to a place with more land in the future.
The bore seems to be OK so it's kind of a shame to open it but I got an inkling to fit one of those 10.25:1 pistons or more while the motor is out. the OEM compression seems more catered for Poor quality fuel which is not the case anymore
And one might say it would be a shame not to do the valve guides while in there. which leads to the question of porting too...
On the local free ads, there has been an EX400 pumper carb sitting for ages at 50 euros and I reckon 30 or 40 would buy it, it's a genuine one, seems to be missing a plastic cover or two but appears complete and the seller says was operational.. This is France so old stuff like that does not tend to rush off the shelves like it would elsewhere. People just buying new Polaris stuff with all this new borrowed money
The question is would a brand-new EX400 pumper China Carb off Amazon be better than a used and probably abused OEM EX400 Honda carb. Have tried the search but there is little info on the subject- only what people have managed to interchange between the 2. Seems one also needs the ultra-rare EX400 intake boot as well to run the pumper carb or have I got that wrong?
I have also read that there is a plug-and-play CDI upgrade .. was it the XR400? confused now as a lot of threads about XR250 / XR650 cdi and swapping flywheels etc.. surely some extra advance would be no harm on high comp better fuel.
Presently it's on standard EU exhaust ( no spark arrestor) I have a slip-on Supertrapp that seems to have about 6 discs ( was supplied with the bike unfitted ) There is also a cheap EX400 stainless header on EBAY UK which seems can be made fit easily enough. But I have no idea if it was standard or upgraded on the EX400. or even if there is a change in inside diameter over the 350x system.
Performance camshaft.. Not sure that is something I 'need', The grunt off the bottom is lovely, and without a Cdi curve to follow/ bigger valves proper ports, you surely never going to get that V-tec, yo
Final thought. E85 ethanol is available at the pump pretty much everywhere here at about 0.80c a liter.
Been running an old Saab turbo wagon on it, Big 760cc injectors dosing it in, and still melts a piston every few months :lol:
With that 12.1 piston, the trike would easily handle E85 but would need to be jetted waaay more and once again the whole goal of E85 is to run wild ign curves as it's equivalent to 105 octane, Was just an idea but for all I use it she can stay on 98 gasoline. would be a nightmare to set up and then it can never handle STD gasoline again without major backpedaling
OH yea and my kickstart pedal is starting to show signs of stress fracture. these don't seem to be available anymore. before I go welding is there a better solution?
Any thoughts or recommendations on what I should do or not do based on the above? Those who say leave it well alone will also be listened to!