Honda TRX250R Forums banner

1 - 20 of 36 Posts

·
Registered
Joined
·
81 Posts
Discussion Starter #1
So I bought my 86 r blowed up and rebuilt it it ran good for about a week then the counter balancer bearing went out and made a mess out of the bottom end I had a spare that came with the bike that had a 310 kit on it so I took the new top end kit on it and it wasn’t firing so I swapped stators and got it running but it ran awful wouldn’t even hit power band so I put new crank seals in it because I thought that was my issue but it didn’t fix the issue I noticed the spark was kinda weak looking and noticed the plug wire was taped up where it had Ben cut it has a nology coil I tried a 8 mm car plug wire but it didn’t help I’m wondering if that may b because it doesn’t have the ground strap I hate to give 42 dollars for a plug wire if that isn’t the problem can a regular plug wire be used with a nology coil I don’t know what would make it run badly from the bottom end considering I changed the stator and everything I noticed that the flywheel on the 310 had Ben grinded on the tab that comes around on the out side I guess to try change timing or something idk about half of the tab was grinded off so I changed the flywheel any awnsers on what my issue might be would be greatly appreciated
 

·
Registered
Joined
·
332 Posts
Also when you put the spark plug cap on the new wire screw it on rather than trying to force the cap on the wire.That can cause a bad connection and weak spark..
 

·
Registered
Joined
·
81 Posts
Discussion Starter #4
I ended up putting new ends on the plug wire and getting it fixed I also found a bad connection to the coil and I think that was my issue I now have a nice blue spark but it’s 24 degrees here so haven’t got to get it out and see if it runs like it did before yet I’m crossing my fingers hoping that’s what it was
 

·
Registered
Joined
·
12,774 Posts
So I bought my 86 r blowed up and rebuilt it it ran good for about a week then the counter balancer bearing went out and made a mess out of the bottom end I had a spare that came with the bike that had a 310 kit on it so I took the new top end kit on it and it wasn’t firing so I swapped stators and got it running but it ran awful wouldn’t even hit power band so I put new crank seals in it because I thought that was my issue but it didn’t fix the issue I noticed the spark was kinda weak looking and noticed the plug wire was taped up where it had Ben cut it has a nology coil I tried a 8 mm car plug wire but it didn’t help I’m wondering if that may b because it doesn’t have the ground strap I hate to give 42 dollars for a plug wire if that isn’t the problem can a regular plug wire be used with a nology coil I don’t know what would make it run badly from the bottom end considering I changed the stator and everything I noticed that the flywheel on the 310 had Ben grinded on the tab that comes around on the out side I guess to try change timing or something idk about half of the tab was grinded off so I changed the flywheel any awnsers on what my issue might be would be greatly appreciated
Make sure you run all OEM electricals, CDI included, not aftermarket. Get a New or good used OEM flywheel...ground on tab's are not a good thing.

Carlos
 

·
Registered
Joined
·
81 Posts
Discussion Starter #7
I had another flywheel I have already changed it and the stator is stock that I put in it the CSU box is dynatek and the coil is nology is it hard on a near stock engine to use the aftermarket firing stuff I really don’t want to go buy all new firing stuff if I don’t have to right now gets a little tight on money around Christmas but I also don’t want to tear up my engine I have got it getting nice blue spark everything seems to be working the way it should thanks Carlos
 

·
Registered
Joined
·
12,774 Posts
oem cdis only.or kickback and you will never jet it right.too much initial timing and not enough total.
Very True :)

I had another flywheel I have already changed it and the stator is stock that I put in it the CSU box is dynatek and the coil is nology is it hard on a near stock engine to use the aftermarket firing stuff I really don’t want to go buy all new firing stuff if I don’t have to right now gets a little tight on money around Christmas but I also don’t want to tear up my engine I have got it getting nice blue spark everything seems to be working the way it should thanks Carlos
Glad it's working better/good, keep an eye out for "Good" Working OEM CDI, hard to find, however; it really helps make the 250R's run as they originally did.

Carlos
 

·
Registered
Joined
·
81 Posts
Discussion Starter #10
I was trying to run a compression test just to c what the numbers on my r is but I must be doing something wrong all I am getting it up to is 60 psi for some reason I am holding throttle wide open and kicking it till gauge stops going up anyone have any ideas on what I may be doing wrong would the spacer plate make any difference on compression also I am doing the test with the engine cold it is very cold outside here and don’t want to drag it out in the cold weather thanks
 

·
Registered
Joined
·
81 Posts
Discussion Starter #11
I am thinking that the bottom end I have is the short rod and not the 88 long rod like I was told when I bought it is there a way to tell from looking at the complete engine ? The engine was set up with a stock 86 model cylinder sleeved to a 310 and the newer style piston in it 88 and it had no spacer plate I’m thinking I might have the spacer plate on an 86 motor and it not support to have it would that make it read a low compression rate
 

·
Registered
Joined
·
4,058 Posts
if you put a lr piston on a shrot rod crank the piston skirt will hit the crank and not turn over..if you have a longrod crank and put a shortrod piston on it the piston will stick out of the cylinder 1-2mm's.if you have a sr crank and a sr piston the piston will be down in the cylinder about 3mms..all have same stroke.
 

·
Registered
Joined
·
81 Posts
Discussion Starter #13
When I switched the top end I left the hard on the cylinder so I wouldn’t have to get another head gasket I’m pretty sure my piston is too far down in the cylinder with the spacer I assumed it was a long rod because I was told it was an 88 engine I put the piston ttdcand stuck a pencil to the top of piston and went to the outside of the head where the plug screws in and measured the pencil and came up with 40 mm
 

·
Registered
Joined
·
81 Posts
Discussion Starter #14
I’m thinking spacer needs to come out but I’m not sure which crank is in it guess it’s time to tear it down and see what is going on with it
 

·
Registered
Joined
·
83 Posts
As long as you have the short rod piston to go with the oem ka4 short rod crank you don't need the spacer plate. As stated before if you put a LR piston on the SR crank the skirt will hit the tins before it gets to bdc. There's about 5mm difference in rod lengths which is the reason for the .190" spacer when using the SR piston on the LR crank. The piston's are easily identifiable by SR having a "half moon" cut out on the bottom of the intake side & no window & the LR piston has a full skirt on intake side with a window instead of the cut out... Another good thing to do would be a leak down test, it should hold 6psi for 6 minutes.
 

·
Registered
Joined
·
12,774 Posts
A bit of confusion posted..."if you put a LR piston on the SR crank the skirt will hit the tins before it gets to bdc"....only true for an OEM cylinder NOT re-sleeved to 293CC...as the OP states he has.

If you have a re-sleeved OEM cylinder with a 293 Sleeve, aka 310 (72-73.5MM Bores), then the piston will be an 85-86 style, not 87-89. If it's a long rod, it will need a 3/16" spacer plate plus two OEM base gaskets. If it is a short rod, no spacer plate is needed.

Best way to determine is remove the head, and see if the outer edges of the piston are flush or within -1MM to '0' of the top of the cylinder at TDC....if you have a short rod with spacer plate installed you will easily see if it's to far below deck at TDC. Basically these 293's are set up for the 85-86 style piston outer edges to be Flush with cylinder deck at TDC.

Carlos
 

·
Registered
Joined
·
83 Posts
A bit of confusion posted..."if you put a LR piston on the SR crank the skirt will hit the tins before it gets to bdc"....only true for an OEM cylinder NOT re-sleeved to 293CC...as the OP states he has.

Carlos
What I posted is 100% accurate & there is no confusion. I basically reiterated what American opal stated about piston & rod combo's. Your right that a 72mm piston is the same design as the oem piston for the short rod crank since long rod piston's are only available up to 68mm.
 

·
Registered
Joined
·
81 Posts
Discussion Starter #19
I am having a firing issue with my r hopefully someone can help me with I am getting no spark and sometimes intermittent spark I read some forums and did ohm test and here are my results stator was 217- pulse generator was 112- primary side of coil I could not get a reading it just said 0 and secondary coil side I was getting 3.5 so I'm thinking it is the coil because everything else is within spec I think. I also put a test light on the plug end of the coil and was getting a verry faint light flashing so I am assuming that means the pulse generator is working properly it is a nology coil I hate to go buying parts if it's not likely the coil so I need a little help from some of you that know more about it thanks with the coil lighting test light still has no spark
 

·
Registered
Joined
·
158 Posts
Check to see if you have a good ground. If you go online to service honda you can get a brand new oem honda coil.
 
1 - 20 of 36 Posts
Top